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<strong>📄 Archived:</strong> 2025-08-31 12:16:05 UTC
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<strong>🔗 Source:</strong> <a href="https://en.wikipedia.org/wiki/Methoxypropylamino_cyclohexenylidene_ethoxyethylcyanoacetate">https://en.wikipedia.org/wiki/Methoxypropylamino_cyclohexenylidene_ethoxyethylcyanoacetate</a>
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<hr>
<h1>Methoxypropylamino cyclohexenylidene ethoxyethylcyanoacetate</h1>
<html><body><div><div class="vector-body-before-content">
<p class="mw-indicators">
</p>
<p class="noprint" id="siteSub">From Wikipedia, the free encyclopedia</p>
</div>
<div class="mw-body-content" id="mw-content-text"><div class="mw-content-ltr mw-parser-output" dir="ltr" lang="en"><p class="shortdescription nomobile noexcerpt noprint searchaux">Organic compound used in sunscreen</p>
<p class="shortdescription nomobile noexcerpt noprint searchaux">Chemical compound</p>
<p><b>Methoxypropylamino cyclohexenylidene ethoxyethylcyanoacetate</b> (<a href="/wiki/International_Nomenclature_of_Cosmetic_Ingredients" title="International Nomenclature of Cosmetic Ingredients">INCI</a>) is an <a href="/wiki/Organic_compound" title="Organic compound">organic compound</a> used in <a href="/wiki/Sunscreen" title="Sunscreen">sunscreens</a> to absorb <a class="mw-redirect" href="/wiki/UVA_radiation" title="UVA radiation">UVA radiation</a>. It is marketed as <b>Mexoryl 400</b> by <a href="/wiki/L%27Or%C3%A9al" title="L'Oréal">L'Oréal</a>. MCE has an absorption maximum of 385 nm, which is in the long-wave UVA range (<a class="mw-redirect" href="/wiki/UVA_radiation" title="UVA radiation">UVA1</a>, 360400 nm).<sup class="reference" id="cite_ref-:0_1-0"><a href="#cite_note-:0-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><sup class="reference" id="cite_ref-2"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup><sup class="reference" id="cite_ref-3"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup><sup class="reference" id="cite_ref-4"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup><sup class="reference" id="cite_ref-5"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup><sup class="reference" id="cite_ref-6"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup><sup class="reference" id="cite_ref-7"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> Like Mexoryl SX (<a href="/wiki/Ecamsule" title="Ecamsule">Ecamsule</a>) and Mexoryl XL (<a href="/wiki/Drometrizole_trisiloxane" title="Drometrizole trisiloxane">Drometrizole trisiloxane</a>), it is used exclusively in products manufactured by L'Oréal.<sup class="reference" id="cite_ref-8"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> MCE was developed by L'Oréal and <a href="/wiki/BASF" title="BASF">BASF</a>.<sup class="reference" id="cite_ref-9"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup>
</p>
<p>MCE is a yellow solid in the form of powder or small chunks.<sup class="reference" id="cite_ref-:0_1-1"><a href="#cite_note-:0-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> At 25 °C, it is soluble in <a href="/wiki/Phenoxyethanol" title="Phenoxyethanol">phenoxyethanol</a>, dimethyl capramide, <a class="mw-redirect" href="/wiki/Ethoxydiglycol" title="Ethoxydiglycol">ethoxydiglycol</a>, dimethyl isosorbide, and alcohol (<a href="/wiki/Ethanol" title="Ethanol">ethanol</a>), which are ingredients used in cosmetics.<sup class="reference" id="cite_ref-:0_1-2"><a href="#cite_note-:0-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><sup class="reference" id="cite_ref-10"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup><sup class="reference" id="cite_ref-11"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup><sup class="reference" id="cite_ref-12"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup><sup class="reference" id="cite_ref-13"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup><sup class="reference" id="cite_ref-14"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup>
</p><p>It is considered a <a href="/wiki/Cyclic_compound" title="Cyclic compound">cyclic</a> <a href="/wiki/Merocyanine" title="Merocyanine">merocyanine</a>.<sup class="reference" id="cite_ref-15"><a href="#cite_note-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup>
</p>
<div class="mw-heading mw-heading2"><h2 id="Safety_and_regulation">Safety and regulation</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Methoxypropylamino_cyclohexenylidene_ethoxyethylcyanoacetate&amp;action=edit&amp;section=2" title="Edit section: Safety and regulation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div>
<p>In 2019, MCE was approved for use up to a maximum concentration of 3% as a UV filter in cosmetics in the <a href="/wiki/European_Union" title="European Union">EU</a>.<sup class="reference" id="cite_ref-:0_1-3"><a href="#cite_note-:0-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> It is not currently recognised or approved by the <a href="/wiki/Food_and_Drug_Administration" title="Food and Drug Administration">FDA</a> for use in cosmetics in the <a href="/wiki/United_States" title="United States">US</a>.
</p>
<div class="mw-references-wrap mw-references-columns"><ol class="references">
<li id="cite_note-:0-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-:0_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-:0_1-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-:0_1-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-:0_1-3"><sup><i><b>d</b></i></sup></a></span> <span class="reference-text"><cite class="citation web cs1"><a class="external text" href="https://health.ec.europa.eu/system/files/2021-08/sccs_o_227_0.pdf" rel="nofollow">"Scientific Committee on Consumer Safety"</a> <span class="cs1-format">(PDF)</span>. <i>europa.eu</i><span class="reference-accessdate">. Retrieved <span class="nowrap">28 July</span> 2024</span>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=unknown&amp;rft.jtitle=europa.eu&amp;rft.atitle=Scientific+Committee+on+Consumer+Safety&amp;rft_id=https%3A%2F%2Fhealth.ec.europa.eu%2Fsystem%2Ffiles%2F2021-08%2Fsccs_o_227_0.pdf&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AMethoxypropylamino+cyclohexenylidene+ethoxyethylcyanoacetate"></span></span>
</li>
<li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><cite class="citation journal cs1" id="CITEREFMarionnetde_DormaelMaratRoudot2022">Marionnet, Claire; de Dormael, Romain; Marat, Xavier; Roudot, Angélina; Gizard, Julie; Planel, Emilie; Tornier, Carine; Golebiewski, Christelle; Bastien, Philippe; Candau, Didier; Bernerd, Françoise (January 2022). <a class="external text" href="https://doi.org/10.1016/j.xjidi.2021.100070" rel="nofollow">"Sunscreens with the New MCE Filter Cover the Whole UV Spectrum: Improved UVA1 Photoprotection In Vitro and in a Randomized Controlled Trial"</a>. <i><a class="new" href="/w/index.php?title=JID_Innovations&amp;action=edit&amp;redlink=1" title="JID Innovations (page does not exist)">JID Innovations</a></i>. <b>2</b> (1). <a class="mw-redirect" href="/wiki/Doi_(identifier)" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1016%2Fj.xjidi.2021.100070" rel="nofollow">10.1016/j.xjidi.2021.100070</a>. <a class="mw-redirect" href="/wiki/ISSN_(identifier)" title="ISSN (identifier)">ISSN</a> <a class="external text" href="https://search.worldcat.org/issn/2667-0267" rel="nofollow">2667-0267</a>. <a class="mw-redirect" href="/wiki/PMC_(identifier)" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8762479" rel="nofollow">8762479</a></span>. <a class="mw-redirect" href="/wiki/PMID_(identifier)" title="PMID (identifier)">PMID</a> <a class="external text" href="https://pubmed.ncbi.nlm.nih.gov/35072138" rel="nofollow">35072138</a>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.jtitle=JID+Innovations&amp;rft.atitle=Sunscreens+with+the+New+MCE+Filter+Cover+the+Whole+UV+Spectrum%3A+Improved+UVA1+Photoprotection+In+Vitro+and+in+a+Randomized+Controlled+Trial&amp;rft.volume=2&amp;rft.issue=1&amp;rft.date=2022-01&amp;rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC8762479%23id-name%3DPMC&amp;rft.issn=2667-0267&amp;rft_id=info%3Apmid%2F35072138&amp;rft_id=info%3Adoi%2F10.1016%2Fj.xjidi.2021.100070&amp;rft.aulast=Marionnet&amp;rft.aufirst=Claire&amp;rft.au=de+Dormael%2C+Romain&amp;rft.au=Marat%2C+Xavier&amp;rft.au=Roudot%2C+Ang%C3%A9lina&amp;rft.au=Gizard%2C+Julie&amp;rft.au=Planel%2C+Emilie&amp;rft.au=Tornier%2C+Carine&amp;rft.au=Golebiewski%2C+Christelle&amp;rft.au=Bastien%2C+Philippe&amp;rft.au=Candau%2C+Didier&amp;rft.au=Bernerd%2C+Fran%C3%A7oise&amp;rft_id=https%3A%2F%2Fdoi.org%2F10.1016%2Fj.xjidi.2021.100070&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AMethoxypropylamino+cyclohexenylidene+ethoxyethylcyanoacetate"></span></span>
</li>
<li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><cite class="citation journal cs1" id="CITEREFAguileraGracia-CazañaGilaberte2023">Aguilera, José; Gracia-Cazaña, Tamara; Gilaberte, Yolanda (2023-10-01). <a class="external text" href="https://doi.org/10.1007%2Fs43630-023-00453-x" rel="nofollow">"New developments in sunscreens"</a>. <i>Photochemical &amp; Photobiological Sciences</i>. <b>22</b> (10): <span class="nowrap">2473</span>2482. <a class="mw-redirect" href="/wiki/Bibcode_(identifier)" title="Bibcode (identifier)">Bibcode</a>:<a class="external text" href="https://ui.adsabs.harvard.edu/abs/2023PhPhS..22.2473A" rel="nofollow">2023PhPhS..22.2473A</a>. <a class="mw-redirect" href="/wiki/Doi_(identifier)" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a class="external text" href="https://doi.org/10.1007%2Fs43630-023-00453-x" rel="nofollow">10.1007/s43630-023-00453-x</a></span>. <a class="mw-redirect" href="/wiki/ISSN_(identifier)" title="ISSN (identifier)">ISSN</a> <a class="external text" href="https://search.worldcat.org/issn/1474-9092" rel="nofollow">1474-9092</a>. <a class="mw-redirect" href="/wiki/PMID_(identifier)" title="PMID (identifier)">PMID</a> <a class="external text" href="https://pubmed.ncbi.nlm.nih.gov/37543534" rel="nofollow">37543534</a>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.jtitle=Photochemical+%26+Photobiological+Sciences&amp;rft.atitle=New+developments+in+sunscreens&amp;rft.volume=22&amp;rft.issue=10&amp;rft.pages=2473-2482&amp;rft.date=2023-10-01&amp;rft_id=info%3Adoi%2F10.1007%2Fs43630-023-00453-x&amp;rft.issn=1474-9092&amp;rft_id=info%3Apmid%2F37543534&amp;rft_id=info%3Abibcode%2F2023PhPhS..22.2473A&amp;rft.aulast=Aguilera&amp;rft.aufirst=Jos%C3%A9&amp;rft.au=Gracia-Caza%C3%B1a%2C+Tamara&amp;rft.au=Gilaberte%2C+Yolanda&amp;rft_id=https%3A%2F%2Fdoi.org%2F10.1007%252Fs43630-023-00453-x&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AMethoxypropylamino+cyclohexenylidene+ethoxyethylcyanoacetate"></span></span>
</li>
<li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><cite class="citation journal cs1" id="CITEREFBernerdPasseronCastielMarionnet2022">Bernerd, Françoise; Passeron, Thierry; Castiel, Isabelle; Marionnet, Claire (January 2022). <a class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9368482" rel="nofollow">"The Damaging Effects of Long UVA (UVA1) Rays: A Major Challenge to Preserve Skin Health and Integrity"</a>. <i>International Journal of Molecular Sciences</i>. <b>23</b> (15): 8243. <a class="mw-redirect" href="/wiki/Doi_(identifier)" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a class="external text" href="https://doi.org/10.3390%2Fijms23158243" rel="nofollow">10.3390/ijms23158243</a></span>. <a class="mw-redirect" href="/wiki/ISSN_(identifier)" title="ISSN (identifier)">ISSN</a> <a class="external text" href="https://search.worldcat.org/issn/1422-0067" rel="nofollow">1422-0067</a>. <a class="mw-redirect" href="/wiki/PMC_(identifier)" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9368482" rel="nofollow">9368482</a></span>. <a class="mw-redirect" href="/wiki/PMID_(identifier)" title="PMID (identifier)">PMID</a> <a class="external text" href="https://pubmed.ncbi.nlm.nih.gov/35897826" rel="nofollow">35897826</a>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.jtitle=International+Journal+of+Molecular+Sciences&amp;rft.atitle=The+Damaging+Effects+of+Long+UVA+%28UVA1%29+Rays%3A+A+Major+Challenge+to+Preserve+Skin+Health+and+Integrity&amp;rft.volume=23&amp;rft.issue=15&amp;rft.pages=8243&amp;rft.date=2022-01&amp;rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC9368482%23id-name%3DPMC&amp;rft.issn=1422-0067&amp;rft_id=info%3Apmid%2F35897826&amp;rft_id=info%3Adoi%2F10.3390%2Fijms23158243&amp;rft.aulast=Bernerd&amp;rft.aufirst=Fran%C3%A7oise&amp;rft.au=Passeron%2C+Thierry&amp;rft.au=Castiel%2C+Isabelle&amp;rft.au=Marionnet%2C+Claire&amp;rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC9368482&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AMethoxypropylamino+cyclohexenylidene+ethoxyethylcyanoacetate"></span></span>
</li>
<li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><cite class="citation web cs1" id="CITEREFPubChem">PubChem. <a class="external text" href="https://pubchem.ncbi.nlm.nih.gov/compound/71226339" rel="nofollow">"2-ethoxyethyl (2Z)-2-cyano-2-[3-(3-methoxypropylamino)cyclohex-2-en-1-ylidene]acetate"</a>. <i>pubchem.ncbi.nlm.nih.gov</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2024-07-30</span></span>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=unknown&amp;rft.jtitle=pubchem.ncbi.nlm.nih.gov&amp;rft.atitle=2-ethoxyethyl+%282Z%29-2-cyano-2-%5B3-%283-methoxypropylamino%29cyclohex-2-en-1-ylidene%5Dacetate&amp;rft.au=PubChem&amp;rft_id=https%3A%2F%2Fpubchem.ncbi.nlm.nih.gov%2Fcompound%2F71226339&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AMethoxypropylamino+cyclohexenylidene+ethoxyethylcyanoacetate"></span></span>
</li>
<li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><cite class="citation journal cs1" id="CITEREFde_DormaelBernerdBastienCandau2022">de Dormael, Romain; Bernerd, Francoise; Bastien, Philippe; Candau, Didier; Roudot, Angelina; Tricaud, Caroline (September 2022). <a class="external text" href="https://doi.org/10.1002%2Fjvc2.38" rel="nofollow">"Improvement of photoprotection with sunscreen formulas containing the cyclic merocyanine UVA1 absorber MCE: In vivo demonstration under simulated and real sun exposure conditions in three randomised controlled trials"</a>. <i><a class="new" href="/w/index.php?title=JEADV_Clinical_Practice&amp;action=edit&amp;redlink=1" title="JEADV Clinical Practice (page does not exist)">JEADV Clinical Practice</a></i>. <b>1</b> (3): <span class="nowrap">229</span>239. <a class="mw-redirect" href="/wiki/Doi_(identifier)" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a class="external text" href="https://doi.org/10.1002%2Fjvc2.38" rel="nofollow">10.1002/jvc2.38</a></span>. <a class="mw-redirect" href="/wiki/ISSN_(identifier)" title="ISSN (identifier)">ISSN</a> <a class="external text" href="https://search.worldcat.org/issn/2768-6566" rel="nofollow">2768-6566</a>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.jtitle=JEADV+Clinical+Practice&amp;rft.atitle=Improvement+of+photoprotection+with+sunscreen+formulas+containing+the+cyclic+merocyanine+UVA1+absorber+MCE%3A+In+vivo+demonstration+under+simulated+and+real+sun+exposure+conditions+in+three+randomised+controlled+trials&amp;rft.volume=1&amp;rft.issue=3&amp;rft.pages=229-239&amp;rft.date=2022-09&amp;rft_id=info%3Adoi%2F10.1002%2Fjvc2.38&amp;rft.issn=2768-6566&amp;rft.aulast=de+Dormael&amp;rft.aufirst=Romain&amp;rft.au=Bernerd%2C+Francoise&amp;rft.au=Bastien%2C+Philippe&amp;rft.au=Candau%2C+Didier&amp;rft.au=Roudot%2C+Angelina&amp;rft.au=Tricaud%2C+Caroline&amp;rft_id=https%3A%2F%2Fdoi.org%2F10.1002%252Fjvc2.38&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AMethoxypropylamino+cyclohexenylidene+ethoxyethylcyanoacetate"></span></span>
</li>
<li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text"><cite class="citation journal cs1" id="CITEREFFlamentMercurioMullerLi2024">Flament, F.; Mercurio, D. G.; Muller, B.; Li, J.; Tricaud, C.; Bernerd, F.; Roudot, A.; Candau, D.; Passeron, T. (January 2024). <a class="external text" href="https://doi.org/10.1111%2Fjdv.19486" rel="nofollow">"The impact of methoxypropylamino cyclohexenylidene ethoxyethylcyanoacetate ( MCE ) UVA1 filter on pigmentary and ageing signs: An outdoor prospective 8-week randomized, intra-individual comparative study in two populations of different genetic background"</a>. <i>Journal of the European Academy of Dermatology and Venereology</i>. <b>38</b> (1): <span class="nowrap">214</span>222. <a class="mw-redirect" href="/wiki/Doi_(identifier)" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a class="external text" href="https://doi.org/10.1111%2Fjdv.19486" rel="nofollow">10.1111/jdv.19486</a></span>. <a class="mw-redirect" href="/wiki/ISSN_(identifier)" title="ISSN (identifier)">ISSN</a> <a class="external text" href="https://search.worldcat.org/issn/0926-9959" rel="nofollow">0926-9959</a>. <a class="mw-redirect" href="/wiki/PMID_(identifier)" title="PMID (identifier)">PMID</a> <a class="external text" href="https://pubmed.ncbi.nlm.nih.gov/37655436" rel="nofollow">37655436</a>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.jtitle=Journal+of+the+European+Academy+of+Dermatology+and+Venereology&amp;rft.atitle=The+impact+of+methoxypropylamino+cyclohexenylidene+ethoxyethylcyanoacetate+%28+MCE+%29+UVA1+filter+on+pigmentary+and+ageing+signs%3A+An+outdoor+prospective+8-week+randomized%2C+intra-individual+comparative+study+in+two+populations+of+different+genetic+background&amp;rft.volume=38&amp;rft.issue=1&amp;rft.pages=214-222&amp;rft.date=2024-01&amp;rft.issn=0926-9959&amp;rft_id=info%3Apmid%2F37655436&amp;rft_id=info%3Adoi%2F10.1111%2Fjdv.19486&amp;rft.aulast=Flament&amp;rft.aufirst=F.&amp;rft.au=Mercurio%2C+D.+G.&amp;rft.au=Muller%2C+B.&amp;rft.au=Li%2C+J.&amp;rft.au=Tricaud%2C+C.&amp;rft.au=Bernerd%2C+F.&amp;rft.au=Roudot%2C+A.&amp;rft.au=Candau%2C+D.&amp;rft.au=Passeron%2C+T.&amp;rft_id=https%3A%2F%2Fdoi.org%2F10.1111%252Fjdv.19486&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AMethoxypropylamino+cyclohexenylidene+ethoxyethylcyanoacetate"></span></span>
</li>
<li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a class="external text" href="https://www.cosmeticsandtoiletries.com/formulas-products/sun-care/news/22249181/loreal-loral-breaks-the-ultralong-uva-code-with-uvmune-400" rel="nofollow">"L'Oréal Breaks the Ultra-long UVA Code with UVMune 400"</a>. <i>Cosmetics &amp; Toiletries</i>. 2022-05-24<span class="reference-accessdate">. Retrieved <span class="nowrap">2024-07-28</span></span>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=unknown&amp;rft.jtitle=Cosmetics+%26+Toiletries&amp;rft.atitle=L%27Or%C3%A9al+Breaks+the+Ultra-long+UVA+Code+with+UVMune+400&amp;rft.date=2022-05-24&amp;rft_id=https%3A%2F%2Fwww.cosmeticsandtoiletries.com%2Fformulas-products%2Fsun-care%2Fnews%2F22249181%2Floreal-loral-breaks-the-ultralong-uva-code-with-uvmune-400&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AMethoxypropylamino+cyclohexenylidene+ethoxyethylcyanoacetate"></span></span>
</li>
<li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a class="external text" href="https://labmuffin.com/la-roche-posay-uvmune-400-science-and-review/" rel="nofollow">"La Roche-Posay UVMune 400: Science and Review"</a>. <i>Lab Muffin Beauty Science</i>. 2024-06-10<span class="reference-accessdate">. Retrieved <span class="nowrap">2024-07-28</span></span>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=unknown&amp;rft.jtitle=Lab+Muffin+Beauty+Science&amp;rft.atitle=La+Roche-Posay+UVMune+400%3A+Science+and+Review&amp;rft.date=2024-06-10&amp;rft_id=https%3A%2F%2Flabmuffin.com%2Fla-roche-posay-uvmune-400-science-and-review%2F&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AMethoxypropylamino+cyclohexenylidene+ethoxyethylcyanoacetate"></span></span>
</li>
<li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><cite class="citation web cs1" id="CITEREFPubChem">PubChem. <a class="external text" href="https://pubchem.ncbi.nlm.nih.gov/compound/31236" rel="nofollow">"Phenoxyethanol"</a>. <i>pubchem.ncbi.nlm.nih.gov</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2024-07-29</span></span>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=unknown&amp;rft.jtitle=pubchem.ncbi.nlm.nih.gov&amp;rft.atitle=Phenoxyethanol&amp;rft.au=PubChem&amp;rft_id=https%3A%2F%2Fpubchem.ncbi.nlm.nih.gov%2Fcompound%2F31236&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AMethoxypropylamino+cyclohexenylidene+ethoxyethylcyanoacetate"></span></span>
</li>
<li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><cite class="citation web cs1" id="CITEREFPubChem">PubChem. <a class="external text" href="https://pubchem.ncbi.nlm.nih.gov/compound/26690" rel="nofollow">"N,N-Dimethyldecanamide"</a>. <i>pubchem.ncbi.nlm.nih.gov</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2024-07-29</span></span>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=unknown&amp;rft.jtitle=pubchem.ncbi.nlm.nih.gov&amp;rft.atitle=N%2CN-Dimethyldecanamide&amp;rft.au=PubChem&amp;rft_id=https%3A%2F%2Fpubchem.ncbi.nlm.nih.gov%2Fcompound%2F26690&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AMethoxypropylamino+cyclohexenylidene+ethoxyethylcyanoacetate"></span></span>
</li>
<li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"><cite class="citation web cs1" id="CITEREFPubChem">PubChem. <a class="external text" href="https://pubchem.ncbi.nlm.nih.gov/compound/8146" rel="nofollow">"Diethylene Glycol Monoethyl Ether"</a>. <i>pubchem.ncbi.nlm.nih.gov</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2024-07-29</span></span>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=unknown&amp;rft.jtitle=pubchem.ncbi.nlm.nih.gov&amp;rft.atitle=Diethylene+Glycol+Monoethyl+Ether&amp;rft.au=PubChem&amp;rft_id=https%3A%2F%2Fpubchem.ncbi.nlm.nih.gov%2Fcompound%2F8146&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AMethoxypropylamino+cyclohexenylidene+ethoxyethylcyanoacetate"></span></span>
</li>
<li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text"><cite class="citation web cs1" id="CITEREFPubChem">PubChem. <a class="external text" href="https://pubchem.ncbi.nlm.nih.gov/compound/62990" rel="nofollow">"Dimethyl isosorbide"</a>. <i>pubchem.ncbi.nlm.nih.gov</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2024-07-29</span></span>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=unknown&amp;rft.jtitle=pubchem.ncbi.nlm.nih.gov&amp;rft.atitle=Dimethyl+isosorbide&amp;rft.au=PubChem&amp;rft_id=https%3A%2F%2Fpubchem.ncbi.nlm.nih.gov%2Fcompound%2F62990&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AMethoxypropylamino+cyclohexenylidene+ethoxyethylcyanoacetate"></span></span>
</li>
<li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><cite class="citation journal cs1" id="CITEREFLachenmeier2008">Lachenmeier, Dirk W (2008-11-13). <a class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2596158" rel="nofollow">"Safety evaluation of topical applications of ethanol on the skin and inside the oral cavity"</a>. <i>Journal of Occupational Medicine and Toxicology</i>. <b>3</b> (1): 26. <a class="mw-redirect" href="/wiki/Doi_(identifier)" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a class="external text" href="https://doi.org/10.1186%2F1745-6673-3-26" rel="nofollow">10.1186/1745-6673-3-26</a></span>. <a class="mw-redirect" href="/wiki/ISSN_(identifier)" title="ISSN (identifier)">ISSN</a> <a class="external text" href="https://search.worldcat.org/issn/1745-6673" rel="nofollow">1745-6673</a>. <a class="mw-redirect" href="/wiki/PMC_(identifier)" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2596158" rel="nofollow">2596158</a></span>. <a class="mw-redirect" href="/wiki/PMID_(identifier)" title="PMID (identifier)">PMID</a> <a class="external text" href="https://pubmed.ncbi.nlm.nih.gov/19014531" rel="nofollow">19014531</a>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.jtitle=Journal+of+Occupational+Medicine+and+Toxicology&amp;rft.atitle=Safety+evaluation+of+topical+applications+of+ethanol+on+the+skin+and+inside+the+oral+cavity&amp;rft.volume=3&amp;rft.issue=1&amp;rft.pages=26&amp;rft.date=2008-11-13&amp;rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC2596158%23id-name%3DPMC&amp;rft.issn=1745-6673&amp;rft_id=info%3Apmid%2F19014531&amp;rft_id=info%3Adoi%2F10.1186%2F1745-6673-3-26&amp;rft.aulast=Lachenmeier&amp;rft.aufirst=Dirk+W&amp;rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC2596158&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AMethoxypropylamino+cyclohexenylidene+ethoxyethylcyanoacetate"></span></span>
</li>
<li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text"><cite class="citation journal cs1" id="CITEREFWinklerHoeffkenEichinHouy2014">Winkler, Barbara; Hoeffken, Hans Wolfgang; Eichin, Kai; Houy, Wolfgang (2014-03-05). <span class="id-lock-subscription" title="Paid subscription required"><a class="external text" href="https://www.sciencedirect.com/science/article/pii/S0040403914001592" rel="nofollow">"A cyclic merocyanine UV-A absorber: mechanism of formation and crystal structure"</a></span>. <i>Tetrahedron Letters</i>. <b>55</b> (10): <span class="nowrap">1749</span>1751. <a class="mw-redirect" href="/wiki/Doi_(identifier)" title="Doi (identifier)">doi</a>:<a class="external text" href="https://doi.org/10.1016%2Fj.tetlet.2014.01.113" rel="nofollow">10.1016/j.tetlet.2014.01.113</a>. <a class="mw-redirect" href="/wiki/ISSN_(identifier)" title="ISSN (identifier)">ISSN</a> <a class="external text" href="https://search.worldcat.org/issn/0040-4039" rel="nofollow">0040-4039</a>.</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=article&amp;rft.jtitle=Tetrahedron+Letters&amp;rft.atitle=A+cyclic+merocyanine+UV-A+absorber%3A+mechanism+of+formation+and+crystal+structure&amp;rft.volume=55&amp;rft.issue=10&amp;rft.pages=1749-1751&amp;rft.date=2014-03-05&amp;rft_id=info%3Adoi%2F10.1016%2Fj.tetlet.2014.01.113&amp;rft.issn=0040-4039&amp;rft.aulast=Winkler&amp;rft.aufirst=Barbara&amp;rft.au=Hoeffken%2C+Hans+Wolfgang&amp;rft.au=Eichin%2C+Kai&amp;rft.au=Houy%2C+Wolfgang&amp;rft_id=https%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS0040403914001592&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AMethoxypropylamino+cyclohexenylidene+ethoxyethylcyanoacetate"></span></span>
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<strong>📄 Archived:</strong> 2025-08-31 12:24:29 UTC
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<strong>🔗 Source:</strong> <a href="https://papers.lgbt/papers/prog">https://papers.lgbt/papers/prog</a>
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<main class="paper-main flex-1 max-w-4xl mx-auto px-10 sm:px-12 md:px-16 lg:px-20 xl:px-28 2xl:px-36 py-8 lg:py-12" style="max-width: 76rem;"><div class="lg:hidden mb-8"><h3 class="text-xs font-medium uppercase tracking-wider text-muted-foreground mb-2">/prog</h3><h1 class="text-2xl font-medium text-foreground mb-2">progesterone in transsexual female hrt: a review of timing, biology, and what we (dont yet) know</h1><p class="text-sm text-muted-foreground">by emily/endocrinemoder/adenine</p></div><div class="bg-background p-6 mb-8 border"><h2 class="text-lg font-medium text-foreground mb-3">abstract</h2><p class="text-foreground leading-relaxed">this review tackles a hard question in transsexual female care: when to add progesterone.
mechanistically, mammary development runs in two phases. first, estradiol (with gh/igf1) pushes ductal elongation and branching from terminal end buds; later, progesterone (with prolactin) leans the system toward lobuloalveolar differentiation and secretory readiness. that division of labor matters for sequencing. adding progesterone too early, before estradiol has built a decent ductal scaffold—could, in theory, nudge tissue into differentiation at the expense of further branching, ultimately limiting ductal complexity and perhaps final breast size. animal models and cis puberty biology make that hypothesis biologically plausible; direct proof for or against in trans cohorts is not yet here. human data to date: (i) cis/animal literature strongly separates estrogenled branching from progesteroneled alveologenesis; (ii) transsexual female groups show early, frontloaded growth under estradiol with modest absolute volumes after a year; (iii) a small, short prospective study of 100mg oral micronized progesterone (omp) showed no breast staging benefit at 3 months; (iv) patientreported surveys suggest perceived benefits; and (v) a randomized trial testing estradiol±omp with 3d volume endpoints is underway. pending stronger trials, a cautious, timesequenced approach, defer progesterone until ~612 months after starting estradiol, once tanner b2b3 budding is evident, best harmonizes with puberty physiology while minimizing the chance of getting ahead of the biology. </p></div><div class="lg:hidden mb-8"><div class="flex flex-wrap gap-2"><span class="px-3 py-1 bg-secondary text-secondary-foreground text-sm">progesterone</span><span class="px-3 py-1 bg-secondary text-secondary-foreground text-sm">roadmap</span><span class="px-3 py-1 bg-secondary text-secondary-foreground text-sm">breast development</span><span class="px-3 py-1 bg-secondary text-secondary-foreground text-sm">estradiol</span><span class="px-3 py-1 bg-secondary text-secondary-foreground text-sm">CHT</span><span class="px-3 py-1 bg-secondary text-secondary-foreground text-sm">HRT</span></div></div><div class="paper-container bg-background border mx-auto max-w-5xl px-6 md:px-10 lg:px-14 py-10" style="max-width: 70rem;"><article class="prose prose-neutral prose-lg max-w-none [&amp;_*]:break-words [&amp;_table]:prose-table [&amp;_thead_th]:uppercase [&amp;_thead_th]:tracking-wide [&amp;_thead_th]:text-xs [&amp;_h1]:scroll-mt-24 [&amp;_h2]:scroll-mt-24 [&amp;_h3]:scroll-mt-24 [&amp;_h4]:scroll-mt-24 [&amp;_h5]:scroll-mt-24 [&amp;_h6]:scroll-mt-24 [&amp;_a]:text-blue-600 hover:[&amp;_a]:text-blue-700 dark:[&amp;_a]:text-blue-400 dark:hover:[&amp;_a]:text-blue-500 underline-offset-4" style="--para-space: 0.5em;"><p><strong>progesterone in transsexual female hrt: a review of timing, biology, and what we (dont yet) know</strong></p>
<h2><strong>introduction</strong></h2>
<p>crosssex hormone therapy (CHT) for transsexual female individuals aims to induce breast development, shift body composition, and align secondary sex characteristics with gender. with breasts, some individuals achieve satisfactory fullness with estradiol alone, but many plateau early with small absolute volumes despite appropriate estradiol exposure and testosterone suppression. observational program data and narrative reviews consistently note that <strong>most measurable growth happens early</strong>, and that even after years, many remain below an acup equivalent. fueling interest in adjuncts such as progesterone. the question is not “progesterone: yes or no?” but <strong>“progesterone: when?”</strong>. (<a href="https://pubmed.ncbi.nlm.nih.gov/29165635/">PubMed</a>, <a href="https://onlinelibrary.wiley.com/doi/10.1111/joim.13441">Wiley Online Library</a>, <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC12012776/">PMC</a>)</p>
<hr>
<h2><strong>the twophase frame: ducts first, then lobuloalveoli</strong></h2>
<p><strong>phase 1 — branching morphogenesis.</strong> at puberty, estradiol acting within a gh/igf1 milieu drives terminal end buds (tebs) to invade the fat pad, elongate, and bifurcate, laying the primary and secondary ductal tree. this is the <em>branching</em> state: high proliferation at tebs, lateral sprouting, and progressive filling of the fat pad. estradiols priming also induces progesterone receptor and prolactin receptor expression in ductal epithelium, setting the stage for the next phase. (<a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC3404495/">PMC</a>, <a href="https://academic.oup.com/endo/article/141/8/2982/2988701">Oxford Academic</a>)</p>
<p><strong>phase 2 — sidebranching and alveologenesis.</strong> once a ductal scaffold exists, progesterone signaling (largely via prb) promotes tertiary sidebranching and, with prolactin, the <strong>lobuloalveolar</strong> program that ultimately supports lactation. while full alveolar expansion is most dramatic in pregnancy, progesterones imprint on sidebranching and early alveolar buds is well described in nonpregnant models. mechanistically, progesterone acts through paracrine mediators (e.g., rankl, wnt programs) and mitogenic targets (e.g., cyclin d1). (<a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC4596764/">PMC</a>, <a href="https://breast-cancer-research.biomedcentral.com/articles/10.1186/bcr1411">BioMed Central</a>, <a href="https://www.pnas.org/doi/10.1073/pnas.0915148107">PNAS</a>)</p>
<p><strong>takeaway.</strong> the mammary gland toggles between a <strong>growandbranch</strong> state (estradioldominant) and a <strong>differentiateandfill</strong> state (progesterone±prolactin). trying to run both programs at once is biologically awkward. singlecell/spatial work in mice even maps a <strong>tradeoff</strong> between proliferative/branching programs and lineagedifferentiation programs under endocrine cues. (<a href="https://www.sciencedirect.com/science/article/pii/S2211124723013050">ScienceDirect</a>)</p>
<hr>
<h2><strong>why timing matters: the “tooearly progesterone” hypothesis</strong></h2>
<p><strong>the hypothesis.</strong> introduce progesterone before estradiol has meaningfully elongated and branched ducts (i.e., pre or veryearly budding), and you risk shifting epithelial fate toward alveolar differentiation while curtailing further tebdriven branching, potentially locking in a simpler ductal tree and limiting later capacity for volume/shape change. this is a <strong>theoretical</strong> concern, not a proven harm, but it is biologically coherent given (i) estrogens lead role in ductal outgrowth; (ii) progesterones drive toward sidebranching and alveologenesis; and (iii) evidence of a proliferation↔differentiation tradeoff. (<a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC3404495/">PMC</a>, <a href="https://breast-cancer-research.biomedcentral.com/articles/10.1186/bcr1411">BioMed Central</a>, <a href="https://www.sciencedirect.com/science/article/pii/S2211124723013050">ScienceDirect</a>)</p>
<p><strong>what cis puberty teaches about sequencing.</strong> in cis girls, thelarche (breast budding) is typically the first clinical sign of puberty; <strong>consistent luteal progesterone exposure</strong> only becomes regular after ovulatory cycles settle, often years later. in other words, nature tends to <strong>build ducts first</strong> under estradiol and only <strong>layers regular progesterone later</strong>. mirroring that tempo in transsexual female CS is a reasonable default. (<a href="https://www.ncbi.nlm.nih.gov/books/NBK534827/">NCBI</a>, <a href="https://pm.amegroups.org/article/view/4978/html">pm.amegroups.org</a>, <a href="https://renaissance.stonybrookmedicine.edu/system/files/Early%20Puberty.pdf">Renaissance School of Medicine</a>)</p>
<hr>
<h2><strong>evidence base (and its gaps)</strong></h2>
<h3><strong>1) cis biology &amp; animal models (strong on mechanism, not final outcomes)</strong></h3>
<ul>
<li>estrogen+gh/igf1 is sufficient to trigger pubertal ductal outgrowth with classic teb dynamics; progesterone is <em>dispensable</em> for initial elongation in several models but <em>required/sufficient</em> for sidebranching and alveolar budding/differentiation once ducts exist. multiple groups demonstrate progesteroneinduced tertiary branching and alveolar formation. (<a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC3404495/">PMC</a>, <a href="https://academic.oup.com/endo/article/146/3/1170/2500345">Oxford Academic</a>) </li>
<li>progesterones paracrine network (rankl, wnt4, cyclin d1) and estradiols priming of pr/prlr support a staged handoff, estrogen sets competence; progesterone executes differentiation. (<a href="https://academic.oup.com/endo/article/141/8/2982/2988701">Oxford Academic</a>, <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC8052380/">PMC</a>) </li>
<li>singlecell/spatial atlases highlight endocrinelinked <strong>state switching</strong> between proliferative branching and lineage commitment, reinforcing the intuitive “dont ask the gland to do both at once” message. (<a href="https://www.sciencedirect.com/science/article/pii/S2211124723013050">ScienceDirect</a>)</li>
</ul>
<p><strong>mechanistic bottom line:</strong> the <strong>orderofoperations</strong> model (grow ducts under estradiol; differentiate under progesterone) is robust across mammals. that doesnt prove timing harms/benefits in trans adults, but it makes the timing question worth caring about. (<a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC3404495/">PMC</a>)</p>
<h3><strong>2) transsexual female groups (what actually happens with estradiol alone, and what people report with progesterone)</strong></h3>
<ul>
<li><strong>estradiol alone</strong>: prospective data show breast development is <strong>modest and frontloaded</strong>, with the <strong>majority of measurable change in the first 6 months</strong> after starting CHT; many remain below an acup after a year, and augmentation rates are high. (<a href="https://pubmed.ncbi.nlm.nih.gov/29165635/">PubMed</a>, <a href="https://onlinelibrary.wiley.com/doi/10.1111/joim.13441">Wiley Online Library</a>, <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC12012776/">PMC</a>) </li>
<li><strong>patientreported experience</strong>: a 2025 crosssectional survey of transsexual individuals using progestogens found that <strong>most users perceived improved breast development</strong>; such surveys are valuable for hypothesisgeneration but are susceptible to selection and expectation biases. (<a href="https://www.sciencedirect.com/science/article/pii/S1530891X25009437">ScienceDirect</a>)</li>
</ul>
<h3><strong>3) randomized trials (the missing piece)</strong></h3>
<ul>
<li>a multicenter <strong>randomized</strong> study is underway testing <strong>estradiol±oral micronized progesterone</strong> with <strong>3d breast volume</strong> as the primary endpoint; the published protocol frames safety and dosing (e.g., 200400mg) and sets up the first highquality efficacy readout. as of today, <strong>results are pending</strong>. (<a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC10734173/">PMC</a>, <a href="https://bmcpharmacoltoxicol.biomedcentral.com/articles/10.1186/s40360-023-00724-4">BioMed Central</a>)</li>
</ul>
<p><strong>evidence summary:</strong> the mechanistic case for <strong>timing</strong> is coherent; realworld outcomes in trans populations remain <strong>uncertain</strong>. there is no definitive proof that progesterone increases volume, or that starting it early harms it. nonetheless, sequencing it <strong>after estradiolinitiated budding</strong> is a lowregret choice aligned with puberty biology and current observational signals. (<a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC3404495/">PMC</a>, <a href="https://pubmed.ncbi.nlm.nih.gov/29165635/">PubMed</a>)</p>
<hr>
<h2><strong>practical timing: why “after 612 months” is a reasonable default</strong></h2>
<ul>
<li>by ~612 months on estradiol, most patients are at <strong>tanner b2b3</strong> (budding to early mound), and the early estradiolled <strong>branching burst</strong> is underway; adding progesterone <strong>after</strong> this point emulates cis puberty sequencing and is <em>less likely</em> to push the gland out of branching mode prematurely. (<a href="https://www.ncbi.nlm.nih.gov/books/NBK534827/">NCBI</a>, <a href="https://pubmed.ncbi.nlm.nih.gov/29165635/">PubMed</a>) </li>
<li>the <strong>frontloaded</strong> time course of estradiolonly growth (largest gains in months 06) further supports waiting until the initial branching wave has crested before deliberately inviting alveolar programming. (<a href="https://pubmed.ncbi.nlm.nih.gov/29165635/">PubMed</a>)</li>
</ul>
<p><strong>translation:</strong> if your goal is to maximize the ductal scaffold before layering alveolar fullness, <strong>wait for budding</strong>, then consider progesterone, understanding that its volumetric benefit is unproven and may be subtle or personspecific. (<a href="https://pubmed.ncbi.nlm.nih.gov/29165635/">PubMed</a>)</p>
<hr>
<h2><strong>frequently asked timing scenarios (biologically informed takes)</strong></h2>
<ol>
<li><strong>starting progesterone at month 0 with estradiol.</strong> <strong>not preferred</strong> on biological grounds: risks nudging toward alveolar programs before ducts expand, with no evidence of net volumetric gain. if done, counsel that effects (positive or negative) are unproven. (<a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC3404495/">PMC</a>, <a href="https://www.sciencedirect.com/science/article/pii/S2211124723013050">ScienceDirect</a>) </li>
<li><strong>adding progesterone at 612 months, once budding is clear.</strong> <strong>reasonable default</strong> to mirror cis puberty sequencing; aligns with estradiolfrontloaded growth and likely minimizes any theoretical “early differentiation” penalty. (<a href="https://pubmed.ncbi.nlm.nih.gov/29165635/">PubMed</a>, <a href="https://pm.amegroups.org/article/view/4978/html">pm.amegroups.org</a>) </li>
<li><strong>adding progesterone after 1224 months because growth plateaued.</strong> also reasonable, with the caveat that plateau is common and absolute volumes may stay modest; consider documenting changes with standardized photography or 3d tools when possible. (<a href="https://journals.lww.com/prsgo/_layouts/15/oaks.journals/downloadpdf.aspx?an=01720096-202409000-00009&amp;utm_source=chatgpt.com">Lippincott Journals</a>, <a href="https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0305059&amp;utm_source=chatgpt.com">PLOS</a>)</li>
</ol>
<hr>
<h2><strong>conclusions</strong></h2>
<ul>
<li>mammary biology really does split: <strong>estradiol builds the ducts; progesterone matures the alveoli</strong>. starting progesterone <strong>too early</strong> is a <em>plausible</em> way to push tissue into the wrong program at the wrong time. this is <strong>theoretical</strong>, not proven harm. (<a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC3404495/">PMC</a>, <a href="https://breast-cancer-research.biomedcentral.com/articles/10.1186/bcr1411">BioMed Central</a>) </li>
<li>adding progesterone <strong>after 612 months of estradiol</strong>, once budding is evident, <strong>tracks natural puberty</strong> and is <strong>less likely</strong> to hinder ductal expansion. it may or may not add meaningful volume; (<a href="https://pm.amegroups.org/article/view/4978/html">pm.amegroups.org</a>, <a href="https://pubmed.ncbi.nlm.nih.gov/29165635/">PubMed</a>, <a href="https://bmcpharmacoltoxicol.biomedcentral.com/articles/10.1186/s40360-023-00724-4">BioMed Central</a>) </li>
<li>until we have definitive data, <strong>transparent counseling + careful sequencing + measurement</strong> beats allornothing takes. (<a href="https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0305059&amp;utm_source=chatgpt.com">PLOS</a>)</li>
</ul>
<hr>
<h3><strong>selected references (linked inline above)</strong></h3>
<ul>
<li>macias &amp; hinck. <em>mammary gland development.</em> 2012 (review). estradiol → ductal growth; progesterone → alveolar programs. (<a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC3404495/">PMC</a>) </li>
<li>arendt etal. <em>form and function: how estrogen and progesterone regulate mammary gland development.</em> 2015. (<a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC4596764/">PMC</a>) </li>
<li>oakes etal. <em>key stages in mammary gland development: the alveolar morphogenesis.</em> 2006. (<a href="https://breast-cancer-research.biomedcentral.com/articles/10.1186/bcr1411">BioMed Central</a>) </li>
<li>bocchinfuso etal. <em>endocrinology</em> 2000. estrogen priming induces pr/prlr in ductal epithelium. (<a href="https://academic.oup.com/endo/article/141/8/2982/2988701">Oxford Academic</a>) </li>
<li>de blok etal. <em>jcem</em> 2018. most breast growth occurs in the first 6 months of gaht. (<a href="https://pubmed.ncbi.nlm.nih.gov/29165635/">PubMed</a>) </li>
<li>dhoore etal. <em>journal of internal medicine</em> 2022 (review). modest volumes after 1 year; many &lt; aaa. (<a href="https://onlinelibrary.wiley.com/doi/10.1111/joim.13441">Wiley Online Library</a>) </li>
<li>nolan etal. <em>endocrine connections</em> 2022. 100mg omp for 3 months: no change in sleep/distress/tanner vs controls. (<a href="https://ec.bioscientifica.com/view/journals/ec/11/5/EC-22-0170.xml">Bioscientifica</a>) </li>
<li>chang etal. <em>transgender health</em> 2025 (in press/online first). survey: many users perceive benefit from progestogens. (<a href="https://www.sciencedirect.com/science/article/pii/S1530891X25009437">ScienceDirect</a>) </li>
<li>dijkman etal. <em>bmc pharmacology &amp; toxicology</em> 2023. rct protocol: estradiol±omp; primary outcome 3d breast volume. (<a href="https://bmcpharmacoltoxicol.biomedcentral.com/articles/10.1186/s40360-023-00724-4">BioMed Central</a>) </li>
<li>transdermal estradiol and vte risk: casecontrol/metaanalytic evidence in cis cohorts; program data in trans cohorts. (<a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC10081942/">PMC</a>)</li>
</ul>
<hr>
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