Skin Effects of Oestrogen in Transfeminine People: An Evidence Review (ER-006)

This Evidence Review grades the strength of the evidence for how oestrogen affects the skin of transfeminine people on feminising hormone therapy, across seven domains: sebum and oiliness, acne, dryness (xerosis), skin thickness and collagen, hydration and barrier function, wound healing, and pigmentation (melasma). The direction of most changes is biologically plausible and mechanistically coherent, but trans-specific measured evidence is sparse. The best-supported effect is reduced sebum — and, with it, often improved acne — driven mainly by androgen suppression; claims about collagen, thickness, hydration and wound healing rest largely on cisgender menopausal and hormone-replacement research and are flagged as such throughout. Melasma is identified as the one domain where oestrogen may worsen skin. Evidence quality is rated with a traffic-light scheme and summarised in an evidence appendix. The review distinguishes established findings from cisgender extrapolation and from genuine uncertainty, to a clinical-defensibility standard.