I'd imagine the problem with using SERMs instead of AI is that estrogen won't be able to do it's work on the scalp, especially with oral SERMs
That's the standard idea about oral SERMs and it makes sense. But SERMs are unusual because of their dimorphic pharmacological effect on the estrogen receptor. I'm confused about the effect on hair. I've found research on tamoxifen that's mixed: harmful in some reports, no effect in others.
A study on mice showed tamoxifen hurting the follicles:
The HFs were found to be
arrested in telogen phase with clear signs of follicle dystrophy. The hair growth-retarding effect of [tamoxifen] observed in the current study
clearly demonstrates its OR agonistic effect on hair growth.
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Tamoxifen-loaded liposomal topical formulation arrests hair growth in mice, Bhatia, 2010, India
https://www.ncbi.nlm.nih.gov/pubmed/20331445
A case report on a 5-year old girl with McCure-Albright syndrome who was switched from cyproterone acetate to tamoxifen showed that she ended up with hair "on the skin of her upper and lower abdomen, upper and lower back, arms, and thighs", the typical areas of adult men (Kırmızıbekmez, 2015, Turkey,
https://www.ncbi.nlm.nih.gov/pubmed/26024247).
So it looks like tamoxifen blocking estrogen receptors would lead to an increased androgen:estrogen ratio, with male-pattern scalp hair loss and hirsutism in women/girls?
But then this 2013 study shows
no effect (or at most very little) from tamoxifen on women's scalp hair. It's a small number of patients, but it's pretty thorough, and in contrast to most cancer-drug studies, is focused very specifically on hair loss. Women being treated for breast cancer were analyzed about their hair loss. n=17 patients (avg age=50) were treated with chemotherapy, n=17 patients (avg age=58) treated with 20mg daily of tamoxifen. The chemotherapy patients lost hair density and had anagen effluvium (started at week 1-3, and eventually recovered 3 months after stopping treatment). But the tamoxifen patients had essentially no hair loss, no change in anagen:telogen ratio, and the only real difference in their hair was a very small loss of anagen hairs and density in the frontal area from week 6 to 18.
The lack of effect of tamoxifen is striking enough that the authors comment in the discussion:
Considering the wide use of tamoxifen, the data reported [about its supposed harmful effects on hair] are rather limited and partly questionable...
There is little evidence in the current literature that oestrogens affect human hair growth one way or the other, possibly indicating
a role of genetic predisposition in oestrogen-related hair changes.
Our results argue against an effect of tamoxifen on hair growth.
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Analysis of quantitative changes in hair growth during treatment with chemotherapy or tamoxifen in patients with breast cancer: a cohort study, Kanti, 2013, Germany,
https://www.ncbi.nlm.nih.gov/pubmed/24641211
I could go PubMed-Warrior mode and find literature to counter the authors about estrogens affecting human hair growth, and n=17 isn't huge, etc, but still.... it's a very striking conclusion.
Any thoughts on what's going on with this? Anyone have personal experience or seen reports of tamoxifen's effect on hair loss?
Edit to add: I think I saw that @jgray201 used tamoxifen (Genox) 20mg while taking spironolactone to fight against gyno?