Anyone thought about using estriol instead of estradiol?

[noszbe]

Has anyone considered using estriol cream instead of estradiol?

A summary as to why it looks interesting:

Estriol agonizes ER-beta (ESR2) more than ER-alpha [1]. ER-beta agonism is associated with anti-proliferative effects in a variety of cancers [2]. Estradiol agonizes both about the same [1]. The third estrogen recepter GPER (GRP30) is antagonized by estriol which may have anti-proliferative effects [3].

1 pubmed.ncbi.nlm.nih.gov/167...

2 e.g. "Activation of ERβ in early prostate cancer, as well as in benign prostatic hyperplasia, leads to an antiproliferative and pro-apoptotic effect [11]. Furthermore, ERβ seems to inhibit the epithelial-mesenchymal transition (EMT) in prostate cancer cells by destabilizing hypoxia-inducible factor 1α (HIF-1α), thus reducing their invasive potential [12]. Therefore, there is hope that an ERβ-selective agonist might be used to treat these pathologies." ncbi.nlm.nih.gov/pmc/articl...

3 ncbi.nlm.nih.gov/pmc/articl...

As an aside, high doses of endogenous estriol (from full term pregnancy) has a long term (many years) suppressive effect on the incidence of breast cancer. There's extensive literature that hints at the protective effect of ER-beta agonism on many lymphomas, as well as the negative effect of ER-alpha agonism. I'm not familiar with other cancers but ref [2] above has a more extensive list.

[henukit]

Interesting, that I've been studying this topic all morning and went through similar articles. I got E2 patches from my MO but before using them decided to study the issue in depth and went down the rabbit hole.

Here are some more to ponder on:

ncbi.nlm.nih.gov/pmc/articl...

frontiersin.org/articles/10...

academic.oup.com/jcem/artic...

hormonebalance.org/images/d...

eje.bioscientifica.com/down...

[noszbe]

One factor I neglected is that estriol is a poor suppressor of LH and FSH in women [1]. Which is probably why a combination of estradiol and estriol is often used.

1 fertstert.org/article/S0015...

[sammamish]

I wonder if it could be had in patch form? I recall my preventive medicine father was adamant that proper estriol/estrone/estradiol ratios were super important for cancer prevention. Don't recall how he accomplished that in his practice though