#131

From a new study in rhesus macaques:

We found that our dosing regimens (0.30 and 0.20 mg/kg/day) were tolerable as evidenced by a lack of GI distress, changes in blood chemistry or complete blood counts, and unaffected vital signs. We also found that the higher dose did elicit mild benefits on metabolic parameters including body mass, adiposity, and glycosylated hemoglobin.

“Both of our 17α-estradiol trial doses elicited significant feminization to include testicular atrophy, increased circulating estrogens, and suppressed circulating androgens and gonadotropins.”

4 Likes
#132

We suspect that the observed level of feminization results from a saturation of the endogenous conjugation enzymes, thereby promoting a greater concentration of unconjugated 17α-estradiol in serum, which has more biological activity. We also surmise that the elevated level of unconjugated 17α-estradiol was subjected to a greater degree of isomerization to 17β-estradiol, which is aligned with the sevenfold increase in serum 17β-estradiol in 17α-estradiol treated animals in our first trial. Future studies in monkeys, and certainly humans, would likely benefit from the development and implementation of 17α-estradiol transdermal patches, which are commonly prescribed in humans and would circumvent potential issues with bolus dosing effects.

3 Likes
#133

These are pretty high dosing levels… for a 70kg person, thats 14mg to 20mg a day. I wonder how they determined that dosing level. I’ll shoot an email to the paper author.

4 Likes
#134

Using standard allometric scaling, the dose would be divided by 3.1 to determine the human equivalent.

0.2 ÷ 3.1 × (your weight in kg).

For a 175 lb man:

0.2 ÷ 3.1 × 79.3787 = 5.12 mg

So using the most typical scaling formula, their lower dose in the macaques would be about 5 mg in a 175 lb man.

3 Likes
#135

Some other recent studies on 17 alpha-estradiol:

3 Likes
#136

Here is the full Macaque estradiol paper:

Assessing tolerability and physiological responses to 17α-estradiol administration in male rhesus macaques

Stout et al. 2023 (17a Macaques).pdf (915.8 KB)

3 Likes
17-alpha-Estradiol Study in Marmosets
#137

I’ve been in contact with the authors of this paper, and I’m thinking it might be valuable to talk with them and get some questions about this paper answered. If you’ve had a chance to review the paper and have some questions - please post them here.

3 Likes
#138

17α-estradiol Alleviates High-Fat Diet-Induced Inflammatory and Metabolic Dysfunction in Skeletal Muscle of Male and Female Mice

Skeletal muscle has a central role in maintaining metabolic homeostasis. 17α-estradiol (17α-E2), a naturally-occurring non-feminizing diastereomer of 17β-estradiol that demonstrates efficacy for improving metabolic outcomes in male, but not female, mice. Despite several lines of evidence showing that 17α-E2 treatment improves metabolic parameters in middle-aged obese and old male mice through effects in brain, liver, and white adipose tissue little is known about how 17α-E2 alters skeletal muscle metabolism, and what role this may play in mitigating metabolic declines. Therefore, this study aimed to determine if 17α-E2 treatment improves metabolic outcomes in skeletal muscle from obese male and female mice following chronic high fat diet (HFD) administration. We hypothesized that male, but not female, mice, would benefit from 17α-E2 treatment during HFD. To test this hypothesis, we used a multi-omics approach to determine changes in lipotoxic lipid intermediates, metabolites, and proteins related to metabolic homeostasis. In male mice, we show that 17α-E2 alleviates HFD-induced metabolic detriments of skeletal muscle by reducing the accumulation of diacylglycerol (DAGs) and ceramides, inflammatory cytokine levels, and reduced the abundance of most of the proteins related to lipolysis and beta-oxidation. In contrast to males, 17α-E2 treatment in female mice had little effect on the DAGs and ceramides content, muscle inflammatory cytokine levels, or changes to the relative abundance of proteins involved in beta-oxidation. These data support to the growing evidence that 17α-E2 treatment could be beneficial for overall metabolic health in male mammals.

bioRxiv. posted 1 June 2023, 10.1101/2023.05.30.542870

http://biorxiv.org/content/early/2023/06/01/2023.05.30.542870

4 Likes
#139

Still hoping that 17-Alpha Estradiol is semi-permeable of the scalp. Have been using Pantostin for a month now. Difficult to find any evidence from Google searches about the permeability of this hormone. However, given that other hormones are often delivered through skin patches have assumed it would work. Wish I could find out, if it isn’t working would like to know so I could start taking it orally (Dissolve chemical and mix with oil). Do you know where I can find information about the skin permeability of 17-Alpha?

4 Likes
#140

17α-estradiol Alleviates High-Fat Diet-Induced Inflammatory and Metabolic Dysfunction in Skeletal Muscle of Male and Female Mice

Skeletal muscle has a central role in maintaining metabolic homeostasis. 17α-estradiol (17α-E2), a naturally-occurring non-feminizing diastereomer of 17β-estradiol that demonstrates efficacy for improving metabolic outcomes in male, but not female, mice. Despite several lines of evidence showing that 17α-E2 treatment improves metabolic parameters in middle-aged obese and old male mice through effects in brain, liver, and white adipose tissue little is known about how 17α-E2 alters skeletal muscle metabolism, and what role this may play in mitigating metabolic declines. Therefore, this study aimed to determine if 17α-E2 treatment improves metabolic outcomes in skeletal muscle from obese male and female mice following chronic high fat diet (HFD) administration. We hypothesized that male, but not female, mice, would benefit from 17α-E2 treatment during HFD. To test this hypothesis, we used a multi-omics approach to determine changes in lipotoxic lipid intermediates, metabolites, and proteins related to metabolic homeostasis. In male mice, we show that 17α-E2 alleviates HFD-induced metabolic detriments of skeletal muscle by reducing the accumulation of diacylglycerol (DAGs) and ceramides, inflammatory cytokine levels, and reduced the abundance of most of the proteins related to lipolysis and beta-oxidation. In contrast to males, 17α-E2 treatment in female mice had little effect on the DAGs and ceramides content, muscle inflammatory cytokine levels, or changes to the relative abundance of proteins involved in beta-oxidation. These data support to the growing evidence that 17α-E2 treatment could be beneficial for overall metabolic health in male mammals.

2023.05.30.542870v2.full.pdf (2.9 MB)

6 Likes
#141

In this study, they say that pomegranate seed oil contains 17-alpha-estradiol. Interesting.

But since I don’t know of any pomegranate juice or extract that is standardized for 17-alpha-estradiol it is not meaningful to chase 17-A-E that way. But the knowledge makes pomegranates even more exciting.

“The pomegranate seed oil (PSO), containing 17-α-estradiol, is one of the newly found phytosterols with synergistic health effects on estrogen related physiological conditions. Herein, PSO was assessed for its potential improving effects on bone characteristics in a rat model of menopausal syndrome.”

3 Likes
#142

Interesting. There is some science showing pomegranate extract (polyphenols and punicalagins), increases testosterone levels. A friend of mine takes a pomegranate supplement and it doubled his free testosterone levels.

Didn’t one of the studies on 17ae2 report that the mice were more muscular?

3 Likes
#143

Role of Estrogen Receptor α in Aging and Chronic Disease

We also discuss how 17α-estradiol administration elicits health benefits in an ERα-dependent manner, which provides proof-of-concept that ERα may be a druggable target for attenuating aging and age-related disease burden.

HEALTH BENEFITS OF AGONIZING ERα WITH 17α-ESTRADIOL

Although estrogen replacement therapies improve a variety of comorbid conditions and likely elicit benefits on aging processes [136-139], chronic administration has been linked with greater cancer and cardiovascular risks in some female populations [140,141]. Additionally, elevated serum 17β-E2 in males is associated with stroke risk [142], prostate cancer development [143], and feminization [144]. Therefore, the challenge remains of determining how best to exploit the beneficial effects of systemic estrogen therapies while circumventing adverse biological consequences. We and others have begun to address this biological challenge through the use of 17α-estradiol (17α-E2). 17α-E2 is a naturally-occurring diastereomer of 17β-E2 [145,146] that is present in both mammalian sexes [147-149], although circulating levels are quite low. 17α-E2 is also a minor constituent of estrogen replacement therapies [150] but only possesses about 3%–4% of the binding affinity to ERα that 17β-E2 does [151]. 17α-E2 has predominantly been studied as a neuroprotective hormone with mild to moderate efficacy in both male and female models of ischemia, Alzheimer’s, and Parkinson’s diseases [147,150,152-155]. It was not until recently that the effects of 17α-E2 on systemic aging, longevity, and conditions that promote aging (e.g., obesity) were evaluated. The National Institute on Aging Interventions Testing Program has shown that 17α-E2 extends lifespan in male mice when treatment is initiated in mid-life [156,157] and late-life [158]. The magnitude of lifespan extension with 17α-E2 treatment in male mice is similar to that of calorie restriction [159] and rapamycin administration [160], which indicates 17α-E2 elicits potent effects that could conceivably be translated to men.

Our previous work has established that 17α-E2 administration reduces calorie intake and adiposity in conjunction with dramatic improvements in metabolic parameters (e.g., glucose tolerance, insulin sensitivity, ectopic lipid deposition) in obese and/or aged male mice [161-165]. We surmise these benefits underly the lifespan-extending effects of 17α-E2. Others have also reported that 17α-E2 treatment elicits benefits on glucose tolerance, mTORC2 signaling, hepatic urea cycling, markers of neuroinflammation, and sarcopenia [166-170]. Importantly, male-specific benefits occur without overt feminization of sex hormone profiles [161] or reproductive function [171]. Female mice are generally unresponsive to 17α-E2 treatment [166-170,172,173], unless subjected to chronic high-fat feeding over several months (unpublished observation) or following OVX [174]. Until recently the receptor(s) that mediate the actions of 17α-E2 were believed to be uncharacterized [146,148,154,175], although our recent report clearly demonstrated that the majority of health benefits attributed to 17α-E2 treatment are ERα-dependent [163]. This report also established that the hypothalamus and liver are the primary organ systems where 17α-E2 signals to regulate metabolic homeostasis in male rodents. Additional studies are needed to determine if 17α-E2 acts predominantly through ERα in a cell-type-specific manner in the hypothalamus and/or liver to modulate not only systemic metabolic homeostasis, but also aging and longevity. Although not definitive, the data generated thus far indicates that ERα agonism by 17α-E2 in hypothalamic neurons and/or hepatocytes may hold therapeutic potential for attenuating mechanisms that promote aging and chronic disease burden in men.

full paper

2 Likes
#144

Confirmed that Bryan uses 17AE:

17aE2, 4g wk transdermal

It looks like he’s done a typo, and he means 4 mg:

https://twitter.com/bryan_johnson/status/1651612572054089728

I don’t remember if I posted about this elsewhere, the statins dementia might be settling in.

Screen Shot 2023-07-26 at 7.19.08 PM
Screen Shot 2023-07-26 at 7.19.08 PM896×356 31.5 KB

3 Likes
#145

This situation is still a little uncertain for me. You’re right, on his website it states he is taking 4g per week but on the 8/22 tweet he says he is taking 4mg per week. And it looks like a typo because 4g is 1000x more than 4mg and would be a very big increase in dose. And also if you look at the standard womens dose of 17-Beta estradiol .625 mg per day it equals 4.3mg per week. However… in a July 2023 YT Short

Bryan says “I apply this cream to my body, 4gm per week”. This could be referring to the quantity of cream and not the concentration of 17α-E2. But stating the amount of cream and not the drug is of no use to the viewers. The other thing to keep in mind is that 17α-E2 is 100 times less effective than 17β-estradiol, which makes 4gm per week of 17α-E2 incomparable to the 17-Beta estradiol doses for women. And the final thing is that in the 8/22 Tweet he does say “May trial higher dose”. Look, the 4gm per week dose does make more sense than 4g per week, but shit, that would be a huge mistake on the website where is saying “17aE2, 4g wk transdermal”. Thats unintentionally misleading followers to take 1000x more than he is taking!! (the “17aE2, 4g wk transdermal” was added to his website on the 28th April 2023 and has remained unchanged). I am taking 4mg of 17aE2 transdermal per week, but if its meant to be 4g per week, I’m wasting my time. And if it is 4mg, the uncertainty minimises the placebo effect :slight_smile:

5 Likes
#146

Hi All. I emailed Bryan Johnson’s team and they confirmed it was a typo on the website which has now been updated. He is taking 4mg per week not 4g per week.

8 Likes
#147

New Research:

17α-Estradiol Signals Primarily Through Nongenomic Mechanisms: Implications For Its Beneficial Longevity Effects

Recent work indicates that exogenous 17α-estradiol (17α-E2), a stereoisomer of 17β-E2, increases longevity 20% in male mice, despite previous literature that 17α-E2 is a weak estrogen with low affinity for nuclear (n)ESR1. This study aimed to obtain mechanistic insights into uterine 17α-E2 actions in vivo. We hypothesized that 17α-E2 signals preferentially through membrane (m)ESR1 to affect target tissues and promote longevity. To test this, we treated pre-pubertal (postnatal day 20) female CD-1 mice with 3 daily ip injections of vehicle or 10 mg/kg of 17α-E2 or 17β-E2. 17α-E2 treatment did not significantly increase uterine weight - a marker of nuclear (n)ESR1 signaling (20.3 ± 2.1 vs. vehicle 15.7 ± 2.0, p>0.05, n=4), while 17β-E2 strongly increased it to 41.4 + 1.1 mg; p<0.05). Accordingly, histological analysis revealed reduced cell proliferation in 17α-E2- vs. 17β-E2-treated uteri. Both 17α-E2 and 17β-E2 produced robust and similar epithelial p-ERK and p-AKT expression, the active phosphorylated forms of these protein kinases. Western blotting and immunofluorescence showed that 17α-E2 and 17β-E2 stimulated a strong and comparable stimulation of EZH2, a critical mediator of estrogen’s epigenetic effects linked to mESR1 signaling, as well as increases in NRF2 and CBP signaling. Progesterone pre-treatment blocks both the 17α-E2- and 17β-E2-mediated increases in p-ERK. In conclusion, despite limited actions through nESR1, 17α-E2 robustly signals through mESR1 to activate uterine protein kinase cascades and epigenetic effects. Thus, 17α-E2 acts preferentially through mESR1, which may explain its powerful longevity effects despite limited effects on classical markers of estrogen action such as uterine weight.

5 Likes
#148

17α-estradiol Alleviates High-Fat Diet-Induced Inflammatory and Metabolic Dysfunction in Skeletal Muscle of Male and Female Mice

We hypothesized that male, but not female, mice, would benefit from 17α-E2 treatment during a HFD with changes in the mitochondrial proteome to support lipid oxidation and subsequent reductions in DAG and ceramide content. To test this hypothesis, we used a multi-omics approach to determine changes in lipotoxic lipid intermediates, metabolites, and proteins related to metabolic homeostasis. Unexpectedly, we found that 17α-E2 had marked but different beneficial effects within each sex. In male mice, we show that 17α-E2 alleviates HFD-induced metabolic detriments of skeletal muscle by reducing the accumulation of diacylglycerol (DAGs) and ceramides, inflammatory cytokine levels, and altered the abundance of most of the proteins related to lipolysis and beta-oxidation. Similar to male mice, 17α-E2 treatment reduced fat mass while protecting muscle mass in female mice but had little muscle inflammatory cytokine levels. While female mice were resistant to HFD induced changes in DAGs, 17α-E2 treatment induced the upregulation six DAG species. In female mice, 17α-E2 treatment changed the relative abundance of proteins involved in lipolysis, beta-oxidation, as well as structural and contractile proteins but to a smaller extent than male mice. These data demonstrate metabolic benefits of 17α-E2 in skeletal muscle of male and female mice and contribute to the growing literature of the use of 17α-E2 for multi-tissue healthspan benefits.

Paywalled Paper: https://journals.physiology.org/doi/abs/10.1152/ajpendo.00215.2023

3 Likes
#149

Perhaps not many people have seen the patent application from Longevica Therapeutics, since I’ve only seen it mentioned once on this forum.

United States Patent Application Publication — METHODS AND COMPOSITIONS FOR EXTENDING LIFESPAN

They tested a bunch of compounds in female B6C3F1hybrid mice, which is a long-lived strain. The compound which reduced mean lifespan most was 17beta-E2 (-21%). I couldn’t find the exact doses used.

They tested 1033 different compounds, and when the compounds were grouped by pharmacology, the only class which significanlty reduced lifespan was the estrogen agonists. In contrast, SERMs (which act as estrogen antagonists in tissues like breast and uterus, while acting as estrogen agonists in many other tissues) as a group extended lifespan.

17beta-E2 may damage DNA independent of its ER-binding activity, which might partially explain the above results.

We have demonstrated that E2 can bind to DNA directly and that binding not only occurs at the centre of the ERE half site but can also bind to random DNA sequences. E2 is shown to intercalate between base pairs, forming aromatic interactions with these base pairs…We predict that this intercalation will alter the structure of the DNA duplex, and therefore have the potential to affect the biological functions of DNA including the inhibition of transcription, replication, and DNA repair processes [40]. Therefore, excess E2 has the potential to exert some serious side effects such as disruption of ER-DNA binding, DNA damage and possibly the initiation of cancer. Molecular Mechanism of Binding between 17β-Estradiol and DNA

Mendelian randomization suggests that estrogen is causal for ER-positive breast cancer and endometrial cancer, so this could also be contributing to the above results. Obviously this would be an issue specific to female mice.

Another MR study suggests 17beta-E2 supports kidney function in men:

Our two-sample MR analysis based on the instruments assessing estradiol levels below vs. above the detection limit revealed a significant causal effect in males with a positive effect direction, implying that higher levels of estradiol could lead to higher eGFRs. This association was validated in the one-sample MR using continuous levels of estradiol above the detection limit.
Mendelian randomization indicates causal effects of estradiol levels on kidney function in males

2 Likes
#150

Now as for why the female mice don’t benefit in ITP, I think due to higher levels of endogenous estrogen, they already possess the ERalpha and ERbeta-mediated benefits (as studies suggest male benefits occur through these receptors).

We can estimate in women the amount of bound ERalpha using equation: %bound receptor=1/(Kd/[L])+1. Using 17beta-E2’s 115pM Kd @ ERalpha, we can see that going from 200pg/mL to 300pg/mL only increases bound receptor by about 4%. In contrast, going from 10pg/mL to 100pg/mL leads to 314% increase in bound receptor!

In essence, due to the nonlinear nature of the occupancy equation, raising a woman’s estrogen levels will produce a relatively small increase in ERalpha signaling, whereas an equivalent increase in a man’s estrogen levels will produce a much greater increase in ERalpha signaling.

If adding more 17beta-E2 has a relatively small effect in women, then this will especially be the case with 17alpha-E2—due to it’s much weaker affinity at ERalpha. On the other hand, since men would be expected to see a much greater effect from an equivalent increase in 17beta-E2, similar reasoning suggests they would see a much greater effect from an increase in 17alpha-E2.

You can do similar analysis with ERbeta (where 17beta-E2 has a similar Kd), just keep in mind that this is an approximation. Serum levels don’t necessarily reflect tissue or intracellular levels, where the relevant signaling is taking place. Additionally, I used human 17alpha-E2 Kd and serum levels, so this relationship would need to also hold with mouse values.

2 Likes