Androstenedione is a prohormone that’s been used to increase testosterone to improve muscle mass, sports performance, sexual performance, increase energy and reduce body fat.
But how effective is it as a testosterone booster? And can it actually be dangerous?
Androstenedione as a precursor to testosterone
Androstenedione is a naturally produced hormone and a direct precursor to testosterone. It’s converted by 17β-hydroxysteroid dehydrogenase (17β-HSD) to testosterone.
17β-HSD and aromatase are expressed in many human tissues including skeletal muscle and fat. Thus, it is possible that increases in local tissue levels of testosterone, estrone, or estradiol from androstenedione are even greater than the increases in their circulating concentrations (R).
Under normal conditions, androstenedione is produced by the adrenals (2–3 mg/day) and testis (0.5 mg/day). The more stressed you are, the more androstenedione will be created, due to most of it coming from the adrenals.
Androstenedione can convert to testosterone as I already mentioned, and it can also convert to estrone by aromatase. Estrone then gets converted to estradiol.
So androstenedione can have both androgenic and estrogenic effects.
The majority of androstenedione is actually converted to androsterone (via 5α-reductase) and etiocholanolone (via 5β-reductase) and not testosterone. Androsterone can then be converted to DHT, which usually increases with androstenedione supplementation.
How effectively androstenedione increases testosterone
Androstenedione supplementation for 1-12 weeks
Study 1 – 7 days long (R)
2 groups were supplemented with androstenedione. G1 and G2 used 100mg and 300mg per day, respectively.
In the 100-mg/d group:
- Androstenedione increased by 72%
- Testosterone decreased by 4%
- Estrone increased by 74%
- Estradiol increased by 42%
In the 300mg group:
- Androstenedione increased by 697%
- Testosterone increased by 34%
- Estrone by 196%
- Estradiol by 128%
Clearly, androstenedione favors the estrogen pathway more than the testosterone pathway.
Study 2 – Suppression after 4+ weeks
200mg androstenedione increased testosterone by 16% after 4 weeks, but returned to pretreatment levels after 12 weeks. This effect was due to an increase in aromatization and suppression of luteinizing hormone by 18-33% over 12 weeks (R).
Study 3 – Enhanced hormone excretion after 7 days
This study found that androstenedione supplementation dramatically enhanced testosterone detoxification from the body. Hormones (and toxins) undergo glucuronidation to make them more water-soluble. They are then excreted in the urine and bile.
0, 100 and 300mg androstenedione supplementation increased serum testosterone glucuronide by -18 +/- 25%, 579 +/- 572%, and 1267 +/- 1675%, respectively, after 7 days.
“We conclude that the administration of both 100 and 300 mg androstenedione increases the excretion rates of conjugated testosterone, androsterone, etiocholanolone, and dihydrotestosterone and the serum levels of testosterone glucuronide in men. The magnitude of these increases is much greater than the changes observed in serum total testosterone concentrations. These findings demonstrate that orally administered androstenedione is largely metabolized to testosterone glucuronide and other androgen metabolites before release into the general circulation.” (R)
For example, 300mg increases T by 34% but increases testosterone glucuronide 10-fold (R).
Extensive first-pass metabolism (detox via the liver) is also why oral testosterone has such a short half-life and is relatively ineffective.
Study 4 – Diminished results after 4 weeks
After 4 weeks, 200mg androstenedione effects started to diminish in middle-aged men, likely due to suppression and enhanced excretion (R).
Androstenedione’s effect over hours
100mg androstenedione supplementation (R):
- Increased androstenedione by 325% and 350% at 90 and 270min respectively.
- Didn’t increase total or free testosterone over the 360min period.
Study 2 – Suppression in 2 days
200mg androstenedione elevated plasma androstenedione 2 to 3-fold and reduced luteinizing hormone by approximately 70%, without altering testosterone concentration.
Interestingly, exercising after taking androstenedione elevated testosterone, with no difference between conditions, but significantly elevated plasma estradiol by approximately 83% for 90 min in the supplemental group (R).
Androstenedione with an aromatase inhibitor
As you can see, androstenedione increases estrone and estradiol much more than it increases testosterone.
Wouldn’t it thus make sense to combine it with an aromatase inhibitor?
Two studies looked at this by combining it with natural AIs such as chrysin, I3C, Tribulus and Saw palmetto.
Each dose contained 300mg androstenediol, 480mg saw palmetto, 450mg indole-3-carbinol, 300mg chrysin, 1,500 mg gamma-linolenic acid and 1.350-mg Tribulus Terrestris.
They used androstenediol here and not androstenedione, but it yielded more or less the same results as if they were to use androstenedione, which is why I list it here.
The supplement (R):
- Didn’t increase testosterone, but increased free testosterone and DHT by 37% and 57%, respectively.
- Increased androstenedione by 174%.
- Increased estradiol by 85%.
It was clearly not effective at blocking aromatase and increasing T.
Each dose contained 300 mg androstenedione, 150 mg dehydroepiandrosterone, 540 mg saw palmetto, 300 mg indole-3-carbinol, 625 mg chrysin, and 750 mg Tribulus Terrestris.
The supplement increased serum androstenedione (342%), free testosterone (38%), DHT (71%), and estradiol (103%) concentrations (R).
Again, more estrogenic than androgenic.
How about much smaller doses of androstenedione?
Since the body only makes about 3-4mg of androstenedione daily, it would make sense to use much smaller doses, right? Maybe as a topical or sublingual supplement to bypass the liver.
Although there aren’t any studies looking at small doses of topical androstenedione, we have one using androstenediol as a sublingual.
Sublingual intake of 21.4 mg androstenediol increases serum testosterone concentrations whereas swallowing 200 mg androstenediol does not.
- Testosterone increased by approximately 115% and 107% after 60 and 120 min respectively.
- Estradiol increased by approximately 33% and 45% after 60 and 120min respectively.
Clearly sublingual is better in the sense that it increases testosterone more than estradiol, however, serum testosterone returned to baseline by 240 min and serum estradiol returned to baseline by 720 min post-intake (R). Thus the estrogenic effects last much longer than the androgenic effects.
- Increases T very mildly and only short term, before it causes suppression and enhances testosterone excretion.
- Increases estrogens to a great extent and for longer. It also directly stimulates aromatase (R).
- Doesn’t enhance skeletal muscle adaptations to resistance training in young men with normal testosterone and may result in adverse health consequences due to excess estrogen production (R).
Too much estrogen can contribute to vascular complications, sexual dysfunction, cognitive impairment (R), mood disorders, water retention, cancer growth, sperm count reduction, impotence, gynecomastia, hypothyroid symptoms, prostate enlargement, etc.
Can you make it work with a small dose of topical or sublingual androstenedione with an AI?
Perhaps, but the increase in testosterone is less than 270min with sublingual, thus you’ll have to dose every 4 hours or so, which is a big pain in the butt.
Blocking aromatase might take care of the suppression issue, but won’t stop the enhanced detoxification issue.
As mentioned above, androstenedione is converted mostly to 5-alpha-reduced steroids, which is good. So perhaps, small doses topically with an AI can be a good way to boost androsterone and DHT, which are potent steroids that help make you feel more androgenic.
But personally, I’d just go with topical DHEA. It’s also very effective at increasing androsterone and DHT, without the same risk of estrogen issues and suppression.
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Great stuff, keep it up my man
Honestly bro this guy knows so much, I thought I knew a lot but after I found Hans my trajectory in health and fitness genuinely changed. Thanks so much for all the knowledge Hans