Androstenedione is useless

[powerliftmike]

Here is the abstract from a study in The Journal of Clinical Endocrinology & Metabolism Vol. 85, No. 1 55-59. Blake B. Rasmussen, Elena Volpi, Dennis C. Gore and Robert R. Wolfe . Title: Androstenedione Does Not Stimulate Muscle Protein Anabolism in Young Healthy Men

Androstenedione is the immediate precursor of testosterone . Androstenedione intake has been speculated to increase plasma testosterone levels and muscle anabolism. Thus, androstenedione supplements have become widely popular in the sport community to improve performance. This study was designed to determine whether 5 days of oral androstenedione (100 mg/day) supplementation increases skeletal muscle anabolism.

Six healthy young men were studied before the treatment period and after 5 days of oral androstenedione supplementation. Muscle protein turnover parameters were compared to those of a control group studied twice as well and receiving no treatment. We measured muscle protein kinetics using a three-compartment model involving infusion of L-[ring-2H5]phenylalanine, blood sampling from femoral artery and vein, and muscle biopsies. Plasma testosterone, androstenedione, LH, and estradiol concentrations were determined by RIA.

After ingestion of oral androstenedione, plasma testosterone and LH concentrations did not change from basal, whereas plasma androstenedione and estradiol concentrations were significantly increased (P < 0.05). Compared to a control group, androstenedione did not affect muscle protein synthesis and breakdown, or phenylalanine net balance across the leg.

We conclude that oral androstenedione does not increase plasma testosterone concentrations and has no anabolic effect on muscle protein metabolism in young eugonadal men.

[powerliftmike]

The introduction is also interesting:

ANDROSTENEDIONE is the immediate precursor to testosterone during steroid biosynthesis (1). Recently, it has been speculated that exogenous androstenedione is converted to testosterone and thus may have an anabolic effect on skeletal muscle. Numerous studies have shown that testosterone increases muscle size (2, 3, 4, 5, 6) by increasing muscle protein synthesis (4, 7, 8, 9) in healthy and hypogonadic men, and that it increases maximum voluntary muscle strength in eugonadal men (3). Because of these speculations, but without any published reports on the effects of exogenous androstenedione on muscle protein synthesis, androstenedione has, on the one hand, been banned from use by the Olympic Committee and many professional sports organizations and, on the other hand, become a widely popular, commercially available, oral supplement. However, a 1966 study from Horton and Tait (10) evaluated the pharmacokinetics of androstenedione and showed that if androstenedione was given through the gastrointestinal route, only about 2% was converted to testosterone. On the other hand, androstenedione is a steroid possessing an androgenic activity of 10–20% relative to the activity of testosterone (11). Thus, it is possible that even if androstenedione does not stimulate testosterone release, it may directly stimulate muscle protein synthesis.

The purpose of this study was to assess 1) whether 5 days of oral androstenedione supplementation increases plasma testosterone concentration, and 2) whether oral androstenedione has an anabolic effect on skeletal muscle.

[powerliftmike]

Compound its ineffectiveness to its recent classification as a controlled substance under US Federal law.

[Bryan2]

androstendione was the very first pro hormone discovered to directly convert to testosterone but as these studies showed it was incredibly weak. plus given the fact that the body only absorbs 5% of what is administered orally.

coupled with the minimal amount that does get absorbed the rest then has to convert.


4 androstenediol was latter discovered that had a higher conversion rate at 15% to testosterone.

ive done a cycle using 4androstenediol cyp dosed at 2100mgs a week leaving me with 315mg of test converted plus the remaining mg that doesnt convert being anabolic on its own. The results were very good but the volumous injections were not too fun.

[Baller9]

Since some of it does convert to testosterone , does that mean that it can shut you down and still cause some of the ill effects...while not providing the benefits?

[chest6]

man that stuff was such crap...

[powerliftmike]

Since some of it does convert to testosterone, does that mean that it can shut you down and still cause some of the ill effects...while not providing the benefits?

The shutdown would be so minimal if it existed that it would not make much difference in regards to testosterone 's effect on the HPT axis. The rising estrogen levels might have some inhibitory effects on the HPT axis tho. Disruptions in the HPA (hypo-pitituary-adrenal) axis are possible too, as much androstenedione is manufactured in the adrenal glands.