There’s a good reason more stallions than fillies win horse races: Stallions have bigger muscles and more of the muscle-powering hormone testosterone than fillies do. Knowing that, most racehorse trainers would feed prohormone products to the stallions they train for the track if only they could!

Prohormones are hormone precursors that liver enzymes convert to anabolic hormones in the body. Though earlier versions of prohormone products were banned from the marketplace, luckily for human athletes who want to increase their muscle size, strength, and endurance, a new version called 1-Androsterone is available.

Manufactured by Advanced Muscle Science, a company with more than 20 years of experience in producing cutting-edge bodybuilding supplements and ergogenic aids for the sports-nutrition industry, 1-Androsterone offers many of the same beneficial effects that 1-androstendiol and 1-test did—and because the formulation is 100 percent legal, you can take it knowing your body is protected from dangerous substances. Unlike virtually every “methyl” prohormone on the market, 1-Androsterone is completely nontoxic, an orally active compound that occurs naturally in the human body. Moreover, in addition to being exceedingly powerful, it’s also completely non-aromatizable to estrogen.

The question of whether or not prohormones work is widely debated among bodybuilders. Yet some of the most notable and successful bodybuilders have been using them for years to build lean muscle and reduce body fat, with excellent results. Furthermore, many bodybuilders feel that stacking prohormones can further boost muscle gains, though there is a consensus that prohormones should be used in cycles that allow the body to rest for at least two weeks in between courses in order to avoid the deleterious effects of too much testosterone. Stacking prohormones can be an essential part of a bodybuilder’s training regimen because prohormones provide unparalleled muscle-building and fat-reducing abilities.

1-Androsterone converts to 1-testosterone at a high rate, giving your body the capability for strength and size gains just like other products that are now unavailable in the marketplace. And because it combines the safest and most-advanced delivery method available in a prohormone product, it delivers better results than those older products did, without converting to estrogen or DHT, and hair loss is not a concern.

However, prohormones do have side effects everyone should know about before taking them. Among these are acne, elevated plasma estrogen concentration (which can lead to breast development as well as breast or pancreatic cancers), premature baldness, enlarged prostate, decreased sperm production, increased aggression, infertility, libido loss, and impotence in men; and in increased facial hair, enlarged clitoris, and disrupted menstrual cycles in women. Even though side effects from 1-Androsterone are rare (and can be controlled by giving the body a rest as described above), like all andro products, this one is not recommended for teenagers, whose hormonal systems are still developing and who probably have raging hormones anyway!

Advanced Muscle Science 1-Androsterone reviews reveal that users are experiencing gains in lean muscle mass and strength with little (if any) water gain, lending a more sculpted look to the physique. The company advises that it is best stacked with its other legal and effective prohormone superstar, 4-AD, and with its Arom-X to boost the body’s natural hormone production during off-cycle rest periods.

—Julie Crawshaw