Prohormones: Are They Safe to Use for Muscle Building?

Supplements being poured from a bottle into someone's hand

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As of late, performance-enhancing drugs are becoming quite the norm inside gym walls, in bodybuilding competitions, and with athletes on the field.

One such popular chemical compound that has risen through the supplement market is known as a prohormone, also known as over-the-counter androgens. Manufacturers claim that these supplements will to help weightlifters build muscle and lose fat, and unlike steroids, consuming them is legal.

Rather than go the old-fashioned route of following a regimented diet and workout schedule that requires a heavy dose of your personal time, people turn to anything from steroids to hormone supplements to boost their athletic performance and/or muscle size.

Many seek out a quick fix rather than putting in the physiological effort needed to significantly increase muscle mass. On the other hand, some people may feel pressure to take these kinds of drugs to stay competitive with everyone else who currently uses performance-enhancing drugs.

What Are Prohormones?

Prohormones are chemical compounds that claim to help weightlifters and athletes in enhancing their muscle mass and performance—similar in scope to the purpose of steroids.

In the body, these compounds are converted by an enzymatic process into anabolic hormones which help generate protein synthesis and stimulate muscle growth.

These supplements can produce expeditious results, allowing bodybuilders to shift their body composition within a short time frame. Bodybuilders can build muscle and decrease their body fat percentage often much quicker than they typically could without prohormones.

However, results obtained from prohormone use are usually short term and come with a price—they can accelerate testosterone levels which leads to side effects similar to those of anabolic steroids (which are against the law to consume).

Legality of Prohormones

Because of the nature of this supplement, some athletic associations have banned prohormones. If you are a competing athlete and get drug tested, you should stay cognizant of what you can and can't use. Some prohormones might test positive for drugs depending on what the association has deemed illegal for their athletes.

You also should be aware that some manufacturers will add prohormone mixtures into supplements without disclosing them on the ingredients.

But, how is this legal you ask? The Federal Food & Drug Administration (FDA) regulates dietary supplements with a different set of regulations than other food and drugs. Manufacturers are responsible for their own evaluation of the safety and labeling of their products before marketing.

Prohormones Have a Checkered Past

In 1996, when prohormones were first introduced, athletes enjoyed their new, powerful abilities.

For example, Major League Baseball legend Mark McGwire was known to take prohormones as he worked to break home run records. He soon became a central figure in the steroid scandal that rocked the sports industry.

Because of such media attention, lawmakers took notice and in 2004, they ended up banning almost all prohormones on the market, thereby creating the Anabolic Steroid Control Act of 2004.????This act stated said that all prohormones for sale are illegal and using them is the same as taking a steroid.

But prohormones didn't stay off the shelves for long. Rather, manufacturers simply worked around the law of 2004 and started to sell them again in 2005.

Although they are now legal, prohormones still can cause the same negative side effects on the body as they did pre-2004.

How Well Do Prohormones Work?

A few clinical studies demonstrate the effectiveness or ineffectiveness of prohormones. These studied are discussed in the following sections.

For Body Composition and Physical Performance Enhancements

In a review of the effects of prohormone supplementation in humans published in the Canadian Journal of Applied Physiology, researchers found that prohormones might indeed lead to anabolic and/or physical performance effects, but not enough to make taking them worth it.??

Oral ingestion of greater or equal to 200 milligrams per day increases testosterone concentration in men and is also accompanied by increases in estrogen (hence female breasts can develop).

Doses greater than 300 milligrams per day for as long as 12 weeks have no effect on body composition or physical performance and can cause a decrease in high-density lipoprotein cholesterol.

The bottom line: The authors suggest that based on the research reviewed, over-the-counter oral prohormones are ineffective at increasing muscle mass and athletic performance. In addition, the risk-to-benefit ratio of usage is unfavorable.

For Resistance Training

Researchers studied the effects of serum testosterone and adaptations to resistance training in young men using prohormones, and published their results in the Journal of the American Medical Association.

In this study,? 30 healthy men ages 19 to 29 not taking any nutritional supplements or steroids and not engaged in any resistance training were placed into groups.?? Twenty men performed eight weeks of whole-body resistance training.

During weeks 1, 2, 4, 5, 7 and 8, the men were randomly given either a prohormone of 300 milligrams or a placebo. Ten men were given a single 100 milligram prohormone dose.

Researchers measured testosterone changes, estrogen concentrations, muscle strength, muscle fiber, body composition, blood lipids, and liver activities.

Results showed no significant increases in lean body mass and decreases in fat mass in both the prohormone and placebo group. In the prohormone group, liporprotein cholesterol was reduced after two weeks and remained low.

The bottom line: The authors suggest that prohormone supplementation doesn't increase testosterone concentrations or enhance any muscles when resistance training and might result in negative health consequences.

For Medicinal Usage

In a study on secondary hyperparathyroidism (caused by a declining renal function in chronic kidney disease) published in the International Journal of Nephrology and Renovascular Disease,? researchers found that patients supplementing with prohormones was of limited efficacy in later stages of the disease.?? Only patients with early stages of the disease found success in treatment with prohormones.

The bottom line: Supplementing medication with prohormones in serious illnesses may help patients during particular treatment periods. This could possibly help with atrophied muscles or vitamin deficiencies.

Side Effects

Because prohormones are legal to sell, people assume they are safe for consumption, but it is important to understand that they do have the potential to cause substantial and damaging side effects.

Prohormone effects can vary by the person, as is the case with any supplement. For some, the effects can be severe and long lasting, similar to the side effects of steroids.

Some of the prohormone side effects include the following:

  • Headaches
  • Increased heart rate
  • Nausea
  • Stomach pain
  • Sleeplessness
  • Increased anxiety
  • Fatigue
  • Acne
  • Mood changes, which can range from slight moodiness to drastic swings in personality
  • Hair loss
  • Testicular shrinkage
  • Aggressive behavior
  • Increased or decreased libido
  • Enlarged female breast tissue (sometimes men will develop breasts)
  • Lack of motivation to do activities you used to do (similar to how you feel when you experience depression)

Long-lasting side effects can include cardiovascular events, such as a stroke or heart attack, irreparable liver and other organ damage, decreased immune system functions, type 2 diabetes, increased blood pressure and elevated cholesterol levels.

Who Should Avoid Using Prohormones?

Because of the side effects and the relative lack of evidence of what these over-the-counter supplements can do to the body, all individuals should consult their healthcare provider before using them. Individuals who fit the following categories should opt out of using prohormones:

  • People under 18 years of age
  • People who are breastfeeding
  • Those who are pregnant or actively trying to become pregant
  • Individuals who want to lose weight

Because of the significant side effects, anyone considering prohormone use should consult with their healthcare provider prior to incorporating these supplements into their daily regime.

Should You Try Prohormones?

Simply not enough research is currently available to make a distinguishable vote of confidence that you could benefit from supplementing your diet with prohormones.

Future peer-reviewed, placebo-controlled, randomized clinical trials should be conducted to demonstrate that oral prohormone supplementation can increase muscle mass. Until then, you should look to other, more substantive, scientifically-backed ways to add muscle.

If you do decide to try prohormones, you should keep the mindset that they might not work, you would be out the money and you might experience significant side effects.

The most effective way to build muscle, according to the American Heart Association,? is to add moderate- to high-intensity muscle-strengthening activities, such as lifting weights or using body-weight training, at least two days per week.?? You should also spend less time sitting and gradually increase the intensity of your exercise throughout time.

A Word From Verywell

Before beginning a muscle-building exercise routine, you might benefit from seeking the advice of a medical professional and a registered dietitian. This team can help determine what is best for your body.

You should make them aware of any medications that you take. These medications may not be suitable for heavy workouts. Medical professionals will also know the amount of protein you need to safely consume to create the body composition and body mass index you desire (or whether trying to isn't safe at all). 

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Article Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. NIDA. What is the history of anabolic steroid use?. National Institute on Drug Abuse. February 2018.

  2. Ziegenfuss TN, Berardi JM, Lowery LM. Effects of prohormone supplementation in humans: a review.?Can J Appl Physiol. 2002;27(6):628-646. doi:10.1139/h02-037

  3. King DS, Sharp RL, Vukovich MD, et al. Effect of oral androstenedione on serum testosterone and adaptations to resistance training in young men: a randomized controlled trial.?JAMA. 1999;281(21):2020-2028. doi:10.1001/jama.281.21.2020

  4. Friedl C, Zitt E. Vitamin D prohormone in the treatment of secondary hyperparathyroidism in patients with chronic kidney disease.?Int J Nephrol Renovasc Dis. 2017;10:109-122. Published 2017 May 11. doi:10.2147/IJNRD.S97637

  5. American Heart Association. American Heart Association Recommendations for Physical Activity in Adults and Kids. Updated April 18, 2018.

Additional Reading
  • Federal Food and Drug Administration. Dietary Supplements.