I get asked a lot of questions about supplementation, especially about prohormones and testosterone/hormone boosters. Prohormones are what many people refer to as ‘natural steriods’ or steroid pre-cursors. Most large supplement companies manufacture a prohormone, or at least some type of ‘hormone booster’ supplement, along with outrageous claims. 

They will claim how theirs is unique and far superior to everything else on the market. As I’ve always said – with 90% of supplements, it’s all BS and hype.  

The most important thing when it comes to prohormone supplements is to know and understand the ingredients. 
There are only a couple of ingredients in them with the potential to build muscle or boost testosterone, and even then it’s debatable (see detailed info on these ingredients below.) 

My intention with this article is to de-mystify some of the science and B.S. surrounding these supplements, to better inform you and help you make more intelligent choices when spending your hard-earned money.

What are prohormones?

Prohormones are essentially pre-cursors to hormones, or metabolic intermediates formed in the production of hormones. The prohormones of interest to athletes or bodybuilders are precursors to testosterone and estrogen. 

The rationale behind taking these supplements, is that by increasing the levels of the pre-cursor, you increase your levels of testosterone. Testosterone is the primary male hormone responsible for building and maintaining muscle tissue, 
as well as producing masculinizing effects.

Common ingredients in Prohormone supplements.

In the past, there were two main ingredients used in prohormone formulas, Dehydroepiandrosterone (DHEA) and Androstenedione* (usually just referred to as Andro). They are both naturally occurring hormones in the body and precursors to testosterone and estrogen. 

Other common ingredients found in these supplements include Tribulus Terrestris and MethoxyIsoflavone.

* In the United States, Andro was banned in 2004 when amendments were made to the Steroid Control Act. However, there are still plenty of Andro products on the market in other countries, and many websites sell Andro products, so it appears it’s still a player in the prohormone market, at least outside of the U.S.


What is DHEA?

DHEA is a steroid hormone produced by the adrenal glands. It is the most abundant circulating steroid hormone in humans (1). Males also produce it in their testes as an intermediate in testosterone production and women produce it in their ovaries as an intermediate in estrogen production.

Does DHEA help build muscle?

In early studies using men between the ages of 20-25, supplementation with DHEA did not significantly increase testosterone levels, although it did help decrease body fat and increase lean bodyweight. However, when this study was later duplicated, no significant changes in body composition of test subjects were observed.

Other studies have shown DHEA to cause an increase in IGF-I, an important growth promoter in muscles, yet no significant changes in lean body mass were observed along with the elevated levels of IGF-1.

Other studies have yielded inconclusive results, with no statistically significant increases in lean body mass, strength, or testosterone levels found in randomized placebo-controlled trials (2).

Here is some further information on DHEA from well-known fitness and nutrition author, Will Brink (http://www.brinkzone.com/) 

Is DHEA safe to use? 

Even though the results as to its efficacy are inconclusive, perhaps you are thinking  you’d still like to take a chance and see if DHEA supplements work for you. You need to take their safety into consideration.

In a study by Chang et al, DHEA was administered at a dose of 200 mg/day for 24 weeks with only slight androgenic (masculinizing) effects noted (3).  

A multitude of additional studies utilizing doses from 25 mg up to 2,250 mg per day for up to 24 months of therapy in men and women all showed DHEA to be well-tolerated, with no major adverse effects reported.

Is DHEA legal?

In the United States, DHEA is legal and can be sold as a dietary supplement. It is exempt from the Anabolic Steroid Control Acts of 1990 and 2004 (4). However, DHEA is a banned substance under the World Anti-Doping Code of the World Anti-Doping Agency, so if you are competitive athlete subject to testing, this is something to be aware of.


What is Androstenedione?

Like DHEA, Androstendione is a steroid hormone produced in the adrenal glands. It is an intermediate in the biochemical pathways producing testosterone and estrogen.

Does Androstendione help build muscle?

One needs to be very careful when listening to the hype regarding the andro’s ability to increase testosterone and build muscle. Supplement companies will often back up their claims with “scientific evidence”. They love to cite a study by V.B. Mahesh and R.B. Greenblatt (12) to substantiate their claims that andro boosts testosterone and increases muscle growth and strength.

You need to realize that this study made use of only 4 non-athletic women. The results of the study were based on one-time doses  of either 100mg DHEA taken by 2 of the women or 100mg andro taken by the other 2 women. Blood samples taken shortly after ingesting either the DHEA or andro, did show a rise in serum testosterone levels. 

However, when later Andro studies were conducted on male test subjects, they did not show a significant rise in testosterone, or improvements in muscle size and strength.

A paper in 2006 reviewing several other studies mentioned that at doses of 50-100mg per day, andro showed no significant increases in muscle size or strength(5).

A different study reviewed in this same paper, in which test subjects were given doses of up to 300mg of Andro per day also showed no increase in muscle size and strength compared with the test subjects receiving the placebo. 

The author of this paper did however mention, he suspects that at sufficiently high doses, Andro MAY cause increases in muscle size and strength, although few studies have been done to support this, and the potential side effects of taking much higher doses is not known. (5)

Finally, a well known study called “The Andro Project” conducted by scientists at East Tenessee State university, showed that Andro does not increase muscle mass or strength. (6)

Is Andro safe to use?

Because Androstenedione is an intermediate in estrogen production, people taking high levels of this supplement may experience estrogenic side-effects.

In April 2004, The United States Food and Drug Administration banned the sale of Androstenedione, purporting it posed many health risks commonly associated with the use of Anabolic steroids.

Is Andro Legal?

Androstenedione has been legally classified as an anabolic steroid according to the Anabolic Steroid Control Act of 2004, even though all of the evidence above shows very little proof of it having significant anabolic properties. 

Possession of it is a federal crime in the United States. 

It is also banned by the World Anti Doping Agency and by the Olympic games.

Tribulus Terrestris

Another ingredient commonly found in most prohormone formulations is Tribulus Terrestris. Whilst considered more of a ‘natural product’  and not as controversial as DHEA and Andro, it is claimed to boost testosterone levels, improve sexual performance and increase muscle size. 

Several controlled studies have shown its failure in causing any significant increase in testosterone levels. (7,8, 9). Another study conducted on rugby players also showed it to have no strength building properties. (10)


Also making a regular appearance in prohormone formulations prior to the amendments of the Anabolic Steroid Control Act of 2004 was 19-Norandrostenedione (NOR).It is a precursor to the well-known anabolic steroid Nandralone. It was also banned by the FDA and possession of it is a federal crime.

A scientific study showed the oral administration of NOR to be ineffective at stimulating skeletal muscle mass increases (11). This same study, did however show NOR to stimulate skeletal muscle mass increases when administered subcutaneously. 

This difference between effectiveness of oral administration versus subcutaneous administration is an important point to note – as most prohormone supplements are delivered orally, and will therefore be ineffective. This is because of the liver breakdown of the orally administered NOR. By administering it subcutaneously, this is avoided. 

Conclusion: Should you use prohormones, are they worth it?

Evidence clearly points to the fact that most of these substances are ineffective at producing significant gains in muscle size and strength in the majority of male populations. Even where studies have not outright proven an ingredient to be ineffective, results have been inconclusive and/or statistically insignificant. 

There is a great deal of anecdotal evidence out there though – many claiming good results and reporting great gains on some of these products. 

My take on it is that the science has shown them to be ineffective; and the gains people have experienced, while not to be completely discounted, are in my opinion, largely due to a placebo type effect. 

Usually when one starts taking a new supplement they feel more inspired, excited and motivated about their training. They are more likely to train harder and more diligently. 

Also, they are likely concurrently increasing their protein intake; this is often the recommendation of the supplement companies when taking their prohormones or other products.

Therefore, the gains people experience are likely due to the fact they are now finally training hard enough and getting adequate protein, not necessarily due to the prohormones.

Now before people start saying the supplement they are taking has different ingredients to those I have highlighted, realize that when the ban on some of the above ingredients occurred in 2004, the supplement companies were hit hard by it.

They had to modify their supplements to keep them legal. To keep their products on the shelves, they removed the Andro and NOR, and added in other crap, most of which is now some herbal extract (often Tribulus Terrestris) claimed to boost testosterone.

As we have seen, even many of the ‘steroid-like’ compounds now banned, failed to boost testosterone and build muscle. The ‘natural stuff’ like Tribulus also failed to provide any real benefits according to the literature. 

So whilst I have not reviewed every ingredient in every product – an entire book would need to be written for that, it is my opinion that many of these ‘replacement ingredients’ added after the ban on Andro and NOR, are just that, second rate replacements to ingredients  that were already ineffective.

So to conclude, personally, I’d not waste my money on prohormones. But, if you’d like to give them a try, then do your homework, look for legitimate laboratory studies regarding the supplement you intend using, and ALWAYS be skeptical of what supplement companies will have you believe, because as is often the case, the only thing you’ll be getting from them is some nice, expensive urine.

Disclaimer:  I am not a medical doctor, registered nurse, dietician or other healthcare provider. The information I have provided is based on my personal experience and thorough studies on the subject matter. The possible risks of using any nutritional supplement should always be discussed with your doctor. For more information, please see the full Disclaimer page.


1.   William F Ganong MD, ‘Review of Medical Physiology’, 22nd Ed, McGraw Hill, 2005, page 362.

2.   Wallace, M. B.; Lim, J.; Cutler, A.; Bucci, L. (1999). “Effects of dehydroepiandrosterone vs androstenedione supplementation in men”. Medicine and Science in Sports and Exercise 31 (12): 1788–92.

3.   Chang DM, Lan JL, Lin HY, Luo SF. Dehydroepiandrosterone treatment of women with mild-to-moderate systemic lupus erythematosus: a multicenter randomized, double-blind, placebo-controlled trial. Arthritis Rheum. 2002 Nov;46(11):2924-7.

4.   http://www.deadiversion.usdoj.gov/fed_regs/rules/2005/fr1216.htm

5.   Brown, G., Vukovich, M., and King, D.:“Testosterone Prohormone Supplements”, Medicine and Science in Sports and Exercise, 38(8):1451-1461.

6.  Broeder, CE; Quindry, J; Brittingham, K; Panton, L; Thomson, J; Appakondu, S; Breuel, K; Byrd, R et al (2000). “The Andro Project: Physiological and hormonal influences of androstenedione supplementation in men 35 to 65 years old participating in a high-intensity resistance training program”. Archives of internal medicine 160 (20): 3093–104. PMID 11074738.

7.  Brown GA, Vukovich MD, Reifenrath TA, Uhl NL, Parsons KA, Sharp RL, King DS (2000). “Effects of anabolic precursors on serum testosterone concentrations and adaptations to resistance training in young men”. International Journal of Sport Nutrition and Exercise Metabolism 10 (3): 340–59. PMID 10997957.

8.  Brown GA, Vukovich MD, Martini ER, Kohut ML, Franke WD, Jackson DA, King DS (2001).“Endocrine and lipid responses to chronic androstenediol-herbal supplementation in 30 to 58 year old men”. J Am Coll Nutr 20 (5): 520–8. PMID 11601567.

9.  Neychev VK, & Mitev VI. (2005). “The aphrodisiac herb Tribulus terrestris does not influence the androgen production in young men”. Journal of Ethnopharmacology 101 (1-3): 319–23.doi:10.1016/j.jep.2005.05.017. PMID 15994038.

10.  Rogerson S, Riches CJ, Jennings C, Weatherby RP, Meir RA, Marshall-Gradisnik SM. (2007).“The Effect of Five Weeks of Tribulus terrestris Supplementation on Muscle Strength and Body Composition During Preseason Training in Elite Rugby League Players”. The Journal of Strength & Conditioning Research 21 (2): 348–53. doi:10.1519/R-18395.1. PMID 17530942.

11.  Parr, MK; Laudenbach-Leschowsky, U; Höfer, N; Schänzer, W; Diel, P (2009). “Anabolic and androgenic activity of 19-norandrostenedione after oral and subcutaneous administration–analysis of side effects and metabolism”. Toxicology letters 188 (2): 137–41.doi:10.1016/j.toxlet.2009.03.024. PMID 19446246.

12. Mahesh, V.B. and R. B. Greenblatt. The in vivo conversion of dehydroepiandrosterone and androstenedione to testosterone in the human, Acta Endocrinology, Vol. 41 (1962), pp. 400–406.) 

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