Prohormones - A Comprehensive Guide to Prohormones - Updated

Technical Definition

Prohormones are compounds which are converted via an enzymatic process to anabolic hormones in the body. As such they will cause similar effects in the body to anabolic steroids, inducing rapid muscle and strength gains, but of a lesser magnitude than anabolic steroids, due to the rate limiting effect caused by the enzyme conversion. However, this technical definition is nowadays considered out of date due to the innovation displayed in the supplement industry since the introduction of the very first prohormone, androstenedione. Today the term prohormones is used to cover not just precursors to steroid hormones but also covers compounds which are active in their own right and which require no conversion to a different hormone to engender any anabolic effects. For the sake of simplicty, in this article the term 'prohormone' will cover all products which work via a hormonal mechanism to cause anabolic effects, and not just those which convert from one compound into another after ingestion.


First Base

Prohormones were introduced on to the supplement world in 1996 by reknowned US chemist Patrick Arnold who developed the supplement androstenedione and unleashed it on an unsuspecting public.

Androstenedione certainly created a buzz in the sports world and is heavily linked in the popular press with baseball greats such as Mark McGwire whose use of the supplement was brought to light as he chased the baseball home run record in 1998. In breaking the record that year McGwire brought notoriety both to that sport and captured the attention of law makers in the United States.

Androstenedione was quickly followed by a number of other supplements ? androstenediol, norandrostenediol, 1-4-androstadienedione and 5 alpha androstenediol to name just a few. These all had different effects, some being converted to testosterone in the body, while others were converted in the body to anabolic hormones such as nandrolone, boldenone, and dihydrotestosterone (DHT). We still see precursors to some of these products on the bodybuilding market today, such as I Force Nutrition's BOLD 200 product which is a precursor to Boldenone which is the generic term for the steroid Equipoise.

After some time, Patrick Arnold's company Ergopharm introduced the prohormone 1-AD, which converted into a hormone called 1-testosterone. This was the first prohormone considered to be of comparable effectiveness to illegal steroids such as Winstrol or Primobolan. In fact at the time of its introduction much was made of the fact that it was qualitatively similar to the steroid Trenbolone Acetate.

With the introduction of 1-AD, prohormones had clearly progressed in leaps and bounds since the introduction of androstenedione (widely considered within bodybuilding to be pretty worthless by that time). With the introduction of 1-AD, the prohormone market changed dramatically. A number of supplement companies, aware that the process of enzymatic conversion meant that prohormones were weaker than taking an equivalent amount of the target hormone they converted into, decided to market products such as 1-testosterone (the hormone which 1-AD would convert to) and, eventually, the now notorious methyl-1-testosterone (M1T), which was a 17-alpha alkylated or methylated hormone. In simple terms, 17-Alpha Alkylation/Methylation meant that M1T was highly resistant to breakdown by the liver, making it the most powerful product on the market, causing rapid strength and muscle gains even for long-time steroid users, as well as causing a host of disastrous side effects such as high blood pressure, and dangerous elevation of liver enzymes.


The End of the Beginning

Many in the supplement industry, Arnold among them, argued that the proliferation of powerful products such as M1T would eventually result in negative publicity to attach itself to the supplement industry as a whole and considered it madness that such products had been introduced on to the supplement market. These doomsayers were proven right and eventually the US congress passed into law the Anabolic Steroid Control Act of 2004 which effectively classed all the prohormones then on the market as illegal drugs on a par with anabolic steroids. By early 2005 they had been removed from the market in the United States.


Prohormone Characteristics

A rundown of the actions of individual prohormone products follows so this section shall only cover actions attributable to all classes of prohormone products. This in itself could be an article in its own right so here is the shortened version.

Prohormones exert their effects through several different pathways, but the ones that are most important to people considering using them are their actions via their effects on the body's androgenic, estrogenic and progestogenic receptors. It is through these receptors that prohormone effects are largely mediated, with other pathways of secondary importance.

Prohormones, just like anabolic steroids, are androgen agonists meaning they work via their effect on the androgen receptor. A strong androgen receptor agonist will mean effects related to the male hormone testosterone will be particularly prominent ? these include increased aggression, sex drive, alpha male type characteristics in general, as well as heightened risk of side effects related to high androgen levels such as an increased susceptibility to hair loss and acne, although these side effects are very much individual in nature and will depend on the person taking them. They tend to only be an issue for those already susceptible to these conditions.

Linked to these androgenic effects is the propensity for prohormones to induce sizeable increases in muscle strength, large muscle gains, and a hardening effect on the muscles, such that muscles feel denser and more solid. Prohormones that do not convert to estrogen such as Epistane or RPN's Havoc tend to exhibit these types of muscle gains with no water retention.

Away from their effects on androgren receptors, prohormones can also cause effects via estrogen and progesterone receptors. These effects tend to be quite similar in nature ? prohormones that convert to estrogen and progesterone have the baility to cause large increases in mass and strength although much of the mass is of a poor quality visually and such gains often disappear rapidly being associated with water retention more than anything else. Estrogenic side effects are feared by most bodybuilders and include increased water weight, increased susceptibility to fat gain in the presence of high estrogen and worst of all, from a cosmetic standpoint at least, the dreaded gynecomastia.

It should be stated that while there are some products which are almost exclusively androgenic in nature with little to no risk of estrogenic/progestogenic side effects (such as Epistane or Havoc), the reverse is not true, in that compounds with high affinity for estrogen and progesterone receptors will still have an impact on the androgen receptor. You will often hear of prohormones being called androgenic or estrogenic or even both, but it should be stated this is often based on their primary method of action and that allwill have an androgenic effect at some level, as they all primarily work via their effect on the androgen receptor.

Separate from their effects via androgen, estrogen, and progesterone receptors, prohormones will also differ in their impact on other body systems. Typically, strong androgens are useful for promoting strength gains via the central nervous system (CNS) stimulation, independent of their anabolic or muscle building effects. A strong androgen would often be something similar in nature to Dihydrotestosterone. Furthermore, prohormones will promote enhanced red blood cell production which is why users of prohormones usually experience great pumps and vascularity. Generally speaking, liver toxicity is a concern only for methylated, oral compounds, which is most prohormones nowadays but even then, as the list below shows, they can differ by a wide degree in magnitude of effect.


Prohormones Today

Since the removal of the first generation of prohormones in 2005, various supplement companies have worked hard on creating products which can provide a sizeable anabolic effect while complying with the requirements of the 2004 law. One of the most important considerations was to ensure that not only did they manufacture a product that was effective and legal, but also safe, as the wave of methylated prohormones released in the wake of M1T were certainly of doubtful safety given their widely noted negative effects on a range of body tissues, most notably liver values.

As a result of the innovations in the industry since 2005, we now have a number of products on the market which have been around for some time and in favour with bodybuilders and athletes alike. To make things easy we will refer to the compounds by their brand names:

Halodrol- 50(4-chloro-17a-methyl-1,4-diene-3,17 diol)

Halodrol-50 was introduced to the bodybuilding world by Gaspari Nutrition and is a prosteroid of Turinabol, the banned East German designer steroid. This means it converts to Turinabol once ingested. Although Halodrol is no longer available, there are generic equivalents today such as Fusion Supplements' Halodrol. The typical dose for products such as Halodrol is 50mg a day, which equates to one tablet daily.

Effects: Solid gains in muscle and strength, often taken while dieting to aid preservation of muscle mass.

Side effects: Considered stressful on the liver and can raise blood pressure somewhat in users.



RPN's product Havoc and IBE's Epistane were introduced at practically the same time and considered interchangeable by many. However, it should be noted that even when two products are identical, users can experience different effects depending on the quality of the isomer, manufacturing process and so on.

With Havoc and Epistane they are listed very slightly different 2a,3a-epithio-17a-methyl-5a-androstan-17b-ol 2 (Havoc), and 2, 3a-epithio-17a-methyletioallo cholan-17b-ol (Epistane). Dosages are usually in the 20-50mg range.

Effects: Good for promoting solid, lean muscle gains with a concomitant reduction in estrogen leading to a drier physique, and significant strength gains. This will contribute to the vascularity users typically report. Havoc and Epistane are also sometimes used purely to combat gynecomastia as they act in the body as an anti-estrogen, so that endogenous testosterone levels are less suppressed by this compound than other prohormones.

Side effects: Less hepatoxic and damaging to lipid levels than other orals but the usual androgenic side effects associated with prohormones remain a possibility.


Delta 2 (Delta-2 Androstenone)

Trials on male subjects have revealed that dosages of 150-300 mg a day are effective, with particularly profound results being seen at 450-600 mg a day. This product produces relatively dry gains and shows a remarkable lack of side effect. It is three times as anabolic as it is androgenic.

Effects: Delta 2 users should expect steady, consistent gains in lean body mass which should be easy to maintain. As a non-methylated compound, Delta 2 is an excellent choice for stacking or for using for those wanting to avoid liver toxicity issues.

Side Effects: There is a low risk of side effects with Delta 2 but as with any prohormone there remains a possibility for some androgenic side effects.


Estrabolan: (Estra-4,9-diene-3,17-dione)

Sold by a number of different brands Estrabolan is Brinkwelton Pharma's version of this compound. This product has Dienolone as a target hormone and is non-methylated, making it safer on the liver and an excellent choice as part of a prohormone stack.

Effects: Estrabolan is well suited to athletes looking for muscle gains with an increase in vascularity and strength that are compared as qualitatively similar to the compound Trenbolone. It is a noted lean mass builder.

Side Effects: Tren products can negatively impact upon libido in some people.


Trenazone: (17 hydroxyestra-4,9-dien-3-one)

While Estrabolan is a prohormone to Dienolone, there are now products available such as Trenazone which provide Dienolone itself which by bypassing the need for enzymatic conversion make them more powerful than Estrabolan or similar products which require conversion. Otherwise, Dienolone supplements share similar characteristics as Tren supplements but are more potent so will provide greater muscle and strength gains.

Effects: Rapid gain in muscle and strength without any estrogenic side effects as Dienolone does not convert to estrogen. Trenazone, being a topical supplement will lead to an even greater gain in size and strength than comparable oral versions of dienolone.

Side Effects: Similar to the case for Estrabolan, dienolone products can be quite suppressive on testosterone so a thorough PCT is highly recommended.


Ultradrol: (2,17a-dimethyl-5a-androsta-1-en-17▀-ol-3-one)

Ultradrol (replaced by Nanodrol) is by some distance the most potent prohormone ever released. Nanodrol is renowned for producing massive gains in strength, muscle mass, and being an active compound does not require any enzymatic conversion.

Effects: Huge strength and mass gains in a short time as well as notable repartitioning benefits which means many Nanodrol users experience a considerable degree of fat loss along with their lean body mass gains. Resistance to metabolic breakdown further potentiates the positive effects of Nanodrol.

Side Effects: Notably liver toxic and suppressive, Ultradrol is only for users with multiple prohormone cycles under their belt already.


Cynostane: (2-cyano-17a-methyl-17b-hydroxy-androst-3-one - 10mg)

Cynostane is a brand new prohormone which features an alteration of the superdrol compound, with a cyano bond instead of the 2a methyl superdrol bond.

Effects: Cynostane, developed by Anabolic Innovations, is an extremely anabolic compound with remarkably low androgenic action, making it qualitatively similar to the likes of Oxandrolone or Methenolone (Primobolan). It is non-aromatizing meaning it will not produce estrogen mediated side effects and its high degree of anabolic action makes it a favourable choice for athletes concerned with losing bodyfat while maintaining, or increasing, muscle mass. From feedback to date, Cynostane has very potent recomposition effects making it ideal for athletes and when dieting. If using to bulk up, calories would need to be increased considerably.

Side Effects: Bloodwork conducted by users shows that Cynostane has a more favourable effect on blood lipids, and liver values than superdrol itself. Although feedback to date is limited, the combination of low androgenic action, lack of aromatization to estrogen, and low level of general health effects, makes cynostane an intriguing newcomer to the prohormone world.

For more on Cynostane check out this article.



Protodrol was introduced by I Force Nutrition, designed to be a less toxic compound than some of the older prohormones on the market. Daily dosage is 50-75mg a day.

Effects: Protodrol is considered to be a potent mass builder, with a low incidence of side effects being very favourable on both liver and lipid profiles. As it does not convert to estrogen, Protodrol will impart muscle and strength gains with an absence of water retention. As such it is a very versatile compound which can be used for both bulking, recompositioning and dieting.

Side Effects: Protodrol was designed specifically to provide a bulking compound with a low risk of side effects so the only side effects you could expect to have would be those associated with all prohormone products.



Superdrol was introduced by Designer Supplements, the old name for Driven Sports, and earned a reputation as a very powerful product. Although it is no longer made by Driven Sports, Fusion Supplements currently produce a clone called Methdrol.

Effects: Good lean mass gainer with effective repartitioning effects.

Side Effects: Notably hepatoxic, and androgenic. Can aggravate hairloss if prone to male pattern baldness. Highly recommended to stack this product with a product from our Liver Support category to help support healthy liver function.


 Discontinued Prohormones


The following prohormones are no longer manufactured and there are no legitimate versions of these remaining on sale. We have still listed them for educational purposes.


Pheraplex was a brand name of the supplement company Anabolic Xtreme (AX). This product is also sold by Competitive Edge Labs as P-Plex as well as Phera-Vol by EST. Typically dosed at 20-30mg a day.

Effects: Gains with this product tend to be of a 'wet' nature, in other words, you will see some weight gain due to water retention. Given this, P-Plex is often used to gain mass quickly for users.

Side effects: It is a risk for anyone with gynecomastia based on user feedback (making the use of an estrogen blocker such as Reversitol or Novedex XT mandatory), and is considered to be both hepatoxic and damaging to lipid levels.



This product was brought to the market by Bioscience Technologies and is usually dosed at 6-12mg to see results.

Effects: Not a strong bulking product unless doses are pushed high despite its androgenic profile. In this respect it is not dissimilar to AAS such as Masteron and Proviron which are not efficient for bulking.

Side effects: Androgenic side effects such as hair loss are reported quite frequently by users if this product, and many users report a damaging effect on libido.


Ergomax LMG(17-methyl-delta-2-etioallocholane & 17-methyl-delta-3-etioallocholane)

Introduced by ALRI, this is another 'wet' prohormone dosed at 20-40mg usually.

Effects: This compound is quite similar to Pheraplex so is useful for someone wanting to gain mass quickly even if the visual appearance of this will not be the best.

Side effects: Can cause gynecomastia making use of an estrogen blocker a wise option, and has a detrimental effect on liver and lipid values, meaning cycles should be kept short.


11-Oxo(andrenosterone, 11-oxo-androstenedione)

11-Oxo was introduced by Ergopharm, whose owner Patrick Arnold first brought prohormones to the bodybuilding world. 11-Oxo is well regarded for its ability to lower cortisol levels. It is dosed at between 300-600mg a day with 450mg typical.

Effects: Used mainly as a recomposition agent and to promote fat loss, 11-OXO is also a good choice for individuals looking to stack one prohormone with another.

Side effects: Although it can cause the same side effects as other prohormones, it is considered very mild in this regard so a good choice for people looking to diet with minimal side effects.


Propadrol(12-ethyl-3-methoxy-gona-diene / 6-17 dihydroxyetiocholove-3-ol proponate)

This was developed by EST Nutrition and is usually dosed at 90mg a day.

Effects: Noted to be good for reducing body fat and for promoting rapid strength and muscle gains.

Side effects: Relatively mild with this compound, although those who worry about gyno or androgenic side effects should exercise caution. Tends to be expensive!



ALRI introduced this compound and it is dosed at 3-6mg by most users.

Effects: Reviews are mixed on this product but those who do like it often claim very good muscle and strength gains allied to a reduction in body fat.

Side effects: Being both quite androgenic and estrogenic it should be used with caution and remedies to combat hair loss and gyno. Reversitol is worth considering.


Max LMG(13-ethyl-3methoxygona-2, 5(10)-dien-17-one)

Yet another product by ALRI. This one is usually dosed at around 100mg a day.

Effects: Max LMG can cause rapid gains in bulk of a wet nature due to its progestogenic nature. Great for those needing fast weight gain and unconcerned about looking smooth or fat.

Side effects: One to avoid for anyone worried about a quality looking physique, gynecomastia, or hair loss. This is also very expensive! Reversitol is definitelty a smart move to combat estrogenic effects if using Max LMG.


3-AD(2-androstenol acetate)

Anabolic Xtreme formulated this product and brought it on to the bodybuilding market. Usually dosed at around 4-6 capsules a day, 3-AD contains various other nutrients, but the active prohormone is 2-androstenol acetate.

Effects: Effective overall mass gainer. Gains are a little wet, but not too bad for those worried about estrogen.

Side effects: It is not the worst, but estrogenic and androgenic side effects remain a possibility.


Dymethazine- (2,17-dimethyl-5-androstan-17-ol-3,3'-azine)

Dymethazine, also known as Dimethazine, is a DHT derived compound with an interesting chemical structure. It is essentially a double bonded Superdrol, with an Azine bridge. A relatively recent introduction to the prohormone world by I Force Nutrition, Dymethazine is a product that has attracted a great deal of interest given its unique chemical structure.

Effects: Users of this compound reported similar effects to those seen in Superdrol.

Side Effects: Although not having any estrogenic action, Dymethazine use poses the same issue of liver toxicity and androgenic effects as other prohormones.

The One: (17a-methyl-etioallocholan-17b-ol-3-hydroxyimine)

The One was developed by Applied Nutriceuticals and is a prohormone of Dihydrotestosterone.

Effects: Being a prohormone to DHT, The One can be expected to be notably androgenic, resulting in dry, muscle gains with an absence of water retention and solid gains in strength.

Side Effects: Being that it converts into DHT, The One can be expected to be tough on the hairline as DHT is the hormone most responsible for hair loss. As it does not convert to estrogen or progesterone, side effects related to those should not be an issue. Liver toxicity would remain a concernthough and it would be a good idea to take this product with something to support health liver function.


Furazadrol: (5a-androstano(2,3-c) furazan-17b-tetrahydropyranol ether - 50mg)

Furazadrol was developed by Axis Labs as an alternative to methylated prohormones such as Havoc or Dymethazine. As a non-methylated compound it will appeal on the grounds of being very safe and is often used by beginners new to prohormones either alone or in a stack with Bold 200.

Effects: Furazadrol has a high anabolic to androgenic ration meaning muscle gains with low risk of androgenic side effects. It does not convert to estrogen meaning gains will be lean in nature, with an absence of water retention.

Side Effects: Although the risk of side effects is low, it is usually required to be dosed in dosages of 200-400mg a day making it quite expensive. Given its otherwise favourable profile it makes an excellent choice for someone looking to stack with another prohormones.


What is best for me?

So here we come to the part where readers ask 'which is the best prohormone to take and when?' It is not possible, nor advisable, to offer specific advice on such a subject. People need to consider their own objectives and risk factors before taking any prohormone. Generally speaking, all we can say is that it is advisable to start with a mild steroid first and keep doses low, typically for 3-4 weeks. For a novice this will still lead to excellent gains. It is critical in our opinion, that an estrogen blocking product should be held ready at the start of a prohormone cycle. Users unworried about estrogen can take it for 3-4 weeks after the end of their cycle. Those concerned about estrogen, should employ it both during and after. In this respect, Havoc and Epistane make good choices as they negate the need for an anti-estrogen during the cycle, due to the fact they are inherently anti-estrogenic. Still, even with them, an estrogen blocker should be applied after all cycles with prohormones.


Dietary and Supplement Advice

Assuming a good clean diet is eaten, normally the only advice we would recommend is to increase protein intake to at least 2g of protein per pound of bodyweight. So for a 200lb individual, 400g of protein a day. Given the fact prohormones are all oral in nature, we recommend increasing water intake also and employing the use of a liver protectant such as silymarin and N-acetyl cysteine, along with fish oil dosed at 6g a day. Those who are particularly anal may want to consider taking their prohormones with grapefruit juice. In theory, this will help increase their gains via inhibition of enzymes that break down drugs leading to enhanced absorption.


Training Advice

Given the fact you are taking a powerful prohormone which will rapidly boost muscle mass, training volume should be increased but we recommend limiting the increase in weights. Instead, after your cycle has concluded, given the catabolic environment present post cycle, it is an excellent time to reduce volume and increase the weight which will help preserve your muscle and strength gains whilst keeping cortisol (a hormone indicated in the breaking down of muscle) levels low. A good rule of thumb is to double your normal training volume on cycle and then reducing it to a half of your normal training volume in the first few weeks post cycle while your body gets back to a homeostatic state (normal hormonal environment). So, if you do 10 sets a session normally, go to 20 on prohormones, and then reduce to 5 until your post cycle estrogen blocker has finished its job.



Prohormones are powerful compounds with the ability to impart significant gains in muscle and strength mass. We hope this article has provided some useful information for you to help understand their benefits, applications and how to structure their use within your overall training and dietary plan.

Author: Reggie Johal

Reggie Johal


Reggie Johal is a former Great Britain American Football player with a background in strength and fitness coaching with articles published in many leading online and print magazines including Muscle and Fitness. Reggie is the founder of Predator Nutrition.


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