Protabol (thiomesterone) is an oral anabolic steroid that is derived from methyltestosterone. This drug was sold back in the 1960's by AB Drago in Sweden, and under the Emdabolin brand name by Chugai Labs in Tokyo Japan. It saw an extremely limited period of use in Europe, and has gone practically unseen in the United States. Thirty years ago American athletes were treated to rumors of thiomesterone, and how this rare and highly coveted steroid was the holy grail of anabolics. The problem is, nobody could obtain a cycle to verify its effect. Little was even known about the compound itself. To date I have never even seen its chemical structure disclosed in any of the bodybuilder's steroid reference books. Dan Duchaine made the single note of this steroid I could find, and wrote of it in his Underground Steroid Handbook II only, "This is the elusive thiomesterone,always written up in the research as the most promising, most potent anabolic with no androgenic side effects. Let me know if you ever find any."
Although there is no real-world feedback on this steroid to make reference of, it was possible to locate its chemical structure and some basic research into its pharmacological properties. We have enough to look at now to say that thiomesterone is certainly no magic steroid, however it does indeed appear to display very favorable properties. Despite being a derivative of the potent oral methyltestosterone, thiomesterone is far more anabolic than it is androgenic. In fact, standard laboratory assays show that its anabolic potency exceeds its androgenic by a factor 7.5. Milligram for milligram it is also about 4.5 times more anabolic than methyltestosterone, while having only about 60% of its androgenic component. Perhaps not quite the "pure" anabolic that it was rumored to be thirty years ago, in regards to potency and anabolic/androgenic separation, thiomesterone is still very much in the same class as the popular anabolics stanozolol and oxandrolone.
As mentioned, thiomesterone is a derivative of methyltestosterone. It differs from this base steroid by the addition of two acetylthio groups, one at carbon 1 and the other at carbon 7.This creates a hormone with significantly different behavior than methyltestosterone. For one, occupation of a bond at C-1 by the first acetylthio group prevents aromatization. This eliminates any tendency for estrogen-linked side effects like water retention, increased fat deposition and gynecomastia. The second acetylthio modification at C7,furthermore, inhibits 5-alpha reduction. As this is a testosterone analog, one would expect its 5-alpha reduced "dihydro" metabolite to be significantly stronger.This accounts for the stronger androgenic activity of testosterone-based drugs in general. No such increase in potency is possible with thiomesterone, however. The C7 acetylthio group contributes, at a very significant level, to the high anabolic to androgenic ratio of this agent.
Since thiomesterone has a similar level of anabolic potency to stanozolol and oxandrolone, we would expect that oral effective daily dosages for men would fall in the range of 15-25mg. Here we should see effective lean tissue gains, modest strength gains, increased muscle definition and heightened vascularity.The fact that estrogen levels will be kept low definitely helps this agent when it comes to tightening up or contest preparations.Thiomesterone is a very versatile steroid in general, and should stack well with other mild injectable anabolics like Primobolan or Deca-Durabolin for cutting cycles, or stronger androgens/aromatizable steroids like testosterone or boldenone for bulking phases. Being that this steroid is a c-17 alpha alkylated (methylated) compound, it will present some level of liver toxicity. It would therefore be best not to stack it with other c-17aa orals, so that this toxicity is kept to a minimum.
Thiomesterone is a steroid of low androgenic side effects. Sensitive individuals would probably notice some oily skin or acne, but should not be responding with heightened aggression and mood elevations the same way they would with something stronger like testosterone or Dianabol. It might also be one of the few orals that those worried about hair loss might experiment with in low doses. Its low androgenic and estrogenic component may put many of this drug's more sensitive users at risk for incurring a loss of libido and even lethargic side effects, however. This would be readily corrected by the addition of some other aromatizable or more androgenic compound (testosterone would be the preferred remedy). One might want to be prepared by having some on hand. As a highly anabolic agent, thiomesterone would also be a preferred agent among women, and would be used in a versatile manner very similar to Primobolan or Anavar. Doses would be kept low, of course, and would probably not exceed 5mg per day.
It is unfortunate that thiomesterone is not a steroid we have available on the global steroid market today.With its exceptional profile and high level of potency, it certainly would be a popular product if it were. Things have been changing rapidly in the steroid business though, and if current trends continue we may very well see this steroid again. Many companies are searching out old steroids in an effort to provide their customers something new. For now, at the very least, we can say it is no longer an agent of myth and legend. We have pulled back the curtain, and seen thiomesterone for the steroid that it is. It is nothing magic, but an excellent steroid nonetheless. Even if it is not possible to put this information to practical use right now, I suspect many readers will still find this profile of interest as rare look into a very poorly known and understood drug. Perhaps it may even spark an interest in the right person, who will be responsible for resurrecting thiomesterone one day. We can hope, anyway.