Emdabol — thiomesterone

Thiomesterone is an oral anabolic steroid that is derived from testosterone. It is a close chemical cousin of methyltestosterone, although in spite of this association the agent is far more anabolic than it is androgenic in nature. More specifically, standard laboratory assays show that its anabolic potency exceeds its androgenic by a factor of 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. Although these values may vary somewhat with humans, in regards to potency and anabolic/androgenic separation, thiomesterone is still very much in the same class as the popular anabolics stanozolol and oxandrolone. This drug, though scarcely used by athletes, especially in modern, years, was highly valued for its ability to promote lean gains in muscle size and strength without water retention or significant side effects.

Brand name Emdabol, Protabol, Thiomesterone
Androgenic 61
Anabolic 456
Standard Methyltestosterone (oral)
Chemical Names 1,7-bis(acetylthio)-17b-hydroxy-17-
Estrogenic Activity none
Progestational Activity none

Emdabol History

Thiomesterone was first described in 1964. It was developed by E. Merck AG, and presented as a medicine at the 16th German Therapy Congress and Pharmaceutical Exhibition. Merck had given the agent the trivial name thiomesterone (tiomesterone), and would sell it in Germany under the trademark name Emdabol. This steroid was designed for oral administration, and was indicated for all consumptive illnesses and for cachectic states. Essentially, it was applied as a general anabolic substance when weight gain (lean body mass) was necessary due to severe illness or debilitation. Merck described the drug to the public for the first time in 1964, stating, "Its anabolic activity is twice that of methyltestosterone. It has an extremely favorable anabolic/androgenic index and is said to exhibit no gestagenic or mineralocorticoid side-effects."

Following the release of the drug in Germany, thiomesterone would be produced by AB Drago in Sweden, sold as Protabol. Merck would also sell it for a brief time in Spain as Vitabonifen Forte, which was a vitamin preparation that included thiomesterone and other ingredients. Vitabonifen Forte was used to treat a loss of strength with aging, lean body mass wasting, and osteoporosis. This preparation also included bromelains, which are concentrated proteolytic enzymes from the pineapple plant used to help aid the digestion of proteins from whole foods. Outside of Europe, the drug was even more scarcely produced. The only preparation of note was Emdabolin, made by Chugai Labs in Tokyo, Japan. All such thiomesterone preparations have since been removed from commerce, however, and the drug is no longer available to athletes as a commercial product.

Thiomesterone was always more whisper than substance in athletic circles. While available, it saw extremely limited use even by European athletes, due to its very limited supply. It has, likewise, gone practically unseen in the United States. Thirty years ago, American bodybuilders were treated only to rumors of thiomesterone, and how this rare and highly coveted steroid was the holy grail of anabolic steroids. Nobody could obtain a cycle to vary its effect, however, which only further fed the myth. Little was known about the compound in the West at the time; even its chemical structure was elusive. Dan Duchaine mentions 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." Few other books even discussed it at all.

Although there has been little real-world feedback on this steroid over the years to make reference of, there is enough known about its pharmacological properties to paint a more complete picture than we had before. As detailed above, its anabolic and androgenic properties were assayed, and were shown to be quite favorable. Studies published in 1966 also showed that thiomesterone was more effective than equal doses of methyltestosterone, methandrostenolone, or methenolone acetate for blocking the catabolic actions of corticosteroid treatment on bone mass. Still, its effects are consistent with that of other potent anabolic agents, and nothing unusual has been found of note. While thiomesterone may indeed be an effective drug with a low inclination for side effects, it is certainly not the "pure" anabolic agent it was rumored to be thirty years ago. Simply stated, it is a steroid that retains very favorable properties if one is looking for a primarily tissue-building (as opposed to masculinizing) steroid, and would behave in a very similar manner to Anavar (oxandrolone) for most users.

How is Emdabol Supplied

Thiomesterone is no longer available as a prescription agent. When manufactured, it came in the form of an oral tablet.

Structural Characteristics of Emdabol

Thiomesterone is a modified form of testosterone. It differs by 1) the addition of a methyl group at carbon 17-alpha, which helps protect the hormone during oral administration, and 2) the addition of two thioacetyl groups, one at carbon 1 and the other at carbon 7, which inhibit aromatization and 5-alpha reduction and shift the anabolic to androgenic ratio in favor of the former. Thiomesterone has significantly enhanced anabolic potency relative to methyltestosterone, with reduced androgenicity.

Emdabol Side Effects (Estrogenic)

Thiomesterone is not aromatized by the body, and is not measurably estrogenic. An anti-estrogen is not necessary when using this steroid, as gynecomastia should not be a concern even among sensitive individuals. Since estrogen is the usual culprit with water retention, clostebol instead produces a lean, quality look to the physique with no fear of excess subcutaneous fluid retention. This makes it a favorable steroid to use during cutting cycles, when water-and fat retention are major concerns.

Emdabol Side Effects (Androgenic)

Although classified as an anabolic steroid, androgenic side effects are still possible with this substance. This may include bouts of oily skin, acne, and body/facial hair growth. Anabolic/androgenic steroids may also aggravate male pattern hair loss. Women are also warned of the potential virilizing effects of anabolic/androgenic steroids. These may include a deepening of the voice, menstrual irregularities, changes in skin texture, facial hair growth and clitoral enlargement. Additionally, the 5-alpha reductase enzyme does not metabolize thiomesterone, so its relative androgenicity is not affected by finasteride or dutasteride. Note that thiomesterone is a steroid with very low androgenic activity relative to its tissue-building actions, making the threshold for strong androgenic side effects comparably higher than with more androgenic agents such as testosterone, methandrostenolone, or fluoxymesterone.

Emdabol Side Effects (Hepatotoxicity)

Thiomesterone is a cl 7-alpha alkylated compound. This alteration protects the drug from deactivation by the liver, allowing a very high percentage of the drug entry into the bloodstream following oral administration. Cl 7-alpha alkylated anabolic/androgenic steroids can be hepatotoxic. Prolonged or high exposure may result in liver damage. In rare instances life-threatening dysfunction may develop. It is advisable to visit a physician periodically during each cycle to monitor liver function and overall health. Intake of cl 7-alpha alkylated steroids is commonly limited to 6-8 weeks, in an effort to avoid escalating liver strain.

The use of a liver detoxification supplement such as Liver Stabil, Liv-52, or Essentiale Forte is advised while taking any hepatotoxic anabolic/androgenic steroids.

Emdabol Side Effects (Cardiovascular)

Anabolic/androgenic steroids can have deleterious effects on serum cholesterol. This includes a tendency to reduce HDL (good) cholesterol values and increase LDL (bad) cholesterol values, which may shift the HDL to LDL balance in a direction that favors greater risk of arteriosclerosis. The relative impact of an anabolic/androgenic steroid on serum lipids is dependant on the dose, route of administration (oral vs. injectable), type of steroid (aromatizable or non-aromatizable), and level of resistance to hepatic metabolism. Although not extensively studied in humans, the high relative potency and non-aromatizable nature of thiomesterone suggests that this agent is extremely prone to negatively altering lipid values and increasing atherogenic risk.

Anabolic/androgenic steroids may also adversely affect blood pressure and triglycerides, reduce endothelial relaxation, and support left ventricular hypertrophy, all potentially increasing the risk of cardiovascular disease and myocardial infarction.

To help reduce cardiovascular strain it is advised to maintain an active cardiovascular exercise program and minimize the intake of saturated fats, cholesterol, and simple carbohydrates at all times during active AAS administration. Supplementing with fish oils (4 grams per day) and a natural cholesterol/antioxidant formula such as Lipid Stabil or a product with comparable ingredients is also recommended.

Emdabol Side Effects (Testosterone Suppression)

All anabolic/androgenic steroids when taken in doses sufficient to promote muscle gain are expected to suppress endogenous testosterone production. Without the intervention of testosterone-stimulating substances, testosterone levels should return to normal within 1-4 months of drug secession. Note that prolonged hypogonadotrophic hypogonadism can develop secondary to steroid abuse, necessitating medical intervention.

Emdabol Administration (General)

Prescribing guidelines generally advise that oral steroids can be taken with or without meals. The difference in bioavailability is generally not regarded as substantial. However, a 2016 study on newborn infants did find the absorption of oxandrolone to be significantly improved when dissolved directly in fat (MCT oil). If the diet includes considerable fat content, taking this oral steroid with meals might be more advantageous.

Emdabol Administration (Men)

Effective doses for physique- or performance-enhancing purposes fall in the range of 15-25 mg per day, taken for no more than 6-8 weeks to minimize hepatic stress. Here, one is likely to see measurable lean tissue gains, modest strength increases, greater muscle definition, and > heightened vascularity. 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. The fact that estrogen levels will be kept low makes this agent very favorable when it comes to tightening up or contest preparations. Its low androgenic and estrogenic components, however, may put many of this drug's more sensitive users at risk for incurring a loss of libido and even lethargic side effects. This is often corrected by the addition of some other aromatizable or more androgenic compound (testosterone would be the preferred remedy).

Emdabol Administration (Women)

Effective doses for physique- or performance-enhancing purposes fall in the range of 5 mg per day or less,taken for no longer than 4-6 weeks to minimize the chance for virilizing side effects. Note that while thiomesterone is highly anabolic relative to its androgenic properties, side effects are still possible, and should be carefully monitored.

Emdabol Availability

Thiomesterone is no longer available as a prescription agent.


Wlliam Llewellyn (2017) - Anabolics

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