Methosarb — calusterone

Calusterone is an oral androgen structurally related to methyltestosterone. It differs only by the addition of a methyl group at C-7 beta, which studies have shown eliminates or considerably reduces steroid (anabolic/androgenic) activity. The drug was developed as a less-toxic alternative to other androgens used for breast cancer, such as testosterone propionate and fluoxymesterone, which tend to induce strong virilizing side effects in women. What was produced was a steroid with minimal anabolic effect and low to moderate androgenic activity, far removed from its 7-alpha isomer cousin (bolasterone) in overall appearance. Although technically an androgen with some inherent value as such, calusterone has never been popular with athletes, and likely has very little to offer when compared with numerous other commercial anabolic agents.

Brand name Methosarb, Riedemil, Calusterone
Androgenic 20
Anabolic no data available
Standard Testosterone
Chemical Names 17beta-Hydroxy-7beta,17-dimethylandrost-4-en-3-one
Estrogenic Activity no data available
Progestational Activity no data available

Methosarb History

Calusterone was first described in 1959. It was FDA approved for sale in the U.S. as a prescription drug product in 1973. It was developed into a medicine by The Upjohn Company, and sold under the Methosarb brand name. It was reportedly also sold in other (limited) drug markets as Riedemil. Calusterone was indicated for the treatment of advanced inoperable or metastatic breast cancer in postmenopausal women or those that have had their ovarian function terminated as a course of therapy. According to early product literature, the drug was effective in approximately 25% of patients receiving it, provided that they met a series of criteria for therapy first. The drug was also investigated successfully in men with breast cancer, a rare but not unseen occurrence. Aside from its actions relating to breast cancer in women, calusterone was not FDA approved for use in any other forms of treatment, as an anabolic agent or otherwise.

When calusterone was first introduced, it was described as an improved synthetic androgen for breast cancer treatment, with increased therapeutic potential and reduced toxicity compared to testosterone. It was believed that the molecule had been modified in such as way as to eliminate many of its undesirable traits. Ultimately, these notions were poorly supported by medical investigations, and the drug seemed to perform with a comparable level of efficacy, and similar side effects, to other forms of androgen therapy. Calusterone was voluntarily removed from the U.S. drug market by the 1980's, and was officially removed from the FDA's list of therapeutic substances in 2001 at the request of Pharmacia & Upjohn. The drug remains unavailable today worldwide.

How is Methosarb Supplied

Calusterone is no longer available as a prescription drug product. When manufactured, it came in the form of a 50 mg tablet.

Structural Characteristics of Methosarb

Calusterone is a modified form oftestosterone. lt differs by 1) the addition of a methyl group at carbon 17-alpha, which helps protect the hormone during oral administration, and 2) the introduction of a methyl group at carbon 7 (beta), which significantly reduces its relative biological activity.

Methosarb Side Effects (Estrogenic)

Calusterone is not described as a steroid with significant estrogenic activity. Studies have demonstrated that this agent actually reduces the binding capacity of estrogen to its corresponding receptor. It may, likewise, offer some level of anti-estrogenic effect.

Methosarb Side Effects (Androgenic)

Calusterone is classified as an androgen. Androgenic side effects are common with this substance, and may include bouts of oily skin, acne, and body/facial hair growth. Anabolic/androgenic steroids may also aggravate male pattern hair loss. Those genetically prone to male pattern hair loss may wish to opt for a milder, less androgenic, anabolic steroid. Women are additionally 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.

Methosarb Side Effects (Hepatotoxicity)

Calusterone 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. Studies administering 200 mg per day for at least 3 months have demonstrated increased sulfobromophthalein (BSP) retention, a marker of hepatic stress, in approximately one third of patients.

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.

Methosarb 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. Calusterone is expected to have a strong effect on the hepatic management of cholesterol due to its structural resistance to liver breakdown and route of administration. 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.

Methosarb 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.

Methosarb 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.

Methosarb Administration (Men)

Calusterone was not FDA-approved for use in men, although clinical studies with the drug tended to use comparable doses as women. Effective doses for physique- or performance-enhancing purposes have not been determined, but would likely fall in the range of 100-200 mg per day. Note that this drug is not strongly anabolic, and does not offer high value as a musclebuilding substance.

Methosarb Administration (Women)

Calusterone was most commonly used in a clinical dose of 200 mg per day, taken for at least 3 consecutive months. Doses of 150-300 mg per day have also been used. Note that at the recommended therapeutic dose, mild to moderate virilizing side effects, including deepening of the voice, acne, and facial hair growth, occurred in up to 25% of patients. This drug is generally not recommended for women for physique- or performance-enhancing purposes due to its weak anabolic and stronger androgenic nature.

Methosarb Availability

Calusterone is no longer produced as a prescription drug, and is unavailable on the black market.


Wlliam Llewellyn (2017) - Anabolics

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