Methyltestosterone is or has been used in the treatment of delayed puberty, hypogonadism, cryptorchidism, and erectile dysfunction in males, and in low doses to treat menopausal symptoms, postpartumbreast pain and engorgement, and breast cancer in women. It is specifically approved in the United States for the treatment of hypogonadism and delayed puberty in males and the treatment of advanced inoperable breast cancer in females. It was also approved in low doses in combination with esterified estrogens for the treatment of moderate to severe vasomotor symptoms associated with menopause in women in the United States, but this formulation was discontinued and hence is no longer used. Methyltestosterone is less effective in inducing masculinization than testosterone, but is useful for maintaining established masculinization in adults. The dosages of methyltestosterone used are 10 to 50 mg/day in men for common medical uses like hypogonadism and delayed puberty as well as physique- and performance-enhancing purposes and 2.5 mg/day in women for menopausal symptoms. Higher dosages of 50 to 200 mg/day have been used to treat women with inoperable breast cancer that has failed to respond to other therapies, although such dosages are associated with severe irreversible virilization.
Non-medical
Methyltestosterone is used for physique- and performance-enhancing purposes by competitive athletes, bodybuilders, and powerlifters, although it is not commonly used relative to other AAS for such purposes.
Methyltestosterone should be used with caution in women and children, as it can cause irreversible virilization. Due to its estrogenicity, methyltestosterone can also accelerate epiphyseal closure and thereby produce short stature in children and adolescents. It can worsen symptoms in men with benign prostatic hyperplasia. Methyltestosterone should not be used in men with prostate cancer, as androgens can accelerate tumor progression. The drug should be used with caution in patients with pre-existing hepatotoxicity, due to its own potential for hepatotoxicity.
s can be used to reduce or prevent the estrogenic effects of methyltestosterone and 5α-reductase inhibitors can be used to prevent its potentiation in so-called "androgenic" tissues and thereby improve its ratio of anabolic to androgenic activity and reduce its rate of androgenic side effects. Antiandrogens like bicalutamide and cyproterone acetate can block both the anabolic and androgenic effects of AAS like methyltestosterone.
Pharmacology
Pharmacodynamics
As an AAS, methyltestosterone is an agonist of the androgen receptor, similarly to androgens like testosterone and dihydrotestosterone. It is a substrate for 5α-reductase like testosterone, and so is potentiated analogously in so-called "androgenic" tissues like the skin, hair follicles, and prostate gland via transformation into the more potent AR agonist mestanolone. As such, methyltestosterone has a relatively low ratio of anabolic to androgenic activity, with a similar ratio to that of testosterone, and this makes it among the most androgenic AAS. Due to efficient aromatization into the potent and metabolism-resistantestrogenmethylestradiol, methyltestosterone has relatively high estrogenicity and hence potential for estrogenic side effects such as gynecomastia and fluid retention. The drug possesses negligible progestogenic activity. Due to its combined disadvantages of a relatively poor ratio of anabolic to androgenic activity, unusually high estrogenicity, and the potential for hepatotoxicity, methyltestosterone has not been used as commonly as many other AAS either in medicine or for physique- or performance-enhancing purposes.
Pharmacokinetics
Absorption
Methyltestosterone has dramatically improved oral bioavailability and metabolic stability relative to testosterone. This difference is due to the C17α methyl group, which results in steric hindrance and prevents metabolism. The oral bioavailability of methyltestosterone is about 70%, and it is well-absorbed from the gastrointestinal tract. Methyltestosterone can also be taken buccally or sublingually. Although effective orally, methyltestosterone is more effective by these non-oral routes, which are said to approximately double its bioavailability and require half the oral dosage. Circulating levels of methyltestosterone with administration of 1.25 to 2.5 mg/day oral methyltestosterone in women are in the range of 20 to 30 ng/dL. For comparison to testosterone, methyltestosterone is at least as potent as an AAS. However, due to the large decrease in sex hormone-binding globulin levels and hence increase in free unbound testosterone caused by methyltestosterone, androgenic effects may be greater than reflected merely by methyltestosterone levels.
Distribution
Methyltestosterone is highly protein-bound, by approximately 98%. The medication has low but significant affinity for human serum sex hormone-binding globulin, about 25% of that of testosterone and 5% of that of DHT.
Metabolism
The biological half-life of methyltestosterone is approximately 3 hours. The duration of action of methyltestosterone is said to be 1 to 3 days, and is described as relatively short among AAS.
Excretion
Methyltestosterone is excreted 90% in the urine as conjugates and other metabolites, and 6% in feces.
Chemistry
Methyltestosterone, also known as 17α-methyltestosterone or as 17α-methylandrost-4-en-17β-ol-3-one, is a synthetic, 17α-alkylatedandrostane steroid and a derivative of testosterone differing from it only in the presence of a methyl group at the C17α position. Close synthetic relatives of methyltestosterone include metandienone and fluoxymesterone.
Methyltestosterone was first synthesized in 1935 along with methandriol and mestanolone. It was the second synthetic AAS to be developed, following mesterolone in 1934, and was the first 17α-alkylated AAS to be synthesized. The drug was introduced for medical use in 1936.
Society and culture
Generic names
Methyltestosterone is the,,,, and of the drug and its generic name in English and Japanese, while méthyltestostérone is its and French name and metiltestosterone is its and Italian name. The generic name of the drug is methyltestosterone in Latin, methyltestosteron in German, and metiltestosterona in Spanish. Methyltestosterone is also known by its former developmental code name NSC-9701.
Brand names
Brand names under which methyltestosterone is or has been marketed for medical use include Afro, Agovirin, Android, Androral, Mesteron, Metandren, Methitest, Methyltestosterone, Methyl Testosterone, Oraviron, Oreton, Oreton Methyl, Testormon, Testovis, Testred, and Virilon, among others.
With an estrogen
Methyltestosterone is available at a low-dose in combination with esterified estrogens for the treatment of menopausal symptoms like hot flashes in women under the brand names Covaryx, Essian, Estratest, Menogen, and Syntest.