Methyltestosterone

Plain testosterone is almost completely broken down in the liver on its first pass after swallowing. The extra methyl group at position 17-alpha slows this breakdown, so enough of the compound reaches the blood. In the pharmacology of anabolic steroids this very change is also regarded as the reason for the strain on the liver.

Yes. ChEMBL lists methyltestosterone with phase 4 as the highest phase and gives 1973 as the year of first approval. The ClinicalTrials.gov registry holds only six trials, most of them on the combination with estrogens in postmenopausal women. Everything here is the state of research, not a recommendation.

In a double-blind study with 218 women, adding it to estrogens for 4 months raised bioavailable testosterone, lowered SHBG and increased sexual interest more than estrogens alone. In a second study with 102 women free testosterone roughly doubled within 8 weeks and SHBG fell below a third. That study missed its main questionnaire but met several secondary ones.

A case report describes jaundice from cholestasis after 6 months of daily intake. Liver biopsies from 10 patients after up to 3 years of high amounts showed hyperplasia of liver cells, in 9 of them cells inside the walls of the liver veins. One patient developed a liver tumour after 37 months. In other patients tumours partly regressed after stopping and liver damage also reversed after switching to non-alkylated androgens.

In healthy women glucose uptake under insulin fell by about a third after 10 to 12 days, although hardly more insulin was released. Triglycerides and apolipoprotein C-III fell when it was added to estrogens, but so did HDL cholesterol. In a 12-month study body weight and visceral fat rose slightly only in the methyltestosterone group.

In a small study with 17 healthy men a short course over 6 days changed the messengers in the spinal fluid: a breakdown product of serotonin rose and one of noradrenaline fell. The rise went along with more energy, sexual arousal and less sleep. The amount was far above the studies in women.

An analysis of reports on an estrogen and methyltestosterone combination over 13 years estimates more than 3 million treatment years. Of the reports 3.1 percent were serious, the most frequent among the others were hair loss, acne and excess hair growth in women. Reports do not show a frequency among everyone treated.