SARMs – Selective Androgen Receptor Modulators

SARMs – Selective Androgen Receptor Modulators

SARMs belong to a group of molecules that selectively bind to sex hormone receptors. By their action they are similar to SERMs -Selective Estrogen Receptor Modulators (e.g. :clomiphene: and :tamoxifen:) with the only difference that they bind to androgen receptors.

As SARMs are not steroids, they do not undergo conversion by steroid enzymes, therefore there are no undesirable side-effects. The initial aim of SARMs was to reduce the adverse effects of testosterone on prostate. But later scientists found out that they can increase muscle mass. Since that time bodybuilders started to test these compounds on themselves even before clinical trials.

In the following article it was shown that GTx-024 (ostarine, enobosarm) is well tolerated and produces a dosage dependent gain of muscle mass in elderly men and postmenopausal women.

For instance, according to the trials  3mg of Ostarine (orally) during 12 weeks increases lean muscle mass by 1.4kg and reduces body fat by 300 grams without any physical load. It is also effective to prevent muscle loss (due to excessive catabolism) in cancer patients.

Nowadays there are several types of SARMs which have already passed human trials and very soon will appear on the market. However none of them is actually selective. In general they have high anabolic properties. The ratio of anabolic to androgenic properties vary from 3:1 to 10:1 (comparing to testosterone, which is 1:1)

Almost all selective androgen receptor modulators are freely available in the form of tablets. One should also mention that they don’t have liver toxicity. SARMs  became an optimal option for females, due to minimal influence on libido, blood cholesterol, liver and so on.

The major representatives of SARMs

Ostarine (MK-2866, GTx-024, Enobosarm) – affects bones and muscles

BMS-564,929 – muscle tissue

:ligandrol: (Anablicum, LGD-4033) – similar to Ostarine

LGD-2226 – bones and muscles, the trials are stopped due to high toxicity

S-40503 (Andarin) – mostly bone tissue, treatment of osteoarthritis (the research is suspended)

S-23 – male contraceptive

YK-11 (Myostine, Myostan) inhibitor of myostatin (under development)

RAD140 (Radarine, Radium) anabolic effect, increases endurance and has a neuroprotective effect

Reversol (Reverol, edrophonium, Endorol, Stenabol or SR9009) increases endurance (due to the formation of new mitochondria), treatment of obesity, muscular hypertrophy. It binds to Rev-ErbA, which in its turn performs different regulatory functions in human organism.

:ibutamoren: – Nutrobal (MK-677) – stimulates growth hormone production.

AICAR – increases endurance