SARMs, or Selective Androgen Receptor Modulators, are a newer class of androgen receptor (AR) modulators, and a relatively safe alternative to anabolic-androgenic steroids (AAS). SARMs have minimal side-effects, yet exhibit many of the benefits of traditional steroids. Importantly, SARMs are not the same as prohormones or peptides.
The reduction in adverse biological affects are attributed to the way SARMs selectively affect only specific tissue types — namely, muscle tissue and, with some SARMs, bone tissue — while avoiding others.
Brief History of SARMs
Even though SARMs have started making waves in the news and bodybuilding/weightlifting communities only recently, their development dates to the 1940s . Scientists were looking for ways to harness the anabolic, or tissue building, properties of AAS without incurring their undesirable androgenic effects, which are responsible for the development of male secondary sex characteristics, as seen with other androgens such as DHT. These undesirable side-effects include development of breast tissue, hair loss/balding, prostate growth, testicular atrophy, acne, and unwanted enlargement of the heart and other organs.
The modern-day era of SARMs began when the scientists at Ligand Pharmaceuticals and the University of Tennessee developed a series of compounds with anabolic activity on the skeletal muscle with some degree of tissue selectivity . Since then, many pharmaceutical companies have developed their own synthetic non-steroidal SARMs and have begun researching their potential clinical applications.
Advantages of SARMs over AAS
AAS (steroids) have been used for medical purposes since a German chemist Adolf Butenandt first successfully distilled the steroidal pheromone androstenone from over 4,500 gallons of male urine and, together with fellow chemist Leopold Ruzicka, synthesized the concoction for human use shortly thereafter.
To this day, doctors depend on AAS for stimulating the growth of bone marrow as a crucial part of treatments for leukemia or kidney failure, for stimulating the growth of children with growth failure, for stimulating the appetite and preservation of muscle mass when treating people with chronic wasting conditions such as cancer and AIDS, and for preventing or reversing osteoporosis in postmenopausal women and elderly men with low levels of testosterone.
As beneficial as AAS are for medical purposes, their application is severely restricted by the adverse side-effects of steroids, most of which stem from their non-selective nature. While AAS are very effective in promoting muscle growth, as professional bodybuilders clearly illustrate, they also promote the growth of all muscles in the body, including unwanted growth in the heart and other organs.
Prolonged use of AAS often leads to the enlargement and thickening of the left atrial ventricle, which significantly reduces the volume of blood the heart can eject with each contraction and relaxation, often leading to heart attacks and sudden cardiac death. On the other hand, SARMs selectively target only muscle and bone tissues in the body and almost entirely avoid others. For example, Ostarine, also known as Enobosarm, MK-2866, or GTx-024 (where to buy Ostarine), is a SARM that selectively affects muscle and bone tissue. It is currently being tested for the treatment of osteoporosis and a wasting syndrome in cancer patients known as cancer cachexia.
In a randomized, double-blind, placebo-controlled multi-center study to evaluate the effect of the compound by administering 3 mg or 1 mg to 159 male and female test subjects for 16 weeks, they discovered that Ostarine improved the subjects’ LBM (lean body mass), muscle performance, and quality of life .
AAS have a number of sex-specific side effects. In men, the side effects include the development of breast tissue (called gynecomastia, or “gyno”), reduced sexual function, testicular atrophy, and even infertility. In women, the side effects include increases in body hair, deepening of the voice, decreases in menstrual cycles, and enlarged clitoris.
The male-specific side-effects of AAS are caused by the enzyme aromatase, which is responsible for aromatization (conversion) of androgens into estrogens. Because an increase of the amount of testosterone in the body leads to an increase of estrogen, many professional bodybuilders use a class of drugs known as aromatase inhibitors to reduce the undesired estrogen conversion when using external, or exogenous, testosterone.
The adverse side-effects of aromatase inhibitors include an increased risk for developing osteoporosis and various joint disorders, as well as infertility, kidney failure, hair loss, and liver dysfunction.
SARMs have a much more favorable ratio of anabolic to androgenic effects, and because they target androgen receptors differently than steroids, SARMs do not aromatize into estrogen, thus avoiding “gyno” and other undesirable side-effects, and are able to be administered without aromatase inhibitors.
Conventional steroids have an anabolic-to-androgenic ratio of around 3:1 (with Testosterone as a baseline at 1:1), but SARMs have a much more favorable ratio. RAD-140 (Testolone), for example, has been shown to have a ratio as high as 90:1 .
SARMs, unlike aromatase inhibitors and oral steroids, are also orally active without causing liver damage, making them safe to administer orally in liquid, tablet, or capsule form.
Disadvantages of SARMs
There is a lack of historical data. SARMs seem to be safe and beneficial for improving physical function in healthy and diseased individuals alike, and potentially capable of providing new therapies for muscle wasting, cancer, and several other debilitating conditions . Clinical tests indicate that SARMs could be a very safe and effective alternative to traditional AAS. However, there is simply a lack of historical data upon which to draw definitive conclusions about overall health and safety of these drugs. It will take much more use, testing over a period of decads before scientists and medical professionals will be able to say conclusively whether SARMs are or are not safe, especially regarding their long-term use.
SARMs are not FDA approved. Although SARMs are legal to own in the US and in many other countries, they are legal to sell only as research chemicals, not for human consumption. However, due to high demand in athletic and bodybuilding circles, many opportunists have entered the market to sell expensive SARMs as dietary supplements, regardless of their non-dietary supplement legal status. See our disclaimer below.
SARMs (Selective Androgen Receptor Modulators) are a promising new class of drugs that have the same desirable effects as anabolic-androgenic steroids (AAS), such as increased muscle growth and size, body strength, and weight loss, but virtually none of the undesirable androgenic side-effects, such as gynecomastia, acne, high blood pressure, increased body hair, mood swings, liver damage, and other internal organ damage.
SARMs are currently being researched for their effects in curing, mitigating, or treating a number of medical conditions. Despite their lack of FDA approval, they have also been embraced by the bodybuilding and weightlifting community for their strong muscle-building properties, tissue selectivity, high ratios of anabolic to androgenic effects, and relative safety, comparing SARMs to traditional steroids.
Bhasin, Shalender, and Ravi Jasuja. “Selective Androgen Receptor Modulators (SARMs) as Function Promoting Therapies.” Current Opinion in Clinical Nutrition and Metabolic Care 12, no. 3 (May 2009): 232–40. https://doi.org/10.1097/MCO.0b013e32832a3d79.
Dalton, James T., Ryan P. Taylor, Michael L. Mohler, and Mitchell S. Steiner. “Selective Androgen Receptor Modulators for the Prevention and Treatment of Muscle Wasting Associated with Cancer.” Current Opinion in Supportive and Palliative Care 7, no. 4 (December 2013): 345–51. https://doi.org/10.1097/SPC.0000000000000015.
Edwards, J. P., S. J. West, C. L. Pooley, K. B. Marschke, L. J. Farmer, and T. K. Jones. “New Nonsteroidal Androgen Receptor Modulators Based on 4-(Trifluoromethyl)-2(1H)-Pyrrolidino[3,2-g] Quinolinone.” Bioorganic & Medicinal Chemistry Letters 8, no. 7 (April 7, 1998): 745–50.
Hanada, Keigo, Kazuyuki Furuya, Noriko Yamamoto, Hiroaki Nejishima, Kiyonoshin Ichikawa, Tsutomu Nakamura, Motonori Miyakawa, Seiji Amano, Yuji Sumita, and Nao Oguro. “Bone Anabolic Effects of S-40503, a Novel Nonsteroidal Selective Androgen Receptor Modulator (SARM), in Rat Models of Osteoporosis.” Biological & Pharmaceutical Bulletin 26, no. 11 (November 2003): 1563–69.
Steiner, M. S., K. G. Barnette, M. L. Hancock, S. T. Dodson, D. Rodriguez, and R. A. Morton. “Effect of GTx-024, a Selective Androgen Receptor Modulator (SARM), on Stair Climb Performance and Quality of Life (QOL) in Patients with Cancer Cachexia.” Journal of Clinical Oncology 28, no. 15_suppl (May 20, 2010): 9147–9147. https://doi.org/10.1200/jco.2010.28.15_suppl.9147.
 Bhasin and Jasuja, “Selective Androgen Receptor Modulators (SARMs) as Function Promoting Therapies.”
 Edwards et al., “New Nonsteroidal Androgen Receptor Modulators Based on 4-(Trifluoromethyl)-2(1H)-Pyrrolidino[3,2-g] Quinolinone.”
 Steiner et al., “Effect of GTx-024, a Selective Androgen Receptor Modulator (SARM), on Stair Climb Performance and Quality of Life (QOL) in Patients with Cancer Cachexia.”
 Hanada et al., “Bone Anabolic Effects of S-40503, a Novel Nonsteroidal Selective Androgen Receptor Modulator (SARM), in Rat Models of Osteoporosis.”
 Dalton et al., “Selective Androgen Receptor Modulators for the Prevention and Treatment of Muscle Wasting Associated with Cancer.”