Selective Androgen Receptor Modulators (SARMs) have gotten a lot of attention in the last decade. Preliminary studies have revealed that specific SARMs and similar compounds — such as MK-677, Cardarine, RAD-140, and Ostarine — have benefits that warrant further investigation. Researchers are eager to unravel the full potential of this unique class of compounds.
Here are a few basic facts to keep in mind:
- SARMs are nonsteroidal anabolic compounds that are selective modulators of the androgen receptor (AR).
- They have close similarities to the natural ligands for the ARs, which are testosterone and dihydrotestosterone (male hormones).
- SARMs have “selective” activity at the androgen receptor, which means they can offer anabolic benefits without causing many of the unwanted (androgenic) side effects that are associated with conventional anabolic steroids.
- SARMS are approved as investigational drugs intended for research purposes only and are not intended for human consumption.
- They are prohibited by the World Anti-Doping Agency (WADA) and fall under “Other Anabolic Agents” on WADA’s Prohibited List, so athletes taking part in competitive sports should not participate in clinical research with SARMs.
- SARMs can cause you to fail a sports-related drug test. Employment tests generally do not test for SARMs.
The Food and Drug Administration (FDA) has not yet approved the use of SARMs. Researchers are allowed to explore the potential of SARMs as therapeutic and performance-enhancing agents, however. A 2019 review published in Sexual Medicine Reviews demonstrated the usefulness of SARMs in managing cancer-related cachexia, BPH, hypogonadism, and breast cancer. Researchers are also looking into the muscle-building properties of some SARMs.
This brief guide explains everything you need to know about some promising SARMs in the eyes of researchers. It expounds on their effects, potential benefits, side effects, and other extra features.
A List of SARMs, Plus Potential Benefits and Side Effects
Research into SARMs is still in its infancy, and there’s a lot to be learned about these compounds. The list below includes those that are of particular interest to researchers because of their therapeutic potential. It includes one or two compounds that are not “typical SARMs” because they exert their actions by binding to different receptors other than the androgen receptor. These compounds have striking similarities with SARMs, however, and are thus categorized or sold alongside them.
1. MK-677 (Ibutamoren)
MK-677 is an orally active Ghrelin agonist that increases GH levels by mimicking the action of GH-releasing peptides. A 1998 study published in The Journal of Clinical Endocrinology & Metabolism showed that MK-677 reverses diet-induced protein catabolism. The study showed MK-677 has the potential to treat catabolic conditions. The SARM was offered to healthy adults in a two-year, double-blind, randomized, placebo-controlled clinical trial. The study demonstrated that it increased GH levels without causing severe adverse effects, plus increased bone density and fat-free mass. 
Ibutamoren Side Effects
Studies have found increased appetite, frequent hunger pangs, fatigue, water retention, and mild swelling and muscle pain in the lower extremities associated with the use of MK-677.
2. GW501516 (Cardarine)
Cardarine is an agonist of the PPAR (peroxisome proliferator-activated receptor), making it an “atypical SARM.” It has a high affinity for PPARs, a group of steroid and thyroid proteins that regulate metabolism. Cardarine binds these receptors, which are in muscle cells, to help the body burn fat and produce cellular energy. One study conducted in 2015 showed that Cardarine could help increase endurance in mice. The trained mice increased their running distance by 31% after receiving Cardarine for three weeks, while sedentary mice increased their distance by 68%. 
Cardarine Side Effects
Cardarine’s potential in metabolism, endurance, and blood lipids is a subject of interest for researchers. Some mice studies have linked Cardarine to carcinogenic effects, raising concerns about the safety of this compound. A 2007 clinical study, however, didn’t replicate the preclinical findings when Cardarine was administered to humans in controlled doses and for shorter durations. 
3. LGD-4033 (Ligandrol)
LGD-4033, aka Ligandrol, is a SARM that’s known for its anabolic properties. It binds to androgen receptors on skeletal muscle cells and triggers a cascade of events that results in muscle growth and repair. Ligandrol is thus referred to as a bulking agent. A human clinical trial published in 2013 showed that it increases lean muscle mass without increasing fat mass. Seventy-six healthy men were offered 1 mg of Ligandrol for three weeks (or placebo). Those offered the LGD gained approximately three pounds during the three weeks. The Ligandrol was well tolerated, and no serious adverse events were observed. 
A subsequent human clinical trial that involved participants over 65 years old recovering from hip fracture showed that Ligandrol helped build muscle mass and increase the recovery rate of these patients.
Ligandrol Side Effects
Studies have shown subjects to suffer headaches, dry mouth, and acne. Ligandrol also has the potential to suppress natural testosterone levels. This may cause symptoms such as reduced libido, erectile dysfunction, infertility, and loss of bone density.
4. RAD-140 (Testolone)
Testolone is a relatively new but powerful SARM that has a high selective affinity for the androgen receptor. Testolone has potent anabolic properties and has shown potential in improving muscle mass and enhancing endurance. It has also demonstrated neuroprotective properties useful in treating Alzheimer’s and related neurodegenerative diseases.  Testolone has an impressive anabolic to androgenic ratio of 90:1, which means it has potent anabolic properties with limited androgenic adverse effects.
Testolone Side Effects
Subjects in studies have reported headaches, fatigue, back pain, and nausea. Testolone may also suppress natural levels of testosterone. This may cause a decrease in sexual drive, erectile dysfunction, increased body fat, and reduced bone density.
5. MK-2866 (Ostarine)
MK-2866, aka Ostarine, is among the most popular investigational nonsteroidal SARMs. It’s an orally active anabolic compound that mimics testosterone’s action, and helps burn fat and build muscle mass. MK-2866 has been shown to build muscle mass, aid in connective tissue recovery, and prevent severe muscle wasting in cachexia.
Ostarine is currently under investigation for the management of muscle wasting in patients with non-small-cell lung cancer. A previous study demonstrated its usefulness in improving lean body mass in cancer patients without causing any of the toxic effects associated with androgens and progestational agents. The participants in this study were offered oral Ostarine doses of 1 mg, 3 mg, or placebo once daily for up to 113 days.  Ostarine may also accelerate the recovery of muscle, bone, and connective tissue after an injury.
Ostarine Side Effects
Research has found that Ostarine can cause stomach pain, constipation, and back pain. It’s known to suppress the production of natural testosterone, however, when consumed in higher doses. This may cause a decrease in sexual drive, erectile dysfunction, and increased body fat after cessation.
The use of SARMs should be restricted to investigative purposes. SARMs are not dietary supplements and should not be used by athletes or consumers.
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For the highest quality RAD 140, Ligandrol, Ostarine, MK 677, and other SARMs, look no further than Sports Technology Labs. Visit our research blog for information about new products, updates in the industry, side effects, new scientific literature, and product comparisons.
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