What are SARMs? SARMs, or selective androgen receptor modulators, are compounds that bind to the androgen receptor and are designed to act differently in different tissues. This guide explains how SARMs work, summarises the main SARMs research to date, and clears up some common misconceptions.
What are SARMs and how do they work?
The androgen receptor is a protein inside cells that responds to hormones such as testosterone. It is present in many tissues, including muscle, bone, skin and the prostate. Steroidal androgens activate the receptor broadly in all of these tissues.
Selective androgen receptor modulators were developed to separate those effects. In preclinical models, many SARMs show strong activity in muscle and bone with weaker activity in tissues such as the prostate. This tissue selectivity is the defining research interest behind the class. Most SARMs are non-steroidal, meaning their chemical structure is unrelated to testosterone.
A short history of SARMs research
Non-steroidal androgen receptor ligands were first reported by academic groups in the late 1990s. Pharmaceutical companies then developed a range of candidates for conditions involving muscle and bone loss. A PubMed search for selective androgen receptor modulators shows how large the literature has become.
Commonly studied SARMs
Ostarine (MK-2866, enobosarm)
Ostarine is one of the most extensively studied SARMs. Ostarine research has included clinical trials in muscle wasting associated with cancer, and later investigations in other indications. Despite this programme, it has not been approved as a medicine.
RAD 140 (Testolone)
RAD 140 was developed as a potent non-steroidal SARM. RAD 140 research includes preclinical work and early-phase clinical investigation in certain hormone-receptor-positive breast cancers, an area where androgen receptor activity is of scientific interest.
Ligandrol (LGD-4033)
Ligandrol has been evaluated in early clinical studies, including a short study in healthy volunteers that examined lean mass, hormone levels and lipids, and later trials in other settings.
Andarine (S-4) and S-23
Andarine and S-23 come from the same early chemical series. They have mainly been studied in preclinical models of muscle, bone and, for S-23, male fertility research.
Compounds that are often grouped with SARMs but are not SARMs
Several popular research compounds are sold alongside SARMs but work through entirely different targets:
| Compound | What it actually is |
|---|---|
| MK-677 (Ibutamoren) | A growth hormone secretagogue acting on the ghrelin receptor |
| Cardarine (GW-501516) | A PPAR-delta agonist |
| SR-9009 (Stenabolic) | A Rev-Erb agonist |
| YK-11 | A steroidal compound described as a partial androgen receptor agonist |
Keeping these distinctions clear matters when you design experiments and interpret published data.
Regulatory status
No SARM has been approved as a medicine by the US FDA or by European regulators. The FDA has warned consumers about bodybuilding products containing SARMs. The World Anti-Doping Agency prohibits SARMs at all times under its Prohibited List. SARMs are therefore research compounds only. They are not supplements and are not for human consumption.
Practical points for SARMs research
- Choose the right format. SARMs are supplied as powders, capsules, tablets and liquids. Pick the format that suits your protocol and analytical methods.
- Verify identity and purity. Where your work depends on it, confirm material identity using appropriate analytical techniques.
- Store correctly. Keep compounds sealed, cool, dry and away from light.
- Record everything. Note lot numbers, formats and storage conditions so results can be reproduced.
Key takeaways
- SARMs are androgen receptor ligands designed for tissue-selective activity.
- SARMs research spans preclinical work and clinical trials, but none has been approved.
- Several compounds often sold as SARMs, such as MK-677 and Cardarine, act on different targets.
- SARMs are prohibited in sport and are for laboratory research only.
Browse the full Pure Rawz SARMs range, including research stacks, or read our BPC-157 research overview for a look at peptide research.
Research use only. This article summarises published research for educational purposes. It is not medical advice. Products sold by Pure Rawz are intended for laboratory research only and are not for human or animal consumption.