Are SARMs safe? What research tells us about the risks

SARMs are often discussed online alongside muscle-building supplements, but their safety needs closer scrutiny. Published research and regulatory warnings do not justify describing them as risk-free or proven safe for recreational use.

This article explains what SARMs are, what a human trial can tell us, and why product testing cannot answer every safety question.

Disclosure: This website sells SARMs and has a commercial interest in this subject. This article provides general information, not personalised medical advice.

What are SARMs?

SARMs stands for selective androgen receptor modulators. These compounds act on androgen receptors, which are involved in the body's response to hormones such as testosterone.

Researchers have investigated SARMs for potential medical applications, including conditions involving muscle loss. However, a compound being studied as a possible treatment does not establish that products sold online are safe or effective for bodybuilding.

The US Food and Drug Administration states that SARMs are not FDA-approved and advises consumers against using them. This is US regulatory guidance, not a statement of UK law.

Read the FDA's consumer guidance on SARMs.

What does human research actually show?

One placebo-controlled trial, published in 2013, studied LGD-4033 in 76 healthy men over a 21-day treatment period. Researchers reported increased lean body mass, alongside dose-dependent reductions in total testosterone and HDL cholesterol.

That finding deserves careful interpretation. The trial provides evidence about one compound under specific, controlled conditions. It does not demonstrate that every SARM has the same effects, or establish the safety of longer-term recreational use.

A short study also cannot reliably rule out uncommon adverse effects. Questions about repeated exposure and different combinations require their own evidence.

Read the LGD-4033 clinical trial by Basaria and colleagues.

What health risks have been reported?

The FDA warns of serious health problems associated with SARMs, including liver injury, sexual dysfunction, infertility and a potentially increased risk of heart attack or stroke.

These warnings should not be interpreted as a precise prediction of what will happen to every person. Equally, uncertainty about an individual's risk is not evidence of safety.

If you are using a SARM and experience suspected side effects, speak to a healthcare professional and explain exactly what you have taken.

Read the FDA's safety warning and advice.

Can you trust what is on the label?

Product composition is a separate concern from the effects of the compound itself.

A study published in JAMA in 2017 analysed 44 products marketed online as SARMs. Only 52% contained a SARM, 25% contained substances not listed on the label, and 59% had quantities that differed substantially from the label.

These figures describe that particular sample, purchased in 2016. They should not be presented as a measurement of every supplier or today's entire market. They do show why a product name or label alone is insufficient evidence of its contents.

Read the JAMA study on online SARMs product labelling.

Does a lab report prove a SARM is safe?

A certificate of analysis and a clinical safety study answer different questions.

Depending on its scope, a lab report can provide information about the sample tested. It cannot establish how that substance will affect a person over months or years.

When reading a report, useful questions include:

• Is the tested sample linked to the product's batch?
• Who performed the analysis, and when?
• Which substances or contaminants were actually tested?
• Does the report measure identity, quantity, purity, or only some of these?

These are practical questions for assessing a report, not a checklist that makes a product safe. Even an accurately identified compound requires separate evidence about its effects on people.

How to judge claims about SARMs

Look for sources that identify the specific compound, study participants, treatment duration and limitations. A claim about people should not rest solely on an animal experiment or an online testimonial.

Be cautious when an article uses a single positive finding to support much broader promises. Ask whether its conclusion matches what the research actually measured.

For SARMs, the evidence needs to be read alongside the uncertainties. Short-term findings, accurate labels and laboratory reports each provide different information; none alone establishes long-term safety for recreational use.