New to SARMs? This page gives you the essentials in a few minutes and shows where to go next. The short version: SARMs are experimental drugs, none is an approved medicine, trials found modest muscle gains with real side effects, products sold online often do not match their labels, and they are banned in sport and restricted in many countries.
What SARMs are
SARMs (selective androgen receptor modulators) are drugs designed to act on the same receptor as testosterone, with more effect on muscle and bone and less elsewhere. Examples include ostarine (enobosarm), LGD-4033 (ligandrol) and RAD-140 (UK Anti-Doping). Companies tested them as possible treatments for muscle loss in patients and older adults and for some breast cancers, but none has been approved in more than 25 years of development, and the tissue selectivity seen in animals turned out to be small in people (Adolf 2026).
Several compounds sold next to SARMs are not SARMs at all: MK-677 is a growth hormone secretagogue, cardarine (GW501516) is a PPARδ agonist and SR9009 is a Rev-erbα agonist; WADA lists them in different sections (WADA). For the full background, read our complete SARMs guide.
What the evidence shows
- Across randomized trials, lean mass rose by roughly 1 to 1.5 kg, while physical function improved inconsistently (Adolf 2026).
- Ostarine, the best-studied SARM, reached Phase 3, but both lung cancer trials (about 650 patients) missed their main goals (GTx 2014).
- LGD-4033 at 1 mg a day for 21 days added 1.21 kg of lean mass in young men; strength and stair climbing did not improve significantly (Basaria 2013).
- RAD-140 has one human trial, in 22 women with advanced breast cancer; its muscle data come from animals (LoRusso 2022).
Much of what circulates online comes from user reports. We keep those apart from study results and label every finding with its evidence type, so you can see whether it rests on a controlled trial, a case report or an animal study.
The main risks
| Risk | What studies found | Evidence |
|---|---|---|
| Lower testosterone | LGD-4033 and ostarine lowered total testosterone and SHBG in trials (Basaria 2013; Dalton 2011). | Trial |
| Lower HDL cholesterol | HDL fell 17% on 1 mg and 27% on 3 mg of ostarine over 86 days (Dalton 2011). | Trial |
| Liver injury | Liver enzyme rises in trials; jaundice and cholestatic liver injury in case reports of ostarine, LGD-4033 and RAD-140 users, the main serious harm seen in practice (Adolf 2026). | Trial, case report |
| Heart | Case reports of heart inflammation (Schwartzman 2024) and heart failure (Skorupski 2024) with RAD-140. With MK-677, a hip-fracture trial in frail older adults stopped early after more heart failure cases (FDA 2024). | Case report, trial |
| Blood sugar | MK-677 raised fasting glucose and lowered insulin sensitivity over 12 months (Nass 2008). | Trial |
| Cancer in animals | Cardarine caused tumors in rats and mice in its developer’s two-year studies (Toxicologist 2009); development stopped and WADA warned athletes directly (WADA 2013). | Animal |
| Wrong product | Of 44 products sold online as SARMs, only 52% contained a SARM and 41% matched the label amount (Van Wagoner 2017). | Lab analysis |
Every reported side effect, by body system and compound, is in our SARMs side effects guide.
The law in brief
- US: the FDA says products sold as SARMs are unapproved drugs, not dietary supplements, and are illegally marketed (FDA). They are not federally scheduled: a 2019 bill to schedule them was introduced and sent to committee, and GovInfo holds no later version (GovInfo).
- Australia: SARMs are prescription-only, and possession without authority, such as a prescription, is illegal (Poisons Standard 2026).
- UK: selling SARMs for human consumption is illegal (UK Anti-Doping). Brazil banned their sale, import and use in 2021 (Anvisa).
- “Research use only” labels do not make a product legal (Health Canada).
- Sport: all SARMs are banned at all times (WADA).
Country by country: are SARMs legal? In sport: SARMs and WADA.
Bloodwork: what the studies measured
SARM trials tracked the same markers again and again: total and free testosterone, LH and FSH, SHBG, a lipid panel (HDL, LDL, triglycerides), liver enzymes (ALT, AST) and bilirubin. MK-677 trials added IGF-1, fasting glucose, HbA1c and prolactin. Each compound’s fact sheet lists the markers its studies tracked. These are tests a doctor can order and interpret; our SARMs bloodwork guide explains each marker, and the testosterone blood test guide covers the basics.
Recovery depends on what was taken and for how long. In the 21-day LGD-4033 trial, testosterone and SHBG were back to baseline by day 56 (Basaria 2013). After longer use of anabolic steroids, one study found testosterone recovered within 3 months in most men, but sperm took about a year and 11% still had low testosterone at the end (Smit 2021). More on this in PCT after SARMs.
How to use Sarmguide
- Look a compound up in the SARMs database, then open its fact sheet: MK-677, ostarine, LGD-4033, RAD-140, cardarine, enclomiphene.
- Use the tools: compare, stack checker, PCT planner and goal finder. All of them are on the tools page.
- Look up a word in the glossary, from HPTA to Specified substance.
- Check our work. Updated articles list their sources and their publish date; the database shows when its data was last checked. Our methodology and editorial policy explain how the Sarmguide Editorial Team chooses and checks sources.
- Know how we are funded. Sarmguide is reader-supported. We may earn a commission from partner links; see our affiliate disclosure.