SARMs Guide (2026): The 101 on What SARMs Are, the Evidence, Risks and the Law

SARMs (selective androgen receptor modulators) are experimental drugs that act on the same receptor as testosterone and were designed to build muscle and bone with fewer effects elsewhere. None has been approved as a medicine in more than 25 years of development; in randomized trials they added roughly 1 to 1.5 kg of lean mass while lowering testosterone, SHBG and HDL cholesterol (Adolf 2026). Products sold online often do not contain what the label says (Van Wagoner 2017), and SARMs are banned in sport and restricted in many countries (WADA 2026; UK Anti-Doping).

This guide is the complete 101: what SARMs are (and which popular compounds are not SARMs), what the studies show for each one, side effects and testosterone suppression, product forms, the doses studies used, the law, and where to go next. Every compound has its own fact sheet, linked below.

What are SARMs?

SARMs bind the androgen receptor, the receptor that testosterone and other anabolic steroids act on. The idea behind them was tissue selectivity: a drug that acts strongly on muscle and bone and weakly on the prostate, skin and other tissues. Companies tested them for muscle loss in older adults and cancer patients, for osteoporosis and for some breast cancers. A 2026 review sums up the result: the selectivity is reproducible in animal models but small in humans, and no SARM has been approved in more than 25 years (Adolf 2026).

Most SARMs are nonsteroidal, meaning their chemical structure is not a steroid (ostarine, LGD-4033, RAD-140). A few are steroid-based but act like SARMs, such as YK-11 (Kanno 2011). UK Anti-Doping describes them as drugs designed to have similar effects to testosterone and other anabolic steroids (UK Anti-Doping).

Which popular compounds are not SARMs?

Several compounds sold next to SARMs act on completely different targets. WADA lists them in different sections of its Prohibited List:

SARMs vs steroids, prohormones, testosterone and peptides

Detailed comparisons: SARMs vs steroids, SARMs vs prohormones, SARMs vs testosterone, SARMs vs TRT and SARMs vs peptides.

Do SARMs work? What human trials show

For lean mass, yes, modestly. A 2025 systematic review of nine randomized trials (970 patients, six different SARMs) concluded that SARMs improve body composition and physical performance, with moderate rates of mild to moderate side effects and a low rate of severe ones (Wen 2025). A 2026 review puts the lean-mass gain at roughly 1 to 1.5 kg, rising with dose, while physical function improved inconsistently (Adolf 2026). Two examples:

• Ostarine: +1.3 kg lean mass vs placebo on 3 mg a day for 86 days in older adults; HDL fell 27% (Dalton 2011).
• LGD-4033: +1.21 kg lean mass on 1 mg a day for 21 days in young men; strength did not improve significantly; testosterone, SHBG and HDL fell (Basaria 2013).

Those trials used low doses in patients or older adults under medical supervision. Most compounds sold as SARMs have never been tested in people at all, and no trial has tested the higher doses, long “cycles” or stacks that users describe. User results are collected, with this context, in SARMs before and after; timing questions are covered in when do SARMs kick in? and do you lose gains after stopping SARMs?

Source: Sarmguide compound database.

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The SARMs, one by one

Ordered from the most to the least human evidence. Each name links to its full fact sheet, with every study, side effect and source.

Ostarine (MK-2866)

The most studied SARM, tested in more than 1,000 people. Trials at 1–3 mg a day found about 1–1.5 kg more lean mass, but two Phase 3 trials in lung cancer missed their goals (Dalton 2011; GTx 2014). It lowers total testosterone, SHBG and HDL. Veru is now testing it to protect muscle during GLP-1 weight loss (Veru 2025). Full fact sheet: ostarine; results: ostarine before and after.

Ligandrol (LGD-4033)

Two placebo-controlled trials found more lean mass, and even 1 mg a day lowered testosterone and HDL (Basaria 2013; NCT02578095). Case reports link ligandrol products to cholestatic liver injury (Barbara 2020). Fact sheet: LGD-4033.

Testolone (RAD-140)

One human trial, in 22 women with advanced breast cancer, where AST rose in 59% of patients; muscle was never measured in people (LoRusso 2022). Its muscle claims come from rats and monkeys. Fact sheet: RAD-140.

Andarine (S4)

One of the first SARMs; it restored muscle and bone in castrated rats but stopped before human trials (Gao 2005; Leciejewska 2024). Fact sheet: andarine.

S23

Studied in rats as a male contraceptive: it cut LH by more than half and, with an estrogen, stopped sperm production until treatment ended (Jones 2009). Never tested in a human trial. Fact sheet: S-23.

YK11

A steroid-based androgen receptor partial agonist sold as a “myostatin inhibitor” on the strength of one mouse muscle-cell study (Kanno 2013). No human trials. Fact sheet: YK-11.

AC-262, ACP-105 and RAD-150

The least studied. AC-262 and ACP-105 are partial agonists from Acadia Pharmaceuticals with short rat studies and, for ACP-105, a few mouse studies (Piu 2008; Schlienger 2009). RAD-150 has no published study at all; PubChem lists it as an ester of RAD-140 (PubChem CID 68547459). Fact sheets: AC-262, ACP-105 and RAD-150.

Sold next to SARMs: MK-677, cardarine and SR9009

MK-677 has been tested in human trials since the 1990s; its main documented risks are higher blood sugar, fluid retention and, in frail older adults after hip fracture, heart failure (Nass 2008; FDA 2024). Cardarine improved blood fats in short trials, but its developer stopped it after rats and mice developed cancers (Toxicologist 2009). SR9009 has never been tested in people, and two case reports link it to serious liver injury (Shams Bin Shaheen 2026).

Other compounds we cover

LGD-3303, LGD-2226, GW0742 and SR9011. Every compound side by side: the SARMs database.

SARMs side effects and risks

Every side effect by body system: SARMs side effects. Specific questions: liver, testosterone, hair loss, gyno, acne, blood pressure, cancer, kidneys, libido, erectile dysfunction and the brain.

SARMs pros and cons

Testosterone suppression and PCT

SARMs that were measured in trials lowered testosterone. In the 21-day LGD-4033 trial, testosterone and SHBG fell even at 0.1 mg a day and were back to baseline by day 56 (Basaria 2013). Recovery after longer, higher-dose use of SARMs has not been studied; after anabolic steroid cycles, testosterone recovered within 3 months in most men, but sperm counts took about a year and 11% still had low testosterone at follow-up (Smit 2021).

More: PCT after SARMs, signs of suppression, Clomid PCT, Nolvadex PCT, enclomiphene, the PCT and bloodwork planner and the SARMs bloodwork guide.

Forms of SARMs: capsules, liquids and powders

UK Anti-Doping notes that SARMs are mostly sold as pills, often packaged like supplements but labeled “for research purposes only” or “not for human consumption” (UK Anti-Doping). Such labels do not make a product legal (Health Canada). The human trials all used oral doses measured in milligrams or less.

• Capsules: a fixed amount per capsule, as printed on the label.
• Liquids: dosed by volume, so the amount depends on the concentration printed on the bottle (mg per mL). See liquid SARMs and how to take liquid SARMs.
• Powders: dosed by weight. See how to take powder SARMs.
• Injectables: see injectable SARMs.

SARMs doses and cycles: what studies used

Studies tested doses, not “cycles”. The table shows every human dose on record for the SARMs we cover.

No study has tested SARM stacks or the cutting, bulking and recomposition cycles described online. Goal-by-goal evidence: best SARMs for bulking, best SARMs for cutting, SARMs for strength, endurance, SARMs for women and best time to take SARMs. The stack checker shows where the documented risks of a combination overlap.

Are SARMs legal?

• United States: 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).
• United Kingdom: the Food Standards Agency treats SARMs as unauthorized novel foods, so they are illegal to sell or advertise as food or in supplements (UK Anti-Doping).
• Australia: SARMs are prescription-only, and possession without authority such as a prescription is illegal (Poisons Standard 2026).
• Germany: the Anti-Doping Act’s annex lists SARMs such as andarine, ligandrol, ostarine, RAD-140, S-23 and YK-11 (AntiDopG annex); trading in them for doping in sport, or possessing a non-small quantity for that purpose, is banned (AntiDopG §2).
• Brazil: sale, import and use were banned in 2021 (Anvisa).
• Sport: WADA has banned SARMs at all times since 2008 (Adolf 2026; WADA 2026). UK Anti-Doping counts 863 adverse analytical findings (positive tests) for SARMs worldwide from 2011 to 2024 (UK Anti-Doping).

Country by country: are SARMs legal?, Australia, Europe, UK, Ireland and South Africa. Testing: SARMs and WADA, SARMs drug test, how long SARMs stay in your system and military drug tests.

Is there a “safest” or “strongest” SARM?

No SARM has been shown to be safe for building muscle, because none has been approved and no trial has tested the way they are used outside medicine (Adolf 2026). What can be said is which ones are best and least understood:

• Best studied: ostarine and LGD-4033. Their risks are better known, not absent: both lowered testosterone and HDL in trials, and both appear in liver-injury case reports (Dalton 2011; Basaria 2013).
• Least studied: YK-11, S-23, andarine, AC-262, ACP-105 and RAD-150, which have no human trials. For these, “fewer reported side effects” only means fewer studies.
• “Strongest”: no trial has compared SARMs head to head, so there is no evidence-based ranking. S-23 acted as a full androgen in rats (Jones 2010), which says more about its side effects than about results in people.

The goal finder shows the research behind each goal, and the compare tool puts any two compounds side by side.

Buying SARMs: quality problems

Product quality is a risk in its own right. In the JAMA analysis of 44 products sold online as SARMs, 9% contained no active compound, 25% contained substances not on the label, and 59% held an amount that differed substantially from the label (Van Wagoner 2017). In almost all published SARM liver-injury cases, the product was never analyzed, so hidden ingredients cannot be ruled out (Adolf 2026).

If you buy, look for a lot-specific certificate of analysis from an independent lab, and learn how to read a lab test. Our current pick is SwissChems, which publishes lot-specific lab reports; the reasons and its weak points are in our SwissChems review. More: where to buy SARMs, SARMs company recommendations and buy SARMs.

Tools and next steps

• Start here: the essentials in a few minutes.
• SARMs database: every compound, filterable, with sources.
• Compare, stack checker, PCT planner and goal finder; all on the tools page.
• Charts of half-lives, research stages and suppression.
• Glossary of hormone, lab and anti-doping terms, and our methodology.

Bottom line

SARMs are experimental drugs that never made it to approval. The best-studied ones add a little lean mass and reliably lower testosterone and HDL cholesterol; the rest have little or no human data. In real-world use, the serious harm is liver injury, and products are often not what their labels say. They are banned in sport, cannot be sold as supplements in the US, UK or Australia, and every claim beyond the trial data comes from user reports.