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Cutting is where many lifters lose the muscle they worked hard for. Eat less for long enough and the body breaks down some muscle along with fat, which is why SARMs and a few related compounds have become popular for cutting cycles.
Five names come up again and again: RAD-140, Andarine (S4), Ostarine, Cardarine and MK-677. Only the first three are actually SARMs. And none of them leaves your hormones alone: the SARMs suppress natural testosterone, Cardarine was dropped from drug development after cancer findings in rodents, and MK-677 raises appetite and blood sugar.
This guide covers what each compound does on a cut, what the human and animal research shows, commonly reported doses, side effects and PCT, so you can judge the trade-off honestly.
Key Takeaways
- SARMs don’t burn much fat directly. Their main use on a cut is helping you hold onto muscle while you eat in a calorie deficit.
- Of the five compounds most named for cutting, only RAD-140, Andarine and Ostarine are SARMs. Cardarine is a PPAR-delta agonist and MK-677 is a growth hormone secretagogue.
- SARMs still suppress natural testosterone and can lower HDL cholesterol, and liver injury has been described in case reports.
- Cardarine’s development was stopped after long-term rodent studies found cancers in multiple organs.
- None of these compounds is approved for human use, all are banned by WADA, and the doses lifters report are far above those tested in people.
What Are SARMs?
SARMs (selective androgen receptor modulators) are experimental drugs designed to produce some of the muscle-building effects of anabolic steroids with more selectivity for muscle and bone. They were developed for conditions such as muscle wasting and osteoporosis, but none has been approved for any medical use.
Selective does not mean hormone-neutral. SARMs still switch on androgen receptors, and the brain reads that signal much as it reads testosterone: it cuts its own production. Most SARMs suppress natural testosterone, and the effect grows with the dose. In a three-week trial in healthy young men, just 1 mg a day of ligandrol (LGD-4033) lowered total testosterone and HDL cholesterol. SARMs can also cause acne and hair shedding, and liver injury has been reported in people using them.
Lifters use them on cuts mainly to keep muscle while eating less. That benefit is plausible, but the doses used are often many times higher than those tested in trials, and the products are sold as unregulated research chemicals.
How Do SARMs Work for Fat Loss?
SARMs aren’t fat burners. In a calorie deficit, your body breaks down some muscle along with fat. SARMs bind to androgen receptors in muscle and bone and raise protein synthesis, which can help you keep more lean mass while the deficit takes care of the fat.
That’s why the fat-loss effect of a SARM is mostly indirect: more muscle kept, a harder look, and sometimes better training in a deficit. SARM research has focused on muscle and bone; fat loss in healthy lifters has never been tested in a proper trial.
Two of the compounds on most “best for cutting” lists work in completely different ways. Cardarine changes how muscle burns fat for fuel, and MK-677 raises growth hormone. Neither is a SARM, and neither acts on the androgen receptor.
What Are the Best SARMs for Fat Loss?
The five compounds most often named for cutting are RAD-140, Andarine (S4), Cardarine, Ostarine and MK-677. Only RAD-140, Andarine and Ostarine are SARMs. Cardarine (GW-501516) is a PPAR-delta agonist and MK-677 (ibutamoren) is a growth hormone secretagogue; they are on this list because they are so often stacked with SARMs on a cut. None of the five is approved for human use.
1. RAD-140 (Testolone)
RAD-140 is one of the more potent SARMs. On a cut, it is used to protect muscle and strength in a deficit by raising protein synthesis in muscle. It doesn’t burn fat directly; any fat-loss effect comes from holding onto lean mass.
Animal studies in rats and monkeys showed muscle gains with less effect on the prostate than testosterone. The only human data come from an early trial in women with advanced breast cancer, where raised liver enzymes were among the side effects. There are no published trials in healthy lifters.
RAD-140 suppresses natural testosterone, and users commonly report marked suppression at the doses they take, which is why PCT is commonly run after a cycle. Liver injury has been described in case reports of men using RAD-140 products. Users also report irritability, aggression, hair shedding and acne, mostly at higher doses.
Commonly reported doses: 10-20 mg a day for 6-8 weeks. Some users report up to 30 mg, where side effects become more common.
SARMs
Overview
- Form: Oral Capsules
- Researched Dosage: 5 mg to 30 mg daily
- Typical Cycle: 6-8 weeks
- Cost: $89.95
- Stacking Options: MK-677, LGD-4033, GW-501516
Pros
- Designed to stimulate androgen receptors and may support muscle growth and strength.
- Its anabolic activity may help maintain muscle during periods of calorie restriction.
- Unlike injectable anabolic steroids, RAD-140 is typically taken orally, making it more convenient for some users.
Cons
- RAD-140 can suppress the body’s natural testosterone production, potentially affecting hormones after use.
- Changes in liver enzymes, cholesterol, and other health markers have been reported or remain a concern.
- RAD-140 is not an approved human medication, so its long-term safety, effectiveness, and risks are not well established.
2. Andarine (S4)
Andarine is the SARM most associated with cutting. Users report a harder, drier look and good strength retention in a deficit. It is milder in anabolic strength than RAD-140.
Its evidence comes almost entirely from animals. In castrated rats, it preserved muscle and bone that would otherwise have been lost. There are no published trials of Andarine for fat loss, or for anything else, in healthy people.
Andarine is not the “fewest side effects” option it is sometimes sold as. Its best-known side effect is vision change: a yellow tint and trouble adjusting to the dark, reported more often at 50 mg a day and above, which usually clears after stopping. It also suppresses natural testosterone, and headaches are commonly reported.
Commonly reported doses: 25-50 mg a day, split into two or more doses because of its short half-life, for 6-8 weeks.
SARMs
Overview
- Form: Oral Capsules
- Research Dosage: 25–50 mg daily, split into morning/evening doses
- Typical Cycle: 6-8 weeks
- Cost: $65.95
- Stacking Options: Ostarine (MK-2866), Cardarine (GW-501516), SR9009
Pros
- Strong recomposition and cutting research profile
- Preserves lean mass during calorie deficits
- High-purity 25mg dosing format
Cons
- Possible vision-related side effects in some research subjects
- Testosterone suppression potential
- Not ideal for pure bulking phases
3. Cardarine (GW-501516)
Cardarine isn’t a SARM. It’s a PPAR-delta receptor agonist: it switches on genes that make muscle burn more fat for fuel. In mice, it boosted the endurance gains from exercise. Small, short human trials in people with metabolic problems found better blood lipids and more fat burning in muscle. None tested fat loss in lean, healthy lifters.
Cardarine doesn’t act on the androgen receptor and isn’t known to suppress testosterone, so PCT is not part of a Cardarine-only plan. Its concern is different and more serious: GlaxoSmithKline stopped developing it after long-term rodent studies found cancers in multiple organs, and WADA took the unusual step of issuing a public health warning to athletes about it. Whether that risk applies to people at the doses used is unknown, because no long-term human study exists. We cover the findings in Cardarine side effects and cancer risk.
Commonly reported doses: 10-20 mg a day for 6-10 weeks. The short human trials used 10 mg a day or less.
4. Ostarine (MK-2866)
Ostarine, also known as enobosarm, is the most studied SARM and the mildest of the three SARMs here. On a cut, it is used to hold onto lean mass.
In a 12-week trial in older men and postmenopausal women, 3 mg a day increased lean body mass and improved stair-climbing power. Trials in people with cancer-related muscle loss also found lean-mass gains, but it was never approved. Those trials used 1-3 mg a day; lifters commonly report 10-20 mg, several times higher, where there are no safety data.
Mild does not mean hormone-neutral. Ostarine can lower HDL cholesterol and is commonly reported to suppress natural testosterone at the doses lifters use. Claims that it heals joints come from user reports, not human trials.
Commonly reported doses: 10-20 mg a day for 6-8 weeks.
5. MK-677 (Ibutamoren)
MK-677 isn’t a SARM either. It’s an oral growth hormone secretagogue: it mimics ghrelin, the hunger hormone, and makes the pituitary release more growth hormone, which raises IGF-1. It doesn’t act on the androgen receptor and doesn’t suppress testosterone.
Its fat-loss reputation is weaker than its muscle and sleep reputation. In a two-month trial in obese men, 25 mg a day raised growth hormone and fat-free mass but did not significantly reduce total or visceral fat. Longer trials in older adults found more lean mass alongside higher fasting blood sugar and lower insulin sensitivity. It also raises appetite and causes water retention, which works against a cut for many people.
Commonly reported doses: 10-25 mg once a day for 8-16 weeks. Clinical trials used 25 mg a day.
Growth Hormone Secretagogue
Overview
- Form: Oral Capsules
- Dosage: 10 to 25 mg per day
- Typical Cycle: 8-12 weeks on/4 weeks off
- Cost: $69.95
- Stacking Options: RAD-140, LGD-4033, GW-501516
Pros
- Stimulates the ghrelin receptor, which can raise growth hormone and IGF-1 levels.
- Increased GH/IGF-1 signaling may contribute to improvements in lean body mass and recovery, although evidence is limited.
- Can be useful for people struggling to eat enough calories, particularly during a mass-gaining phase.
Cons
- Strong appetite stimulation can make fat gain easier, especially when calorie intake isn't controlled.
- Can reduce insulin sensitivity and increase blood glucose in some users.
- Users may experience edema, lethargy, joint discomfort, or numbness/tingling, and its long-term safety remains uncertain.
How the Five Compare
| Compound | Type | Main Role on a Cut | Suppresses Testosterone? | Main Concern |
|---|---|---|---|---|
| RAD-140 (Testolone) | SARM | Keeping muscle and strength in a deficit | Yes | Suppression, liver injury case reports, mood changes |
| Andarine (S4) | SARM | Harder, drier look; muscle retention | Yes | Vision changes, suppression |
| Ostarine (MK-2866) | SARM | Muscle retention; the most studied SARM | Yes, at the doses lifters use | Suppression, lower HDL |
| Cardarine (GW-501516) | PPAR-delta agonist (not a SARM) | More fat burning in muscle, endurance (mainly animal data) | No | Cancers in long-term rodent studies |
| MK-677 (Ibutamoren) | GH secretagogue (not a SARM) | Higher GH and IGF-1; recovery and sleep | No | Appetite, water retention, higher blood sugar |
Commonly Reported Doses and Cycle Lengths
There are no approved doses for any of these compounds. The figures below are what users commonly report, next to what human studies actually used. For more compounds, see our SARMs dosage chart.
| Compound | Commonly Reported Dose | Reported Cycle Length | Doses in Human Studies |
|---|---|---|---|
| RAD-140 | 10-20 mg/day | 6-8 weeks | No trials in healthy people |
| Andarine (S4) | 25-50 mg/day, split | 6-8 weeks | None published (animal data only) |
| Ostarine | 10-20 mg/day | 6-8 weeks | 1-3 mg/day |
| Cardarine | 10-20 mg/day | 6-10 weeks | Up to 10 mg/day in short metabolic trials |
| MK-677 | 10-25 mg/day | 8-16 weeks | 25 mg/day |
The doses used for bodybuilding are often far above anything tested in people, and none of these compounds has been studied for fat loss in healthy lifters.
PCT After a Cutting Cycle
RAD-140, Andarine and Ostarine all suppress natural testosterone, so users commonly run post-cycle therapy (PCT) after a cycle that includes any of them. Commonly reported protocols use clomiphene or tamoxifen for 3-4 weeks. These are prescription drugs, and none has been tested in trials for recovery after SARMs. Blood work before and after a cycle is the only way to know whether your testosterone has recovered. Our guide to PCT for SARMs covers what the evidence shows.
Cardarine and MK-677 don’t suppress testosterone, so they don’t call for PCT on their own. In a stack, the SARM decides.
Are SARMs Legal?
No SARM is approved by the FDA for any use. In the US, they are sold as research chemicals “not for human consumption”. The FDA has said that products marketed as dietary supplements containing SARMs are illegal, and it has warned that SARMs have been linked to serious risks, including liver toxicity and a higher risk of heart attack and stroke.
Rules differ by country, and some are stricter than the US. Check where you live before buying anything; our country-by-country guide covers the details.
SARMs, Cardarine and MK-677 are all on the World Anti-Doping Agency (WADA) prohibited list and banned at all times, so tested athletes can’t use any of them.
Possible Side Effects of SARMs on a Cut
- Testosterone suppression: RAD-140, Andarine and Ostarine all lower natural testosterone. Low libido, fatigue and flat mood can appear during the cycle or after it.
- Lower HDL cholesterol: SARMs lower HDL (“good”) cholesterol, even at low doses in trials, which matters for heart health.
- Liver injury: case reports describe liver injury, including jaundice, in people using RAD-140 and ligandrol products.
- Vision changes: Andarine (S4) is linked to a yellow tint and trouble adjusting to darkness, mostly at higher doses.
- Mood changes: irritability, aggression and anxiety are commonly reported, especially with RAD-140.
- Acne and hair shedding: androgen receptors in skin and hair follicles still respond to SARMs, so oily skin, acne and hair thinning are possible, mostly with stronger SARMs.
- Compound-specific risks: Cardarine caused cancers in long-term rodent studies; MK-677 raises appetite, causes water retention and can raise fasting blood sugar.
Where to Buy SARMs for Cutting
SARMs are sold as research chemicals, so nobody checks what is in the bottle before it ships. When researchers bought and analysed products sold online as SARMs, only about half actually contained a SARM, and many held a different amount from the label or other unapproved drugs.
If you do buy, use a vendor that publishes independent, batch-specific lab tests, and remember that a certificate of analysis confirms content, not safety. Prices change often, so check the current price on the product page. We cover SwissChems, the vendor behind the products above, in our Swiss Chems review.
The Bottom Line
No SARM melts fat. At best, RAD-140, Andarine and Ostarine help you keep muscle in a calorie deficit, at the cost of suppressed testosterone and unknown long-term risks.
- Only three of the five are SARMs: Cardarine is a PPAR-delta agonist halted over cancer findings in rodents, and MK-677 is a growth hormone secretagogue that raises appetite and blood sugar.
- All three SARMs suppress natural testosterone; users commonly run PCT and blood work after a cycle.
- The doses lifters use are far above those tested in people, and products sold online are often mislabeled.
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