Clenbuterol vs Enobosarm
Written by Aaron CuhaReviewed Sep 2026
The short answer
Two non steroid routes to lean mass, both unapproved for people in the United States. The first human trial of clenbuterol with a dummy group, published in 2025, added 0.91 kg of lean mass in two weeks. It did not change fat at all, and it cut peak fitness, measured as maximum oxygen use, by 7 percent.
- Clenbuterol people
- 11
- Clenbuterol nulls
- 2
- Enobosarm people
- 159
- Enobosarm nulls
- 1
Dose
No human dose established
Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose.
2 completed trials, 11 people given it
Dose
No human dose established
Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose.
1 completed trial, 159 people given it
First-hand reports are counted on each profile and never added together. This page sets two published records side by side. It does not pick a winner.
Column A
ClenbuterolClenbuterol hydrochloride, selective beta-2 adrenergic agonist
The first proper human study, in 2025, found two weeks of clenbuterol added 0.91 kg of lean mass, did nothing to fat, and cut fitness (the most oxygen the body can use) by 7 percent. It is not approved for people in the United States. It has poisoned people in outbreaks, from tainted meat and from heroin cut with it.
Column B
EnobosarmEnobosarm (ostarine, GTx-024, MK-2866)
The drug sold on the grey market as ostarine. In proper studies, 3 mg added to semaglutide cut muscle loss by 71 percent in adults over 60.
Side by side, on the facts we can check
| What we compare | Clenbuterol | Enobosarm |
|---|---|---|
| Category | Muscle & Performance | Muscle & Performance |
| FDA status | Not approved for human use in the United States, at any dose or for any use. Its only US approval is for animals, as a drug that opens the airways in horses. Some other countries license it for people, to open the airways. WADA, the world anti-doping agency, bans it in sport as a muscle-building drug. | Investigational; not approved for any use. SARMs are lab-made drugs that act like testosterone. Unapproved SARM products are illegal to sell as supplements. |
| Half-life | About 35 hours in plasma in healthy volunteers, which is long for a beta-2 agonist and is why effects and detection both persist for days. | ~24 hours (once-daily oral) |
| Molecular weight | 277.2 Da as the free base; the hydrochloride salt used in products is 313.7 Da | 389.3 Da |
| How it works | It switches on beta-2 receptors. In muscle, that sets off a chain of signals inside the cell. In the 2025 human study that chain was strongly switched on, along with a growth signal that drove the lean mass gain. The same receptor type in the heart and blood vessels causes the racing heart, shaking and low potassium seen in poisonings. Repeated doses make the receptor go numb. In that study the signal faded across the two weeks. That is the science behind the on-and-off cycling users worked out by trial and error. | It switches on the androgen receptor mostly in muscle and bone. That helps build muscle protein, with less effect on the prostate and skin than testosterone. |
| Studies in people | 6 | 3 |
| Evidence | Limited: 2 completed trials, 11 people given it | Moderate: 1 completed trial, 159 people given it |
| Legal status, US | Not approved for human use; animal drug only | Investigational; SARMs are not legal supplement ingredients and are banned in sport (WADA) |
Frequently asked questions
What is the difference between Clenbuterol and Enobosarm?
Clenbuterol: The first proper human study, in 2025, found two weeks of clenbuterol added 0.91 kg of lean mass, did nothing to fat, and cut fitness (the most oxygen the body can use) by 7 percent. It is not approved for people in the United States. It has poisoned people in outbreaks, from tainted meat and from heroin cut with it. Enobosarm: The drug sold on the grey market as ostarine. In proper studies, 3 mg added to semaglutide cut muscle loss by 71 percent in adults over 60.
Which has stronger research evidence, Clenbuterol or Enobosarm?
Each compound gets a band worked out from facts we counted, with the math shown. Clenbuterol is Limited (2 completed trials, 11 people given it). Enobosarm is Moderate (1 completed trial, 159 people given it). That counts how much has been done in people. It does not rate whether either one works, and neither one is called the winner.
Are Clenbuterol and Enobosarm FDA-approved?
Clenbuterol: Not approved for human use in the United States, at any dose or for any use. Its only US approval is for animals, as a drug that opens the airways in horses. Some other countries license it for people, to open the airways. WADA, the world anti-doping agency, bans it in sport as a muscle-building drug.. Enobosarm: Investigational; not approved for any use. SARMs are lab-made drugs that act like testosterone. Unapproved SARM products are illegal to sell as supplements..
Reviewed Sep 2026. This page puts two published records side by side. It is for learning, and it is not medical advice. When this site shows a dose, it is the dose a trial or a clinic actually used, or what people say they did, with the source attached. None of it tells you what to take.