Compound profile
Trenbolone
Also known as Tren, Trenbolone acetate (Tren A), Trenbolone enanthate (Tren E), Finaplix, Revalor (cattle implants)
Last reviewed October 2026
Educational only. A summary of published research, not medical advice or a recommendation. No doses are listed.
Quick take
A veterinary steroid made for cattle, known for strong effects on muscle and fat and for frequent, severe side effects.
- Class
- Anabolic steroids
- Status
- Veterinary only
- Evidence
- Mostly animal & lab studies
- Half-life
- Not well documented
Mechanism fingerprint
What it acts on, and how. Each chip links to that pathway on the map.
Binds the androgen receptor very strongly and doesn't convert to estrogen; it also acts on progesterone receptors. In cattle it increases muscle growth and feed efficiency.
What makes it different
Binds the androgen receptor very strongly, can't convert to estrogen, and is approved only as a cattle implant.
Compare side by side
Mechanism & pathways
-
Agonist
Androgen receptor
binds very strongly
Receptor for testosterone and DHT. Activating it builds muscle and drives male traits such as body hair and a deeper voice. Every anabolic steroid binds it.
-
Acts on
Progesterone receptor
Receptor for the hormone progesterone. Some “19-nor” steroids also act on it, which is linked to some of their side effects.
Evidence overview
Mostly animal & lab studies
No controlled human studies. Information comes from veterinary research and case reports of harm in people.
A breakdown into human, animal and cell studies hasn't been added for this compound yet.
Why it's used
In cattle, it speeds weight gain and improves feed efficiency. Bodybuilders use it for fast gains in muscle and strength and for fat loss, despite frequent, severe side effects.
Side effects & risks
Reported side effects
- Insomnia and night sweats
- Aggression, anxiety and mood swings
- Coughing fits right after injection (often called “tren cough”)
- Acne and oily skin
- Lower libido and erectile problems
Risks and warnings
- Raises blood pressure and sharply lowers HDL (“good”) cholesterol
- Long-term use is linked to high blood pressure, heart muscle damage (cardiomyopathy), heart attacks and early death.
- Shuts down the body's own testosterone production: testicles shrink and sperm counts fall, and recovery after stopping can take months or be incomplete.
- Irritability and aggression while using, and depression after stopping; dependence can develop.
- In women: masculinizing effects (deeper voice, facial and body hair, clitoral enlargement) that can be permanent.
- Human products are made by underground labs, often from cattle implant powder; quality is unknown
- Schedule III controlled substance in the US: illegal to possess without a prescription.
- Prohibited in sport by the World Anti-Doping Agency (WADA).
FAQ
Short answers taken from this profile.
What is Trenbolone?
A veterinary steroid made for cattle, known for strong effects on muscle and fat and for frequent, severe side effects.
How does Trenbolone work?
Binds the androgen receptor very strongly and doesn't convert to estrogen; it also acts on progesterone receptors. In cattle it increases muscle growth and feed efficiency.
What receptors or pathways does Trenbolone act on?
androgen receptor (agonist; binds very strongly) and progesterone receptor (acts on).
How is Trenbolone different from similar compounds?
Binds the androgen receptor very strongly, can't convert to estrogen, and is approved only as a cattle implant.
Is Trenbolone approved?
Approved only as an implant to speed weight gain in beef cattle; never approved for use in humans. The cattle implant labels state “not for use in humans.”
What has Trenbolone been studied for?
In cattle, it speeds weight gain and improves feed efficiency. Bodybuilders use it for fast gains in muscle and strength and for fat loss, despite frequent, severe side effects.
How strong is the evidence?
Mostly animal & lab studies. No controlled human studies. Information comes from veterinary research and case reports of harm in people.
What are the main risks?
Raises blood pressure and sharply lowers HDL (“good”) cholesterol. Long-term use is linked to high blood pressure, heart muscle damage (cardiomyopathy), heart attacks and early death. Shuts down the body's own testosterone production: testicles shrink and sperm counts fall, and recovery after stopping can take months or be incomplete. More are listed under risks and warnings.
Sources
- FDA animal drug labeling for Revalor and Finaplix implants (“not for use in humans”).
- Kicman AT. Pharmacology of anabolic steroids. Br J Pharmacol 2008.
- Pope HG et al. Adverse health consequences of performance-enhancing drugs: an Endocrine Society scientific statement. Endocr Rev 2014.