Trenbolone Enanthate
A long-ester form of trenbolone, an extremely potent 19-nor androgen that does not aromatise but is strongly progestogenic. It produces dramatic strength and recomposition effects but carries the heaviest side-effect burden of common anabolic steroids — night sweats, insomnia, aggression, cardiovascular strain and 'tren cough'. Almost all data are veterinary or anecdotal; no human trials exist.
01 Overview
Trenbolone is a 19-nortestosterone with an 11,9-diene structure that makes it bind the androgen and progesterone receptors extremely strongly while being completely resistant to aromatase. It was developed only for veterinary and livestock use (as the acetate); the enanthate ester is a purely underground bodybuilding formulation with no human clinical development, which is why its research score sits low despite widespread use — the evidence is essentially veterinary pharmacology plus dense anecdote.
Its potency cuts both ways: users report rapid, high-quality strength and body-recomposition, but also the most severe and characteristic side effects of any popular steroid — heavy night sweats, insomnia, mood disturbance and aggression, elevated prolactin/progestogenic effects, cardiovascular strain, and reduced aerobic capacity. Because it does not aromatise, low-oestrogen effects can occur if run without an aromatising base. The enanthate ester extends dosing to twice weekly versus the acetate's every-other-day schedule.
02 Mechanism
Exceptionally high-affinity androgen-receptor agonist that also activates the progesterone receptor; resistant to aromatase and 5-alpha reductase, driving potent anabolic and nutrient-partitioning effects with strong progestogenic activity.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Common | 200–300 mg/wk | IM | Very potent; low doses are effective. Injected twice weekly. |
| Heavy | 400–500 mg/wk | IM | Side-effect burden rises steeply; not advisable. |
Ester comparison
| Ester | Half-life | Injection freq. | Testosterone by mass |
|---|
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Rapid strength and muscle gainPotent anabolic and anti-catabolic effect demonstrated in livestock; human evidence is anecdotal. | Preclinical | ||
| Body recomposition / fat lossStrong nutrient-partitioning effect; animal studies show simultaneous lean gain and fat reduction. | Preclinical | ||
| Increased feed efficiency / nutrient partitioningThe basis of its veterinary use for livestock growth. | Preclinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Night sweats and insomniaProfuse night sweating and disrupted sleep are hallmark trenbolone effects. | Moderate | Very common | Anecdotal | |
| Mood disturbance and aggressionIrritability, anxiety and aggression are commonly reported; can be marked. | Moderate | Common | Anecdotal | |
| Cardiovascular strain and reduced enduranceMarked HDL suppression, blood pressure elevation and notably reduced aerobic capacity. | Severe | Common | Anecdotal | |
| Progestogenic effects (prolactin-related)Libido/erectile problems and gynaecomastia via progesterone-receptor activity and prolactin elevation, despite no aromatisation. | Moderate | Common | Anecdotal |