Anabolic steroidAndrogenTestosterone esterInjectable
Testosterone Enanthate
Also known as Test E · Delatestryl · Xyosted · Testoviron Depot
17β-Hydroxyandrost-4-en-3-one 17-heptanoate
17β-Hydroxyandrost-4-en-3-one 17-heptanoate
Testosterone enanthate is a long-acting ester of testosterone, the primary endogenous androgen in men. It is a licensed medicine for male hypogonadism and the most widely used compound in non-medical performance and physique contexts — both on its own and as the base of nearly every multi-compound protocol. Because it is bioidentical to endogenous testosterone once the ester cleaves, its effect profile is the reference point against which every other anabolic compound is described.
01 Overview
Enanthate is a seven-carbon (heptanoate) ester attached at the 17β position. The ester makes the molecule more lipophilic, so an intramuscular oil depot releases it slowly over days rather than hours; esterases then cleave it to free testosterone. The ester itself has no independent activity — a milligram of enanthate delivers slightly less testosterone by mass than a milligram of the shorter propionate ester, which is why doses are not directly comparable across esters.
Its ~4.5 day half-life gives a serum curve that peaks around 24–48 hours after injection and declines over the following week. Once- or twice-weekly injection is the usual consequence; twice-weekly produces a flatter curve and, in practice, fewer swings in mood, libido, and oestradiol-related side effects.
02 Mechanism
Testosterone is an agonist at the androgen receptor. AR binding drives transcription of genes governing muscle protein synthesis, satellite cell activation, and erythropoiesis. It also acts through two active metabolites, which is where most of its side effect profile actually originates:
| Aromatase → oestradiol | Drives the beneficial effects on bone density, libido, lipids and joint comfort — and, in excess, gynaecomastia and water retention. Suppressing it too aggressively causes its own problems. |
| 5α-reductase → DHT | Roughly 3–5× the AR affinity of testosterone. Responsible for most androgenic effects: acne, scalp hair loss in genetically predisposed individuals, prostate growth. |
Why the 100:100 rating is misleading. The anabolic:androgenic ratio comes from a 1950s rat assay (levator ani muscle vs. ventral prostate weight), and testosterone is defined as 100:100 by convention rather than measurement. It predicts human outcomes poorly. It is listed here because it is the shared vocabulary of the field, not because it is a good metric.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Therapeutic | 75–200 mg/wk | IM | Licensed TRT range. Targets mid-normal serum levels (400–700 ng/dL trough). Usually split into two doses. |
| Common | 300–500 mg/wk | IM | Typical first non-medical protocol. Supraphysiological; expect full HPTA shutdown and measurable lipid and haematocrit shifts. |
| High | 500–750 mg/wk | IM | Lean mass gains continue to scale across this range; side effect frequency scales faster. Oestrogen management usually becomes necessary. |
| Very high | 750 mg+/wk | IM | Little controlled human data above this point. Cardiovascular and haematological effects become the limiting factor, not androgenic ones. |
Dose–response, measured. In the most-cited controlled trial, 600 mg/week for 10 weeks produced +3.2 kg fat-free mass with no training, and +6.1 kg combined with resistance training — against +1.9 kg for training on placebo. This is the figure that claims on both sides of the argument get compared against.
Ester comparison
| Ester | Half-life | Injection freq. | Testosterone by mass |
|---|---|---|---|
| Propionate | ~0.8 d | Every other day | 83% |
| Enanthate | ~4.5 d | 1–2× weekly | 72% |
| Cypionate | ~5 d | 1–2× weekly | 70% |
| Undecanoate | ~34 d | Every 10–14 weeks | 63% |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Increased lean body massDose-dependent and largely independent of training | +3–6 kg / 10 wk | Clinical | |
| Increased maximal strengthLeg press and bench press, 600 mg/wk | +9–22% | Clinical | |
| Reduced fat massModest; larger at higher doses and in hypogonadal men | −1–2 kg | Clinical | |
| Improved libido and erectile functionReliable in hypogonadal men; little added benefit if already eugonadal | Marked | Clinical | |
| Improved mood and energyDemonstrated where baseline testosterone is low | Moderate | Clinical | |
| Increased bone mineral densityLumbar spine, over 12–36 months of therapy | +3–8% | Clinical | |
| Faster recovery between sessionsConsistently reported; not isolated from the lean mass effect in controlled work | Unquantified | Anecdotal | |
| Improved cognition and memoryTrials in older men have not shown a consistent effect despite frequent marketing claims | None demonstrated | Disputed |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| HPTA suppressionTesticular atrophy and cessation of spermatogenesis. Usually reverses over 3–12 months; occasionally does not. | Severe | Universal | Clinical | |
| ErythrocytosisRaised haematocrit and blood viscosity. The most consistently abnormal lab value at supraphysiological doses. | Severe | Common | Clinical | |
| HDL suppressionTypically −20 to −30% at therapeutic doses; substantially more above them. | Moderate | Very common | Clinical | |
| Elevated blood pressurePartly fluid retention, partly raised haematocrit. | Moderate | Common | Clinical | |
| Left ventricular hypertrophyReduced ejection fraction and greater coronary plaque volume in long-term users versus non-using lifters. | Life-threatening | Long-term use | Observational | |
| GynaecomastiaFrom aromatisation to oestradiol. Glandular tissue does not regress once established. | Moderate | Common | Clinical | |
| AcneTruncal and facial, DHT-mediated. Dose-related. | Mild | Very common | Clinical | |
| Accelerated androgenic alopeciaOnly in those genetically predisposed — it advances existing susceptibility rather than creating it. | Mild | Common (predisposed) | Clinical | |
| Irritability and aggressionRare at therapeutic doses. Blinded trials show a real but small effect at high doses, concentrated in a minority of subjects — far below the popular characterisation. | Moderate | Uncommon | Observational | |
| Post-cessation depressionOccurs during the hypogonadal window after discontinuation; can persist for months. | Severe | Common | Observational | |
| Prostate cancer initiationLong assumed, and the basis of decades of prescribing caution. Trial and cohort data have not supported a causal link; testosterone does accelerate growth of pre-existing hormone-sensitive disease. | Life-threatening | Not established | Disputed | |
| Major adverse cardiac events at therapeutic dosesA 2013 retrospective study reporting increased events drove an FDA label change; it was widely criticised, and a 2023 randomised trial in 5,200 men at cardiovascular risk found non-inferiority to placebo. | Life-threatening | Not established | Disputed |
06 Commonly used with
What testosterone is combined with, and why. This is about intent rather than safety — the interactions table below covers what is dangerous. Nothing here is listed without what it costs.
| Compound | Frequency | Purpose & trade-off |
|---|---|---|
| Stacked compounds | ||
| Nandrolone DecanoateDeca | Added for mass and joint comfort on longer runs; the classic pairing.Trade-off: Progestogenic activity and prolactin-related sexual dysfunction, plus a 12–18 month detection window. | |
| MethandienoneDianabol · oral | Run for the first 4–6 weeks to produce results while the long ester saturates.Trade-off: 17α-alkylated — the largest single contributor to lipid and hepatic strain in a typical stack. | |
| OxandroloneAnavar · oral | Strength and definition without added water retention; the usual choice for a cutting phase.Trade-off: Severe HDL suppression relative to its mild reputation. | |
| DrostanoloneMasteron | DHT-derived; cosmetic hardening at low body fat and mild anti-oestrogenic action.Trade-off: Strongly androgenic — accelerates hair loss and acne. Does nothing visible above ~12% body fat. | |
| Trenbolone Acetate | Potent recomposition; substantially stronger than the dose implies.Trade-off: By a wide margin the highest side effect burden in common use — sleep, mood, cardiovascular and prolactin. Not a reasonable early addition. | |
| Support & ancillaries | ||
| AnastrozoleAromatase inhibitor | Controls oestradiol → counters gynaecomastia, water retention and the blood pressure that follows.Trade-off: Over-suppression is the more common error. Dose against a sensitive assay, never on a schedule. | |
| hCG | Maintains testicular volume and function on cycle, easing later recovery and preserving fertility.Trade-off: Raises aromatisation independently — expect to adjust oestrogen management alongside it. | |
| Finasteride | Blunts DHT-mediated hair loss without affecting the anabolic response.Trade-off: No protection against non-DHT compounds; lowers PSA readings, which complicates prostate screening. | |
| Telmisartan or equivalentAntihypertensive | Manages blood pressure where oestrogen and haematocrit control aren't enough on their own.Trade-off: Prescription medicine with its own monitoring requirements — properly a physician's decision. | |
| Post-cycle | ||
| TamoxifenSERM | Restarts LH output after clearance; also the first-line treatment for early gynaecomastia on cycle.Trade-off: Timing against ester clearance is what determines whether it works — begun too early it is largely wasted. | |
| ClomifeneSERM | Stronger stimulation of the axis than tamoxifen, often run alongside it.Trade-off: Notably worse mood and visual side effects in a minority — the reason many switch away from it. | |
07 Bloodwork
| Marker | Direction | Typical magnitude | Note |
|---|---|---|---|
| Haematocrit | ↑ Increase | +3–8 pts | Action threshold commonly set at 54% |
| HDL cholesterol | ↓ Decrease | −20–40% | Recovers within weeks of cessation |
| LDL cholesterol | ↑ Variable | 0 to +15% | Much smaller effect than with oral compounds |
| Oestradiol (sensitive) | ↑ Increase | Proportional | Tracks dose and body fat. Order the sensitive assay, not the standard one |
| LH / FSH | ↓ Decrease | → undetectable | Expected on any suppressive dose — not itself a warning sign |
| SHBG | ↓ Decrease | −10–30% | Raises the free testosterone fraction relative to total |
| ALT / AST | — Minimal | ± | Injectable esters are not hepatotoxic; elevations usually reflect training |
| PSA | ↑ Increase | +0.2–0.5 | A small rise on starting therapy is expected |
08 Interactions
| With | Severity | Description |
|---|---|---|
| Oral 17α-alkylated steroids | Unsafe | Compounds lipid and hepatic strain. The combination, not testosterone itself, drives most of the liver findings attributed to "steroids". |
| Warfarin / anticoagulants | Unsafe | Androgens potentiate anticoagulant effect; INR requires monitoring and dose adjustment. |
| Aromatase inhibitors | Caution | Effective for controlling oestradiol; over-suppression causes joint pain, low libido and bone loss. The failure mode is usually too much, not too little. |
| Stimulants incl. clenbuterol | Caution | Additive cardiovascular load on top of raised haematocrit and blood pressure. |
| Insulin / antidiabetics | Caution | Testosterone improves insulin sensitivity; existing medication may need downward adjustment. |
| Finasteride / dutasteride | Low risk | Blunts DHT-mediated hair loss without affecting anabolic response. No protection against non-DHT compounds. |
09 Legal status
United States
Schedule III controlled
Prescription only · as of Jan 2026
United Kingdom
Class C controlled
Personal possession lawful · as of Jan 2026
Netherlands
Prescription only · Geneesmiddelenwet
as of Jan 2026
Germany
Prescription only · AMG
Quantity thresholds apply · as of Jan 2026
Canada
Schedule IV controlled
as of Jan 2026
Australia
Schedule 4 · state offences apply
as of Jan 2026
10 References
The effects of supraphysiologic doses of testosterone on muscle size and strength in normal menBhasin S. et al. — New England Journal of Medicine, 1996 · doi:10.1056/NEJM199607043350101
Cardiovascular safety of testosterone-replacement therapy (TRAVERSE)Lincoff A.M. et al. — New England Journal of Medicine, 2023 · doi:10.1056/NEJMoa2215025
Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guidelineBhasin S. et al. — J Clin Endocrinol Metab, 2018
Cardiovascular toxicity of illicit anabolic-androgenic steroid useBaggish A.L. et al. — Circulation, 2017
Association of testosterone therapy with mortality, myocardial infarction and strokeVigen R. et al. — JAMA, 2013 · origin of the disputed cardiac claim
11 Discussion0 comments
Discussion is moderated. No sourcing, vendor names or price talk — those comments are removed, and repeat posts are banned.
This page is reference information, not medical advice. Doses and protocols are documented as they appear in the clinical literature and in practice — describing them is not a recommendation to use them. Countermeasures listed here are not a substitute for a physician. Legal status varies by jurisdiction and changes.