Testosterone Enanthate
Test E · Test Enth · Delatestryl
Testosterone enanthate is a long-ester injectable form of testosterone, the primary male androgen and the prototypical anabolic-androgenic steroid. The enanthate ester gives it a plasma half-life of approximately 7-10 days, supporting weekly or twice-weekly injections. It is FDA-approved for primary and secondary male hypogonadism and for delayed puberty in adolescent males. It has been in continuous medical use in the United States since the 1950s.
Starting dose. 100-200mg/week — (TRT) | 300-500mg/week (athletic)
Split weekly total into 2 injections (Monday/Thursday) for stable blood levels given the 7-10 day half-life. Many TRT users now prefer every-3.5-days or twice-weekly subcutaneous injection at a half dose, which produces smoother levels. Compatible with other oil-based AAS in the same syringe.
Start here. Every protocol below is ordered lowest-first. Begin at the smallest effective dose, hold about a week to assess tolerance, and step up only if needed.
How it works
Testosterone binds the androgen receptor (AR) in skeletal muscle, brain, reproductive tissue, bone, and other target organs, driving masculinizing androgenic effects and anabolic protein-synthesis/nitrogen-retention effects. As the endogenous reference androgen, it has balanced anabolic-to-androgenic activity (1:1 ratio by definition).
Testosterone is a substrate for aromatase, which converts it to estradiol. This produces estrogenic effects - some beneficial (bone density, cognitive function, libido via estrogenic pathways) and some unwanted at supraphysiologic doses (water retention, gynecomastia, emotional reactivity). An aromatase inhibitor (Anastrozole or Aromasin) is typically used only when TRT doses push estrogen above the physiologic range or at athletic doses.
Testosterone is also a substrate for 5-alpha-reductase, converting to dihydrotestosterone (DHT). DHT drives the classical androgenic effects on hair (both scalp loss and body hair growth), skin, and prostate.
The enanthate ester is cleaved by plasma esterases to release free testosterone, with peak serum levels 2-3 days post-injection and a plasma half-life of ~7-10 days. Once-weekly injections produce significant trough-to-peak variation; many TRT users and all athletic-dose users split into 2x/week for smoother blood levels. At any supraphysiologic dose, endogenous testosterone production via the HPT axis is suppressed.
What to expect
First 2-3 weeks: energy, libido, and mood improvements as levels rise toward steady state. Strength gains begin to appear by end of week 3.
Weeks 4-8: full physiological effect, visible mass gains, strength plateau. Blood work checkpoint - estradiol, hematocrit, lipids.
Weeks 8-16: sustained benefits. TRT is typically lifelong; athletic cycles run 12-16 weeks and then transition to PCT or cruise.
Evidence
References for this compound are being re-checked against their source records. We are not showing them until each one is confirmed to support the claim it sits under.
Side effects & safety
Commonly reported
- Elevated hematocrit (polycythemia risk)
- Aromatization to estradiol - water retention, possible gyno without AI at athletic doses
- Acne and oily skin
- Accelerated hair loss in genetically predisposed users
- Suppression of endogenous testosterone production
Less common & notes
- Mood changes (positive or negative), sleep apnea exacerbation, lipid shift (HDL drop, LDL rise), cardiac strain at very high doses, prostate enlargement in older men (monitor PSA), gynecomastia if estrogen uncontrolled.
- Women taking testosterone for masculinizing HRT: expected virilization (voice deepening, facial/body hair, clitoral enlargement, menstrual cessation) - intended effect in HRT context but a side effect in cycling context.
- Rare but serious: thromboembolic events from polycythemia, significant cardiac events at supraphysiologic long-term use, severe acne or hair loss.
Pharmacokinetics
Post-injection
IM (oil depot); ~100% SubQ (depot)
Per injection - supports 1-2x weekly dosing
Hepatic metabolism. Renal excretion of metabolites. Aromatization to estradiol and 5-alpha-reduction to DHT are major metabolic pathways.
Storage. Store at controlled room temperature (20-25°C / 68-77°F). Protect from light. Oil-based solution - do not refrigerate or freeze (may precipitate). Draw with a larger gauge needle and inject with a smaller one (18G draw, 23-25G inject for IM; 27-29G for SubQ). Keep out of reach of children and in a locked location - Schedule III controlled substance in the United States.
Regulatory status
Schedule III controlled substance in the United States under the Anabolic Steroids Control Act of 1990. FDA-approved brand names include Delatestryl (Endo) and multiple generic formulations. Requires a prescription. Legitimate use cases include primary and secondary male hypogonadism, delayed puberty in adolescent males, and off-label uses including hormone therapy for transgender men. Possession or distribution without a valid prescription is a federal offense. Classified similarly in most international jurisdictions though some countries permit over-the-counter or pharmacy-access purchase.
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