What Is Testosterone Enanthate?
Testosterone enanthate is an oil-based injectable testosterone with a 4-5 day half-life, designed to deliver steady hormone levels through weekly or biweekly shots.1 It's functionally identical to testosterone cypionate but with a slightly shorter ester chain, causing faster initial absorption and higher early peaks.
FDA-approved since 1953 for treating primary and secondary hypogonadism, it's available as brand-name Delatestryl (intramuscular) and Xyosted (subcutaneous auto-injector).1 Compounded versions are widely available through specialized pharmacies at lower cost.
It's a Schedule III controlled substance — legal only with a prescription. Most TRT protocols use 100-200 mg weekly, though FDA labeling for Delatestryl lists 200-400 mg every 2-4 weeks.1
Best for men who want injectable TRT without committing to the twice-weekly frequency that cypionate sometimes requires. Also a good choice if cypionate isn't available through your pharmacy or insurance.
Testosterone Enanthate at a Glance
Testosterone enanthate is an oil-based injectable testosterone with a 4-5 day half-life, requiring weekly or biweekly dosing to maintain stable levels.
It's the most widely prescribed injectable outside the US and a cost-effective alternative to cypionate with near-identical clinical outcomes.
- Mechanism: Ester prodrug releases free testosterone gradually from injection depot
- Dosing: 100-200 mg intramuscular or subcutaneous weekly
- Safety: Monitor hematocrit quarterly; hold if >54%
- Cost: $30-50/month generic, $800-1000/month Xyosted brand
How Testosterone Enanthate Works
Enanthate is a prodrug — your body's esterase enzymes cleave the enanthic acid chain to release free testosterone into your bloodstream.1 The ester chain slows absorption from the injection site, creating an oil depot that releases testosterone gradually over several days.
Once free, testosterone binds to androgen receptors in muscle, bone, brain, and reproductive tissue. The hormone-receptor complex moves into the cell nucleus and turns on genes for protein synthesis, red blood cell production, and bone density maintenance.2
About 40% of circulating testosterone binds tightly to sex hormone-binding globulin (SHBG), 2% floats free, and the rest loosely attaches to albumin.1 Only the free and albumin-bound fractions are biologically active.
Peak Levels and Metabolism
Intramuscular shots peak around 12 hours post-injection, with levels staying in the physiologic range (300-1100 ng/dL) for 7-14 days depending on dose.1 The shorter ester means higher peaks and steeper troughs than cypionate — manageable with weekly dosing but noticeable if you stretch to biweekly.
Enzymes in the liver (CYP3A4) break testosterone down into metabolites. Some converts to DHT via 5α-reductase (driving hair loss and prostate growth), some to estradiol via aromatase (supporting bone health but potentially causing gynecomastia).1
Clinical Response Timeline
Sexual function improves first — libido and erections typically rebound within 3-6 weeks. Energy and mood stabilize by 6-12 weeks. Muscle mass and strength gains take 12-24 weeks and continue accruing with sustained treatment.3
Phase 3 trials showed 89-91% of patients reached target testosterone levels (300-1100 ng/dL) with weekly dosing, compared to 5-10% on placebo.1 Long-term extensions out to 182 weeks confirm sustained efficacy without tolerance.
Sex Hormone-Binding Globulin (SHBG) is a plasma protein that binds approximately 40% of circulating testosterone, making it unavailable for biological activity. Only free and albumin-bound testosterone fractions can activate androgen receptors.
Dosing and Administration
Standard TRT protocols start at 100-150 mg weekly, injected into the thigh or glute muscle. Most men self-administer at home after the first supervised injection. Rotate sites to prevent tissue irritation.
The Xyosted auto-injector delivers subcutaneous shots (75-100 mg weekly) through an easy-push mechanism — no drawing from a vial.1 Traditional Delatestryl vials require manual drawing with a syringe.
| Parameter | Standard Protocol | Clinical Notes |
|---|---|---|
| Starting Dose | 100-150 mg IM weekly or 75 mg SC weekly | Older men or first-time TRT users may start at 75-100 mg |
| Titration Window | Adjust after 6-8 weeks | Increase by 25-50 mg/week if trough <400 ng/dL or symptoms persist |
| Target Trough Level | 400-700 ng/dL mid-week | Measure 3-4 days post-injection, not at peak |
| Baseline Labs | Total testosterone (2x morning), free testosterone, estradiol, CBC, CMP, lipids, PSA | Two morning draws confirm diagnosis (both <300 ng/dL) |
| Follow-Up Labs | Weeks 6-8, 12, then quarterly | Monitor hematocrit (hold if >54%), PSA (hold if >4 ng/mL or rapid rise), lipids |
Side Effects and Safety Profile
Most side effects stem from supraphysiologic peaks or aromatization to estradiol. Common issues include acne, oily skin, and injection site soreness — typically mild and manageable with technique adjustments.
Serious risks involve hematocrit elevation (polycythemia), cardiovascular strain, and suppression of natural testosterone production.1 Regular monitoring catches these early.
| Frequency | Side Effect | Management Strategy |
|---|---|---|
| Common (>10%) | Acne, oily skin | Topical benzoyl peroxide, lower dose if severe |
| Common (>10%) | Injection site pain/redness | Rotate sites, warm vial before injection, use smaller needle |
| Common (>10%) | Testicular atrophy | Expected — testes shrink when exogenous testosterone suppresses LH/FSH |
| Occasional (1-10%) | Elevated hematocrit | Donate blood if >52%, reduce dose if >54%, hold therapy if >55% |
| Occasional (1-10%) | Gynecomastia (breast tissue) | Add aromatase inhibitor if estradiol >40-50 pg/mL with symptoms |
| Occasional (1-10%) | Hair loss (androgenic alopecia) | Genetic predisposition — finasteride or topical minoxidil may slow |
| Rare (<1%) | Sleep apnea worsening | Screen with STOP-BANG, refer for sleep study if high risk |
| Rare (<1%) | Venous thromboembolism | Higher risk with hematocrit >54% or known clotting disorder |
Cost and Access
Generic testosterone enanthate costs $30-50 per month through compounding pharmacies — the most affordable injectable option. Brand-name Delatestryl runs $50-80 monthly. Xyosted auto-injector is the outlier at $800-1000 monthly without insurance.
Insurance typically covers generic enanthate if you meet diagnostic criteria (two morning testosterone readings <300 ng/dL plus symptoms). Prior authorization is standard. Most plans don't cover Xyosted unless you've failed traditional injections.
Where to Get It
Local urologists and endocrinologists prescribe enanthate through retail pharmacies. Telehealth TRT clinics ship compounded enanthate directly to your door, usually with faster titration protocols than traditional clinics.
Compounding pharmacies offer custom concentrations (200 mg/mL is standard) and preservative-free options for men sensitive to benzyl alcohol. Most accept GoodRx coupons if you're paying cash.
Expect to pay $50-100 for your first month (includes needles, syringes, alcohol swabs), then $30-60 monthly for refills. Lab monitoring adds $100-200 quarterly depending on your insurance.