Prescription only
Testosterone Enanthate
Sold as Xyosted.
What the label states
Two products, one ester, two different labelled regimens. The generic 200 mg/mL intramuscular vial states: “Male hypogonadism: As replacement therapy, i.e., for eunuchism, the suggested dosage is 50 to 400 mg every 2 to 4 weeks.” The same label adds: “In general, total doses above 400 mg per month are not required because of the prolonged action of the preparation. Injections more frequently than every two weeks are rarely indicated.” XYOSTED, the subcutaneous autoinjector, states instead: “The starting dose of XYOSTED is 75 mg, administered subcutaneously in the abdominal region once a week.”
Quoted from the approved product label. Clinics commonly prescribe differently — more frequent, smaller injections of the same weekly total are routine — and where this site describes that, it is named as practice rather than as labelling.
- Route
- Intramuscular, deep in the gluteal muscle, for the vial — or subcutaneous in the abdomen only, for the XYOSTED autoinjector. The same ester, two labelled routes.
- Vehicle
- Sesame oil. The Hikma 200 mg/mL vial is preserved with chlorobutanol 5 mg/mL; the XYOSTED autoinjector is sesame oil with no preservative at all.
- Usual barrel
- 1 mL luer-lock
- Strengths covered
- No strength page yet
Which syringe, and why
This applies to the vial, and only to the vial. Testosterone enanthate is dissolved in sesame oil — a viscous vehicle — and the label directs you to “slowly inject the preparation deeply into the gluteal muscle”. That combination is what selects a luer-lock barrel with a detachable needle: you draw the cold oil through a wide gauge (18–21G) because a fine one takes minutes, then change to a finer needle to inject (22–25G), and you need 1 to 1.5 inches of needle to reach gluteal muscle in most adults. A fixed 29–31G insulin needle fails on both counts, and an insulin barrel is numbered in units rather than millilitres, which is the conversion people get wrong. XYOSTED is not this problem at all: it is a sealed 0.5 mL autoinjector that you do not draw, do not measure and cannot dial — the dose is whichever of the three strengths was dispensed, and the label says to discard the unused portion.
Administration
- 1
Confirm the diagnosis first
Both labels open with the same requirement: serum testosterone measured in the morning on at least two separate days, both results below the normal range, before therapy is initiated. This is not a formality — it is the sentence that distinguishes replacement from supplementation.
- 2
Check which product you actually have
A 5 mL multi-dose vial of 200 mg/mL and a single-use XYOSTED autoinjector are the same molecule with opposite instructions: intramuscular versus subcutaneous, every two to four weeks versus weekly, drawn versus sealed. Nothing below transfers from one to the other.
- 3
Inspect the vial or autoinjector
The solution is clear and colourless to pale yellow. The vial label notes that “Use of a wet needle or wet syringe may cause the solution to become cloudy; however this does not affect the potency of the material.” The XYOSTED label is stricter: do not use if the liquid is cloudy, if visible particles are present, or if the seal is broken.
- 4
Warm the vial if crystals have formed
The label gives the fix directly: “Warming and rotating the vial between the palms of the hands will redissolve any crystals that may have formed during storage at low temperatures.” Crystals are a temperature artefact, not a spoiled vial.
- 5
Draw with a wide needle, inject with a finer one
Sesame oil draws slowly. Using a wider gauge to fill the barrel and swapping to a finer one to inject is common practice rather than a labelled instruction, and it is one of the reasons the luer-lock barrel is the right instrument here.
- 6
Inject as the label for your product directs
The vial: slowly, deeply into the gluteal muscle, avoiding intravascular injection. XYOSTED: subcutaneously in the abdominal region only — its label states “Avoid intramuscular or intravascular injection.” Your prescriber confirms site and technique.
- 7
Rotate sites and write the dose down
Alternate sites between doses and log the date and amount. Because no ester half-life is labelled, a written record of when you injected is what makes a trough result interpretable — there is no published decay curve to reconstruct it from.
Storage
- —Vial: store at 20–25 °C (68–77 °F), the USP controlled room temperature range on the label.
- —XYOSTED: “Do Not refrigerate or freeze. Use at room temperature. Store at controlled room temperature, 20°C to 25°C (68°F - 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F). Protect from light (keep in carton until time of use).”
- —Neither product is refrigerated. Cold thickens sesame oil and precipitates crystals; warming the vial in the hands reverses it.
- —XYOSTED is single-dose. The label instructs discarding the unused portion — there is no second draw from an autoinjector.
- —An entered multi-dose vial carries your pharmacy’s beyond-use date rather than a figure printed on the carton.
Monitoring
| Marker | When | Why |
|---|---|---|
| Total testosterone, at a trough | XYOSTED: 7 days after the most recent dose, following 6 weeks of dosing and after each adjustment. Vial: as your prescriber directs | The XYOSTED label names the target outright — “A trough concentration between 350 ng/dL and 650 ng/dL generally provides testosterone exposures in the normal range during the entire dosing interval” — and adjusts in 25 mg steps around it. The generic vial label names no target at all. A measured trough is also the only way to know where a dose is landing, because neither label publishes an ester half-life to calculate from. |
| Haematocrit | Before starting, then approximately every 3 months | The XYOSTED label is explicit: “Evaluate hematocrit approximately every 3 months while the patient is on XYOSTED,” stop if it becomes elevated, and stop permanently if it rises again on restarting. Erythrocytosis is the commonest clinically significant effect of testosterone therapy. |
| Blood pressure | Periodically, and before starting if hypertension is known | Both labels carry the same warning: testosterone can increase blood pressure, and testosterone products “are not recommended for use in patients with uncontrolled hypertension.” Note that XYOSTED’s blood-pressure BOXED warning was removed in March 2025 — the risk statement stayed, its boxed status did not. |
| PSA and prostate symptoms | Baseline and periodically, particularly over 40 | The labels direct monitoring PSA periodically and watching men with benign prostatic hyperplasia for worsening symptoms. The Endocrine Society guideline sets out who is at higher baseline risk. |
| Signs of DVT or pulmonary embolism | At any point during therapy | Both labels carry postmarketing reports of venous thromboembolism and direct evaluating pain, oedema, warmth or erythema in a lower limb, or acute shortness of breath, rather than waiting for a scheduled visit. |
Frequently asked questions
- What is the half-life of testosterone enanthate?
- The label does not state one, and this page will not invent one. The only half-life figure anywhere in the Hikma testosterone enanthate label is for testosterone itself, not for the ester: “There are considerable variations of the half-life of testosterone as reported in the literature, ranging from 10 to 100 minutes.” That is minutes, it describes unesterified hormone, and it is not the depot behaviour anyone means when they ask this question. The widely repeated figure of about 4.5 days appears on neither testosterone enanthate label we fetched, and we could not trace it to a primary source we could cite and re-check, so it is absent here. What the label does say about duration is qualitative: esters in oil “are absorbed slowly from the lipid phase; thus testosterone enanthate can be given at intervals of two to four weeks.”
- How is testosterone enanthate different from testosterone cypionate?
- Different ester, different oil. Enanthate is a seven-carbon chain dissolved in sesame oil with chlorobutanol; cypionate is an eight-carbon chain in cottonseed oil with benzyl benzoate and benzyl alcohol. The labelled range is the same on both — 50 to 400 mg every two to four weeks for replacement in the hypogonadal male — and both specify deep intramuscular injection. The practical difference most likely to matter to you is the oil, not the ester: a sesame allergy rules out enanthate and a cottonseed sensitivity rules out cypionate.
- Can testosterone enanthate be injected subcutaneously?
- For one product, yes, and it is the labelled route. XYOSTED is testosterone enanthate in a subcutaneous autoinjector, and its label says the opposite of the vial’s: “XYOSTED is for subcutaneous injection in the abdominal region only. Avoid intramuscular or intravascular injection.” The generic 200 mg/mL vial is labelled for intramuscular use, deep in the gluteal muscle. So the answer depends entirely on which product is in front of you, and swapping the route of a product on your own is not something either label supports.
- Does XYOSTED still carry a boxed warning?
- No, and this is a place where most secondary sources are out of date. XYOSTED launched with a boxed warning about blood pressure increases. The SPL’s own Recent Major Changes section records “Boxed Warnings, Blood Pressure Increases Removed 03/2025”, and the current version of the label has no boxed warning section. The blood pressure risk is still on the label — it moved to Warnings and Precautions 5.4, where it reads that testosterone can increase blood pressure and that the product is “Not recommended for use in men with uncontrolled hypertension.” The warning did not go away; its boxed status did.
- Does this page tell me what dose to take?
- No. It quotes what two FDA labels state and converts nothing you have not already been prescribed. Choosing a dose requires two low morning testosterone results, your own labs, and a clinician who can adjust against a trough. The one thing worth carrying away is that “testosterone enanthate” alone does not identify a regimen — 75 mg weekly under the skin and 200 mg every fortnight into muscle are both fully labelled uses of this ester.
Sources
- [1]FDA label — Testosterone Enanthate Injection, USP 200 mg/mL, Hikma Pharmaceuticals USA Inc. DailyMed SPL version 10, effective 2026-05-08, marketing category ANDA (ANDA091120)
- [2]FDA label — XYOSTED (testosterone enanthate) injection, for subcutaneous use, Antares Pharma, Inc. DailyMed SPL version 16, effective 2025-07-01, marketing category NDA (NDA209863)
- [3]Bhasin S, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(5):1715–1744
- [4]FDA — Testosterone postmarket drug safety information for patients and providers
Related
Educational reference, not medical advice. Dose, route and whether this compound is appropriate at all are decisions for your clinician.