What testosterone enanthate is
Testosterone enanthate is testosterone bonded to a seven-carbon ester called enanthate, then dissolved in oil for slow release after injection. It is one of the two classic long-acting testosterone esters in the United States, alongside testosterone cypionate.
As of October 2026, it is FDA-approved for testosterone replacement in men with primary or hypogonadotropic hypogonadism, and like every testosterone product it is a Schedule III controlled substance. The generic vial label describes 200 mg per mL of testosterone enanthate in sesame oil, preserved with chlorobutanol, injected deep into the gluteal muscle.
How does it compare with cypionate?
The two esters are close cousins. Enanthate’s side chain is slightly shorter, and it is generally described as a little shorter-acting than cypionate. The labels show how small the gap is in practice: the cypionate label gives a half-life of about eight days, the enanthate label notes that reported half-lives vary considerably between people, and both list the same broad range of 50 to 400 mg every two to four weeks for men with hypogonadism. That range is context only; your provider sets your dose and schedule.
| Feature | Testosterone enanthate | Testosterone cypionate |
|---|---|---|
| Oil | Sesame oil | Cottonseed oil |
| Preservative | Chlorobutanol (vial) | Benzyl alcohol |
| Half-life on label | Varies considerably | About 8 days |
| Label interval | Every 2 to 4 weeks | Every 2 to 4 weeks |
| Subcutaneous approved product | Yes, Xyosted autoinjector | No approved subcutaneous product |
| Controlled substance | Schedule III | Schedule III |
Because the two behave so similarly, most men cannot tell them apart once the dose and schedule are matched. Our full cypionate versus enanthate comparison goes ingredient by ingredient.
Xyosted: the weekly autoinjector
The one clear practical difference is Xyosted, an FDA-approved autoinjector of testosterone enanthate approved in 2018. Its label calls for a once-weekly injection under the skin of the abdomen, using single-dose pens of 50, 75 or 100 mg. Six weeks after starting, a trough testosterone level drawn just before the next dose guides whether the dose stays, rises or falls.
For men who dislike drawing up oil from a vial or injecting into muscle, that format is the main attraction. Subcutaneous injection in general is covered in whether subcutaneous testosterone is effective and our guide to injecting testosterone under the skin. The Xyosted label once carried a boxed warning about blood pressure increases; it was removed in March 2025 as the FDA moved blood pressure warnings onto the labels of all testosterone products. The label still says Xyosted is not recommended for men with uncontrolled high blood pressure, so a reading is taken before the first pen and rechecked during treatment. Because the dose comes fixed in each pen, fine-tuning happens in steps of 25 mg guided by the trough level rather than by drawing up a little more or less.
Why would a man switch to or from enanthate?
Three reasons come up most often.
Oil allergy. Each ester rides in a different oil, and both labels rule out use in anyone hypersensitive to an ingredient. A man who reacts to cypionate’s cottonseed oil may do well on enanthate, and a man with a sesame allergy should not use enanthate. Reactions such as hives, itching or swelling around the injection site need a prompt conversation; our answer on being allergic to testosterone injections covers the workup.
Supply. Specific testosterone products and vial sizes go in and out of stock. The FDA drug shortages database lists current shortages, and when one ester or strength is hard to get, switching to the other is a common workaround rather than going without.
Format. Men who want a weekly prefilled pen may move to Xyosted, while others prefer the flexibility of a multi-dose vial.
A switch is not a free swap. Concentration, schedule and injection site can all change, so a repeat testosterone level and hematocrit after the switch confirm the new plan is working. If treatment suddenly feels different after a change, see why TRT can feel different with a new pharmacy.
Side effects, warnings and monitoring
Side effects match other injectable testosterone: acne, injection site soreness, fluid retention, breast tenderness, rising hematocrit, testicular shrinkage and reduced sperm production. The labels warn about blood pressure increases, blood clots, worsening urinary symptoms with an enlarged prostate, abuse at high doses, and, on the Xyosted label, depression and suicidal thoughts. Enanthate is not used in men with breast cancer or known or suspected prostate cancer. MedlinePlus explains which symptoms to report.
Monitoring follows the same backbone as any TRT plan: testosterone level at a consistent point in the cycle, hematocrit (the Xyosted label suggests about every three months during treatment), PSA, blood pressure and estradiol when symptoms suggest it.
Chest pain, sudden breathlessness, slurred speech, one-sided weakness or a hot, swollen calf are emergencies on any testosterone product. Call 911.
How Ultimate Male decides on the ester
Injectable testosterone is one of the TRT options at Ultimate Male, given in the clinic or at home, and compounded medicines come from licensed U.S. pharmacies. The clinic has not published which ester or product it uses for every patient, because that choice depends on your allergy history, what the partner pharmacy can reliably supply, whether you prefer muscle or under-the-skin injections, and how your labs respond.
If you are transferring from another clinic on enanthate, bring your current product, dose and recent labs; our testosterone injections page explains the in-clinic and at-home options. Every plan begins with the TRT pre-screening panel and a one-on-one consultation with a PA-C or MD. To get started, read about testosterone therapy at Ultimate Male or call 626-319-5261.
