Testosterone enanthate is testosterone attached to an enanthate ester and dissolved in oil. It is used for testosterone replacement therapy (TRT), by injection into muscle or, as Xyosted, under the skin.
Also known as: Xyosted, Delatestryl, Test E.
In the US, generic testosterone enanthate comes as 200 mg/mL in 5 mL multi-dose vials. Xyosted is a weekly autoinjector. Outside the US, 250 mg/mL is also common. It is already a solution, so there is nothing to mix.
Testosterone enanthate is already a solution, so there is no mixing. The only math is turning an amount in mg into a volume. Here it is at 200 mg/mL for 100 mg.
100 mg ÷ 200 mg/mL = 0.5 mL0.5 mL × 100 = 50 units| Amount | Volume | U-100 syringe |
|---|---|---|
| 50 mg | 0.25 mL | 25 units |
| 100 mg | 0.5 mL | 50 units |
| 150 mg | 0.75 mL | 75 units |
| 200 mg | 1 mL | 100 units |
Published half-lives for testosterone enanthate injected into muscle differ, so we give a range instead of one number. Older literature cites about 4.5 days (Behre 1995). A small study in 10 men already on regular injections (Kaminetsky 2015) measured an apparent half-life of about 7 days, with levels peaking about 33 hours after the shot on average; because those men were already on treatment, that figure may run long. The US labels give no half-life for the ester. The Xyosted label reports a median time to peak of about 12 hours after an injection under the skin, which is a different route.