Short answer: Very little. Both are testosterone esters in oil, injected into muscle, and their US labels give the same dose range: 50 to 400 mg every 2 to 4 weeks.12 They differ mainly in the oil (cottonseed vs sesame) and strengths. Half-life: about 8 days for cypionate, about 7 days for enanthate in one study.
| Testosterone cypionate | Testosterone enanthate | |
|---|---|---|
| Mechanism | Testosterone prodrug; the ester is cleaved to release testosterone, an androgen receptor agonist | Same |
| Approval status | FDA approved (Depo-Testosterone and generics); Schedule III controlled substance | FDA approved (generic IM vials; Xyosted subcutaneous autoinjector); Schedule III |
| Label dosing schedule (male hypogonadism) | 50 to 400 mg into muscle every 2 to 4 weeks1 | 50 to 400 mg into muscle every 2 to 4 weeks2. Xyosted: 75 mg under the skin weekly to start3 |
| Half-life | about 8 days (label: approximately eight days)1 | Not on the label. About 7.2 days (172.6 hours) after 200 mg into muscle in one study of men already on treatment4 |
| Time to peak (Tmax) | Not stated on the label | Xyosted (under the skin): median about 12 hours3 |
| Dosing frequency | Label: every 2 to 4 weeks. Guideline example: weekly or every 2 weeks5 | Same; Xyosted weekly |
| Strengths | 100 and 200 mg/mL; 1 mL and 10 mL vials1 | 200 mg/mL in 5 mL multi-dose vials2 |
| Oil vehicle | Cottonseed oil with benzyl benzoate; benzyl alcohol preservative1 | Sesame oil with chlorobutanol preservative2 |
| Notable label warnings | Raised hematocrit (polycythemia), blood pressure increases, worsening BPH, blood clots (VTE), abuse and dependence | Same class warnings. Xyosted's boxed blood pressure warning was removed in 2025 under FDA class-wide changes6 |
The difference is small and the evidence uneven. The Depo-Testosterone label states about 8 days for cypionate.1 No US label gives a half-life for enanthate. In a study of men already on injections, enanthate given into muscle had an apparent half-life of about 7.2 days.4 An older figure of about 4.5 days is often quoted, but it is a background citation, not a measurement in that form. In practice both are dosed on the same schedules.
It can for some people. Cypionate is in cottonseed oil and enanthate in sesame oil, with different preservatives.12 Someone sensitive to one oil or preservative may tolerate the other. That is a reason to talk to your prescriber or pharmacist, not to switch on your own.
The Endocrine Society guideline suggests measuring testosterone midway between injections and checking hematocrit at baseline, at 3 to 6 months and then yearly.5 Logging injection times makes it easy to know when "midway" is.