Testosterone Cypionate vs Enanthate

Two esters, nearly the same curve. What actually differs between cypionate and enanthate: carrier oil, preservative, devices, which countries stock them, and what to expect when switching.

Testosterone cypionate and testosterone enanthate behave almost the same in the body. The Depo-Testosterone label gives cypionate a half-life of about eight days¹, and a controlled study measured 172.6 hours, about 7.2 days, for intramuscular enanthate⁴. The US labels give both the same dose range: 50–400 mg every 2–4 weeks for hypogonadism^1,2. The real differences are practical ones: the carrier oil and preservative in the vial, whether a subcutaneous autoinjector exists, and which ester your country actually stocks. This guide compares them point by point. For how both fit alongside propionate, undecanoate and blends, see the testosterone ester half-life hub.

The short version

Pharmacokinetics: closer than the forum debates suggest

Both esters work the same way. A side chain on the 17-beta hydroxyl group slows release from an oil depot in muscle, and the labels for both say the esters are "absorbed slowly from the lipid phase," which is why they can be given two to four weeks apart^1,2. The side chains differ a little. Cypionate carries a cyclopentylpropionyl group¹ and enanthate a heptanoyl (oxoheptyl) group². The molecular weights are 412.61 and 400.59^1,3. So, milligram for milligram, enanthate delivers about 3% more testosterone, too small a difference to matter at the dose steps prescribers use.

The half-life figures overlap more than they differ. Cypionate's single label value is about eight days¹, but a population-pharmacokinetic model of weekly cypionate injections in 31 healthy men estimated 4.05 days, or 6.87 days when endogenous testosterone was assumed to be zero⁵. For enanthate, a 2015 phase II trial measured 172.6 hours (about 7.2 days) in men on 200 mg intramuscular injections⁴, while a UK product label reports 2–3 days in healthy volunteers⁶. Put side by side, the spread between methods for each ester is larger than any gap between the two esters.

Peak timing tells a similar story. A 2022 review that pooled data from separate studies lists a time to peak of 4–5 days for intramuscular cypionate and 24 to 36–48 hours for intramuscular enanthate, depending on dose⁸. Those figures come from different studies with different doses and populations, so they are not a head-to-head comparison. The 2015 trial found a mean time to peak of 33.3 hours for 200 mg IM enanthate⁴. The UK enanthate label reports a peak of 1,233 ± 484 ng/dL at 24 hours after 200 mg⁶.

Carrier oil and formulation

Most of the practical difference between the two is in what else is in the vial. In the US:

1. Cypionate (Depo-Testosterone) is dissolved in cottonseed oil, with benzyl benzoate as a co-solvent and benzyl alcohol as a preservative. The 200 mg/mL strength contains 0.2 mL of benzyl benzoate per mL, and the 100 mg/mL strength 0.1 mL¹.
2. Enanthate (generic vial) is 200 mg/mL in sesame oil with 5 mg/mL chlorobutanol as the preservative, supplied in a 5 mL multi-dose vial².
3. Enanthate (Xyosted) is testosterone enanthate in sesame oil in a single-dose autoinjector, 0.5 mL per dose, at 50, 75 or 100 mg³.

Outside the US the vehicle can be different again. The UK enanthate product uses castor oil and benzyl benzoate at 250 mg/mL⁶. "Enanthate" therefore doesn't mean one formulation, and the label on your own vial is what counts.

Allergies

The Xyosted label contraindicates it in men with known hypersensitivity to any of its ingredients, naming sesame oil³. The Depo-Testosterone label contraindicates it for known hypersensitivity to the drug¹, and both vial labels list hypersensitivity or anaphylactoid reactions among possible adverse effects^1,2. If you have a known seed-oil or preservative allergy, the ingredient list is a reason to raise the choice of ester with your prescriber, not to swap products yourself.

Injection pain (PIP)

Both vial labels list inflammation and pain at the injection site as an adverse reaction^1,2. In the Xyosted one-year study, injection-site bruising was reported in 6.7% of men, bleeding in 3.3% and redness in 2.7%³. That is data for one subcutaneous product, not a comparison with cypionate.

Online, post-injection pain is often blamed on a specific oil or on benzyl alcohol. We found no controlled study comparing injection pain between cypionate and enanthate, so treat those explanations as unproven. Things more clearly in your control are covered elsewhere on this site: site choice and rotation in injection sites & rotation, technique in how to inject testosterone, and the route question in SubQ vs IM testosterone.

Availability: US vs Europe

In the US, both esters have FDA labels. Cypionate is sold as Depo-Testosterone and generics¹, and enanthate comes in generic multi-dose vials² and as the Xyosted autoinjector³. Both are Schedule III controlled substances^1,2.

In the UK the picture is different. The electronic medicines compendium lists a licensed enanthate injection (250 mg/mL), Sustanon 250 and several undecanoate injections, and no cypionate product⁷. We haven't checked the licensed range in every other European country, so we won't generalize. If you move or travel from the US to Europe, expect your prescriber to switch you to whichever ester is licensed locally, often enanthate or undecanoate.

Switching between cypionate and enanthate

With identical labeled dose ranges^1,2, a 3% difference in testosterone content^1,3 and overlapping half-lives^1,4,5, the arithmetic of a switch between intramuscular cypionate and intramuscular enanthate is simple, and the numbers don't force a dose change. Whether anything changes is your prescriber's decision, and the switch is confirmed the same way as any change: a repeat level drawn at a consistent point in the cycle once the new product has settled. Our TRT bloodwork guide covers the timing.

Switching to subcutaneous enanthate (Xyosted) is different. It is its own product with its own starting dose of 75 mg once a week into the abdomen. The dose is adjusted in 25 mg steps based on a trough measured 7 days after the most recent dose, first checked after 6 weeks, with a target of 350–650 ng/dL³. Its half-life at 100 mg was 239.6 hours, compared with 172.6 hours for intramuscular enanthate in the same trial⁴. That's why a milligram-for-milligram carryover from an intramuscular vial isn't how the label sets the dose.

What changes, and what doesn't, after a switch

1. Doesn't change much: the shape of the curve at the same dose and interval, the labeled dose range and the controlled-substance status^1,2.
2. Can change: the oil and preservative you're injecting, the vial strength (100, 200 or 250 mg/mL, so the volume you draw up)^1,2,6, and whether a subcutaneous device is an option³.
3. Worth rechecking: your syringe math if the concentration changes. Our TRT dose calculator converts mg to mL for any vial strength.

Injection frequency is the same question for both

The US labels allow two to four weeks between injections for either ester^1,2. With a half-life of about a week, that interval spans two to four half-lives, so levels drop well below their peak before the next dose. The UK enanthate data show this: a peak at 24 hours, then physiological levels for about 11 days after 200 mg⁶. Choosing cypionate doesn't buy a meaningfully longer interval, and choosing enanthate doesn't force a shorter one. Their curves are too similar for that. Splitting the weekly amount into more frequent, smaller injections narrows the swing just as much for one as for the other. The reasoning is in our TRT microdosing guide, and the math in half-life, explained.

The one real frequency difference comes with the device, not the ester. Xyosted is labeled for once-weekly subcutaneous use only, and the label says to avoid intramuscular and intravascular administration³. The Depo-Testosterone label, by contrast, is for intramuscular use only¹.

Questions worth bringing to your prescriber

1. Which ester and which vial strength does my pharmacy actually stock? A 100, 200 or 250 mg/mL vial changes the volume you inject^1,2,6.
2. Do I have a known sensitivity to sesame oil, cottonseed oil, benzyl alcohol or chlorobutanol? These are the listed excipients on the US labels^1,2,3.
3. Would a weekly subcutaneous autoinjector suit me better than intramuscular vials? Among these two esters, only enanthate is available that way³.
4. If I switch, when should the next level be drawn, and at what point in my cycle?

Modeling either ester

Our half-life calculator has presets for both. Test-C uses the eight-day label value, 192 hours¹, and Test-E uses 173 hours for intramuscular enanthate⁴. Run your dose and interval with each and the two curves come out nearly on top of each other. That is the main argument of this guide, drawn as a graph. In the Peptide Me app, the same engine runs on the injections you actually log and can be calibrated against your own lab results.

The bottom line

If you're asking which ester works better, the evidence doesn't favor either one. Their half-life estimates overlap, and the US labels give them the same doses and intervals. What differs is the formulation: cottonseed oil with benzyl alcohol for cypionate, sesame oil with chlorobutanol for US enanthate vials, and castor oil for the UK enanthate product. Enanthate is also available as a weekly subcutaneous autoinjector, and in the UK it is licensed where cypionate isn't listed. Those practical points, together with your prescriber and your pharmacy, decide which one you end up using.

FAQ

References

Primary sources — PubMed / NEJM / The Lancet.

1. DailyMed. DEPO-TESTOSTERONE (testosterone cypionate) injection, solution — Prescribing Information. U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=cfbb53d4-b868-4a28-8436-f9112eb01c39
2. DailyMed. TESTOSTERONE ENANTHATE injection, solution (Eugia US LLC) — Prescribing Information. U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=82a98132-9d5f-40a5-8c4f-f52f2a5de60e
3. DailyMed. XYOSTED (testosterone enanthate) injection — Prescribing Information. U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8a3d204c-be26-49e0-8599-0ac12a272e81
4. Kaminetsky J, Jaffe JS, Swerdloff RS. Pharmacokinetic Profile of Subcutaneous Testosterone Enanthate Delivered via a Novel, Prefilled Single-Use Autoinjector: A Phase II Study. Sex Med. 2015;3(4):269-279. https://pmc.ncbi.nlm.nih.gov/articles/PMC4721027/
5. Bi Y, Perry PJ, Ellerby M, Murry DJ. Population Pharmacokinetic/Pharmacodynamic Modeling of Depot Testosterone Cypionate in Healthy Male Subjects. CPT Pharmacometrics Syst Pharmacol. 2018;7(4):259-268. https://pmc.ncbi.nlm.nih.gov/articles/PMC5915615/
6. electronic medicines compendium (emc). Testosterone Enantate 250 mg/ml Solution for Injection Ampoules — Summary of Product Characteristics. Alliance Pharmaceuticals Ltd. https://www.medicines.org.uk/emc/product/3733/smpc
7. electronic medicines compendium (emc). Search results for "testosterone" (UK licensed products), accessed September 2026. https://www.medicines.org.uk/emc/search?q=testosterone
8. Pastuszak AW, Gittelman M, Tursi JP, Jaffe JS, Schofield D, Miner MM. Pharmacokinetics of testosterone therapies in relation to diurnal variation of serum testosterone levels as men age. Andrology. 2022;10(2):209-222. https://pmc.ncbi.nlm.nih.gov/articles/PMC9293229/