Testosterone Cypionate vs Enanthate Dosing

Last updated: June 2026

Testosterone cypionate and testosterone enanthate are dosed almost identically on a milligram-per-week basis — the same 100–200 mg weekly target works for either ester — because their half-lives differ by less than a day and the maths you draw into a syringe depends on vial concentration, not which ester it is. The small differences that do exist come down to ester weight (how much of each milligram is actually testosterone) and a marginally longer cypionate half-life, both of which matter far less in practice than the concentration printed on your vial.

Have a vial and a weekly target? Convert any cypionate or enanthate dose to exact mL and U-100 syringe units instantly.

Open the TRT dose calculator →

TL;DR — key takeaways

Dose the same. Cypionate and enanthate are prescribed on the same mg/week scale; a 150 mg/week target is 150 mg/week of either.
Half-lives are close. Enanthate is roughly 4.5–5 days, cypionate roughly 5–8 days — both support once- or twice-weekly injection.
Ester weight differs slightly. About 70% of an enanthate molecule is testosterone vs about 69% for cypionate, so the free-testosterone delivered per mg is nearly identical.
Units follow concentration. Whether you draw 35 or 70 units depends entirely on the mg/mL strength of your vial, not on the ester name.

Why the two esters behave so similarly

Both compounds are testosterone with a fatty-acid ester attached at the 17-beta hydroxyl group. Enanthate adds a seven-carbon (heptanoic) chain; cypionate adds an eight-carbon cyclopentylpropionate chain. That extra carbon is the entire chemical difference between them. After an intramuscular or subcutaneous injection the oil depot releases the ester slowly, enzymes cleave the chain off, and free testosterone enters circulation. The longer cypionate chain makes the molecule fractionally more lipophilic, which is why its release tail runs a day or so longer — but the curves overlap heavily.

Because the body cannot use the ester — only the testosterone it releases — what matters clinically is the testosterone fraction of each milligram. The cypionate ester is heavier, so a milligram of testosterone cypionate contains marginally less testosterone than a milligram of enanthate. The difference is about one percentage point, which is why prescribers and the calculators on this site treat the two as interchangeable on a mg/week basis.

Side-by-side: the two esters at a glance

Property	Cypionate	Enanthate
Ester chain	Cyclopentylpropionate (8 C)	Heptanoate (7 C)
Approx. half-life	~5–8 days	~4.5–5 days
Testosterone per mg	~69%	~70%
Typical TRT dose	100–200 mg / week	100–200 mg / week
Common concentrations	100, 200 mg/mL	200, 250 mg/mL
Usual frequency	Once or twice weekly	Once or twice weekly
Route	IM or SubQ	IM or SubQ

Figures reflect the FDA-approved Depo-Testosterone (cypionate) and Xyosted/testosterone enanthate prescribing information. Compounded or pharmacy vials are drawn manually and require you to calculate the draw volume yourself; always follow your prescriber's protocol.

Half-life and injection frequency, visualised

The reason both esters tolerate once- or twice-weekly dosing is that their release tails are long enough to avoid a sharp daily crash. Cypionate's curve sits a little flatter and longer; enanthate's falls away slightly sooner. Twice-weekly injection (splitting the weekly dose in half) smooths the peaks and troughs of either.

The curves are illustrative of the relative shapes, not exact serum values — individual peaks depend on dose, body composition, and injection site. The practical takeaway is that splitting a weekly dose across two injections narrows the gap between peak and trough for both esters.

How to turn any dose into syringe units

This is the step that trips people up, and it is identical for both esters. The milligram figure on your prescription is not what you read on the barrel — you read units, and a U-100 insulin syringe has 100 units per 1 mL. The conversion is always: take your concentration (mg/mL), divide the dose by it to get mL, then multiply by 100 to get units.

Worked example 1 — cypionate at 200 mg/mL

Vial labelled 200 mg/mL, weekly target 140 mg.

140 mg ÷ 200 mg/mL = 0.7 mL. 0.7 mL × 100 units/mL = 70 units.

Draw 70 units on a U-100 syringe per week (or 35 units twice weekly).

Worked example 2 — enanthate at 250 mg/mL

Vial labelled 250 mg/mL, weekly target 125 mg.

125 mg ÷ 250 mg/mL = 0.5 mL. 0.5 mL × 100 units/mL = 50 units.

Draw 50 units — the identical maths you would use for cypionate.

Worked example 3 — same dose, different concentration

The same 140 mg weekly dose from a 100 mg/mL vial instead of 200 mg/mL: 140 ÷ 100 = 1.4 mL × 100 = 140 units.

Half the concentration, double the units — for the same milligram dose. This is why "how many units" has no single answer without the vial strength, regardless of ester.

Worked example 4 — ester weight cross-check

A 100 mg dose of enanthate delivers roughly 100 × 0.70 = 70 mg testosterone; the same 100 mg of cypionate delivers roughly 100 × 0.69 = 69 mg testosterone.

A ~1 mg gap on a 100 mg dose — well inside normal day-to-day variation, which is why the two are dosed interchangeably.

Dose-to-units reference chart

Common weekly TRT doses shown as units on a U-100 syringe at the two most common concentrations. The numbers are identical whether the ester is cypionate or enanthate — only the concentration changes them. Always confirm against your own vial label.

Weekly dose	At 100 mg/mL	At 200 mg/mL
80 mg	80 units	40 units
100 mg	100 units	50 units
120 mg	120 units	60 units
140 mg	140 units	70 units
160 mg	— (over 1 mL)	80 units
200 mg	— (over 1 mL)	100 units

Note the gap at 160 mg / 100 mg/mL: that draw is 1.6 mL, more than a standard 1 mL syringe holds, so higher doses on a weak vial need either a larger syringe, a split injection, or a stronger vial.

How this is calculated

Every figure above uses two facts only: a U-100 syringe holds 100 units per mL, and concentration is dose-divided-by-volume. There is no ester-specific constant in the syringe maths — cypionate and enanthate use the identical arithmetic, and so does any other injectable. The only place the ester shows up is the optional ester-weight cross-check (about 69–70% testosterone per mg), which moves the delivered testosterone by roughly one percent and is normally ignored for dosing. The TRT dose calculator automates all of this so you can sanity-check the result against the chart above. None of this is medical advice; it is the maths behind a dose your prescriber has set.

Frequently asked questions

Is testosterone cypionate stronger than enanthate?

No. On a milligram-for-milligram basis they are practically equivalent. Cypionate's ester is fractionally heavier, so a milligram of cypionate carries about 1% less testosterone than a milligram of enanthate — a difference too small to change your dose.

Do I need to change my dose if I switch esters?

Switching esters is a clinical decision, but the milligram target usually carries straight across because the two are dosed on the same scale. Your prescriber may keep the same weekly mg and only adjust timing. Do not change a dose yourself.

Does the longer cypionate half-life mean fewer injections?

Marginally, in theory, but in practice both esters are injected once or twice weekly. The roughly one-day half-life difference is small relative to a weekly schedule, so most protocols treat injection frequency the same for both.

Why do my syringe units differ from someone else on the same dose?

Because units depend on vial concentration, not the ester. A 140 mg dose is 70 units from a 200 mg/mL vial but 140 units from a 100 mg/mL vial. Same drug, same dose, different units.

Sources

This guide is for general educational purposes only and does not constitute medical advice. Always follow your prescriber’s specific instructions and consult a qualified clinician before changing any protocol.