What Test 400 is
Test 400 is a high-concentration testosterone blend. The number is the total testosterone ester content per millilitre, not the amount of any one ester and not the amount of testosterone delivered. In the Quanta Pharma preparation the 400 mg/ml is made up of three long and mid-long esters: enanthate, cypionate and decanoate.
- Concentration
- 400 mg/ml
- Number of esters
- Three
- Esters present
- Enanthate, cypionate and decanoate
- Presentation
- 10 ml multi-dose vial
- Storage
- Room temperature, protected from light
Measured composition
Two independent HPLC reports on sealed production vials. These are measured figures, not label claims.
| Ester | August 2026 | March 2026 |
|---|---|---|
| Testosterone Enanthate | 124.67 mg/ml | 126.79 mg/ml |
| Testosterone Cypionate | 128.76 mg/ml | 132.03 mg/ml |
| Testosterone Decanoate | 170.64 mg/ml | 155.16 mg/ml |
| Total | 424.07 mg/ml 106% of label | 413.98 mg/ml 104% of label |
Concentration and solvent
Testosterone esters have a solubility limit in oil. Getting to 400 mg/ml requires a higher solvent load than a 250 mg/ml preparation, and benzyl benzoate is the component most associated with post-injection irritation. That is the trade high-concentration blends make: fewer millilitres for the same hormone, more solvent per millilitre.
- Quanta Pharma Test 400in stock£38
Availability checked 2026-09-01. The product page carries live stock.
The other blends
Common questions
What is in Test 400?
In the Quanta Pharma preparation, three testosterone esters: enanthate, cypionate and decanoate. Two independent HPLC tests measured the combined content at 424.07 mg/ml in August 2026 and 413.98 mg/ml in March 2026, against a 400 mg/ml label.
Is Test 400 the same as Sustanon 250?
No. Both are testosterone blends, but they differ in concentration and in which esters they contain. Sustanon 250 is a four-ester blend at 250 mg/ml built around propionate for fast onset. Test 400 is a three-ester blend at 400 mg/ml with no short ester, so its release profile is longer and flatter.
Why is Test 400 tested above its label?
Both HPLC reports measured above 400 mg/ml, at 106% and 104% of label. Overfill within a few percent is normal in manufacturing and means the vial contains at least the stated concentration rather than less.
Does Test 400 contain a short ester?
No. Enanthate, cypionate and decanoate are all mid-length to long esters, with published half-lives of roughly 4.5, 5 and 7.5 days. There is no propionate fraction, which is the main structural difference from Sustanon 250.
Does this page give dosing information for Test 400?
No. This is a reference resource covering composition, esters, concentration, verification and storage. It does not provide dosing protocols, administration schedules or medical advice.