Testosterone is a single molecule, yet it comes as propionate, enanthate, cypionate, undecanoate, as a suspension and as blends. The difference is not the hormone itself but the ester attached to it — and the ester decides how quickly the hormone is released.
What is an ester?
An ester is a carbon chain bonded to the testosterone molecule. It makes the hormone more soluble in oil, so it stays in the oil depot after an injection and is released gradually. Once in the bloodstream, enzymes cut the ester off and free testosterone remains.
The rule of thumb is simple: the longer the ester chain, the slower the release and the longer the compound stays active. Because the ester adds weight, the amount of actual testosterone per milligram is a little lower for longer esters.
The common forms
| Form | Release | Driada Medical product |
|---|---|---|
| Suspension (no ester) | Fastest — free testosterone in a water-based suspension | Testolad 100 mg/ml |
| Propionate | Short-acting — released over a few days | Propios 100 mg/ml |
| Enanthate | Long-acting — released over about one to two weeks | Testos 250 mg/ml |
| Cypionate | Long-acting — very similar to enanthate | Cypilos 250 mg/ml |
| Undecanoate | Very long-acting — the longest common ester | Andriolos 250 mg/ml |
| Blend (Sustanon type) | Short and long esters combined in one oil | Sustalad 250 mg/ml |
Enanthate vs cypionate
These two are the most common long esters and behave almost identically: cypionate has one more carbon atom and is very slightly slower. Which one is used is mostly a matter of regional availability and preference.
Why blends exist
A blend such as Sustanon combines a short ester, which becomes active quickly, with longer esters that keep releasing afterwards. The aim is a smoother curve from a single preparation.
Ampoule or vial?
Most of our testosterone products come in two formats with the same strength: 10 × 1 ml ampoules and a 10 ml multi-dose vial. See Ampoules vs vials for the difference.
This article is general information, not medical advice. Our products are intended for use under the supervision of a qualified physician and only where permitted by local law.