Sustanon 250 is a blend of four testosterone esters formulated to combine the fast onset of a short ester with the sustained release of a long ester — providing both an immediate increase in testosterone and stable levels that persist for days. Ultima-Mix by Ultima Pharmaceuticals contains 250 mg per millilitre and follows the original Sustanon 250 formula.
Ester Composition
Each millilitre of Ultima-Mix contains:
- Testosterone Propionate — 30 mg (fast-acting, peaks within 24–48 hours)
- Testosterone Phenylpropionate — 60 mg (medium-short, active ~5 days)
- Testosterone Isocaproate — 60 mg (medium, active ~7–9 days)
- Testosterone Decanoate — 100 mg (long-acting, active ~14–16 days)
This combination was originally developed to reduce injection frequency while maintaining consistent testosterone levels — the Propionate provides immediate activity while Decanoate sustains it.
Half-Life and Injection Frequency
Due to the multi-ester composition, Sustanon has an effective half-life of approximately 7–9 days when the blend is considered as a whole. However, the short Propionate component creates a rapid initial peak that then drops before the longer esters fully kick in.
For stable blood levels, twice-weekly injection is strongly recommended — for example, Monday and Thursday. Once-weekly injections (as historically prescribed for TRT) produce noticeable peaks and troughs that many users experience as fluctuating energy, libido and mood.
Who Uses Sustanon 250
- Bodybuilders running bulking or lean-bulking cycles: Sustanon is a versatile base testosterone suitable for any goal. The blend provides a satisfying rapid onset alongside sustained muscle-building levels.
- Users who prefer less frequent injections than Propionate: Sustanon offers most of the multi-ester benefits without the EOD injection schedule of pure Propionate.
- TRT patients: Sustanon 250 is one of the few testosterone preparations licensed in the UK and is still prescribed by some NHS endocrinologists — though twice-weekly dosing is preferred over the traditional once-every-three-weeks protocol for better symptom control.
Benefits
- Rapid onset with sustained release: The Propionate component means effects are felt within 2–3 days of the first injection — faster than pure Enanthate or Cypionate, which can take 3–4 weeks to fully saturate.
- Flexibility: Sustanon can be used for bulking, lean bulking, or as a TRT base during a cut — it is not inherently a bulking or cutting compound; the diet and the rest of the stack determine the outcome.
- Muscle and strength gains: At cycle doses, the anabolic effects of Sustanon 250 are equivalent to any other testosterone at the same total weekly dose. The compound itself is testosterone — the esters only affect release time, not the effect.
Side Effects and Management
Sustanon 250 aromatises to oestradiol in the same manner as all testosterone esters. Users running cycle doses (400 mg/week and above) typically need an aromatase inhibitor (AI) to manage oestrogen. The multi-ester profile makes oestrogen management slightly less predictable than pure Enanthate, particularly in the early weeks of a cycle.
Bloodwork should be checked at 6–8 weeks into the cycle to assess oestradiol, haematocrit, blood pressure, and lipid levels.
Dosing Guide
- TRT: 125–250 mg per week, split into two injections
- Beginner cycle: 250–500 mg per week (1–2 ml per week), split twice weekly, for 10–12 weeks
- Intermediate cycle: 500–750 mg per week
PCT: Due to the Decanoate component, begin PCT 18–21 days after the last injection.
Storage
Store at room temperature (15–25°C), away from direct sunlight. Do not refrigerate.
