What is Sustanon 300 (Astera Labs)?
Sustanon 300 is the standard four-ester testosterone blend at 300mg/ml, in a 10ml vial. The same mixture as a 250, more concentrated, so less oil goes in per dose.
Four esters release at different speeds from one injection. Propionate and phenylpropionate work within days, isocaproate covers the middle, and decanoate holds levels through the rest of the week. That is what lets a single weekly shot behave like a steady base rather than a spike.
Sustanon 300 benefits
- One injection a week covers the full week, thanks to the four release speeds
- 300mg/ml means a 600mg week is 2ml rather than 2.4ml at the standard 250
- Better value per milligram than a 250, and a lower entry price than the 500
- Works alone in a first cycle, or as the testosterone base under a stack
- Suspended in Miglyol 812, thinner than the oils most competitors use
Sustanon 300 dosage
- Beginner
- 300 to 500mg per week, which is 1 to 1.7ml
- Intermediate
- 500 to 750mg per week alone, around 500mg when stacked
- Advanced
- 750 to 1000mg per week, run alone rather than stacked
- TRT base
- 100 to 250mg per week
- Frequency
- Once weekly, or split into two for steadier levels
At 300mg/ml, exactly 1ml is a 300mg week, which is the cleanest beginner dose in the range.
There is no reason to push past the beginner range on a first cycle. The higher figures apply when testosterone is doing all the work alone.
Package content
- Vial
- 10ml sterile multidose
- Strength
- 300mg/ml total testosterone
- Testosterone per vial
- 3000mg
- Testosterone Decanoate
- 120mg/ml, longest acting
- Testosterone Isocaproate
- 72mg/ml
- Testosterone Phenylpropionate
- 72mg/ml
- Testosterone Propionate
- 36mg/ml, fastest acting
- Carrier
- Miglyol 812
- Brand
- Astera Labs
At 500mg a week one vial covers six weeks.
Store below 30°C. Protect from light. Do not freeze. Keep out of reach of children.
Who is Sustanon 300 for?
Anyone who wants the Sustanon blend without either the volume of a 250 or the commitment of a 500. It is the middle option on purpose: better per milligram than the 250, cheaper to buy into than the 500.
The blend itself suits first cycles and experienced users equally. If you want the same mixture as sealed ampoules, SUSTAMED 250 is the Deus Medical version. If you are running high doses and want the fewest millilitres possible, Sustanon 500 is the same blend again at nearly double the strength.
Before you run it. This replaces your own testosterone production for the cycle and for some time after, so
post-cycle therapy is part of the plan, not an optional extra. Testosterone aromatises, which is what the
estrogen management guide covers, and
bloodwork is how you know where you stand. The decanoate ester means levels take weeks to build and weeks to clear, so it is a poor fit for a short cycle. Not for anyone under 18, and not for women who are pregnant or breastfeeding.
How to use Sustanon 300
Intramuscular injection, once weekly or split into two across the week for steadier levels. Wipe the stopper with alcohol before every draw. Rotate between glutes, quads and delts. The injection technique guide covers the technique.
Frequently asked questions
Is Sustanon 300 stronger than Sustanon 250?
No, just more concentrated. The blend is identical: the same four esters in the same 12, 24, 24 and 40 percent proportions. 300mg/ml simply means more testosterone per millilitre of oil.
A 600mg week is 2ml here against 2.4ml at 250. Same hormone, same result, less volume going into the muscle.
Which strength is the best value?
Match the strength to your dose rather than hunting for value. Under 500mg a week the 250 or 300 keeps the measuring simple. Above that, a higher concentration saves real volume per injection.
The 250 is also the only one available as sealed ampoules, which matters more to some people than anything on the price tag.
How often should I inject Sustanon?
Once a week works, which is the point of a blend. Splitting into two injections three or four days apart holds levels flatter and softens the swings the short esters can cause.
Going longer than a week between shots means the propionate and phenylpropionate fractions have run out well before the next dose.
Why four esters instead of one?
Because they release at different speeds. Propionate is active within days, phenylpropionate over about four, isocaproate covers the middle, and decanoate holds for a fortnight or more.
Stacked together they cover the whole week from one injection, which no single ester does as evenly.
Do I need PCT after Sustanon?
Yes. Exogenous testosterone shuts down your own production for the duration and beyond.
The decanoate fraction is the timing problem: it clears slowly, so post-cycle therapy cannot start until roughly two weeks after the final injection.
