What is Testosterone Phenylpropionate 100 (Astera Labs)?
Astera Labs testosterone phenylpropionate at 100mg/ml, in a 10ml multidose vial. The middle ester, between propionate's speed and enanthate's convenience.
Also sold as Test-PP, Retandrol, testosterone hydrocinnamate or testosterone fenpropionate.
It is the same ester that makes up a quarter of Sustanon, sold on its own. The phenylpropionate chain is longer than propionate's but shorter than enanthate's, putting the half-life at around four days: fast enough to feel early, slow enough that twice a week holds.
Testosterone Phenylpropionate 100 benefits
- Twice-weekly injections rather than propionate's every other day
- Still fast enough to work inside the first two weeks
- Less water retention than enanthate or cypionate at the same weekly total
- Draw any volume, so a 50mg dose is half a millilitre rather than half an ampoule wasted
- Clears in under a week, so post-cycle therapy starts sooner than with a long ester
Testosterone Phenylpropionate 100 dosage
- Beginner
- 300 to 400mg per week, which is 3 to 4ml
- Intermediate
- 400 to 600mg per week
- Advanced
- 600 to 800mg per week
- Frequency
- Twice weekly minimum, every other day is better
- Half-life
- About 4 days
At 100mg/ml the arithmetic is direct: 1ml is 100mg. A 400mg week is 4ml, usually split as 2ml twice.
Twice a week is the floor. Once weekly leaves a trough that defeats the point of choosing a mid-length ester.
Package content
- Vial
- 10ml sterile multidose
- Strength
- 100mg/ml
- Testosterone per vial
- 1000mg
- Carrier
- Miglyol 812
- Brand
- Astera Labs
At 400mg a week one vial covers two and a half weeks.
Store below 30°C. Protect from light. Do not freeze. Keep out of reach of children.
Who is Testosterone Phenylpropionate 100 for?
People who want propionate's speed and low water retention without injecting every other day. It suits shorter cycles and cutting phases, where a long ester's slow build and slow clearance both work against you.
TESTOMED PP 100 is the same 100mg/ml at the same price as 10 sealed ampoules. Choose on format: the vial suits doses that are not whole millilitres, the ampoules suit anyone who wants each dose sterile until opened.
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. Not for anyone under 18, and not for women who are pregnant or breastfeeding.
How to use Testosterone Phenylpropionate 100
Intramuscular or subcutaneous injection, twice weekly or every other day. Wipe the stopper with alcohol before every draw and use a fresh needle each time. The injection technique guide covers both routes.
Frequently asked questions
Phenylpropionate or propionate?
Phenylpropionate lasts about twice as long, which halves the injections. Propionate is marginally faster in and faster out.
For most people the injection frequency decides it. Every other day versus twice a week is the difference between a protocol you keep and one you abandon in week six.
Can I inject it subcutaneously?
Yes. Phenylpropionate is one of the testosterone esters that tolerates subcutaneous injection well, using a smaller needle into abdominal fat rather than into muscle.
Absorption is slightly slower that way, which is not a problem at twice-weekly dosing. Many find it far more comfortable than intramuscular, and it is easier to do from a vial than from ampoules since you can draw exactly what you need.
Is this the same ester as in Sustanon?
One of them, yes. Phenylpropionate makes up 24% of the Sustanon blend, alongside propionate, isocaproate and decanoate.
Running it alone gives you that one release profile without the long decanoate tail that makes Sustanon slow to clear.
How long does an opened vial stay good?
An oil-based multidose vial is stable for the length of a normal cycle provided it is kept clean, out of light and below 30°C. Contamination from repeated entry is the risk, not the oil itself.
Fresh needle every draw, alcohol on the stopper every time. Cloudiness, particles or a colour change mean it goes in the bin.
Do I need PCT?
Yes, as with any exogenous testosterone. The advantage here is timing: it clears in under a week, so post-cycle therapy starts far sooner than after enanthate or cypionate.
