P21_Dosage, benefits & legal status
Also known as P021
An experimental peptide studied for new brain cells and memory.
Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.
What is P21?
Plain language first. The technical label stays, but it never stands alone.Overview
It is studied for growing new brain cells and protecting memory, but there is no human data.
P21 is a small peptide derived from CNTF, a natural nerve-growth factor.
What it's used for
An experimental peptide studied for growing new brain cells and protecting memory.
How does P21 work?
What it does in the body, and where.P21 is a small peptide derived from CNTF, a natural nerve growth factor, built to keep the growth-promoting activity while avoiding CNTF's side effects.
- 01It mimics a nerve growth factorPromoting the birth of new brain cells in the hippocampus, the region tied to memory formation.
- 02Mouse results were positiveIncluding in Alzheimer's models, which is the source of the interest.
- 03No human has ever taken it in a studyConfirmed by the Alzheimer's Drug Discovery Foundation. Everything claimed about it in people is extrapolation.
A schematic of the compound's mechanism, not a diagnostic image.
What else is it used for?
Each use below carries its own evidence level. Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.
- Growing new brain cells and protecting memoryResearch only
The published record
Papers and trials about P21
Searched: P021, peptide 021, P21 peptide, ciliary neurotrophic factor, CNTF.
Left out: P21 (too short to disambiguate without context); P021 (too short to disambiguate without context).
2 papers tagged human · 1 not reviews or lab · 0 clinical trial publications
Furthest stage reached: No clinical trial on record
Counted from Europe PMC indexing, not read by a person; a human tag can land on reviews, commentary or lab papers; clinical trial publications is the narrower count.
At a glance
Four things to know about P21
Evidence
Category
Brain, mood and sleep
Common vial
10 mg
Half-life
Nothing published
How much, and do you cycle it?
The range, and whether you take breaks.Research only, as studied. No established schedule No range
No published study has established how long to take this or whether a break is needed. Schedules quoted online come from vendors and forums, and different sources disagree.
Nothing publishedNo figure
Nothing published.
You can compare this against the whole library to see where it sits.
How do I dose and price it?
Enter your vial and your dose. Pick a mix. We show the draw and the cost.The vial holds a fixed amount of drug. Adding more water does not make more drug, it just spreads it thinner, so you draw a bigger number on the syringe for the same dose.
Choose your mix
Measuring the water1 mL = one full 100-unit syringe.
P21 starts at $38.00 across 28 vendors, typically $7.50 – $23.20 per mg.
29 listings, last read Oct 24, 2026. Shipping and card fees are not included.
How do you store it?
Before mixing, and after.Dry powder in the freezer or fridge. Once mixed, fridge, and use within about a month.
Unmixed lyophilized P21 keeps for a long time cold. Once you add water the clock starts: most reconstituted vials hold up for roughly 28 to 30 days at fridge temperature. Keep it out of light, and do not freeze it after mixing.
What are the side effects and cautions?
Known cautions and warnings for this compound.Who should avoid it
- Pregnancy or breastfeeding
- Active cancer, as a precaution with anything that promotes tissue or blood-vessel growth
- Any prescription medicine you take regularly, without checking for interactions first
- Anyone who wants established safety data, because none exists for this compound in humans
Stop and get help
- Spreading hives, swelling of the face or throat, or trouble breathing, which can happen with any injection and is a medical emergency
- Redness, heat, or pus at the injection site, which can signal infection
- Any severe or unexpected symptom
- Anything unusual, since there is no known safety profile to compare it against
Common effects
- There is no human data.
- Redness, soreness, or a small bump at the injection site
- Beyond the above, unknown. There is no reliable human data on what this compound commonly causes
Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.
Is P21 approved?
And where the numbers on this page come from.No. P21 is not approved for any use, anywhere. It is sold labeled for laboratory research only, and there is no legal route to buy it for human use.
- Approval statusResearch only
- RouteUnder the skin (subcutaneous)
- Checked22 September 2026
- DoseFrom community reports. No regulator or trial established this dose.
- Vial sizeFrom what vendors typically list; not a recommendation.
- SourcesNone traced yet.
What has happened recently
We have not yet written a full regulatory note for this compound. The status above is current as of the date shown.
You can compare this against the whole library, or read how to check a seller.
What else is like P21?
Others in Brain, mood and sleep, side by side.If you're weighing P21, it's worth reading N-Acetyl Semax Amidate, N-Acetyl Selank Amidate, and Adamax 1032 in the same class.
An experimental peptide studied for new brain cells and memory.
- Dose
- Research only
- How often
- As studied
A longer-lasting version of Semax for focus and memory.
- Dose
- 0.2 up to 0.4 mg per day
- How often
- 1-2x daily
A longer-lasting version of Selank, with no study of its own.
- Dose
- Research only
- How often
- 1-2x daily
The adamantane form of Adamax, identified by its weight rather than by any published study.
- Dose
- Research only
- How often
- No established schedule
Guides for this compound
- How to Reconstitute a Peptide
Mix peptide powder with bacteriostatic water, step by step.
- How to Read an Insulin Syringe
Read the units, convert to millilitres, and draw the exact dose.
- mcg vs mg: The Peptide Dosing Mistake to Avoid
Your vial says mg and your protocol says mcg. Here is the conversion and how to check it.
- How to Read a Peptide COA
What the purity number does and does not tell you, and how to spot an edited report.
- How to Vet a Peptide Vendor
Independent COAs, HPLC purity, and the red flags that mean walk away.
Sources
No primary source has been traced for this compound yet. Treat everything on this page as unverified until one is. How we grade evidence
Beyond these, 8 records are indexed. Browse the records