Longevity · Dosing reference

P-21 dosage

What the human evidence does and does not show, how long studies ran, and the arithmetic for working with vials.

Not approved — research use onlyCPreclinical researchNone established

Full research page Cycle-length evidence Compare Prefer Amiravo on Google

Regulatory status: Not approved — research use only
Human amounts: None established in humans
Route studied: —
Frequency: Not established
Half-life: Not established
Evidence grade: Grade C · Preclinical research
Vial sizes on the market: 5 mg
Other forms seen: —

What P-21 is

P-21 is a synthetic peptide derived from the neurotrophic factor CNTF, studied in preclinical research on neurogenesis and neuronal plasticity.

P021 was developed from an 11-amino-acid stretch within the biologically active region of human ciliary neurotrophic factor (CNTF). The reported design intent was to retain the neurogenic and neurotrophic activity of the parent protein while overcoming the blood-brain barrier impermeability, short half-life and adverse effects that stopped earlier attempts to use whole neurotrophic factor proteins ^6. The 2010… How it works →

Key evidence

Li et al., FEBS Letters · 2010 · Animals (adult C57Bl/6 mice)
The compound Ac-DGGLAG-NH2, named P21, was associated with enhanced learning and short-term and spatial reference memory and with increased neurogenesis and maturation of newborn neurons in the dentate gyrus. ¹
Bolognin et al., Neurobiology of Aging · 2014 · Animals (22-24-month-old Fisher rats)
P021 was associated with reduced age-dependent decline in learning and memory, inhibition of the neurogenesis deficit, increased BDNF expression, restored synaptic markers and reduced hippocampal myo-inositol. ²
Khatoon et al., Journal of Alzheimer's Disease · 2015 · Animals (aged Fisher rats)
P021 was reported to be blood-brain-barrier permeable and to reduce brain and cerebrospinal fluid total tau but not cerebrospinal fluid amyloid-beta/APP; no detectable immune reaction was reported. ³

All studies on the research page

What the human evidence shows

No approved or established human dose

We searched PubMed and ClinicalTrials.gov and found no human studies that administered P-21. The research described on its page is from cells or animals, and animal amounts do not translate to people.

How long did human studies run?

No human study durations are recorded for P-21.

Cycle-length evidence for P-21

P-21 draw calculator

Pick the vial strength and the water added, enter an amount, and see the concentration, the units to draw and how many draws the vial holds. Arithmetic only.

1 · Vial strength

sizes on the market

2 · Water added

3 · Amount per draw

4 · Syringe

Your mix

5 mg + 2 mL water = 2.5 mg/mL

10 units holds 0.25 mg (250 mcg)

Draw toEnter an amount in step 3

U-100 syringe · 100 units = 1 mL

Computed from your inputs. Not a dose or a recommendation.

Compare water volumes for this vialShow

More water = lower concentration = a larger, easier-to-measure draw. Tap a row to use it.

Water	mg/mL	Draw
0.5 mL	10	—
1 mL	5	—
1.5 mL	3.333	—
2 mL	2.5	—
2.5 mL	2	—
3 mL	1.667	—
5 mL	1	—

Supplies and handling

Lyophilized vial
Sealed vial with the freeze-dried cake. Check the label, lot and the certificate of analysis before opening.
Sterile diluent
The diluent named on the product documentation. Bacteriostatic water contains benzyl alcohol; sterile water does not.
Graduated syringes
Sized to the volume being measured. U-100 insulin syringes are graduated in units where 100 units = 1 mL.
Alcohol prep pads
For wiping vial stoppers before each puncture.
Nitrile gloves
Clean gloves for aseptic handling.
Sharps container
Puncture-resistant container for used needles.

Step-by-step reconstitution guide Storage and transport accessories

Storage

General research-context handling only. Lyophilised small peptides of this type are typically stored dry, frozen and protected from light and moisture, with solutions treated as short-lived and freeze-thaw cycling avoided. Defer to the supplier's documentation for the specific lot. No temperatures, volumes or preparation steps are given here, and nothing in this section is an administration instruction.

Lyophilized (unmixed) vials: typically stored cold and dry, away from light, as the documentation directs. Many are stable longer frozen.
Reconstituted vials: typically refrigerated (about 2–8 °C), protected from light and not frozen.
Bacteriostatic water contains benzyl alcohol, which inhibits bacterial growth in multi-use vials; sterile water has no preservative.

Handling mistakes and troubleshooting

Added the wrong volume of diluent: The concentration changes, not the amount of compound in the vial. Recalculate with the volume actually added and relabel the vial.
Shook the vial and it foamed: Let it settle in the refrigerator. Foam is a sign of agitation; some peptides aggregate when shaken. Note it on the label.
The solution is cloudy or has particles: Do not use it. Cloudiness can indicate incomplete dissolution, contamination or degradation. Record the lot and contact the supplier with the certificate of analysis.
The powder cake looks melted or shrunken before reconstitution: This can indicate the vial was exposed to heat or moisture. Record the lot and condition on arrival.
Liquid sprayed back when the needle was removed: Pressure built up in the vial. Withdraw a small volume of air while adding diluent to keep pressure neutral.

Regulatory status

Status: P021 is not approved by the FDA for any use and does not appear in any of the three categories of FDA's 503A bulk drug substances list as updated May 14, 2026 ^9. A ClinicalTrials.gov search did not identify any registered interventional trial of P021 in humans ^10. All efficacy data identified are from rodents and cultured cells ^1,2,3,4,5,7.
United States (FDA): P021 has no approved FDA application and no openFDA drug label. It does not appear in any of the three categories of FDA's 503A bulk drug substances list (Category 1 under evaluation, Category 2 raising significant safety concerns, Category 3 nominated without adequate support) as updated May 14, 2026 ^9.
Sport (WADA): P021 is not named in the WADA 2026 Prohibited List ^11. This is hedged negative evidence and not a clearance. The S0 Non-Approved Substances class states that "Any pharmacological substance which is not addressed by any of the subsequent sections of the List and with no current approval by any governmental regulatory health authority for human therapeutic use (e.g. drugs under pre-clinical or clinical development or discontinued, designer drugs, substances approved only for veterinary use) is prohibited at all times", and S0 is prefaced "This class covers many different substances including but not limited to BPC-157, 2,4-dinitrophenol (DNP), ryanodine receptor-1-calstabin complex stabilizers [e.g. S-107, S48168 (ARM210)] and troponin activators (e.g. reldesemtiv and tirasemtiv)" ^11. A substance's absence from the named examples does not place it outside the class. Athletes should seek a ruling from their anti-doping organisation.

Status varies by country and changes over time. How we describe regulatory status.

P-21 compared with related compounds

Compound	Status	Evidence	Human amounts	Half-life
P-21	Not approved — research use only	C	None established	—
Cerebrolysin	Approved outside the US	A	Ex-US label	Not directly measurable (peptide mixture
Methylene Blue	FDA-approved	A	FDA label	Approximately 24 hours
L-Glutathione	Not approved — research use only	B	None established	—
Epithalon	Not approved — research use only	C	None established	—
N-Acetyl Epithalon Amidate	Not approved — research use only	—	None established	—

Frequently asked questions

What doses of P-21 have been studied in humans?

None that establish an amount. P-21 is not approved anywhere and we found no human studies that administered it. Amiravo does not publish community or vendor figures.

Is there an established P-21 cycle length?

No. We found no human studies that report treatment duration for P-21.

How much bacteriostatic water should be added to a P-21 vial?

There is no compound-specific volume. The diluent volume only sets the concentration: concentration = mass in the vial ÷ volume added (for example, 10 mg in 2 mL gives 5 mg/mL). The calculator on this page shows the arithmetic for any combination.

How many units is a given amount on an insulin syringe?

On a U-100 syringe, 100 units = 1 mL. Units for an amount = amount ÷ (concentration per unit). The calculator converts any amount you enter at the concentration you choose; a unit is a volume mark, not an amount of compound.

Is P-21 FDA-approved?

Not approved — research use only. P021 is not approved by the FDA for any use and does not appear in any of the three categories of FDA's 503A bulk drug substances list as updated May 14, 2026 ^9. A ClinicalTrials.gov search did not identify any registered interventional trial of P021 in humans ^10. All efficacy data identified are from rodents and cultured cells ^1,2,3,4,5,7.

References

Neurotrophic peptides incorporating adamantane improve learning and memory, promote neurogenesis and synaptic plasticity in mice FEBS Letters. 2010
Rescue of cognitive-aging by administration of a neurogenic and/or neurotrophic compound Neurobiology of Aging. 2014
Elevated Tau Level in Aged Rat Cerebrospinal Fluid Reduced by Treatment with a Neurotrophic Compound Journal of Alzheimer's Disease. 2015
Early neurotrophic pharmacotherapy rescues developmental delay and Alzheimer's-like memory deficits in the Ts65Dn mouse model of Down syndrome Scientific Reports. 2017
Prenatal to early postnatal neurotrophic treatment prevents Alzheimer-like behavior and pathology in mice Alzheimer's Research & Therapy. 2020
Alzheimer's Disease: Challenges and a Therapeutic Opportunity to Treat It with a Neurotrophic Compound Biomolecules. 2022
Effects of a ciliary neurotrophic factor (CNTF) small-molecule peptide mimetic in an in vitro and in vivo model of CDKL5 deficiency disorder Journal of Neurodevelopmental Disorders. 2024
Corrigendum to: Diffusion MRI measures detect brain microstructure changes due to early treatment with neurotrophic peptide mimetic P021 in the 3xTg-AD mouse model of Alzheimer's disease Magnetic Resonance Imaging. 2026
Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act (updated May 14, 2026) FDA. 2026
ClinicalTrials.gov search for interventional studies of P021 (no records identified) ClinicalTrials.gov. 2026
World Anti-Doping Code International Standard Prohibited List 2026 WADA. 2026

Last reviewed October 23, 2026 by the Amiravo editorial team. Editorial policy · Report an error