P21 (P021) is sold here for laboratory research, in 1 size (5mg), starting at $95.00 a vial. Every batch arrives with a certificate naming the test that identified it, the test that measured its purity, and the date each was run. It is not an FDA-approved medicine. Research use only, and never for people or animals.
P21 specifications
| Product name | P21 (P021) |
|---|---|
| Also sold as | P21 (P021), P021, P21 peptide |
| Physical form | Freeze-dried powder — a solid cake in a sealed vial |
| Appearance | White to off-white cake |
| Sizes on this page | 5mg |
| Purity specification | ≥99% by RP-HPLC. The number for the lot you receive is whatever its own certificate says. |
| Identity check | Mass spectrometry, read against the mass this compound should have |
| Net content | Weighed per lot and reported separately from purity |
| Lot documentation | At the laboratory — each certificate posts here the day it clears |
| Storage | Sealed, cold and out of the light |
| Ships from | Santa Ana, California — same business day on verified in-stock orders placed before 12 PM Pacific |
| Intended use | Laboratory research only. Not for human or animal use. |
What is P21, and what is it used for?
P21 is also listed and searched as P21 (P021), P021, P21 peptide. They all mean the same compound. Supplier lists write it as P21 peptides or peptide P21 as well; every one of those is this record. A name is not a test, which is why the lot record further down counts for more than the wording on a label.
Small peptidergic compound derived from ciliary neurotrophic factor, sequence Ac-DGGL(A)G-NH2 — an acetylated and amidated tetrapeptide with an adamantylated residue.
Derived from an active region of ciliary neurotrophic factor. The reported effect is increased brain-derived neurotrophic factor expression, with downstream reduction in glycogen synthase kinase-3-beta activity. Not a receptor agonist in the conventional sense; no receptor has been identified for it.
Chronic oral treatment in a triple-transgenic mouse model of Alzheimer's disease, examining tau phosphorylation, amyloid burden, neurogenesis and synaptic plasticity.
No receptor identified, no human trials, no approved product. The work comes principally from one laboratory.
P21 for sale: 5mg vials, price per mg
P21 is sold in 1 size here, 5mg, from $95.00 a vial. The per-mg column is the honest comparison between sizes; the two tier columns show what ten and twenty vials of one size bill at, because the volume discount is per size and mixed sizes do not combine.
| Size | One vial | Per mg | 10 vials −10% | 20 vials −15% | Availability |
|---|---|---|---|---|---|
| P21 5mg | $95.00 | $19.00 | $855.00$17.10/mg | $1,615.00$16.15/mg | Backordered — waitlist |
P21 discounts: bulk pricing, Subscribe & Save, and codes
Three things move this price and nothing else does: how many vials of one size are on the order, whether that order repeats, and one code. The fourth column prices each route against the 5mg vial.
| Buying option | Takes off | When it applies | 5mg at this option |
|---|---|---|---|
| One vial, one time | — | Any order | $95.00 |
| 10–19 vials of one size | 10% | This order | $855.00$85.50 a vial |
| 20 vials of one size | 15% | This order | $1,615.00$80.75 a vial |
| Subscribe, every 1 month | 6% | Shipment 2 onward | First $95.00, then $89.30 |
| Subscribe, every 2 months | 4% | Shipment 2 onward | First $95.00, then $91.20 |
| Subscribe, every 3 months | 2% | Shipment 2 onward | First $95.00, then $93.10 |
| 10 vials on a monthly subscription | 10%, then 6% more | Shipment 2 onward | First $855.00, then $803.70 |
| Sign-up code | 10% of the order | One use, dead 24 hours after signup | $85.50 for one vial |
| Friday newsletter code | 5% of the order | Live 24 hours, a new one each Friday | $90.25 for one vial |
| On-site offer code | 5% of the order | Live 30 minutes from when it appears | $90.25 for one vial |
| Free standard shipping | The shipping charge | Orders over $200 | 3 vials |
The first three stack; the codes do not. A volume discount comes off the line, a subscription cadence comes off that same line from shipment 2, and one code comes off what is left. One code per order, never two. A subscription runs a minimum of two shipments and can be cancelled once the second has shipped, and the first shipment always bills at today's eligible price with no cadence discount on it. The lowest this record ever bills is $15.18 per mg: twenty 5mg vials on a monthly subscription, from shipment 2 onward.
Every figure above is what you pay; nothing is added at checkout — dispatch and delivery work the same on every order.
Where to buy P21: five checks before you order from anyone
P21 for sale, or P21 peptide for sale, means this page: one record, 1 size, a lot certificate for each. You can buy P21 online here with guest checkout; verified in-stock orders placed before 12 PM Pacific are dispatched the same day.
Run these on us too. A supplier who cannot pass them is asking you to take their word for it, and their word is the one thing a certificate exists to replace.
- Check the certificate on the lab’s own site, not ours.
- See whether it was written for the seller.
- Match the lot number on the paper to the one on the vial.
- Look for a method and a date next to every number.
- Make sure identity was tested, not assumed.
Each of those is worked through, with what a failed check actually looks like, on verifying a certificate.
The P21 certificate: lot, purity, identity, and how to verify it
A certificate answers identity, purity and net content as three separate questions, each with the method that produced it and the date it was run — how to read one covers what each field does and does not cover.
The certificate below belongs to one lot, and its number matches the one printed on the vial you receive. A real report for a different batch is still the wrong report.
| Size | Lot | Identity method | Purity | Test date |
|---|---|---|---|---|
| 5mg | Pending verification | Pending verification | Pending verification | Pending verification |
No lot documentation is published for P21 (P021) yet. Rather than display a placeholder certificate, this record shows the gap until each field has been verified against the lot in hand. The certificate index lists every lot the moment its report clears.
Solution arithmetic for the bench, with no administration guidance: the vial concentration calculator, preset to P21 (P021).
Where the FDA stands on P21
The FDA has not approved this compound for anything, and nothing in this catalogue is a medicine. Where a compound stands legally depends on what it is, what form it is in, what it is being used for and which country you are in, and it changes over time, so the status shown here carries the date it was last checked.
Status verified 2026-08-25. Regulatory positions move; check the primary source before relying on any summary, including this one.
It is sold here as laboratory material under the research-use restriction that closes this page, which is not an approval, and not a statement that the compound is safe, effective or right for any purpose.
P21 research: what the published studies examine
Status: No FDA-approved application. This compound is sold as laboratory material. Where research on it has been published, it sits at the animal, cell or early-human stage, and this record does not summarise what it found. A supplier is not a neutral judge of evidence about its own catalogue.
P021 is a small compound derived from ciliary neurotrophic factor, with the sequence Ac-DGGL(A)G-NH2 — the acetyl and amide caps and the adamantylated residue are stability and permeability modifications rather than active features. The design idea is a real one in neuroscience: full neurotrophic proteins are too large and too poorly distributed to administer, so the field has repeatedly tried to reduce them to short active fragments that survive in circulation and reach the brain.
What P021 is proposed to do once there is raise BDNF expression, with a consequent fall in GSK3-beta activity — GSK3-beta being one of the kinases implicated in tau phosphorylation. That is a plausible chain and it is described as an inference from the observed changes rather than a demonstrated pathway; no receptor for the compound has been identified.
| Reported observation | Model | Source |
|---|---|---|
| Triple-transgenic and wild-type mice were treated for 12 months with P021 or vehicle diet from 9 to 10 months of age. Treated animals showed significantly reduced abnormal hyperphosphorylation and accumulation of tau at major neurofibrillary-pathology-associated sites. The effect on amyloid pathology was LIMITED — a significant decrease in soluble amyloid-beta and only a non-significant trend toward reduced plaque load in hippocampal CA1. Increased BDNF expression and decreased GSK3-beta activity were found, and deficits in cognition, neurogenesis and synaptic plasticity were reduced. | 3xTg-AD transgenic mice, 12 months of chronic oral treatment | Kazim and colleagues, Disease modifying effect of chronic oral treatment with a neurotrophic peptidergic compound in a triple transgenic mouse model of Alzheimer's disease, Neurobiology of Disease (2014)The amyloid result is explicitly partial — a trend rather than a significant plaque reduction — and the authors say so. |
Open questions. This is a well-conducted single study in a transgenic mouse model, and both halves of that description matter. Twelve months of chronic oral dosing with multiple orthogonal endpoints is real work; a 3xTg-AD mouse is a model that has produced a long series of compounds that did not translate, which is a general problem in this field rather than a criticism of this one. The amyloid result was partial by the authors' own reporting.
No receptor has been identified, which means the mechanism is described by its downstream correlates rather than by a target. The literature comes principally from one laboratory and there are no human trials and no approved product. Anyone reading claims about this compound should notice how far they travel from a mouse diet study.
Each row above describes an observation in the stated model. None of it describes what P21 (P021) would do in a person or an animal outside that model, and none of it is a recommendation to use it for anything.
Questions about P21
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What is P21 (P021) used for?
What is P21 peptide?
How do I verify the certificate of analysis is real?
FOR LABORATORY AND IN-VITRO RESEARCH USE ONLY. NOT FOR HUMAN OR ANIMAL CONSUMPTION. NOT FOR PERSONAL, MEDICAL, DIAGNOSTIC, THERAPEUTIC, OR RECREATIONAL USE.
