Skip to content
Peptide Evidence Registry

Neuro & cognitive

P021

A CNTF-derived, adamantylated tetrapeptide studied in Alzheimer's mouse models; no human trial identified. Not the same as 'P21'.

L1Theory onlyNot approved for this usePreclinicalPeptide analogue
How settled this rating is:
low confidence in the current evidence rating
Routes studied:
Not established · Nasal, Oral (marketed but never approved)
Also known as:
Peptide 021, Ac-DGGL(A)G-NH2, CNTF-derived peptidergic compound
Last reviewed:
2026-09-26
Jump to section

Evidence passport

P021

A one-screen evidence identity for this compound. These fields describe research maturity, confidence and legal status. They are not a safety guarantee, efficacy percentage or recommendation.

Reviewed 2026-09-26
Evidence level
L1Theory only
Confidence
Low confidence in rating
Regulatory status
Not approved for this use
Development status
Preclinical

Evidence strength

Human efficacy evidence2 of 100 evidence strength

Higher = more and better-quality human evidence. It does not mean the effect is bigger or that the compound works for you.

Human safety evidence3 of 100 evidence strength

Higher = more mature, better-documented human safety data. It does not mean the compound is safer than one with a lower number.

The 0-100 values rate the strength and maturity of evidence, not how effective or safe the compound is.

Evidence base
Mostly animal and laboratory research
Furthest established stage
Not established
Human research maturity
Preclinical (transgenic mouse studies)
Source curation
Sources fully curated

Routes recorded

Nasal· unapprovedOral· unapproved

Most of this evidence comes from animals and cells

The supporting research for P021 is predominantly preclinical (Level 1–2). That is a legitimate starting point for science and a poor basis for personal decisions. Human results are not simply a scaled-up version of mouse results.

Overview

Human efficacy evidence strength2 of 100 evidence strength

Higher = more and better-quality human evidence. It does not mean the effect is bigger or that the compound works for you.

Preclinical (animal / lab) evidence strength28 of 100 evidence strength

Higher = more animal, tissue or cell research. Preclinical results are a starting point, not proof of a human benefit.

Human safety evidence strength3 of 100 evidence strength

Higher = more mature, better-documented human safety data. It does not mean the compound is safer than one with a lower number.

How to read these scores

Every number here rates the evidence, not the compound. They are editorial 0-100 strength ratings, not percentages, and not a rating out of five stars.

  • Human efficacy evidence strength — Higher = more and better-quality human evidence. It does not mean the effect is bigger or that the compound works for you.
  • Preclinical evidence strength — Higher = more animal, tissue or cell research. Preclinical results are a starting point, not proof of a human benefit.
  • Human safety evidence strength — Higher = more mature, better-documented human safety data. It does not mean the compound is safer than one with a lower number. A score of 80 does not mean “80% safe”.
  • Evidence level (L0-L5) — the strongest type of study behind the compound, from anecdote (L0) to large replicated human trials (L5). It is a description of the study evidence, not a quality, safety or recommendation rating.
  • Confidence — how likely we think it is that this rating changes as new research lands. Low confidence means the picture is unsettled, not that the compound is bad.

None of these ratings is medical advice, a safety guarantee, or a recommendation to use anything. How we grade evidence.

How far human research has progressed: Preclinical (transgenic mouse studies)

Routes & formulations

Marketed / research routes — never approved

Nasal· unapprovedOral· unapproved

Mouse studies gave P021 in the diet. That is not evidence of absorption or effect for any human route.

Route availability is not evidence of efficacy, and evidence from one route does not transfer to another. The Registry never provides dosing or sourcing information.

Peptide lifecycle

  1. Discovery

  2. Preclinical

  3. Phase I

  4. Phase II

  5. Phase III

  6. Approved

PreclinicalFurthest stage not established in our curated record

What it is

A tetrapeptide from the most active region of ciliary neurotrophic factor (CNTF), with an adamantylated glycine added to improve stability and brain entry, from Khalid Iqbal's group (New York State Institute for Basic Research). Online 'P21' products are often conflated with P021; the name P21 is also used for the unrelated cell-cycle protein p21, so identity must not be assumed from the label.

What people claim

  • Cognitive enhancement
  • Neurogenesis
  • Alzheimer's prevention

What the evidence actually says

Mouse studies report reduced tau pathology and improved cognition and neurogenesis in the 3xTg-AD model. No human trial was identified. Transgenic mouse results in Alzheimer's research have a poor record of translating to people.

Related evidence

Useful next reads based on this compound — not recommendations.

Human evidence

  • No human interventional study of P021 was identified in our curated record.

Preclinical evidence

  • 12-month oral treatment in 3xTg-AD mice: reduced tau hyperphosphorylation, reduced soluble Aβ and rescued cognitive deficits (PMID 25046994).
  • Preventive treatment from 3 months of age in 3xTg-AD mice: reported rescue of dendritic and synaptic deficits (Alzheimer's Research & Therapy 2017).
  • Review of neurotrophic-factor mimetics including P021 from the same group (PMID 27400746).

Animal and cell findings are Level 1–2 evidence.

Mechanism and pathways

  • Proposed to increase BDNF expression and reduce GSK-3β activity in mouse brain.
  • Mechanism data come from the originating laboratory and are not independently confirmed in humans.

Safety and unknowns

  • No human safety data identified.
  • Material sold online is unregulated: identity, purity, sterility and labelled quantity are separate questions from what the published molecule does.

Cancer relevance

This section covers questions raised by how the compound works in the body, plus anything regulators and trial teams keep an eye on. It is not a statement that this compound causes cancer — for most compounds here, no human data exist in either direction.

Theoretical / mechanistic concern only

Not established. Neurotrophic signalling is a theoretical consideration only; no data either way.

Regulatory status

Regulatory decisions apply to specific jurisdictions, products, formulations and indications. An approval elsewhere is not automatically an approval in your country.

Check the regulatory note and linked primary sources for jurisdiction-specific details.

Not an approved medicine in any major jurisdiction. Sale as a 'research chemical' is a legal and supply-chain statement, not evidence of benefit or harm.

Evidence grade

L1Theory onlyLow confidence in rating

Mechanistic rationale or early development without qualifying compound-specific outcome evidence. A registered trial is not a result.

What would change our rating?

  • Independent replication outside the originating laboratory.
  • A registered human Phase 1 study.

References and sources

Source transparency

A provenance snapshot of this profile. Counts show what kinds of sources are cited, not how much scientific weight each source deserves.

Sources fully curated
Last editorial review
2026-09-26
Recently reviewed · 20 days ago
Linked curated sources
2
Sources still pending
0
External specialist reviews
0
None recorded for this profile
Peer-reviewed: 2

Review provenance

Registry editorial review: Colin Jackson-White, creator and editor, who is not a doctor or clinician. External specialist review is credited only when a named reviewer has completed a review of this exact profile.

Literature-discovery and AI tools may help locate or challenge candidate evidence, but they are not counted as evidence sources here. Registry judgements are tied to the underlying papers, trial records, regulator documents and official study records.

Source hierarchy: regulatory documents and trial registries first, peer-reviewed work next, sponsor material flagged as non-independent. We never use supplier or clinic marketing as evidence, and where a verified source has not yet been curated we say so rather than inventing one.

Evidence change history

These entries record changes to our assessment of the published evidence — not changes to the compound itself.

No recorded changes yet. Baseline position set on 2026-09-26.