LTP·01learntopeptide
Cognitive & neuroEvidence C3 cited

P21

aka P21 peptide · CNTF-derived peptide · Ac-DGGL-NH2

A synthetic BDNF mimetic tetrapeptide derived from Cerebrolysin that promotes neurogenesis without the side effects of full-length BDNF. Enhances dentate gyrus neurogenesis and improves spatial memory.

Molecular wt
578.7g/mol
Formula
C27H42N6O8
CAS
1246751-68-7
Half-life
3 h
estimated
Tmax
1 h
PubChem
56599151

Sequence

Read this before quoting the sequence
P021 (also written P-21) is a small peptidergic compound derived from an active region of human ciliary neurotrophic factor (CNTF). PubChem's systematic name is 'N-acetyl-L-alpha-aspartylglycylglycyl-N-(3-(aminocarbonyl)tricyclo[3.3.1.1(3,7)]dec-1-yl)-L-leucinamide' and the depositor synonym is 'Ac-dggl-adamantanylglycine-NH2': an acetylated Asp-Gly-Gly-Leu tetrapeptide capped with an adamantylated glycine amide, added to raise lipophilicity and blood-brain barrier penetration and to resist exopeptidases. Because of the adamantane cap, a plain one-letter sequence is not applicable.
Source ↗

Mechanism of action

P21 mimics the neurotrophic effects of BDNF by binding to the TrkB receptor and activating downstream PI3K/Akt and MAPK/ERK signaling pathways. Unlike full-length BDNF, P21 crosses the blood-brain barrier efficiently and does not activate the p75NTR receptor (associated with apoptosis). This selectivity promotes neurogenesis in the dentate gyrus of the hippocampus without pro-apoptotic signaling.

What the evidence actually shows

Grade C

Animal studies show robust neurogenesis and cognitive improvement. P21 improved spatial memory in aged rats. No completed human clinical trials yet. Derived from Cerebrolysin research.

Regulatory status

Status
Not approved anywhere. No marketing authorisation and no identified regulatory filing.
Clinical stage
Preclinical. No human trial of P021 was identified in PubMed/Europe PMC searches; the compound has been studied only in rodent models of Alzheimer disease, Down syndrome and related conditions.
Source ↗

Pharmacokinetics

Half-life
3 h
Tmax
1 h
Absorption
subcutaneous
Elimination
renal
Washout
3 days
Low-confidence pharmacokinetics
These figures are recorded as estimated rather than measured in a published PK study. Treat them as an order of magnitude. Anything downstream of them — accumulation, steady state, washout — inherits that uncertainty.

Dosing — what backs each figure

P21 (P021, a ciliary neurotrophic factor peptide mimetic) has never been given to a human. All dosing data is rodent: 60 nmol/g of medicated diet for 70 days, or 750 nmol per mouse per day intraperitoneally for 30 days. There is no human dose, route or schedule to report.

PreclinicalAnimal studies — not a human dose

  • P021 in formulated diet at 60 nmol/g feed (approximately 150 nmol/mouse/day) for 70 days from postnatal day 21; and, separately, 750 nmol/mouse/day by intraperitoneal injection daily for 30 days in 4-month-old animals

    mouse (Cdkl5 knockout, CDKL5 deficiency disorder model) · oral (medicated diet) and intraperitoneal · PMID 39592934

Animal doses do not convert to human doses by body weight alone. Route matters too — a compound dosed intraperitoneally in mice tells you little about subcutaneous use.

No established human dose
No approved label or completed human trial establishes a dosing regimen for this compound. Anything presented as a standard protocol for it — anywhere — is someone's convention rather than a finding.

Handling and storage

No compound-specific stability data exists
No peer-reviewed or regulatory stability data specific to P021 was located. There is no approved product and no label. Only generic peptide handling guidance exists. General peptide handling still applies — reconstitute gently, keep it cold, keep it dark — but any specific figure you see quoted for this compound elsewhere is someone's assumption, not a measurement.
→ Reconstitution walkthrough→ Reconstitution calculator

Safety

References (3)

Data provenance

Chemistry and citations on this page were checked against primary sources on 2026-08-14. Values that could not be verified were left blank rather than filled with a plausible guess.

Could not verify
storage.lyophilized, storage.reconstituted, storage.lightSensitive, reconstitution.solvent, regulatory.wada

Research use only
This profile is educational reference material. It is not medical advice, not a prescription, and not an endorsement of self-administration. Compounds discussed here are research chemicals and most are not approved for human therapeutic use.

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Cerebrolysin
A porcine-derived neuropeptide complex researched for neuroprotection, cognitive recovery, and stroke rehabilitation.