SingleCognitive & Sleep

P21 10mg

A synthetic CNTF-derived pentapeptide engineered with an adamantyl group to investigate blood-brain barrier transport and neurogenesis.

Mechanism

P21 enhances BDNF expression and reduces neuroinhibitory LIF signaling via a stable, blood-brain barrier-permeable adamantylated pentapeptide modeled after active CNTF domains.

Dosing

Standard laboratory conventions describe a starting reference of 500 mcg administered subcutaneously once daily.

Reconstitution

Reconstituting a 10 mg vial with 2.0 mL of bacteriostatic water creates an injectable laboratory solution at a concentration of 5,000 mcg/mL (5 mg/mL).

Storage

Keep lyophilized vials refrigerated or frozen protected from light, and store reconstituted solution between 2 and 8 °C for up to 28 days.

Mix & measure P21 10mg

Pre-filled with this protocol's recommended BAC water and documented starting dose — edit any field to run your own numbers.

Mix & measure P21 10mg

Vial strength → BAC water → target dose

Vial strength

BAC water

Target dose

Concentration5.00mg/mL

Draw volume0.100mL

On the syringe10.0units

Total doses in vial: 20.0

100u80u60u40u20u0

U-100 syringe: 100 units = 1 mL

Reconstitution math only — not dosing advice. U-100 syringe: 100 units = 1 mL. Advanced calculator →

Dosing Chart

Phase / Day(s)	Dose & Frequency	Volume (U-100 units / mL)
Conservative Start (Convention)	500 mcg, once daily	10 units (0.10 mL)
Common Reference (Convention)	1,000 mcg, once daily	20 units (0.20 mL)
Typical Research Cycle	4–12 weeks continuous	Dependent on protocol

Reconstitution Steps

1
Swab the rubber stoppers of both the P21 vial and the bacteriostatic water vial with sterile alcohol wipes and permit them to air-dry completely.
2
Draw precisely 2.0 mL of bacteriostatic water using an appropriate reconstitution syringe.
3
Insert the needle into the P21 vial and slowly dispense the diluent down the inner glass wall to prevent mechanical shearing of the lyophilized cake.
4
Gently swirl the vial in circular motions until the lyophilized powder dissolves entirely; do not shake.
5
Note the reconstitution date on the vial label and place it immediately into refrigerated storage at 2–8 °C.

Supplies Needed

Peptide Vial

Supplies 10 mg of purified, lyophilized P21 peptide for scientific evaluation.

Insulin Syringes (U-100)

Calibrated 100-unit syringes used to precisely measure and draw micro-volumes for research assays.

Bacteriostatic Water

Provides sterile diluent preserved with 0.9% benzyl alcohol for sterile peptide dissolution.

Alcohol Swabs

Employed to decontaminate vial stoppers and injection equipment interfaces prior to each draw.

Why researchers study it

Hippocampal neurogenesis and dentate gyrus neuronal proliferation

Restoration of synaptic density markers and dendritic structures

Preclinical models of neurodegeneration and developmental memory impairment

Blood-brain barrier permeability of adamantane-conjugated peptides

These describe what is being studied, not proven benefits, approved uses, or promised results.

Overview

P21 (also designated as P021) is an engineered synthetic pentapeptide modeled on the active region of ciliary neurotrophic factor (CNTF residues 148–151). To circumvent the poor pharmacokinetics and undesirable systemic reactions historically seen with native CNTF, investigators conjugated an adamantylated glycine moiety to its terminal segment. This structural modification enhances enzymatic stability against endogenous peptidases and permits penetration through the blood-brain barrier. Preclinical research has largely centered on animal models evaluating synaptic plasticity, adult neurogenesis in the dentate gyrus, and cellular responses related to cognitive aging, Down syndrome, and Alzheimer's disease pathology. In vivo rodent assessments demonstrate that the peptide acts primarily by augmenting brain-derived neurotrophic factor (BDNF) transcription while repressing neurogenesis-inhibiting leukemia inhibitory factor (LIF) signaling. All formal experimental literature derives strictly from animal paradigms—frequently involving chronic oral administration in chow—with no human clinical trials ever having been completed. Independent investigations have revealed mixed results across divergent experimental disease states, emphasizing that the compound remains purely an experimental neurobiological probe with unvalidated translation to human physiological profiles.

References

1.Baazaoui & Iqbal, Alzheimer's Research & Therapy, 2017 — Prevention of dendritic and synaptic deficits and cognitive impairment with a neurotrophic compound
2.Kazim et al., Neurobiology of Disease, 2014 — Disease modifying effect of chronic oral treatment with a neurotrophic peptidergic compound in a triple transgenic mouse model of Alzheimer's disease
3.Kazim et al., Scientific Reports, 2017 — Early neurotrophic pharmacotherapy rescues developmental delay and Alzheimer's-like memory deficits in the Ts65Dn mouse model of Down syndrome
4.Wei et al., Alzheimer's Research & Therapy, 2020 — Prenatal to early postnatal neurotrophic treatment prevents Alzheimer-like behavior and pathology in mice
5.Wei et al., Journal of Alzheimer's Disease, 2021 — Neurotrophic Treatment Initiated During Early Postnatal Development Prevents the Alzheimer-Like Behavior and Synaptic Dysfunction
6.Mottolese et al., Journal of Neurodevelopmental Disorders, 2024 — Effects of a ciliary neurotrophic factor (CNTF) small-molecule peptide mimetic in an in vitro and in vivo model of CDKL5 deficiency disorder