PinnyPeptide

P21 (P021) vs Selank

Side-by-side comparison: effects, dosing ranges, side effects, regulatory status, and reconstitution.

Peptide A

P21 (P021)

Cognitive

Neurogenic, anti-tau peptide derived from ciliary neurotrophic factor — Alzheimer's research.

Peptide B

Selank

Cognitive

Russian-approved anxiolytic peptide derived from tuftsin with nootropic and immunomodulatory properties.

Typical vial

5 mg

Typical dose

Per kg dosing mcg

Half-life

Variable; designed for sustained activity

FDA status

Not FDA approved.

Typical vial

5 mg

Typical dose

250-500 mcg

Half-life

~15-30 minutes (extended biological effect due to downstream signaling)

FDA status

Not FDA approved for human use.

P21 (P021) effects

  • Promotes adult hippocampal neurogenesis
  • Increases dendritic spine density
  • Reduces tau hyperphosphorylation (anti-tauopathy)
  • Improves learning and memory in Alzheimer's mouse models
  • Crosses the blood-brain barrier after peripheral administration

Selank effects

  • Reduces anxiety without sedation or cognitive impairment
  • Enhances memory consolidation and learning
  • Modulates serotonin, dopamine, and GABA neurotransmitter systems
  • Provides immunomodulatory effects through cytokine balance regulation
  • Increases brain-derived neurotrophic factor (BDNF) expression

P21 (P021) side effects

  • Essentially uncharacterized in humans
  • Theoretical: off-target effects on CNTF / leptin receptor pathways
  • Possible effects on appetite and metabolism (CNTF-family signaling)
  • Injection-site reactions

Selank side effects

  • Mild nasal irritation (intranasal administration)
  • Fatigue during initial use (transient)
  • Occasional lightheadedness

P21 (P021) dosing ranges

Neurogenesis research (preclinical)

40-200 mcg/kg · Daily or alternate-day SubQ · Per research protocol

Selank dosing ranges

Anxiolytic and cognitive enhancement (intranasal)

250-500 mcg · Two to three times daily · 2-4 weeks

Subcutaneous injection

250-500 mcg · Once daily · 2-4 weeks

Full P21 (P021) guide → Full Selank guide →

P21 (P021) vs Selank — common questions

What is the difference between P21 (P021) and Selank?

P21 (P021): Neurogenic, anti-tau peptide derived from ciliary neurotrophic factor — Alzheimer's research. Typical dose Per kg dosing mcg. Selank: Russian-approved anxiolytic peptide derived from tuftsin with nootropic and immunomodulatory properties. Typical dose 250-500 mcg. Both fall under the Cognitive category.

Can you stack P21 (P021) and Selank?

Stacking P21 (P021) with Selank is a protocol-design question best raised with a clinician — it depends on your goal, current bloodwork, and whether both peptides target overlapping mechanisms. Both peptides should be tracked independently with separate injection sites and timing. PinnyPeptide supports multi-peptide stacks with automatic injection site rotation.

Which is dosed more frequently, P21 (P021) or Selank?

P21 (P021) is typically dosed: Daily or alternate-day SubQ for Neurogenesis research (preclinical). Selank is typically dosed: Two to three times daily for Anxiolytic and cognitive enhancement (intranasal); Once daily for Subcutaneous injection.

Are P21 (P021) and Selank FDA approved?

P21 (P021): Not FDA approved. Selank: Not FDA approved for human use.

Related peptide comparisons

adamax vs p21colivelin vs p21dihexa vs p21dnsp-11 vs p21p21 vs pe22-28p21 vs pinealon

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