Quick Verdict

PE-22-28 is a nootropic peptide primarily researched for antidepressant, neuroplasticity, trek-1 channel blockade, fast-acting mood elevation, while Semax is a cognitive peptide studied for mental clarity, focus, neuroprotection. Semax has substantially more indexed research (20 studies) compared to PE-22-28 (2 studies). A key distinction: Semax has FDA approval status.

Side-by-Side Analysis

DimensionPE-22-28Semax
CategoryNootropic PeptideCognitive Peptide
MechanismSynthetic hexapeptide fragment derived from the propeptide of sortilin, an endogenous regulator of the TREK-1 potassium channel.BDNF upregulation, nootropic effects.
Half-Life~1 hours~20 minutes
RouteSubQNasal
Typical Dose500–1000 mcg300–300 mcg
FrequencyDaily7x/wk
Evidence LevelPreclinicalModerate
Indexed Studies2+ indexed20+ indexed
FDA StatusResearch OnlyApproved
Lowest Price$29.99 / 10mg via Amino Club

Mechanism of Action Comparison

How PE-22-28 Works

PE-22-28 PE-22-28 is a spadin-derived peptide that blocks the TREK-1 potassium channel — a key culprit in depression — producing fast-acting antidepressant effects in animal models without typical SSRI side effects.

Synthetic hexapeptide fragment derived from the propeptide of sortilin, an endogenous regulator of the TREK-1 potassium channel. PE-22-28 competitively inhibits TREK-1, a background leak channel whose overactivation is implicated in depression and anxiety. By blocking TREK-1, PE-22-28 increases neuronal excitability in serotonergic circuits and promotes BDNF expression, producing rapid antidepressant effects in rodent models comparable to fluoxetine.

How Semax Works

Semax Semax is a synthetic ACTH-derived cognitive peptide approved in Russia studied for enhancing memory, focus, and neuroprotection by upregulating brain-derived neurotrophic factor (BDNF).

BDNF upregulation, nootropic effects. Enhances neural plasticity, protects neurons from oxidative stress, and improves cerebral blood circulation.

Key Mechanistic Difference

PE-22-28 operates as a nootropic peptide, while Semax functions as a cognitive peptide — these are fundamentally different pharmacological approaches. PE-22-28 has a significantly longer half-life (~1 hours) compared to Semax (~20 minutes), which impacts dosing frequency and sustained activity.

Research Evidence

PE-22-28

2 studies
View all PE-22-28 research

Semax

20 studies
View all Semax research

Vendor Pricing

· Affiliate links · Prices verified 2026

PE-22-28

Pricing coming soon

Semax

4 vendors
Amino ClubEditor's Pick
10mg vial · $3.00/mg
$29.99Buy
Ascension Peptides
10mg vial · $5.50/mg
$55.00Buy
Limitless Life Best Value
30mg vial · $1.50/mg
$44.99Buy
Bio Longevity LabsTriple-Tested
20mg vial · $3.25/mg
$64.97Buy

Affiliate disclosure: PeptiDex may earn a commission from purchases via vendor links at no extra cost to you. See our methodology.

Frequently Asked Questions

Can I take PE-22-28 and Semax together?

Yes — PE-22-28 and Semax are identified as synergistic in interaction databases. They operate through complementary mechanisms and are commonly combined in research protocols.

Which has more research evidence — PE-22-28 or Semax?

PE-22-28 has 2 indexed studies (highest evidence: Preclinical). Semax has 20 indexed studies (highest evidence: Moderate). Semax has a more extensive research base.

Which is better for brain focus — PE-22-28 or Semax?

Both are researched for brain focus. PE-22-28 addresses this via antidepressant, neuroplasticity, trek-1 channel blockade, fast-acting mood elevation. Semax approaches it through mental clarity, focus, neuroprotection. The optimal choice depends on your specific research protocol and which mechanism aligns with your objectives.

Is PE-22-28 or Semax FDA-approved?

Semax has FDA approval (or is derived from an FDA-approved compound). PE-22-28 is a research compound without FDA approval for human use. FDA status reflects regulatory evaluation — not necessarily superiority for all research applications.

Related Comparisons

Research Use Only — Not Medical Advice

This comparison is provided for educational and research purposes only. It does not constitute medical, prescribing, or treatment advice. Clinical data cited here is sourced from published peer-reviewed trials and FDA labels. Consult a qualified healthcare professional before making any decisions about medications or research compounds. PeptiDex is an informational resource and does not sell pharmaceutical products.