Nootropic Peptides: Selank vs Semax vs DSIP (2026)

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Cognitive & Neuro Peptides (9)

Selank

A nootropic peptide for anxiety relief, focus, and mental clarity.

Semax

A cognitive-enhancing peptide for focus, memory, and neuroprotection.

DSIP

A sleep peptide that enhances natural delta wave sleep without sedation or dependence.

Pinealon

A Khavinson tripeptide (Glu-Asp-Arg / EDR) marketed as a neuroprotective brain peptide; evidence is preclinical cell-culture and rodent only, with no human trials.

Cortagen

A Khavinson cerebral-cortex tetrapeptide (Ala-Glu-Asp-Pro / AEDP) studied in small animal models for nerve regeneration and CNS support; preclinical only.

Dihexa

An angiotensin-IV-derived research peptide studied in animal models for synaptogenesis via the proposed HGF/c-Met pathway; the core mechanism papers were retracted in 2025 and no human trials exist.

Noopept

A dipeptide-derived racetam-class nootropic (omberacetam) with Russian human trial data in cognitive impairment; metabolized to the endogenous peptide cycloprolylglycine, sold in the West as a research chemical.

NSI-189

A neurogenic small molecule that reached a Phase 2 depression trial which failed its primary endpoint; preclinical work reports hippocampal neurogenesis, now sold as a discontinued research chemical.

P-21

A CNTF-derived adamantylated tetrapeptide (P021) studied in rodent Alzheimer's models for neurogenesis and tau reduction; no human trials exist, sold as a research chemical.

clinical

FDA's Next Peptide Panel: GHK-Cu, Melanotan, Dihexa

The FDA scheduled a second peptide panel by early 2027: GHK-Cu, Melanotan II, LL-37, Dihexa, and PEG-MGF are next. What buyers should know.

side-effects

Cortagen Side Effects: What the Evidence Shows

Its originators claim near-zero side effects, but independent safety data barely exists. What the research shows — and the risks it leaves out.

P-21 Side Effects: The No-Human-Data Reality

P-21 has zero human safety data — every figure is preclinical or anecdotal. The sleep-disruption signal and theoretical cautions, graded by source.

NSI-189 Side Effects: The Trial Safety Record

NSI-189 was well tolerated in trials at ≤12 weeks with no serious adverse events — but its Phase 2 failed and there is no long-term safety data. Graded by source.

Noopept Side Effects: Trials vs Reports

Noopept's side effects, graded by source: what Russian trials documented vs what community users report — headache, blood pressure, and choline depletion.

Dihexa Side Effects: The No-Human-Data Reality

Dihexa has zero human safety data and a retracted mechanism literature. The theoretical cancer concern and anecdotal effects, graded by source.

Semax Side Effects: What Russian Trial Data Shows

Russian clinical data describes clean safety in stroke and ischemia. Community reports add overstimulation and headache. Full breakdown.

results

Cortagen Results: Week-by-Week Timeline

Cortagen has no human efficacy trials — so what drives the reported timelines? Preclinical nerve data and labeled community reports, week by week.

P-21 Timeline: What the Evidence Shows

No human trial sets a P-21 timeline. Here's the gap between rodent chronic-dosing data and community-reported onset, each clearly labeled.

NSI-189 Timeline: What the Evidence Shows

Its Phase 2 depression trial failed the primary endpoint. So what does an NSI-189 timeline actually rest on? Trial data vs anecdote, labeled.

Noopept Results Timeline: Onset Evidence

Russian trials measured Noopept effects over weeks; community users report onset in 15-60 minutes. Here's the gap between the two, each labeled.

Dihexa Timeline: What the Evidence Shows

No placebo-controlled human data sets a Dihexa timeline. Here's the gap between rodent onset data and community-reported onset, each labeled.

Pinealon Results: What to Expect & When

There's no human timeline for Pinealon — only preclinical data and community reports. What that evidence actually suggests over a short course.

reconstitution

Cortagen Reconstitution: 20mg Vial Mixing Chart

Cortagen has no validated human concentration. See how community resources describe mixing the 20mg vial, plus syringe-unit math and storage limits.

P-21 Reconstitution: 5mg Vial Bac Water Math

P-21 ships as a 5mg lyophilized vial with no validated human dose. Here's the bac-water math community sources use for the ~500mcg-1mg subQ range.

Pinealon Reconstitution: 10mg + 1mL Chart

At 10mg/mL, a community-documented 5mg draw is exactly 50 units. Most mixing errors happen at the syringe math. Pinealon dilution chart, storage, and steps.

dosing

Cortagen Dosing: 10-20 Day Course Protocol

A synthetic cortex tetrapeptide with no validated human dose. What research-chem sources report for short courses, plus the extract-vs-synthetic caveat.

P-21 Dosing: What the Community Reports

P-21 has no trial-set dose. See the 500 mcg-1 mg figure community sources actually use, the route mismatch, and the all-rodent evidence behind it.

NSI-189 Dosing: The 40-80 mg/day Trial Figure

NSI-189's 40-80 mg/day comes from a depression trial that failed its primary endpoint. See where the community dose really comes from.

Noopept Dosing: What the Data Shows

People take 10-30 mg/day, but Russian trials used 20 mg. See where each number comes from and why it's oral, not injected.

Dihexa Dosing: What the Community Reports

Dihexa's 5-20 mg/day dose comes from forums, not trials. See the oral-vs-transdermal route debate and the 2025 retractions behind it.

Pinealon Dosage: What the Research Shows

There's no human-trial dose for Pinealon. Community protocols cluster at 5-10mg/day in short courses — here's the math and where the numbers come from.

guides

Where to Buy Cortagen: Price & Vendor Guide

Cortagen is a synthetic AEDP tetrapeptide, not the Cortexin extract. How to read a 430 Da COA, spot the mix-up, and what a course really costs.

Where to Buy Pinealon: Price & Vendor Guide

Pinealon ships almost only as 10mg vials around $45-$90 — about $4.50-$9.00/mg. How to verify COAs and pick a vendor for an unproven research tripeptide.

Where to Buy Semax/Selank Stack: Vendor Guide

Combined nasal spray runs $50-110 — Russian-approved nootropic + anxiolytic pair. Which COAs verify both peptides, red flags.

Where to Buy Semax: Price & Vendor Guide

5mg nasal spray vials run $35-80 — Russian-approved, no FDA approval. Which COAs verify the 813 Da ACTH(4-7) analog, red flags.

Where to Buy Selank: Price & Vendor Guide

5mg vials run $30-70 — Russian-approved anxiolytic, GAD trial vs medazepam. Which COAs verify the 751 Da target, red flags.

Where to Buy DSIP: Price & Vendor Guide

5mg vials run $30-70 — small clinical trial base for sleep, no FDA approval. Which COAs verify the 850 Da nonapeptide, red flags.

benefits

Cortagen for Nerve Regeneration: Rat Data

The nerve-repair reputation for Cortagen traces to rat studies and a brain-tissue extract, not the synthetic peptide. What the research actually reported.

P-21 Benefits: What the Research Shows

P-21's neurogenesis and tau-reduction claims come entirely from rodent studies — clean of retractions, but zero human data. Sorted by evidence.

NSI-189 Benefits: What the Evidence Shows

NSI-189 reached human trials for depression — then its Phase 2 failed. What's left, what's preclinical, and what's purely anecdotal.

Noopept Benefits: What the Evidence Shows

Noopept is one of the few research nootropics with real human data. What the Russian trials show, what's preclinical, and what's only anecdotal.

Dihexa for Memory: What the Evidence Says

Dihexa's most-cited claims sit on retracted papers. What's left, what's independent, and what's purely anecdotal — sorted by evidence.

Pinealon Benefits: What Preclinical Data Shows

Pinealon is marketed as a brain peptide — but every benefit traces to cell-culture and rodent studies. What the research reports, and what it can't.

buying-guide

Where to Buy P-21: Forms, COA & Red Flags

P-21 has no human trials and no established dose — here's what that means for buyers, plus how to read a COA before you spend a dollar.

Where to Buy NSI-189: Forms, COA & Red Flags

NSI-189's Phase 2 depression trial failed its primary endpoint — here's what that means for buyers, plus how to read a COA before spending a dollar.

Where to Buy Noopept: Forms, COA & Dose Facts

Noopept is one of the few research nootropics with human trial data — how to read a COA, what the 20 mg trial dose means, and what to verify first.

Where to Buy Dihexa: Forms, COA & Red Flags

The foundational Dihexa papers were retracted in 2025 — here's what that means for buyers, plus how to read a COA before you spend a dollar.

Peptides Under $50/vial: 12 Picks

12 peptides priced under $50/vial with real vendor links — healing, cognitive, sexual, metabolic. $/mg shown for every pick so you can buy smart.

comparison

Selank vs Semax: Best Nootropic Peptide?

Selank calms, Semax stimulates — pick wrong and you'll get the opposite effect. Full comparison on cognition, anxiety, and dosing.

articles

Best Peptides for Sleep: 4 Options Ranked

Ranking of the peptides people use for sleep — what each one does, who it suits, and what users actually report.

Best Peptides for Brain Health: 3 Ranked

Ranking of the peptides community sources describe for focus, memory, and sleep — what each does and what users actually report.

Price Comparisons

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This page is for educational and research purposes only. It does not constitute medical advice. Always consult a qualified healthcare professional before starting any peptide protocol.