Semax

Also called Met-Glu-His-Phe-Pro-Gly-Pro, MEHFPGP, ACTH(4–7)PGP, Семакс^{1, 11}

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Semax is a 7-amino-acid peptide built from a piece of the stress hormone ACTH, with no hormone effect of its own. Russia registers it as prescription nasal drops for stroke and memory problems after vascular brain disease.^{11, 12} Its stroke trials are small, published in Russian and often linked to the developing institute.²⁸ FDA's 2026 review left out Russian-language papers, so it did not weigh those trials, and it found the evidence it did review insufficient for stroke, migraine or nerve pain.¹ No published controlled study shows it sharpens focus or memory in healthy people.²² Since October 28, 2026, HHS has said it won't act against licensed pharmacies that compound semax free base as a nasal product, with a prescription.⁶

See every peptide's status in the regulatory tracker

At a glance

Where to get it

MoveWell sells no peptides. All options and prices

Molecular structure

A short straight chain of 7 amino acids. The first four come from ACTH. The last three, Pro-Gly-Pro, were added to make it last longer.

The Pro-Gly-Pro tail (residues 5 to 7)

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MMetEGluHHisFPhePProGGlyPPro

Sequence

MEHFPGP

Length

7 amino acids

Formula

C37H51N9O10S

Weight

813.9 g/mol

Acetate

C39H55N9O12S, 874.0 g/mol

CAS

80714-61-0

FDA UNII

I5FAL2585H (free base)

Drawn from the sequence FDA and HHS list. Formula and weight are for the free base, the form HHS covers.^{1, 6}

What it is

ACTH is a stress hormone that tells the adrenal glands to make cortisol. Short pieces of it, such as ACTH(4–10), affect the brain without that hormone effect. Semax was designed from this idea at the Institute of Molecular Genetics in Moscow; by 1997 its developers described 15 years of work on it.¹³ FDA calls it "a synthetic analogue of the ACTH 4-10 fragment."¹

In practice it keeps ACTH's amino acids 4 to 7 (Met-Glu-His-Phe) and adds Pro-Gly-Pro, which slows its breakdown.²³ The Russian label describes it as having no hormonal activity.¹¹ Its sibling selank, from the same institute, uses the same Pro-Gly-Pro tail on a different peptide.

In Russia, PEPTOGEN sells two prescription nasal drops. The 0.1% drops are for memory and thinking problems after vascular brain disease, stroke recovery, brain injury and some optic nerve conditions. The 1% drops are for the acute phase of moderate or severe ischemic stroke, alongside other treatment.^{11, 12} Russia classes it as a nootropic.¹¹

"Semax" is a common name, not an official US drug name. FDA said nominations were unclear about which salt was meant, so it reviewed both.¹ HHS describes only the free base.⁶ Modified versions sold online, such as "N-acetyl semax amidate," are different molecules.

How it works

What's known comes from rodents and lab work.¹

• Many effects in rodents. FDA lists brain protection after blocked blood flow, blood-thinning, pain relief and anti-anxiety effects. It calls semax "pleiotropic."¹
• Brain growth factors. Earlier rat stroke studies found it raised the activity of genes for nerve growth factors and their receptors, as a 2021 rat study summarizes.²³
• Enzyme blocking. In human serum in a dish, it slowed enzymes that break down the body's own opioid-like peptides.²⁴
• Getting to the brain. In rats, a nasal dose put more of it in the brain than an IV dose, though still under 0.1% of the dose. Its main breakdown product was Pro-Gly-Pro.¹

No study has measured how the human body absorbs or clears it, by any route.¹

Evidence map

Each claimed use is graded separately, because the evidence differs by use.

Scale: 5 FDA-approved, 4 strong human, 3 limited human, 2 animal or lab only, 1 anecdotal

Key studies

A 2024 review by Russian authors counts 13 stroke studies with 1,011 patients from 1997 to 2023, but gives no pooled effect.¹⁸ FDA counted human use in roughly 33 to 47 healthy adults, 69 adults with medical conditions and 451 children, all by the nasal route. It left out Russian-language papers, including the stroke trials above, and for stroke it reviewed only one meeting abstract.¹ We found no trial registered on ClinicalTrials.gov. Even a provider that plans to sell it says the human evidence is "small, mostly Russian studies not independently replicated."²⁸

By goal and route

Pick your goal to see what the evidence supports.

Sources: HHS policy terms,^{6, 7} FDA briefing,¹ Russian labels,^{11, 12} Superpower.²⁷

How it's used

We don't give a dose. No US-standard trial has set one.

In Russia it is given as nose drops. The 1% stroke product is used in daily 10-day courses, with the amount set by a doctor according to stroke severity.¹² Stroke studies used much higher amounts in the acute phase than in later rehab.^{14, 18} FDA found no study of semax by injection under the skin, and no human study of how it is absorbed by any route.¹ We report these as information, not instruction.

Side effects and who should avoid it

• Nasal irritation. The Russian label lists mild irritation of the nose lining with long use as its side effect.^{11, 12}
• Eye pain. FDA's adverse event database has one report: eye pain and burning after semax 0.1% nasal drops, with a hospital stay reported.¹
• Bleeding. Semax thinned blood in rodents. FDA says this "raises concern about the risk of bleeding, particularly in certain populations at risk for bleeding."¹
• Dopamine. In mice, semax boosted amphetamine's dopamine release. FDA notes this response is "typically induced by drugs of abuse."¹
• Immune reactions and impurities. FDA "cannot rule out the potential for immunogenicity," and the certificates it reviewed listed unidentified impurities and no endotoxin testing.^{1, 10}
• No safety studies. FDA found no repeat-dose or reproductive toxicity studies, and the one cancer study was not adequately designed.¹
• Who should avoid it. The Russian labels rule it out with acute psychiatric illness, anxiety disorders or a history of seizures. The 0.1% drops are not for children under 7, and the 1% drops are not for under-18s. Neither is for use in pregnancy or breastfeeding.^{11, 12}
• Online products. A Belgian medicines lab found semax and selank in seized products sold as cognitive enhancers, as powders for injection and as nasal sprays.²⁶

FDA noted approved treatments exist for stroke, migraine and trigeminal neuralgia.¹ A stroke is an emergency: call 911.

Compared with

Sources: FDA briefing,¹ Russian labels,¹¹ McDermott,⁴ HHS Appendix B.⁶ See our selank guide.

Stacks

Semax is often sold online mixed with selank in one nasal spray. We found no study of that mix. Any blend falls outside the HHS policy, which allows one active ingredient per product.^{6, 8}

Myths vs evidence

All options and prices

MoveWell sells no peptides. Options inside the HHS policy first. Checked November 1, 2026

Licensed compounding, with a prescription

Superpower's listing doesn't name the salt form. The HHS policy covers only semax free base.⁶ Compounded drugs are generally not covered by insurance.

Research use only products

The HHS policy excludes research chemicals, so we don't list sellers.⁷ In August 2026 FDA warned five peptide sellers that a "research use only" label doesn't excuse products clearly meant for people.²⁹ Telehealth listings for semax from before October 28, 2026 predate any legal pathway, so we don't link them.

Legal status history

Newest first.

1. Current statusNov 1, 2026HHS says it won't take action against licensed 503A pharmacies, federal facilities and licensed physicians that compound single-ingredient semax free base for nasal use, with a prescription. Not FDA-approved. Approved in Russia.^{6, 7, 11}
2. Next · no dateA formal rule to add semax to the 503A bulks list. Comments on the HHS policy close two weeks after Federal Register publication, which was scheduled for Oct 30, 2026.^{8, 9}
3. Oct 28, 2026HHS enforcement discretion policy for semax and five other peptides. Not approval, and interim until a final rule.^{7, 8}
4. Jul 24, 2026FDA's compounding advisory committee votes 8–5–1 in favor, for the free base and acetate. The uses reviewed were cerebral ischemia (reduced blood flow to the brain), migraine and trigeminal neuralgia. The vote is advisory.^{2, 3, 4, 5}
5. May 11, 2026FDA staff review recommends against listing: poorly characterized, insufficient evidence, no human absorption data, and approved treatments exist.¹
6. Apr 22, 2026Moved off Category 2 to FDA's "nominated but withdrawn" list. That did not make it legal to compound.^{6, 10}
7. Mar 26, 2025Russia re-registers semax 0.1% nasal drops under a new number.¹¹
8. Sep 29, 2023Placed in Category 2, citing immune risk and too little safety data for the proposed routes.^{6, 10}

What the HHS policy covers

Sources: HHS Appendix B,⁶ BakerHostetler,⁷ FDA Law Blog.⁸ See every peptide's status in the regulatory tracker.

FAQ

Related guides

References