Semax, selank and DSIP: the evidence behind the nootropic peptides

Key points

• Semax stroke studies are non-randomized Russian series. FDA found no human pharmacokinetic studies [1][2][5].
• In mice, semax potentiated amphetamine-induced dopamine release, a possible abuse signal according to FDA [5].
• Selank anxiety trials have no placebo group [3][4].
• DSIP was the only peptide rejected by the FDA committee in 2026. A double-blind insomnia trial found it “not likely to be of major therapeutic benefit” [6][7].

US status (October 2026): Semax and selank are not FDA-approved and have no lawful compounding pathway. MDside providers do not prescribe them. See semax and selank. DSIP has no status page; see the peptide status tracker.

Semax is a Russian drug with Russian evidence

Semax is a synthetic analog of an ACTH fragment [5]. According to FDA, “Semax is a registered drug in Russia and is available as 0.1% and 1% nasal drops” [5]. That registration has no effect in the United States. The published clinical studies are mainly Russian and in ischemic stroke:

• 1997: 30 treated patients vs 80 on conventional therapy, without randomization [1].
• 2018: 110 patients with outcomes such as BDNF and the Barthel index. The abstract does not describe it as randomized or blinded [2].

In its 2026 briefing document FDA added three concerns. In mice, semax “potentiated amphetamine-induced” striatal dopamine release. Its antithrombotic effect “raises concern about the risk of bleeding.” And: “We were not able to find pharmacokinetic studies in humans.” FDA also found only two references for the nominated uses, and both showed a lack of effectiveness [5].

• 0: human pharmacokinetic studies of semax according to FDA [5]
• 0: placebo groups in the selank trials reviewed [3][4]
• 6 to 7: FDA committee vote against DSIP [8]

Selank was tested against benzodiazepines, never placebo

Selank is an analog of tuftsin [10]. The indexed human trials compare it with benzodiazepines: 62 patients with generalized anxiety or neurasthenia vs medazepam [3], and 70 patients who received selank as add-on to phenazepam vs phenazepam alone [4]. Without placebo, you cannot separate the drug’s effect from spontaneous improvement or expectation.

DSIP was the only one the committee rejected

Delta sleep-inducing peptide (DSIP, emideltide) was described in the 1970s [7]. In a double-blind, placebo-controlled trial of 16 patients with chronic insomnia, the significant effects were weak and partly attributable to an incidental change in the placebo group. The authors concluded that short-term treatment “is not likely to be of major therapeutic benefit” [6]. FDA called the insomnia trials “inconclusive and at best preliminary” and warned that its action on the opioid system “could lead to development of addiction” [7]. In July 2026 it was the only one of seven peptides the advisory committee rejected: 6 for, 7 against and one abstention [8].

A foreign registration is not a trial

A peptide being registered in another country does not mean randomized controlled trials exist [1][2][5]. In all three cases, the available human evidence does not include adequately sized placebo-controlled trials for the uses they are promoted for [3][4][6].

The supporters’ side. Semax is a registered drug used clinically in Russia [5]. The FDA committee voted 8 to 5 in its favor [8], and one physician who voted yes explained: “Our patients want peptides” [9]. For its supporters, the lack of Western trials reflects where the research was done and does not necessarily mean an absence of effect.

What this means for you. The committee votes are nonbinding, and FDA has not acted on them. Until it does, nothing about the US status of semax or selank has changed.

When a patient asks you about one of these peptides, three points cover most of the conversation:

1. The human trials are small, mostly Russian, and either unrandomized or without a placebo arm [1][2][3][4].
2. FDA found no human pharmacokinetic data for semax and raised abuse and bleeding concerns [5]. For DSIP it raised an addiction concern [7].
3. A drug registered abroad is still unapproved here, and there is no lawful US compounding pathway for semax or selank.

Products sold online under these names carry “research use only” labels, a framing we cover in research-use-only peptides. The current legal picture is in are peptides legal.

References

1. Gusev EI, et al. [Effectiveness of semax in acute period of hemispheric ischemic stroke]. Zh Nevrol Psikhiatr Im S S Korsakova. 1997;97(6):26-34. PMID 11517472. Link
2. Gusev EI, et al. [The efficacy of semax in the tretament of patients at different stages of ischemic stroke]. Zh Nevrol Psikhiatr Im S S Korsakova. 2018;118(3 Vyp 2):61-68. PMID 29798983. Link
3. Zozulia AA, et al. [Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia]. Zh Nevrol Psikhiatr Im S S Korsakova. 2008;108(4):38-48. PMID 18454096. Link
4. Medvedev VE, et al. [Optimization of the treatment of anxiety disorders with selank]. Zh Nevrol Psikhiatr Im S S Korsakova. 2015;115(6):33-40. PMID 26356395. Link
5. U.S. Food and Drug Administration. PCAC July 2026 briefing document: Semax. Link
6. Bes F, et al. Effects of delta sleep-inducing peptide on sleep of chronic insomniac patients. A double-blind study. Neuropsychobiology. 1992;26(4):193-7. PMID 1299794. Link
7. U.S. Food and Drug Administration. PCAC July 2026 briefing document: Emideltide. Link
8. Eglovitch JS. FDA advisory committee backs two more peptides, rejects one for compounding list. RAPS. 24 July 2026. Link
9. Healio. FDA committee recommends looser restrictions for several peptides. 24 July 2026. Link
10. Kolomin T, et al. The temporary dynamics of inflammation-related genes expression under tuftsin analog Selank action. Mol Immunol. 2014;58(1):50-5. PMID 24291245. Link

This is general information, not medical or legal advice. Rules vary by state and change. Confirm your own facts with counsel.