Updated Oct 29, 2026.

FDA status, as of Apr 22 and May 14, 2026 (source: FDA). Semax: panel said yes, FDA hasn't. Off Category 2 since Apr 2026, recommended 8 to 5 by FDA's advisory panel on Jul 24, 2026, and covered by HHS's interim enforcement policy filed Oct 28, 2026 (semax free base, nasal) [10]. Selank: withdrawn, no review. Off Category 2 since Sept 2024, no panel review found, not in the HHS policy [10]. Neither is approved by FDA for any use. Neither is on the 503A bulks list [1][2]. HHS policy as of Oct 29, 2026.

Part of The Sommar Peptide Guide. Semax and selank get sold side by side as nasal sprays. They look like twins on paper. FDA's files on them are very different sizes.

The short answer

Both are unapproved 7-amino-acid peptides from Russian research, used in the nose. FDA reviewed semax in detail in 2026 and found "insufficient evidence" it works for the uses it checked [3]. FDA never published a review of selank. Its only FDA record we found is two lines on a list [1]. Semax is one of six peptides in HHS's Oct 28, 2026 interim compounding policy. Selank is not [10].

Side by side

Where they match

Neither is approved, neither is listed. Leaving Category 2 put neither on the 503A bulks list, the list a pharmacy needs to compound a substance that is not part of an approved drug. As of FDA's list dated May 14, 2026, neither is on it [2]. Why "off Category 2" does not mean legal: Are Peptides Legal?

Both left Category 2 the same way. Their nominators withdrew them. Selank went in a group of 5 in Sept 2024 [4]. Semax went in a group of 12 in Apr 2026 [5].

Both are used in the nose. Every human report of semax FDA found used the nose [3]. The selank abstract used nasal dosing too [9].

Where they split: the review

The HHS policy splits them. On Oct 28, 2026, HHS filed an interim enforcement discretion policy covering six peptides. Semax free base, used in the nose, is one of them. Selank is not, and it keeps its prior status [10][11]. HHS says it won't take action against state-licensed pharmacies, federal facilities or licensed physicians that compound semax under the policy's conditions. It is interim and approves nothing [10]. Read the full breakdown in HHS's Oct 28 peptide policy. The FDA Peptide Tracker logs each step.

Semax got the full FDA treatment. After its nomination was withdrawn, FDA evaluated it anyway. Its Jul 2026 briefing found "insufficient evidence" for cerebral ischemia, migraine and trigeminal neuralgia, the uses it was nominated for [3]. FDA staff recommended against all 7 peptides on that agenda [6][7]. The panel voted 8 to 5 to recommend semax anyway, per one law-firm report. That vote is advice, and listing it would take rulemaking [6].

Selank got nothing public. FDA's 2024 removal notice set advisory meetings for the other peptides in its group. Selank was not on either agenda [4]. We found no review since.

Where they split: the evidence

Semax. The best-described study, from 1996, gave 37 adults with migraine or facial nerve pain one nasal dose. The authors said pain "was not eliminated but became less severe" for many. No control group, not blinded [3]. FDA found no literature on semax by injection [3].

Selank. The human study we could open was a 2012 conference abstract on 20 adults with generalized anxiety disorder. Anxiety scores fell, 40% within 3 days and the rest by day 14. No control group, and no full paper [9]. A 2016 rat study tied selank to changes in GABA-related brain genes, a possible mechanism, not proof of an effect [8]. Other Russian studies exist. We could not open them.

What neither has. A large, placebo-controlled trial in a peer-reviewed journal. And no study we found compared the two head to head, or used them together.

Where they split: the risks

Neither has enough human data for a reliable side effect list. FDA's flags differ in length.

Semax [3]:

• Immune reactions and impurities. No impurity, aggregate or endotoxin data were provided.

• An unknown nasal device. FDA "would have strong concerns" about a spray without container and pump information.

• Bleeding. Animal studies showed anticoagulant effects.

• Abuse potential. In mice, semax boosted amphetamine-driven dopamine release.

• One adverse event report: eye pain and burning after nasal drops bought online, with a hospital stay.

Selank [1]:

• Immune reactions. It "may pose risk for immunogenicity for certain routes of administration."

• Missing safety data. "FDA lacks important information regarding any safety issues raised by selank acetate administered to humans."

The shorter selank list comes with FDA's own note that it lacks the safety information to judge.

Both. Widely sold online as "research use only," the seller's way of saying the product is not for people. More: Prescription vs Research Peptides.

Full pages: What Is Semax?, What Is Selank?. Same shelf: DSIP, the one the panel voted down.

FAQ

What is the difference between semax and selank? Different parent molecules. Semax is built on a fragment of the hormone ACTH. Selank is built on tuftsin [3][8]. Both are 7 amino acids and end in Pro-Gly-Pro.

Is semax or selank better? No one can say. We found no study comparing them, and FDA found insufficient evidence that semax works for the uses it reviewed [3].

Are semax and selank legal in the US? Neither is approved by FDA for any use or on the 503A bulks list [2]. Semax got an advisory panel vote in Jul 2026. Selank got no review we could find [4][6]. Since Oct 28, 2026, semax free base for nasal use is covered by HHS's interim enforcement policy. Selank is not [10]. This is not legal advice.

Can you take semax and selank together? There is no published human data on the combination that we found. FDA lists separate concerns for each [1][3].

Is selank approved in Russia like semax? FDA's review describes semax as registered in Russia as nasal drops [3]. A selank registration is often claimed, but we could not confirm it with a regulator or a peer-reviewed source [9].

Sources

1. FDA. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (content current as of Apr 22, 2026). https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks

2. FDA. Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act (content current as of May 14, 2026). https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act

3. FDA. Pharmacy Compounding Advisory Committee briefing document, semax-related bulk drug substances (Jul 2026 meeting). https://www.fda.gov/media/193348/download

4. Reed Smith. FDA removes certain peptide bulk drug substances from Category 2 of interim 503A bulks list and sets dates for PCAC review (Client Alert 2024-208, Oct 2024). https://www.reedsmith.com/de/perspectives/2024/10/fda-certain-peptide-bulk-drug-substances-category-2-503a-bulks-pcac

5. Frier Levitt. FDA Peptides "Do Not Compound" List Update (Apr 16, 2026). https://www.frierlevitt.com/articles/fda-peptides-do-not-compound-list-update-2026/

6. Bass Berry. FDA Advisory Committee Recommends Six Peptides for Compounding (Jul 31, 2026). https://bassberry.com/news/fda-advisory-committee-recommends-six-peptides-for-compounding-what-the-evaluation-criteria-tell-us-about-the-road-ahead/

7. AJMC. FDA Panel Backs 6 Peptides for Compounding (Jul 31, 2026). https://www.ajmc.com/view/fda-panel-backs-6-peptides-for-compounding

8. Volkova A, Shadrina M, Kolomin T, et al. Selank Administration Affects the Expression of Some Genes Involved in GABAergic Neurotransmission. Front Pharmacol. 2016;7:31. https://www.frontiersin.org/articles/10.3389/fphar.2016.00031/full

9. Syunyakov T, Teleshova ES, Neznamov GG, Bochkarev VK. P-1114: Rapid and slow response during treatment of generalized anxiety disorder with peptide anxiolytic Selank. European Psychiatry, congress abstract (European Psychiatric Association, 2012). https://core-cms.cambridgecore.org/core/journals/european-psychiatry/article/p1114-rapid-and-slow-response-during-treatment-of-generalized-anxiety-disorder-with-peptide-anxiolytic-selank/7A497218D37084BD079EFE143126F56E

10. HHS. Enforcement Discretion Policy Regarding 503A Compounding Using Certain Peptide Bulk Drug Substances. Docket HHS-OASH-2026-0496, FR Doc 2026-22192 (filed for public inspection Oct 28, 2026; scheduled to publish in the Federal Register Oct 30, 2026). https://public-inspection.federalregister.gov/2026-22192.pdf

11. Hyman, Phelps and McNamara, FDA Law Blog. The PEPTIDE-L Wave Reaches HHS: Enforcement Discretion … Not the Finish Line (Oct 28, 2026). https://www.thefdalawblog.com/2026/10/the-peptide-l-wave-reaches-hhs-enforcement-discretion-not-the-finish-line/

Sommar Club does not prescribe or sell semax or selank. This page is for education only. It is not medical or legal advice. FDA statuses change; check the as-of dates and the FDA Peptide Tracker.