Selank vs Semax: Evidence, Legal Status and Key Differences
Selank vs Semax at a glance
| Fact | Selank | Semax |
|---|---|---|
| Also known as | Selank acetate, TP-7 | Semax acetate |
| What it is | Synthetic tuftsin analogue | Synthetic ACTH(4-10) analogue (registered in Russia) |
| Evidence level | Early human trials | Early human trials |
| Approved products | None | None |
| United States | Not FDA-approved; the nomination of selank for pharmacy (503A) compounding was withdrawn after FDA flagged potential safety risks [12][9]. | Not FDA-approved; FDA staff recommended against adding semax to the 503A compounding list, and although FDA's advisory committee voted to recommend it in July 2026, FDA has not added it [12][5][21]. |
| United Kingdom | No UK-licensed medicine containing selank appears in the MHRA products database [13]. | No UK-licensed medicine containing semax appears in the MHRA products database [22]. |
| European Union | No medicine containing selank is authorized in the EU, according to EMA's central and Article 57 product data [14][15]. | No medicine containing semax is authorized in the EU, according to EMA's central and Article 57 product data [14][15]. |
| Canada | No product containing selank appears in Health Canada's Drug Product Database [16]. | No product containing semax appears in Health Canada's Drug Product Database [16]. |
| Australia | Selank is not named in Australia's Poisons Standard (October 2026) [17]. | Semax is not named in Australia's Poisons Standard (October 2026) [17]. |
| Sport (WADA) | Not named on the 2026 Prohibited List [10]. | Not named on the 2026 Prohibited List [10]. |
| Vendors we track | 57 vendors | 57 vendors |
| Our lab tests | None yet | None yet |
Selank and Semax are short synthetic peptides developed in Russia [4], and both end in the same three amino acids, Pro-Gly-Pro [2]. The rest of each molecule is different. Selank is built on tuftsin, a fragment of an immune protein, and is listed as an anti-anxiety drug; Semax is built on a fragment of the hormone ACTH and is classed as a nootropic [1, 3, 4]. The human evidence for both is small and comes mostly from studies published in Russian, and neither is an approved medicine in the US, UK, EU or Canada (see the table above).
What each one is
Selank is the seven-amino-acid peptide Thr-Lys-Pro-Arg-Pro-Gly-Pro [2]. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as an analogue of tuftsin, a four-amino-acid fragment of human immunoglobulin G, with Pro-Gly-Pro added to make it more stable in the body [1].
Semax is the seven-amino-acid peptide Met-Glu-His-Phe-Pro-Gly-Pro [2]: a fragment of ACTH (amino acids 4 to 7) joined to the same Pro-Gly-Pro tail [3]. FDA describes it as an analogue of the ACTH(4–10) fragment that is registered as a drug in Russia, where it is available as nasal drops [5].
A 2022 review lists both among the peptide drugs developed in Russia: Selank as an anti-anxiety drug and Semax as a nootropic [4].
Some vendors also sell “N-acetyl” or “amidate” versions, which are modified at the ends of the peptide chain. For Semax, researchers found that adding an acetyl group changes its chemical and biological properties [11]. These are different compounds, so we price them separately: N-acetyl Semax and N-acetyl Selank.
How the evidence compares
Selank. The clinical studies we found were published in Russian, and the two summarized here are small [6, 7]. Both compared Selank with a benzodiazepine, and neither abstract describes a placebo group [6, 7]. In 62 patients with generalized anxiety disorder or neurasthenia, its anti-anxiety effect was reported to be similar to medazepam’s [6]. In 60 patients with anxiety disorders compared with phenazepam, the anti-anxiety effect was reported to last a week after treatment ended [7]. Other work is in rats, including a study of genes involved in GABA signaling in the brain [1].
Semax. The human evidence is also small. A 1997 Russian study compared 30 patients given Semax in the acute phase of ischemic stroke with 80 conventionally treated patients [8]. In rats, Semax increased the activity of genes for neurotrophins, proteins that support nerve cells, after an experimental stroke [3]. Reviewing it for compounding in 2026, FDA found that the available references on cerebral ischemia, migraine and trigeminal neuralgia showed a lack of effectiveness and were limited by small sample sizes [5].
One 2001 laboratory study found that both peptides blocked enzymes in human serum that break down enkephalins, the body’s own opioid peptides [2]. That is a test-tube result, not evidence of an effect in people.
Regulation and sport
Neither is an approved medicine in the US, UK, EU or Canada. FDA had placed both in category 2, its group of bulk substances that may present significant safety risks in compounding, and now lists them as nominations withdrawn by their nominators [9]. Neither is named on WADA’s 2026 Prohibited List [10].
Quality risks when buying
Research-grade Selank and Semax are not regulated medicines. FDA says compounded versions of both may cause immune reactions because of aggregation and peptide-related impurities, and that it lacks information on their safety in people [9]. For Semax, FDA adds that sources often don’t say whether they mean the free base or a salt, and that it has encountered multiple salts and derivatives sold under the same name [5].
So a certificate of analysis (COA) should name the exact form tested and confirm identity by mass spectrometry, not just report purity. Our guides explain how to read a COA, how to check a vendor and what “research use only” means.
For more on each compound, see our Selank overview and Semax overview, and today’s prices for Selank and Semax.
Frequently asked questions
What is the difference between Selank and Semax?
Both are seven-amino-acid peptides developed in Russia that end in the same three amino acids, Pro-Gly-Pro. Selank is based on tuftsin, a fragment of an immune protein, and was studied for anxiety. Semax is based on a fragment of the hormone ACTH and was studied mainly in stroke.
Are Selank and Semax approved medicines?
Not in the US, UK, EU or Canada. A 2022 review lists both among peptide drugs developed in Russia, and FDA describes Semax as registered there as nasal drops.
Is N-acetyl Semax the same as Semax?
No. N-acetyl and amidate versions are chemically modified forms. Research on N-acetyl Semax found that the change alters its chemical and biological properties, so findings for one form don't automatically apply to the other.