Two chemicals, different questions
What changes when you compare Semax with Selank
Can one peptide replace the other? No: Semax studies mainly examine brain protection and memory, while Selank studies mainly examine anxiety and calming brain activity.
What animal tests, human tests, and personal accounts show
| What was compared | Semax | Selank |
|---|---|---|
| Starting material | A hormone fragment changed in a lab. | Tuftsin, involved in immune defenses. |
| Make-up | Seven amino acids, protein's small parts. | Seven in another order; also called TP-7. |
| Main result studied | proteins supporting brain cells, brain protection, memory. | Less anxious behavior, changed calming responses. |
| Cell results | More proteins supporting rat brain cells. Slower breakdown of natural pain-relief chemicals. | Changed calming responses in rat cells. Changed immune chemicals in patients' blood. |
| Proteins supporting brain cells | More protein in certain rat brain areas [3][4]. | More protein in rats' memory area; less studied [11]. |
| Calming chemicals | No established finding. | Changed attachment and cell instructions in rats [8][10]. |
| Who was tested | Mainly rats and mice. | Rats and some Russian patients. |
| Human findings | No clear memory benefit established in Western studies. Russian stroke use. | Immune blood chemicals changed [12]; brief anxiety trials don't establish lasting relief. |
| Independent checking | Several animal studies; little Western checking. | Animal and limited human studies; little independent checking. |
| Medicine approval | Prescription in Russia/Ukraine for stroke and thinking problems; no FDA approval. | Prescription in Russia for anxiety and weakness; no US/EU approval. |
| Sports rules | Not named by WADA, the sports drug-testing body; broad bans may apply. | Not separately named; research-chemical rules may apply. |
| Personal accounts | clearer thought, easier speech, better attention; brief effects. | Less worry without heavy sleepiness; less increased energy. |
| Unwanted feelings | Shorter temper, brief effects, no change. | Too much calm, nose discomfort, brief effects, no change. |
| Shared features | Russian origin, added end pieces, nose use, slower pain-relief breakdown, research status outside Russia. | Selank shares these features. |
Both peptides slowed breakdown of natural pain-relief chemicals in human blood liquid tested in a dish. At about 20 micromolar, which describes how dilute Selank was in that liquid, the breakdown fell by half.
Selank slowed that breakdown less strongly than Semax in the same test. This was a dish test, rather than a dose given to people.
GlobalDRO is the sports drug checker mentioned for Semax. A missing name doesn't prove either peptide is allowed in sport.
What these differences leave unanswered about your health
The studies cited here describe several animal findings and some limited human evidence [3][4][7][8][9][10][11][12]. Through 2025, little of that work had been independently checked by Western researchers.
Neither peptide has results from large human trials that test benefits after early research. Such trials are missing for people outside Russia, leaving your likely response uncertain.
These feelings come from people doing their own research; comparison trials haven't checked their accounts. Semax accounts emphasize clearer, more energetic thought, while Selank accounts emphasize less worry.
Some people describe no noticeable change from either peptide despite reading hopeful accounts. You can't predict your own response from the difference between those reports.
Outside Russian medicine products, neither has a proven human dose or evidence establishing long-term safety. Your health choices depend on those missing answers as well as any possible benefit.