Semax vs Selank
How they differ on evidence quality, dosing schedule, half-life and cost.
| Semax | Selank | |
|---|---|---|
| Evidence grade | CSmall or early human studies only | CSmall or early human studies only |
| Studied for | Focus and memory peptide | Calm-focus anxiety peptide |
| Half-life | Minutes, cleared rapidly | Not well characterized in humans |
| Schedule | Once or twice daily, subcutaneous | Daily, intranasal or subcutaneous |
| Amount in research | 200–600 mcg daily | 250–900 mcg daily, split |
| Vial sizes sold | 10 mg, 30 mg | 5 mg, 10 mg |
| Cost | $2.16 per dose | No verified price yet |
On evidence quality these two sit level, both graded C. Small clinical studies only. No large international trials. For Selank: Small clinical trials only. Independent replication is thin. Nothing in the published record separates them, so a choice between them comes down to what is being studied and how it is dosed, and not to one having better support than the other.
An evidence grade describes how strong the research is, and it is not a safety rating or a recommendation. A higher grade on an approved drug does not make a research-use version of it approved.
Semax
Semax is a short peptide based on a fragment of ACTH. It is thought to raise brain derived neurotrophic factor, or BDNF and to influence dopamine and other neurotransmitters, which is the basis for its study as a nootropic and neuroprotective agent. It is used clinically as a nasal spray, with limited trial data so far.
Selank
Selank appears to modulate GABA and serotonin signaling and to influence brain-derived neurotrophic factor and enkephalin activity. It also slows breakdown of enkephalins, which may extend calming and mood effects. Some work links it to changes in immune-related gene expression that could shape stress response. Most detail comes from early laboratory work with limited independent human replication.
Semax
- Studied in clinical trials for recovery after ischemic stroke.
- May raise BDNF and support neuroplasticity.
- Studied for effects on attention, memory and cognitive performance.
- Explored for brain protection during reduced blood flow.
Selank
- Studied for reducing anxiety without strong sedation
- Reported to support steady attention and mental clarity
- May improve mood through effects on BDNF and enkephalin activity
- Non-habit-forming profile in the available research
Semax
- Reported side effects are few, though rigorous long-term safety data are limited.
- Most evidence comes from small studies outside Western regulatory review.
- Intranasal irritation is possible with the nasal formulation.
- Product quality varies since it is unapproved in the US and EU.
Selank
- Nasal irritation or stuffiness with intranasal use
- Mild fatigue or drowsiness in some users
- Headache
- Long-term human safety data is limited
Which has better evidence, Semax or Selank?
Neither. Both are graded C on our four-point scale, so the published record does not separate them.
How do the dosing schedules differ?
Semax: Once or twice daily, subcutaneous. Selank: Daily, intranasal or subcutaneous.
How do their half-lives compare?
Semax: Minutes, cleared rapidly. Selank: Not well characterized in humans. Half-life is what the dosing frequency follows from.
Can Semax and Selank be studied together?
Some research protocols pair compounds and some do not. There is no combined trial data for this pairing on file here, so treat any stacking claim you read elsewhere as untested.
Semax
Focus and memory peptideA focus and memory peptide studied for attention and recall.
CSmall or early human studies onlySelank
Calm-focus anxiety peptideA calming peptide studied for calm focus and lower anxiety without heavy sedation.
CSmall or early human studies only