Peptide comparison
Selank vs Semax
Selank and Semax are both research peptides. This side-by-side compares their mechanism, typical research dosing, half-life, routes and safety so you can see how they differ. For research use only.
| Selank | Semax | |
|---|---|---|
| Category | Cognitive | Cognitive |
| Overview | A synthetic tuftsin-derived heptapeptide studied as an anxiolytic and mild nootropic, with most efficacy data from Russian clinical practice rather than international trials.... | A synthetic ACTH(4-10)-derived heptapeptide studied as a neuroprotective nootropic, used in Russia for stroke and cognitive indications but unapproved elsewhere. Research use only. |
| How it works | Selank's proposed mechanism is multi-target and only partly characterized in humans. The most cited actions are modulation of the GABAergic system (animal and cell-culture work suggests it influences expression of GABA-A receptor subunit and related genes, supporting an inhibitory/anxiolytic tone) and stabilization of endogenous enkephalins by inhibiting the enzymes that degrade them, which is thought to contribute to its anti-anxiety and anti-stress effects. It is also reported to increase expression of brain-derived neurotrophic factor (BDNF) in the hippocampus in rodent models, and to modulate the balance of monoamine neurotransmitters and the expression of interferon-gamma and other immune mediators (consistent with its tuftsin-analog origin). Acute effects are attributed to rapid neurotransmitter and enkephalin modulation, while any longer-lasting effects are hypothesized to involve neurotrophic/neuroplastic changes. These mechanisms are reasonably supported in animal and in-vitro studies but remain provisional as explanations for clinical effects in humans. | Semax's central effects are attributed primarily to modulation of neurotrophic factors and neurotransmitter systems. The most consistently reported action is rapid upregulation of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) and their receptors, which is thought to support neuronal survival, synaptic plasticity, and recovery after ischemic injury. Semax is also reported to influence the dopaminergic, serotonergic, and cholinergic systems, to have antioxidant and anti-inflammatory/neuroprotective effects in ischemia models, and to modulate the activity of regulatory peptidases. A notable feature is that Semax is metabolized to the dipeptide/tripeptide fragment Pro-Gly-Pro (PGP), which is itself biologically active and is thought to contribute to longer-lasting effects despite the parent peptide's very short plasma life. These mechanisms are well supported in animal and cell models; their precise contribution to clinical outcomes in humans is less firmly established. |
| Half-life | Reported to be very short for the intact peptide. Some sources cite a plasma half-life on the order of only minutes after intranasal/IV exposure in animal work, though biological effects are described as outlasting plasma presence. Human pharmacokinetics are not well characterized in the published international literature. | The intact parent peptide has a very short plasma half-life (reported on the order of only a few minutes after administration). However, Semax is broken down to the active fragment Pro-Gly-Pro, and functional/therapeutic effects are reported to persist for many hours (sources commonly cite up to roughly 20-24 hours from a single dose). Detailed human pharmacokinetics are not fully characterized in the international literature. |
| Dosing reference | No FDA/EMA-approved dosing exists. In Russian clinical studies of anxiety, Selank has been used as a 0.15% intranasal solution at roughly 250-500 mcg per administration, around two to three times daily (commonly cited near 900-1350 mcg total per day) for courses of about 14 days. These figures come from small studies within the Russian system and should not be treated as validated international clinical guidance. | No FDA/EMA-approved dosing exists. In Russian clinical practice, intranasal Semax (commonly a 0.1% or 1% solution) has been used for stroke at roughly 12-18 mg per day across multiple administrations for several days, and at lower doses for cognitive/asthenic indications. These figures come from the Russian system and small studies and should not be treated as validated international clinical guidance. |
| Routes | intranasal, subcutaneous | intranasal, subcutaneous |
| Safety & side effects | Selank is generally described as well tolerated in the available Russian studies, which reported few adverse events and notably did not observe the sedation, muscle relaxation, tolerance, dependence, or withdrawal associated with benzodiazepines. However, long-term and large-scale safety data are lacking, and there is little independent international verification. Reported or plausible issues include local nasal irritation, mild fatigue or drowsiness in some individuals, and theoretical immune-modulating effects given its tuftsin origin. Product quality is a real-world risk: material sold outside Russia as a research chemical is unregulated and may vary in purity, identity, or sterility. Selank is not FDA/EMA-approved and is sold for research use only, not for human consumption. This information is for research reference only and is not a recommendation for human use. | Semax is generally described as well tolerated in the available Russian studies, with few reported adverse events at the doses used and no major hormonal effects attributed to it (it is described as lacking the corticotropic activity of full ACTH). However, long-term and large-scale safety data outside Russia are limited, and independent international verification is sparse. Reported or plausible issues include nasal/local irritation with intranasal use and, anecdotally, overstimulation, irritability, or sleep disturbance in some individuals. Product quality is a real-world risk: research-grade material is unregulated and may vary in purity, identity, or sterility. Semax is not FDA/EMA-approved and is sold for research use only, not for human consumption. This information is for research reference only and is not a recommendation for human use. |
For research use only. Not for human consumption. Always verify against current literature.