Selank vs Orexin A
Comprehensive side-by-side comparison of mechanisms, dosing, side effects, and research
Also: Selanc, TP-7
Selank is a synthetic seven-amino-acid peptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) built from the natural immune peptide tuftsin, with a small chemical tweak to make it last longer in the body. It was developed in Russia as an anti-anxiety and nootropic agent and is approved there for generalized anxiety disorder, but it has no FDA or EMA approval and almost no Western clinical data. The pitch is calm and focus without the sedation, dependence, or withdrawal that come with benzodiazepines.
Also: Hypocretin-1, Hcrt-1
Orexin A (also called hypocretin-1) is a 33-amino-acid brain peptide made by a small cluster of neurons in the hypothalamus, and it is one of the main signals that keeps you awake. People with narcolepsy type 1 have lost most of these neurons, and orexin is undetectable in their spinal fluid. Orexin A itself is not an approved drug, but a few small German studies have sprayed it into the nose of narcolepsy patients and healthy men with measurable effects. Interesting science, very early stage.
Key Comparison Insights
- Both peptides belong to the Cognitive category, suggesting similar primary applications.
Detailed Comparison
| Attribute | Selank | Orexin A |
|---|---|---|
| Category | Cognitive | Cognitive |
| FDA Status | Not FDA Approved | Not FDA Approved |
| Clinical Status | Pre I II III IV FDA | Pre I II III IV FDA |
| Mechanism of Action | Selank seems to work through several overlapping systems rather than one tidy target. It influences GABA signaling, the brain's main calming neurotransmitter system, which likely accounts for its anti-anxiety effect. It also slows the breakdown of enkephalins, the body's own opioid-like peptides involved in mood and stress, which is a mechanism entirely different from benzodiazepines or SSRIs. Animal work additionally points to effects on serotonin and dopamine balance and on BDNF, a growth factor tied to learning and neuron health. These pathways are well documented in rodents; the picture in humans is inferred rather than directly measured. | Orexin A activates both orexin receptors (OX1R and OX2R) with high affinity. Those receptors sit on brainstem and hypothalamic arousal centers (the histamine, noradrenaline, dopamine and acetylcholine systems), so orexin acts like a stabilizer that keeps the brain locked in the wake state and stops it slipping into REM sleep at the wrong time. Losing it causes narcolepsy: orexin knockout mice and dogs with a broken OX2R gene both develop narcolepsy, and giving orexin A into the brain of narcoleptic mice suppressed cataplexy. Orexin also drives appetite and raises sympathetic nerve activity. A mouse study found orexin A crosses the blood-brain barrier fairly well, and the nasal route is used in humans to deliver more of it to the brain. |
| Common Dosing | 250-500 mcg 2-3x daily 2-3x daily | 435 nmol (about 1.5 mg) intranasal Single dose in studies |
| Administration | Intranasal spray (most common), subcutaneous injection | Intranasal spray |
| Typical Duration | 14-21 days typical | Single doses only in published human studies |
| Best Time to Take | Morning or as needed for anxiety | Morning |
Possible Side Effects May vary by individual |
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| Research Summary | Most of the rigorous data is preclinical and Russian. In rodents, Selank shows consistent anxiety-reducing and mild cognitive effects, and one PMC-indexed study found it enhanced diazepam's anti-anxiety effect under chronic stress. The main human clinical reference is a Russian comparative trial by Zozulia, Neznamov, and colleagues in patients with generalized anxiety disorder and neurasthenia, reporting that Selank's anxiolytic effect was comparable to the benzodiazepine medazepam on standard rating scales, with added anti-fatigue benefits and changes in enkephalin activity. The honest caveat: that trial was relatively small, the published English abstract gives qualitative results rather than hard effect sizes and p-values, and it has not been replicated by independent Western groups. So the evidence supports a real but modestly studied anxiolytic, mostly validated within the regulatory system that approved it. | The human data comes from a handful of small, placebo-controlled crossover studies, mostly from one group in Kiel, Germany. In 2008, intranasal orexin A improved smell detection thresholds in 7 narcolepsy patients. In 2011, a single 435 nmol nasal dose before bed in 8 patients did not change nighttime wakefulness but reduced REM sleep and wake-to-REM transitions. In 2014, the same dose given in the morning to 14 patients reduced wake-REM transitions and improved divided attention (fewer errors). In 2022, 500 nmol in 10 healthy men acutely raised sympathetic nerve activity to blood vessels, without changing blood pressure or heart rate. In sleep-deprived monkeys, nasal orexin A reversed some of the drop in memory performance (Deadwyler, 2007). That is the whole human record: single doses, tiny groups, short-term outcomes. The real clinical action has moved to small-molecule drugs that mimic orexin at OX2R. Takeda's oveporexton (brand name Orzeyful) was FDA-approved on August 5, 2026 for narcolepsy type 1, which validates the target but is not the same thing as using the peptide. |
Frequently Asked Questions: Selank vs Orexin A
What is the difference between Selank and Orexin A?
Selank is a cognitive peptide that selank is a synthetic seven-amino-acid peptide (thr-lys-pro-arg-pro-gly-pro) built from the natural immune peptide tuftsin, with a small chemical tweak to make it last longer in the body. it was developed in russia as an anti-anxiety and nootropic agent and is approved there for generalized anxiety disorder, but it has no fda or ema approval and almost no western clinical data. the pitch is calm and focus without the sedation, dependence, or withdrawal that come with benzodiazepines. Orexin A is a cognitive peptide that orexin a (also called hypocretin-1) is a 33-amino-acid brain peptide made by a small cluster of neurons in the hypothalamus, and it is one of the main signals that keeps you awake. people with narcolepsy type 1 have lost most of these neurons, and orexin is undetectable in their spinal fluid. orexin a itself is not an approved drug, but a few small german studies have sprayed it into the nose of narcolepsy patients and healthy men with measurable effects. interesting science, very early stage. The main differences lie in their mechanisms of action and clinical applications.
Which is better, Selank or Orexin A?
Neither is universally "better" - the choice depends on your specific goals. Selank is typically used for cognitive purposes, while Orexin A is used for cognitive. Always consult with a healthcare provider to determine which may be appropriate for your situation.
Can Selank and Orexin A be used together?
Some peptide protocols combine multiple compounds for synergistic effects. However, using Selank and Orexin A together should only be considered under medical supervision, as both compounds have their own side effect profiles and potential interactions. Research on their combined use may be limited.