NA-Selank-Amidate Nasal Spray

NA-Selank-Amidate is a chemically stabilised version of selank, a synthetic heptapeptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) developed in Russia. Selank itself is the body's immune peptide tuftsin with the tripeptide Pro-Gly-Pro attached so that it survives longer in the body. The NA variant adds two more protective groups: an acetyl residue at the start of the chain and an amide at the end. Both ends become harder for the body's peptidases to attack, so the molecule should stay intact longer and act more predictably. The two forms have never been compared head to head. Every study listed below was done with classic selank.

This variant is the ready-made nasal spray: 10mg of NA-Selank-Amidate dissolved in 5ml of saline plus 0.4ml of bacteriostatic water, 5.4ml in total, which gives 1.85mg per ml. The pump delivers 0.1ml per spray, so about 185mcg (0.19mg) of peptide. On paper the bottle holds 54 sprays, after priming the pump about 50 remain. The 30mg bottle has the same fill volume but three times the concentration: 5.56mg per ml, about 556mcg (0.56mg) per spray, as much as three sprays of the 10mg bottle. No mixing, no syringe and no maths, the spray is made fresh after you order and ships as an express item. If you prefer the vial and syringe, the NA-Selank-Amidate vial entry has the calculator.

Selank has been used in Russia for years as nasal drops against anxiety and inner restlessness, so the spray is not a workaround but the very route the peptide was studied with clinically. The appeal is the profile: calming, yet without the sedation and dependence risk of classic tranquilisers, plus a mild nootropic component.

This information is for research and educational purposes only. No medical advice.

Selank does not have a single receptor, it touches anxiety regulation at several points. The best documented link is to the GABA system: Vyunova and colleagues (Protein and Peptide Letters 2018) used radioligand binding on brain membranes to show that selank enhances GABA binding at the GABA-A receptor as a positive allosteric modulator, concentration dependent and apparently subtype selective. It apparently does not bind at the same site as the benzodiazepines (the authors do not rule out a partial overlap), but it changes what benzodiazepines do: combined with diazepam the effect was neither additive nor equal to either substance alone. Volkova and colleagues (Frontiers in Pharmacology 2016) fit this picture, finding that selank altered the expression of 45 neurotransmission genes in rat frontal cortex within an hour, in a pattern that correlated with that of GABA itself.

The second pathway is the enkephalin system. Zozulya and colleagues (Bulletin of Experimental Biology and Medicine 2001) found a shortened half-life of endogenous enkephalins in the blood of patients with generalised anxiety and showed that selank inhibits the enkephalin-degrading enzymes in a dose-dependent way (IC50 around 15 micromolar), more potently than the reference inhibitors bacitracin and puromycin. More enkephalin means more of the body's own damping of stress and anxiety signals. In the same group's clinical study (2008), enkephalin half-life rose again under selank and tracked the reduction in anxiety.

On top of that come effects on growth factors and immune messengers: nasally given selank alters expression of the growth factor BDNF in the rat hippocampus (Inozemtseva and colleagues, Doklady Biological Sciences 2008). In a later rat study selank protected against alcohol-induced memory impairment by regulating BDNF content in hippocampus and prefrontal cortex (Kolik and colleagues, Bulletin of Experimental Biology and Medicine 2019). That may explain the nootropic component and the effects on learning and memory. Through its tuftsin part, selank also modulates the expression of inflammation-related genes. There are no separate mechanistic data for the acetylation and amidation, the mechanism is assumed to be identical, only with a longer residence time of the intact molecule.

For small peptides like selank the nose is an unusually good route. Ashmarin and colleagues (Russian Journal of Bioorganic Chemistry 2008) tracked tritium-labelled selank and the fragment Pro-Gly-Pro through rat tissues after intraperitoneal, intranasal, intragastric and intravenous administration and found the nasal route to be the best way to get the peptides into the central nervous system. Part of the dose crosses the thin, richly perfused mucosa into the blood, part travels from the olfactory region towards the brain. Whatever ends up in the throat is digested. Interestingly, the route also seems to shape the effect profile. Vasil'eva and colleagues (2016) saw different receptor fingerprints in mice after five days of selank depending on the route, more GABA binding sites in frontal cortex after intraperitoneal dosing, more NMDA binding sites in hippocampus after nasal dosing, with similar anxiolytic and nootropic effects in the behavioural test.

The peptide itself is short-lived, plasma peptidases break it down within a short time. Its effect, however, clearly outlasts the molecule: in the study by Medvedev and colleagues (2014) the anxiolytic effect persisted for a week after the last dose. That suggests selank sets processes in motion (gene expression, BDNF, enkephalin balance) that do not depend on a steady blood level. In practice this means one to three doses across the day are enough, a constant level is not the goal.

Practically: before first use, pump 2 to 3 times into the air until a fine mist appears. Gently clear your nose first, keep your head upright, point the nozzle slightly outward towards the nasal wall rather than at the septum, breathe in calmly as you spray and do not sniff hard. Avoid blowing your nose for 10 to 15 minutes afterwards. Two sprays in quick succession into the same nostril tend to run down the throat rather than work twice as well, so for two sprays use one per nostril or space them out.

For a peptide from the research scene, selank is unusually well studied in humans, though almost exclusively in Russia. Zozulya and colleagues (Zhurnal Nevrologii i Psikhiatrii 2008) compared selank (30 patients) with the benzodiazepine medazepam (32 patients) in 62 patients with generalised anxiety disorder and neurasthenia. The anxiolytic effect was similar in both groups, while selank additionally acted against the exhaustion component and was mildly activating, measured with the Hamilton, Zung and CGI scales. In parallel, the previously shortened enkephalin half-life in blood recovered.

Medvedev and colleagues (Zhurnal Nevrologii i Psikhiatrii 2014) set selank against the benzodiazepine phenazepam in 60 patients with anxiety, phobic and somatoform disorders: pronounced anxiolysis, a mild nootropic effect, better quality of life and an effect that persisted for a week after the last dose. In a follow-up by the same group (2015), 40 patients received selank on top of phenazepam: the benzodiazepine effect set in faster. Typical benzodiazepine side effects such as impaired attention and memory, sedation, longer sleep, sexual dysfunction and orthostatic problems were less frequent, also after the tranquiliser was withdrawn.

The mechanistic work (GABA-A modulation, enkephalinase inhibition, gene expression, BDNF) is described above. What belongs in the picture honestly: the clinical studies are small, come from the circle around the peptide's developers and are only available in full in Russian. Large Western double-blind trials are missing. A US review of GABAergic substances (Doyno and White, Journal of Clinical Pharmacology 2021) rates selank as poorly studied and criticises that it is sold to US consumers as a dietary supplement without any approval. For the N-acetylated, amidated form there are no published data at all, neither on pharmacokinetics nor on effect, everything above is carried over from classic selank.

• Nose: mild burning, dryness, sneezing or a brief tingle after spraying are the most common observation. The solution is close to isotonic, the irritation mostly comes from the jet itself or from the small share of benzyl alcohol in the bacteriostatic water. Pause if irritation persists or the nose bleeds.
• Central effects: selank is considered non-sedating, yet some users report brief tiredness or a sense of indifference, more rarely headache or grogginess. In the comparative studies selank was clearly superior to benzodiazepines on sedation and cognitive side effects.
• Dependence: the clinical studies describe no withdrawal and no tolerance, the effect even persisted after stopping. That sets selank apart from benzodiazepines, but it rests on small studies over a few weeks, not on long-term data.
• Interactions: selank modulates the GABA-A receptor and, according to Vyunova and colleagues (2018), changes the effect of diazepam on GABA binding in a non-additive way. Caution with benzodiazepines, Z-drugs, alcohol or other GABAergic substances is therefore warranted, not because a dangerous potentiation has been shown, but because the direction of the interaction is hard to predict.
• Immune system: through its tuftsin part, selank alters the expression of inflammation-related genes. Anyone with an autoimmune condition or on immunosuppression belongs in medical hands with that question.
• Data gaps: no data for pregnancy, breastfeeding, children or adolescents. For the NA-amidate form human data are missing entirely, including tolerability.

The spray belongs in the fridge at 2 to 8 degrees, upright, capped and protected from light, for example in its outer packaging. Do not freeze, a freeze-thaw cycle can harm the peptide and the pump. A few hours at room temperature in the post or in a bag do no harm, but the bottle should not sit warm for long.

Selank variants are small, robust peptides. The acetyl and amide groups shield the chain ends further. In cold solution the peptide is stable for months. The limiting factor with the spray is not chemistry but hygiene: the 0.4ml of bacteriostatic water brings only a little benzyl alcohol, this is not a fully preserved product. Wipe the nozzle with a clean tissue after each use, put the cap back on, do not share the bottle and only rest the tip just inside the nostril rather than pushing it in deep. If the solution turns gel-like, lumpy or smells different, stop using it. Slight cloudiness on its own is not a reason.

In practice there is no storage problem: at 1 to 3 sprays a day the bottle is empty after 2 to 7 weeks, within the phase it is meant for. If you pause for longer, leave the spray in the fridge and pump once into the air before the next use.