Selank vs Xanax: How They Differ

Selank is a seven-amino-acid peptide built on tuftsin and studied for anxiety, while Xanax (alprazolam) is a triazolobenzodiazepine, an approved prescription medicine for anxiety and panic disorders that enhances GABA signalling at the benzodiazepine binding site. Both touch the GABA system, but in different ways: alprazolam is a classic benzodiazepine, while Selank’s laboratory research points to enkephalin-degrading enzymes and a separate, allosteric effect on GABA binding. Selank’s own clinical studies used benzodiazepines such as medazepam and phenazepam as comparators. Here is how the two differ and what the human research on each shows.

Findings

• Alprazolam is a triazolobenzodiazepine with an elimination half-life of 9 to 16 hours and peak blood levels 0.7 to 1.8 hours after an oral dose (1993).
• In a placebo-controlled trial of 526 patients with panic disorder, 82% on alprazolam were moderately improved or better at week 4 against 43% on placebo, with differences significant by the end of week 1 (1988).
• Selank is the heptapeptide Thr-Lys-Pro-Arg-Pro-Gly-Pro. In 62 patients with generalised anxiety disorder or neurasthenia, its anti-anxiety effect was similar to the benzodiazepine medazepam’s, with added anti-fatigue and stimulant effects (2008).
• In binding studies, Selank acted as a positive allosteric modulator of GABA binding, and its binding site appeared distinct from diazepam’s, though possibly overlapping (2018).

What is alprazolam?

Alprazolam is a triazolobenzodiazepine, widely prescribed for anxiety and panic disorders. Its receptor binding is qualitatively similar to other benzodiazepines (Greenblatt and Wright, Clin Pharmacokinet, 1993). Benzodiazepines bind a specific site on the GABA-A receptor and increase the effect of GABA, the brain’s main inhibitory transmitter, which accounts for their anti-anxiety, sedative and muscle-relaxant actions (Griffin et al., Ochsner J, 2013). After a single oral dose, alprazolam peaks in blood at 0.7 to 1.8 hours, is 80% to 100% bioavailable and has an elimination half-life of 9 to 16 hours; its side effects, such as drowsiness, rise with blood concentration (Greenblatt and Wright, 1993).

The human trials of alprazolam

The landmark evidence is the Cross-National Collaborative Panic Study, whose first phase compared alprazolam with placebo in more than 600 people at centres in the United States, Canada and Australia (Klerman, Arch Gen Psychiatry, 1988). In the eight-week trial of 526 patients with panic disorder or agoraphobia with panic attacks, alprazolam improved panic attacks, phobic fears, avoidance, anxiety and disability, all significant by the end of week 1. At week 4, 82% were moderately improved or better against 43% on placebo, and 50% were free of panic attacks against 28% (Ballenger et al., Arch Gen Psychiatry, 1988). Completion was 84% on alprazolam against 50% on placebo; sedation, fatigue, ataxia, slurred speech and amnesia were more common on the drug (Noyes et al., Arch Gen Psychiatry, 1988).

For generalised anxiety disorder, a network meta-analysis of 89 trials and 25,441 patients found benzodiazepines effective against placebo but less well tolerated (Slee et al., Lancet, 2019). In 2020 the US Food and Drug Administration required the boxed warning for the whole benzodiazepine class to cover abuse, misuse, addiction, physical dependence and withdrawal reactions.

What is Selank?

Selank is a synthetic heptapeptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, developed from tuftsin, a peptide the body makes (Kolik et al., Bull Exp Biol Med, 2019). Its mechanism research runs along two lines. First, it inhibited the enzymes that break down enkephalins in human plasma, and patients with generalised anxiety had shortened enkephalin half-lives (Zozulya et al., Bull Exp Biol Med, 2001). Second, in radioligand studies it acted as a positive allosteric modulator of GABA binding; it blocked the modulatory activity of diazepam, and its binding site appeared not to be the benzodiazepine site, though the two may partly overlap (Vyunova et al., Protein Pept Lett, 2018). In rats, Selank changed the expression of 45 neurotransmission genes within an hour, in a pattern that correlated with the changes GABA itself produced (Volkova et al., Front Pharmacol, 2016). Its broader research base is covered in Selank peptide: what the research covers.

The human studies of Selank

Selank’s clinical record comes from Russian studies in anxiety disorders, and benzodiazepines were the reference point throughout. In 2008, 62 patients with generalised anxiety disorder or neurasthenia received Selank (30) or medazepam (32). The anti-anxiety effects were similar, and Selank added antiasthenic and psychostimulant effects; serum enkephalin half-life, low in these patients, rose during the Selank course (Zozulia et al., Zh Nevrol Psikhiatr Im S S Korsakova, 2008).

A 2014 study compared Selank with phenazepam in 60 patients with anxiety-phobic and somatoform disorders, reporting a pronounced anti-anxiety effect that lasted a week after the last administration, a mild nootropic effect and better quality of life (Medvedev et al., 2014). In 2015, adding Selank to phenazepam (40 patients, against 30 on phenazepam alone) brought the improvement on sooner and reduced the benzodiazepine’s side effects, including sedation, attention and memory problems and longer sleep, during treatment and after withdrawal (Medvedev et al., 2015). These were small studies against active comparators rather than large placebo-controlled trials. More detail is in Selank and anxiety: the research.

How do Selank and Xanax compare side by side?

Question	Selank	Xanax (alprazolam)
What is it?	Synthetic tuftsin-based peptide	Triazolobenzodiazepine
Size	Seven amino acids	Small molecule, not a peptide
Mechanism focus	Enkephalin-degrading enzymes; allosteric GABA modulation at a site distinct from diazepam’s	Benzodiazepine site of the GABA-A receptor
Main research area	Generalised anxiety, neurasthenia, anxiety-phobic disorders	Anxiety disorders and panic disorder
Human evidence	Russian clinical studies of 60 to 70 patients, 2008 to 2015	Large placebo-controlled trials from the 1980s on
Status	Research compound	Approved prescription medicine
Forms we supply	Lyophilised vial and nasal spray	Not supplied

What the comparison studies do and do not show

• Direct comparisons: Selank was compared with medazepam and phenazepam, both benzodiazepines. We found no published trial comparing Selank with alprazolam itself.
• Profile: in those studies Selank’s anti-anxiety effect came with stimulant and anti-fatigue effects, and adding it to phenazepam reduced sedation, which matters for designs where sedation would be a confound.
• Scale: alprazolam’s evidence comes from multicentre placebo-controlled trials in hundreds of patients; Selank’s from a handful of smaller studies, mostly against active comparators.

Selank’s relationship to its sister peptide is covered in Semax vs Selank, and its pairing with a sleep peptide in DSIP vs Selank.

How is Selank supplied?

Selank comes as a 10 mg lyophilised vial and as the ready-mixed Selank Nasal Spray in two bottle sizes, a metered pump delivering 0.175 mL per press; the Selank + Semax Nasal Spray combines it with Semax. Vials are reconstituted with bacteriostatic water using the Selank reconstitution guide and its calculator, and storage is covered in How long does Selank last?. Certificates of analysis are on the lab reports page, and every order ships from within Canada by Canada Post Xpresspost.

Frequently asked questions

What is the difference between Selank and Xanax?

Alprazolam, the drug in Xanax, is a benzodiazepine that enhances GABA signalling at the benzodiazepine site of the GABA-A receptor. Selank is a seven-amino-acid tuftsin-based peptide whose research points to enkephalin-degrading enzymes and allosteric GABA modulation at a site that appeared distinct from diazepam’s.

Is Selank a benzodiazepine?

No. Selank is a peptide, not a benzodiazepine. Its clinical studies used benzodiazepines (medazepam and phenazepam) as comparators, and laboratory work found it modulated GABA binding through a site that appeared different from the one diazepam uses.

Has Selank been compared with Xanax?

We found no published trial comparing Selank with alprazolam directly. In a 2008 study of 62 patients, Selank’s anti-anxiety effect was similar to the benzodiazepine medazepam’s, with added stimulant and anti-fatigue effects.

Is Selank sedating?

Its clinical studies reported psychostimulant and anti-fatigue effects alongside the anti-anxiety effect, and a 2015 study found that adding Selank to phenazepam reduced the benzodiazepine’s sedation and attention and memory side effects.

Where can I buy Selank in Canada?

Vistara Labs supplies Selank as a 10 mg lyophilised vial and a ready-mixed nasal spray, shipped from within Canada by Canada Post Xpresspost. See Buy Selank in Canada.

Product details from vistaralabs.ca, October 2026. Sources: Greenblatt DJ, Wright CE. Clinical pharmacokinetics of alprazolam. Therapeutic implications. Clin Pharmacokinet. 1993. PMID 8513649. Griffin CE et al. Benzodiazepine pharmacology and central nervous system-mediated effects. Ochsner J. 2013. PMID 23789008. Klerman GL. Overview of the Cross-National Collaborative Panic Study. Arch Gen Psychiatry. 1988. PMID 3282477. Ballenger JC et al. Alprazolam in panic disorder and agoraphobia: results from a multicenter trial. I. Efficacy in short-term treatment. Arch Gen Psychiatry. 1988. PMID 3282478. Noyes R et al. Alprazolam in panic disorder and agoraphobia: results from a multicenter trial. II. Patient acceptance, side effects, and safety. Arch Gen Psychiatry. 1988. PMID 3358644. Slee A et al. Pharmacological treatments for generalised anxiety disorder: a systematic review and network meta-analysis. Lancet. 2019. PMID 30712879. US Food and Drug Administration. FDA requiring Boxed Warning updated to improve safe use of benzodiazepine drug class. 2020. FDA. Kolik LG et al. Selank, peptide analogue of tuftsin, protects against ethanol-induced memory impairment by regulating of BDNF content in the hippocampus and prefrontal cortex in rats. Bull Exp Biol Med. 2019. PMID 31625062. Zozulya AA et al. The inhibitory effect of Selank on enkephalin-degrading enzymes as a possible mechanism of its anxiolytic activity. Bull Exp Biol Med. 2001. PMID 11550013. Vyunova TV et al. Peptide-based anxiolytics: the molecular aspects of heptapeptide Selank biological activity. Protein Pept Lett. 2018. PMID 30255741. Volkova A et al. Selank administration affects the expression of some genes involved in GABAergic neurotransmission. Front Pharmacol. 2016. PMID 26924987. Zozulia AA et al. Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia. Zh Nevrol Psikhiatr Im S S Korsakova. 2008. PMID 18454096. Medvedev VE et al. A comparison of the anxiolytic effect and tolerability of selank and phenazepam in the treatment of anxiety disorders. Zh Nevrol Psikhiatr Im S S Korsakova. 2014. PMID 25176261. Medvedev VE et al. Optimization of the treatment of anxiety disorders with selank. Zh Nevrol Psikhiatr Im S S Korsakova. 2015. PMID 26356395.

More on this: Peptides for Focus and Anxiety: What the Research Shows.