Is hair loss a known side effect of Selank?
Hair loss is not a commonly reported issue in the scientific literature concerning Selank. Based on current studies involving both humans and animals, there is no evidence to suggest that Selank directly causes hair loss, baldness, or increased shedding of hair [1-4].
Selank is a synthetic heptapeptide derived from the naturally occurring immunomodulatory peptide, tuftsin. Its amino acid sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP) [5]. Most research has focused on its effects on anxiety, neurochemical signalling, and cognitive functions, rather than on hormonal pathways that typically affect hair growth and loss.
Is hair loss listed as a side effect of Selank?
Published clinical studies evaluating Selank in individuals with generalised anxiety disorder and neurasthenia have not reported hair loss as an observed adverse effect [3]. Similarly, experimental studies analysing the influence of Selank on neurotransmitters, enkephalin metabolism, and neuroplasticity have not demonstrated alopecia or changes in hair growth related to the peptide's use [1,2].
Reviews concerning the safety profile of Selank generally describe it as well-tolerated, highlighting the absence of many side effects often associated with traditional anxiolytic drugs, such as excessive sedation, cognitive impairment, or the development of dependence [1].
Can Selank Indirectly Influence Hair Growth?
Currently, there is no evidence to suggest that Selank directly affects hormones commonly associated with hair loss, including:
- Dihydrotestosterone (DHT)
- Testosterone
- Thyroid hormones
- Oestrogen
- Cortisol
However, chronic psychological stress and anxiety can contribute to certain types of hair loss, particularly telogen effluvium, where a larger number of hair follicles enter the resting phase of the hair growth cycle.
As Selank exhibits anti-anxiety properties and can improve stress adaptation in some individuals [1–3], researchers suggest that limiting excessive stress responses could theoretically support overall well-being. Nevertheless, no studies have directly analysed the effect of Selank on hair growth, hair loss, or scalp biology.
Does Selank Affect Hair Biology Growth Factors?
Experimental studies have shown that Selank can influence pathways associated with neuroplasticity, including the regulation of brain-derived neurotrophic factor (BDNF) expression in the hippocampus [6]. While growth factors play an important role in many biological processes, there is currently no evidence linking Selank-induced neurotrophic changes to alterations in hair growth or increased risk of hair loss.
Current Scientific Findings
Based on currently available data, Selank is not known to cause hair loss. Neither clinical trials involving humans nor preclinical studies have indicated alopecia or increased hair loss as a recognised adverse effect [1–4]. Furthermore, there is no evidence that Selank directly affects hormonal pathways commonly associated with hair loss.
As long-term safety studies remain limited, further research is needed to fully characterise the effects of Selank across different populations and during prolonged use.
Can Selank cause insomnia?
Can Selank Cause Insomnia?
Insomnia means difficulty falling asleep, staying asleep, or achieving restorative rest despite conducive sleep conditions. As Selank can affect neurochemical signalling and cognitive functions, some individuals wonder if it can disrupt sleep.
Based on the available scientific literature, insomnia has not been identified as a common side effect of Selank [1–4].
Most studies describe Selank as an anxiolytic peptide that regulates neurochemical systems associated with stress, without causing significant sedation, cognitive impairment, or intoxication [1]. Clinical trials involving humans have also demonstrated good tolerability and have not identified insomnia as a significant adverse effect associated with therapy [3].
Why Do Some People Ask About Insomnia?
Some of these concerns may stem from observations that Selank exhibited antiasthhenic and psychostimulant effects in some clinical studies [3].
In a study involving individuals with generalised anxiety disorder and neurasthenia, Selank demonstrated anxiolytic effects comparable to medazepam, while simultaneously improving psychic energy levels and reducing feelings of fatigue [3]. These observations suggest that Selank may support alertness and reduce the sense of mental exhaustion in some individuals.
However, a psychostimulant effect does not automatically mean that a substance causes insomnia. Current data do not indicate that Selank causes the clear central nervous system stimulation typical of classic stimulants.
Can Selank Affect Sleep Patterns?
Since Selank appears to affect cognitive and emotional processes without causing significant sedation [1,3], individual responses may vary.
Some individuals may experience greater mental clarity or increased alertness after taking Selank, particularly if anxiety-related fatigue is reduced. Theoretically, changes in perceived alertness could influence when some people fall asleep. However, this possibility has not been systematically studied, and no clinical trials have demonstrated that Selank causes insomnia.
Can Selank cause anxiety?
The available scientific data suggest the opposite situation.
Selank was developed specifically as an anxiolytic peptide and has demonstrated anxiety-reducing effects in both experimental and human studies [1–4]. Clinical trials have indicated an improvement in anxiety symptoms in individuals with generalised anxiety disorder and neurasthenia [3].
Mechanistic studies suggest these effects may involve several pathways, including positive allosteric modulation of GABA receptor activity, regulation of endogenous opioid peptides such as enkephalins, influence on neuroplasticity-related pathways, and modulation of stress-responsive neurochemical systems [1,2,6].
These mechanisms are usually associated with reducing anxiety, rather than causing it.
Can some people experience an increase in anxiety?
Although available research indicates a anxiolytic profile for Selank, individual responses to neuroactive substances can vary.
Currently, no studies have been published showing that Selank routinely causes anxiety or panic attacks. However, as long-term data is limited and individual neurobiology varies, researchers cannot entirely rule out the possibility of unexpected subjective reactions in some individuals.
It should be stressed that isolated anecdotal reports should not be interpreted as evidence that anxiety or insomnia are confirmed side effects of Selank.
Current Scientific Findings
Current data do not indicate that insomnia is a common side effect of Selank. Similarly, published studies consistently confirm an anxiolytic rather than an anxiogenic effect [1–4]. While individual reactions may vary and long-term data remain limited, neither insomnia nor anxiety exacerbation have been identified as confirmed adverse effects in the available scientific literature.
Disclaimer
This material is for educational and informational purposes only and should not be interpreted as medical advice, diagnosis, or therapeutic recommendation. Selank remains a research peptide in many countries, and a significant portion of available data comes from preclinical studies and limited human trials. Published research suggests that Selank has a favourable tolerability profile and anxiolytic properties, however, long-term safety data remains limited.
For Research Purposes Only The Selank products offered by Semax Polska are intended solely for laboratory and scientific research. They are not authorised for human consumption, medical use, or for the diagnosis, treatment or prevention of any diseases. Further, well-designed human studies are necessary to fully characterise the effects of Selank on sleep, anxiety, hair biology and other long-term safety outcomes.
References
[1] Vyunova, T. V., Andreeva, L., Shevchenko, K., & Myasoedov, N. F. (2018). Peptide-Based Anxiolytics: The Molecular Aspects of Heptapeptide Selank Biological Activity. Protein and Peptide Letters, 25(10), 914–923. https://doi.org/10.2174/0929866525666180925144642
[2] Zozulya, A. A., Kost, N. V., Sokolov, O. Y., Gabaeva, M. V., Grivennikov, I. A., Andreeva, L. N., Zolotarev, Y. A., Ivanov, S. V., Andryushchenko, A. V., Myasoedov, N. F., & Smulevich, A. B. (2001). The Inhibitory Effect of Selank on Enkephalin-Degrading Enzymes as a Possible Mechanism of Its Anxiolytic Activity. Bulletin of Experimental Biology and Medicine, 131(4), 315–317. https://doi.org/10.1023/A:1017979514274
[3] Zozulia, A. A., Neznamov, G. G., Siuniakov, T. S., Kost, N. V., Gabaeva, M. V., Sokolov, O. Y., Serebriakova, E. V., Siranchieva, O. A., Andriushenko, A. V., Telesheva, E. S., Siuniakov, S. A., Smulevich, A. B., Myasoedov, N. F., & Seredenin, S. B. (2008). Efficacy and Possible Mechanisms of Action of a New Peptide Anxiolytic Selank in the Therapy of Generalised Anxiety Disorders and Neurasthenia. Journal of Neurology and Psychiatry named after S.S. Korsakov, 108(4), 38–48. https://pubmed.ncbi.nlm.nih.gov/18454096/
[4] Kost, N. V., Sokolov, O. Y., Zozulya, S. A., & Myasoedov, N. F. (2025). Combined Action of Benzodiazepine Tranquillisers and Peptide Anxiolytic Selank in BALB/c Mice. Neurochemical Journal, 19, 743–748. https://doi.org/10.1134/S1819712425700783
[5] National Centre for Biotechnology Information. (2026). PubChem Compound Summary for CID 11765600, Selank. National Library of Medicine. https://pubchem.ncbi.nlm.nih.gov/compound/Selank
[6] Levitskaya, N. G., Andreeva, L. A., Mezentseva, M. V., Shapoval, I. M., Podchernyaeva, R. Y., Shcherbenko, V. E., Potapova, L. A., Russu, L. I., Ershov, F. I., & Myasoedov, N. F. (2010). Intranasal Administration of the Peptide Selank Regulates BDNF Expression in the Rat Hippocampus In Vivo. Doklady Biological Sciences, 431, 79–82. Available from: https://www.researchgate.net/profile/Natalia-Levitskaya/publication/23306196_Intranasal_administration_of_the_peptide_Selank_regulates_BDNF_expression_in_the_rat_hippocampus_in_vivo