Selank and Afobazole are two Russian preparations developed to reduce anxiety and improve stress resistance. Although both exhibit anxiolytic effects without causing significant drowsiness, they differ in their structure, method of administration, mechanism of action, and the speed at which their effects manifest.
What are Selank and Afobazole?
Selank is a synthetic heptapeptide made up of seven amino acids. It was designed as an analogue of the natural peptide tuftsin, which is involved in communication between the immune and nervous systems. Selank is administered intranasally, and studies suggest it may reach the central nervous system very rapidly. It was developed in Russia and Ukraine in the 1990s and is approved there for the treatment of anxiety disorders and stress-related conditions.
Afobazole (fabomotizole), on the other hand, is a synthetic chemical compound available in tablet form. It was also developed in Russia in the late 1990s. It works primarily by activating sigma-1 receptors, which are involved in regulating cellular responses to stress. Like Selank, it was designed not to cause significant sedation.
How Do They Get into the Body?
| Feature | Selank | Afobazole |
|---|---|---|
| Method of administration | Nasal spray – a few doses into each nostril | Tablet taken orally, usually 3 times a day |
| How quickly does it reach the brain | Very quickly – through the nasal cavity directly to the brain, bypassing the digestion process | It is absorbed via the gastrointestinal tract; maximum blood concentration is reached after approximately 1 hour. |
| How long does it work | The main peptide breaks down in about 2 minutes, but active fragments can last for 3–4 hours | The main compound is eliminated relatively quickly (around 50 minutes), whereas its metabolite remains active for up to 6 hours. |
| How is it removed from the body | Broken down into harmless protein fragments and excreted by the kidneys within 24 hours | Approximately 85% is excreted by the kidneys and 15% via the gastrointestinal tract; it is completely eliminated within one day |
| How many substances become biologically available | High brain availability via intranasal administration and bypassing hepatic metabolism | Approximately 43–55% of the administered dose enters the bloodstream after passing through the liver |
How Do They Reduce Anxiety?
Both preparations reduce anxiety symptoms without acting like typical sedatives or sleeping pills. Neither was designed to cause drowsiness.
| Feature | Selank | Afobazole |
|---|---|---|
| Primary anxiolytic action | Supports the action of GABA – the main inhibitory neurotransmitter – without excessively suppressing brain activity | It activates sigma-1 receptors, which help cells cope with stress signals; it also affects melatonin receptors |
| Impact on brain health | Increases BDNF and NGF levels, supporting communication between neurons, memory, and concentration | It may increase BDNF levels by activating sigma-1 receptors, thereby supporting the regeneration of nerve cells |
| Effect on mood | Gently affects serotonin and dopamine pathways, exhibiting mild mood-lifting effects | The benefits mainly concern the regulation of stress and anxiety, rather than a direct improvement in mood. |
| Impact on the immune system | It exhibits immunomodulatory properties and can influence the regulation of inflammatory processes. | The anti-inflammatory effect appears to be significantly weaker |
| Risk of sedation | No significant drowsiness was observed | No significant drowsiness was observed |
| Risk of addiction | No evidence of tolerance, dependence or withdrawal symptoms | In studies lasting up to 12 weeks, no addiction or withdrawal symptoms were reported. |
How Do They Work Effectively?
| Feature | Selank | Afobazole |
|---|---|---|
| Start of operation | Fast – the first effects can appear within 20-60 minutes | Gradual – the full anxiolytic effect usually develops after 2–4 weeks of regular use |
| Typical dosage used in studies | 400–600 micrograms intranasally, 1–3 times daily | 10 mg three times a day (30 mg total daily) |
| Main research areas | Generalized anxiety, short-term stress, stress-related memory and concentration problems | Generalized anxiety disorder, adjustment disorders, and support during nicotine withdrawal |
| Clinical trials | Around 15 clinical trials in Russia and Ukraine; results more favourable than placebo and comparable to older anxiolytic drugs | Over 20 clinical trials in Russia, some with up to 500 patients, have demonstrated benefits compared to placebo. |
| Impact on memory and concentration | Well-documented benefits for working memory, attention, and mental agility, particularly in stressful situations | Cognitive benefits seem secondary and are not the main goal of the research. |
| Side effects | Mild and infrequent: slight nasal irritation, transient fatigue, occasional headache | Mild and rare: nausea, mild stomach upset, and occasional allergic reactions |
| Interactions with other substances | No significant interactions with liver enzymes are known. | Metabolised by the CYP3A4 enzyme, therefore it may interact with certain medications |
| The biggest limitation | Most research has been conducted solely in Russia and Ukraine; limited long-term data | Similar geographical limitations and a lack of large clinical trials in the USA, UK, and EU |
How do they work for anxiety?
Both preparations reduce anxiety symptoms, but they use different biological mechanisms.
Selank
Research indicates that Selank:
- modulates GABAergic signalling,
- affects neurotrophic factors, such as BDNF and NGF,
- can affect the serotonergic and dopaminergic systems,
- It demonstrates neuroregulatory and immunomodulatory properties.
Afobazole
Research suggests that Afobazole:
- activates sigma-1 receptors,
- supports cell adaptation to stress,
- can affect melatonin receptors,
- It mainly focuses on regulating chronic stress and anxiety.
Neither of the preparations was designed as a classic sedative, and both appear to be characterised by a low risk of sedation and dependence.
Which one works faster?
One of the biggest differences between these substances is the time it takes for the effects to appear.
Selank It is mainly studied in the context of faster reduction of tension and stress, as well as support for cognitive functions.
Afobazole usually requires regular use for several weeks and is more often discussed in the context of chronic, persistent anxiety.
Impact on Cognitive Functions
Research into Selank indicates potential benefits regarding:
- RAM,
- concentration,
- resilience to stress,
- cognitive functions in situations of psychological stress.
Afobazole may also show some cognitive benefits, however, these are not the main area of its research.
Security Profile
Available studies suggest that both preparations are generally well tolerated.
Selank
- sporadic nasal irritation,
- occasional headache,
- fleeting fatigue.
Afobazole:
- Mild stomach upset,
- nausea,
- rare allergic reactions.
No significant risk of addiction or withdrawal symptoms was found for any of these preparations in published studies.
Disclaimer
The content is for educational and informational purposes only and should not be interpreted as medical advice, diagnosis, or therapeutic recommendation. Selank and Afobazole have not been approved by the US Food and Drug Administration (FDA) or the European Medicines Agency (EMA) for the treatment of anxiety disorders or other medical conditions. Most of the available data comes from studies conducted in Russia and Eastern Europe. Further, well-designed clinical trials are needed to better determine their efficacy, safety, and long-term effects.