Evidence Based

Top 7 Uses of Semax (Cognitive Enhancement & More)

Written by Carlos Tello, PhD (Molecular Biology) | Last updated:
Jonathan Ritter
Puya Yazdi
Medically reviewed by
Jonathan Ritter, PharmD, PhD (Pharmacology), Puya Yazdi, MD | Written by Carlos Tello, PhD (Molecular Biology) | Last updated:

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Semax is a medication used for the prevention and treatment of circulatory disorders in Russia and also as a cognitive enhancer. Read below to find out about the potential benefits of this substance and whether they are backed by science.

Disclaimer: By writing this post, we are not recommending this drug. Some of our readers who were already taking the drug requested that we commission a post on it, and we are simply providing information that is available in the clinical and scientific literature.

What Is Semax?

Semax is a peptide drug based on a fragment of the adrenocorticotropic hormone (ACTH) [1].

In Russia, Semax is used as a medication for the prevention and treatment of circulatory disorders including stroke. Semax is listed on the Russian List of Vital & Essential Drugs, a reference of key medications which is reviewed and approved by the Russian government [1, 2].

Semax is also used as a nootropic, or cognitive enhancer, due to evidence that Semax can enhance memory performance and reduce the negative effects of stress.

How It Works

  • Increases brain BDNF levels [3].
  • Prevents the breakdown of enkephalins [4].
  • Protects the nervous system from oxidative damage [1].
  • Affects the expression of genes related to the immune and vascular systems during stroke [5].

Potential Uses of Semax

Although some of the purported health benefits of Semax have been investigated, a lot of studies using this substance (including most clinical trials) haven’t been translated from Russian. This means that we can’t access their specifics for a critical analysis. Some readers may be disappointed to know that evidence is lacking to support part of the inflated online claims.

Semax may have therapeutic value for some conditions, but more clinical research is needed. Talk to your doctor before using this drug.

Likely Effective for:

Brain and Nerve Damage

Semax has been shown to protect the brain from various types of oxidative and inflammatory damage.

In a clinical trial on over 100 people recovering from an ischemic stroke, Semax (used as an add-on to intensive therapy) accelerated the restoration of the damaged brain functions, especially movement disorders [6].

In another trial on almost 200 people with reduced blood flow to the brain (cerebrovascular insufficiency), Semax reduced brain damage, prevented the development of brain strokes, and was well tolerated [7].

Semax was also successfully used together with basic neurotrophic and anti-inflammatory therapy in people with optic nerve disease [8, 9].

In a clinical trial on 27 people with motor nerve disease, Semax didn’t protect the nerves form progressive damage but improved mood and quality of life [10].

Semax prevented brain damage after a stroke in multiple rat studies [1, 11, 12, 13, 14].

Semax also prevented oxidative damage caused by the poisonous effects of lead exposure in the brain [15].

Although promising, the evidence supporting the role of Semax in reducing brain damage is limited. Further clinical research is needed.

Insufficient Evidence for:

Improving Memory

Semax is commonly used as a nootropic. It improved memory and attention in a Russian study of task performance in healthy men [16].

In a small brain imaging study on 24 people, Semax increased the activity in a brain region involved in episodic memory (default mode network) [17].

Some researchers have suggested that the resistance to oxidative damage in the brain and improved brain circulation might explain the improved memory seen in these subjects [16].

Semax also decreased learning time and improved exploratory efficiency in animal studies [16, 17].

In rats recovering from a brain stroke, Semax reduced brain damage and prevented memory loss [18, 19].

Taken together, two clinical trials (one of which can’t be critically evaluated because it hasn’t been translated from Russian) and some animal research cannot be considered sufficient evidence to back the use of Semax as a memory enhancer. Larger, more robust clinical trials are needed.

Animal Research (Lack of Evidence):

No clinical evidence supports the use of Semax for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies listed should not be interpreted as supportive of any health benefit.


In rats, Semax protected the heart from damage after a stroke or heart attack [1].

The drug partially prevented the growth of the heart caused by high blood pressure, thus potentially preventing heart failure development after a heart attack [1].

Negative Effects of Stress

Semax has been shown to decrease the negative physical and mental responses to stress in animal studies.

One negative physical response to chronic stress is the increased production of specific liver enzymes. Treatment with Semax was shown to prevent their increase in several animal studies. Similarly, it prevented white blood cell proliferation and tissue damage in the spleen of stressed rats [20, 21].

Semax normalized behavioral changes associated with increased stress resulting from physical injury and developmental problems in animal studies [22, 23].

Birth of Brain Cells

Semax increased the brain levels of a substance known as brain-derived neurotrophic factor (BDNF) in animal studies [3, 24].

BDNF is a major chemical factor that is essential for cognitive development, synaptic plasticity, and neuronal survival. Studies indicate that low levels of BDNF may also cause or worsen depression and anxiety. By increasing the level of BDNF, Semax could help alleviate anxiety and depression. Animal studies have also suggested that Semax normalizes behavior associated with increased stress and anxiety, possibly as a result of this mechanism [25, 26, 27].


In test tubes, Semax prevented the breakdown of chemicals called enkephalins which regulate the response to pain. An increase in enkephalins may reduce the severity of perceived pain [4].


Semax has a number of effects that may be helpful in the treatment of ADHD, including memory improvement and the increase of neurotransmitters which are often lower in patients with this condition [28].

Researchers have proposed evaluating Semax as a treatment for ADHD, and anecdotes support that Semax is occasionally used in Russia for this purpose [3].

Additional studies are needed to determine if there is a benefit of Semax in the treatment of ADHD. Also, proper dosage and treatment strategy would need to be determined.

Using Semax

Cautions About Semax

Semax is not FDA-approved and has not been evaluated by the FDA. Never use this drug without discussing it with your doctor or in place of what your doctor recommends or prescribes.

Because Semax is an insufficiently researched substance, its safety profile is practically unknown. You should consult your doctor about potential side effects based on your health condition and possible drug or supplement interactions.

In one study in animals, highly concentrated Semax had an anti-oxidant effect at low dosages, but a pro-oxidant effect at higher dosages. Another animal study using various dosages found that each dosage studied had antioxidant effects. More research needs to be done to determine if there is a negative effect associated with high dosages, and at what dosage that effect may occur [20, 29].

Some users have reported increased anxiety as a side effect of using Semax as a nootropic [30, 31, 32].

Buying Semax

Semax is available online. Use the coupon code selfhacked8 for 8% off.

This drug has not been evaluated nor used in the US.

Want More Targeted Ways to Enhance Brain Function?

If you’re interested in improving your cognitive function, we recommend checking out SelfDecode’s Limitless Mind DNA Protocol. It gives genetic-based diet, lifestyle and supplement tips that can help improve your cognitive function. The recommendations are personalized based on your genes.

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About the Author

Carlos Tello

Carlos Tello

PhD (Molecular Biology)
Carlos received his PhD and MS from the Universidad de Sevilla.
Carlos spent 9 years in the laboratory investigating mineral transport in plants. He then started working as a freelancer, mainly in science writing, editing, and consulting. Carlos is passionate about learning the mechanisms behind biological processes and communicating science to both academic and non-academic audiences. He strongly believes that scientific literacy is crucial to maintain a healthy lifestyle and avoid falling for scams.

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