Semax Peptide: Benefits, side effects, dosage details, and how it works

You could probably guess why nootropics, or “smart drugs,” constitute such a popular health market.1 We could all do with a little more brain power, after all.

Better brain function is exactly what the peptide Semax was made to deliver. Developed in Russia in the 1980s, Semax stands out as a promising therapy for cerebral health and neurodegenerative disorders. But because widespread pharmaceutical use and the relevant research are largely limited to its native region, reliable information about its therapeutic applications is somewhat scarce outside of Russia and Eastern Europe. Apart from a relatively light body of English-language scientific literature, a lot of the reportage on Semax comes from niche influencers and online vendors with questionable pedigrees.

So we’ve written this guide with the goal of unifying key takeaways from the most reliable research on Semax to date. By the end of it, you should have the clearest possible understanding of Semax’s potential benefits, risks, and availability.

Over the past two decades, Innerbody Research has helped tens of millions of readers make more informed decisions about staying healthy and living healthier lifestyles.

This Semax guide is part of our ongoing series on therapeutic peptides, an endeavor to which we’ve devoted over 1,000 hours of research and writing so far. As with all of our guides, we familiarized ourselves with Semax through the available scientific literature. Where pertinent, we cross-referenced the studies and reviews on Semax with supplemental research on associated factors, such as the role of the natural peptide that Semax mimics and the efficacy of the nasal route of administration.

Additionally, like all health-related content on this website, this guide was thoroughly vetted by one or more members of our Medical Review Board for accuracy and will continue to be monitored for updates by our editorial team.

Semax is a peptide analog, or a synthetic and modified version of a naturally occurring peptide. It specifically mimics a fragment of the pituitary chemical adrenocorticotropic hormone (ACTH).

While ACTH is best known for its endocrine activity (triggering the release of other hormones, namely cortisol and androgens),2 it also has neurotrophic effects (i.e., it supports the development and survival of neurons).3 However, since Semax mimics only a fragment of ACTH, not the whole molecule, it doesn’t behave exactly the same. According to the Alzheimer’s Drug Discovery Foundation (ADDF), Semax delivers the neurotrophic effects of ACTH but not the hormonal/endocrine ones,4 so it circumvents the onset of symptoms associated with overactive ACTH secretion (e.g., upper-body obesity, “buffalo” hump, high blood pressure).5

Routes of administration

Semax can be administered effectively via injection or intranasal (through-the-nose) administration. This is a point of differentiation from many other therapeutic peptides, which are often less effective through non-injectable routes because their molecules are too large to pass reliably into the bloodstream.6

Further going against the grain, Semax appears to be more effective when administered intranasally, at least in terms of its nootropic benefit. In a 2012 study published in Neuroscience and Behavioral Physiology, researchers found that intranasal Semax yielded a more pronounced improvement in learning in rodent subjects compared to intraperitoneal injection.7 The downside was that intranasal administration provided no analgesic (pain-relieving) action, which is one of Semax’s secondary therapeutic uses.

Semax is a neuropeptide,8 a class of signaling molecules in the brain with numerous functions.9 In Russia and Eastern Europe, Semax’s primary uses are nootropic (cognition-enhancing), neuroprotective (brain-preserving), anxiolytic (anxiety-reducing), antidepressant (mood-improving), and immunomodulatory (immune system–modifying). Below, we discuss the literature that supports Semax’s applications in these areas:

Other benefits of Semax

Varying degrees of research indicate that Semax can provide some benefits outside of its primary therapeutic uses, namely with regard to:

• Pain relief: A 2019 systematic review of Symax’s therapeutic uses proclaimed that “systemic administration of ACTH [from which Semax is derived] leads to an increase in the pain threshold,”30 and one of the studies referenced in the review saw decreased pain sensitivity in rats that received 0.015-0.5mg/kg intraperitoneal injections of Semax (i.e., directly into their abdominal cavities).31 It should be noted, however, that this analgesic effect was absent in subjects who received the peptide intranasally,31 and Semax prescribed to a human isn’t likely to be administered via direct injection into the peritoneum.
• Improved cardiovascular health: In another study with intraperitoneal injection, rats induced with myocardial infarction exhibited preserved cellular architecture of the heart after Semax administration.32 Though there were no improvements in heart function, this finding suggests that Semax can alleviate the cardiovascular cell death that contributes to heart attacks and their complications.
• Ulcer treatment: In a 2002 study in which rats were induced with stomach ulcers, Semax administration appeared to impart a “protective effect.” The researchers theorized this was due to increased blood flow to the gastric wall, stimulated by Semax.33

Safety information on Semax is meager outside of Russian-language scientific literature. The relatively little information we have comes from the ADDF and a 2022 review on Russian peptide biopharmaceuticals.

The ADDF report, published in 2020, notes “very little human evidence for potential side effects” despite “many preclinical trials,” and the authors presume a low side effect profile owing to Semax’s purportedly common use in Russia. Only two common adverse events are mentioned: discoloration of the nasal cavity with intranasal administration (approximately 10% of patients) and increased blood glucose levels in people with diabetes. 4

The 2022 review, largely in corroboration of the ADDF’s conclusion, states that Semax has “low toxicity,” is not habit-forming, and has no ill effects on:34

• Important bodily systems (e.g., central nervous and cardiovascular)
• The metabolism of other drugs
• Mental and physical stress resistance

Research-grade vs. pharmaceutical-grade Semax

Because Semax isn’t FDA-approved or even widely available outside of Russia and Eastern Europe, the curious Westerner may be tempted to purchase the peptide from an online retailer. We can’t promise you that any of these retailers are reputable, nor can we say whether they’re selling research-grade material or a pharmaceutical-grade medical product.

The odds are that if it’s available to you online, it’s research-grade. And you don’t want that. Research-grade peptides, which aren’t subject to the same quality controls as their pharmaceutical-grade counterparts, are for laboratory use only. Scientists can use them in experiments on cells and animal models, but they pose health risks in humans owing to their low purity levels.35 So, by injecting or inhaling research-grade Semax, you put yourself in danger of an immunogenetic reaction,36 in which your immune system perceives the peptide as a threat and mounts a potentially life-threatening anaphylaxis-like reaction against it.

Is it possible to find a proper pharmaceutical-grade Semax powder or nasal spray online? Maybe. If you find something that looks legitimate, you must carefully read the product page to be sure it isn’t meant only for the lab.

Also, as always, speak with your doctor before making any major health decisions, such as starting a peptide regimen.

Without FDA approval or widespread use, Semax presents a minor mystery in terms of its use experience. But because Semax is a therapeutic peptide, it has a few things in common with other treatments in its class, and by consolidating findings from our research we can give you a broad yet accurate view of what to expect (should Semax become available to you).

Dosing and administration

Clinical studies in humans have administered Semax starting at doses of 1.2mg (intranasal) and ranging up to 1mg per kilogram (injectable). 4 For medical use, the actual dosage can be much lower or higher depending on your desired health outcome.

Intranasal Semax will come in a ready-to-use vessel similar to, say, a Mucinex bottle, whereas the injectable version ought to come as a powder in a vial. To use injectable Semax, you must first reconstitute the powder with bacteriostatic water.

Though dosing frequencies may vary, a common protocol entails daily nasal administration or near-daily injections.

As with many therapeutic peptides, your protocol may require that you cycle your Semax use — several months of regular administration, followed by a one-month break. This pattern can help maintain efficacy by preventing drug tolerance.

Timeline of benefits

Some users report feeling cognitive enhancement benefits in as little as 30 minutes after Semax administration. Pain relief benefits may have a similarly rapid onset.

Any neuroprotective, immunomodulatory, and cardiovascular benefits are likely to take much longer to take effect — 2-4 weeks at least — and aren’t likely to be apparent to you in a daily-quality-of-life kind of way.

Storage

Reconstituted Semax powder ought to remain stable under refrigerated conditions (the U.K.’s National Institute for Biological Standards and Control recommends a storage temperature of 4°C, or 39°F).37

Intranasal Semax can be stable at higher temperatures and doesn’t always need to be refrigerated — it may depend on the manufacturer. But at the very least, you should keep the bottle in a cool, dry environment under 10°C (50°F) and out of direct sunlight.

People who stand to gain the most benefit from Semax are those who have or at risk for:

• Cognitive disorders: Semax’s nootropic properties may help increase one’s focus, memory, and capacity to learn.
• Cognitive diseases or dysfunctions: As a neuroprotectant, Semax is often administered post-stroke to aid in recovery, as well as in cases of age-related cognitive decline.

Interestingly, despite its potential as an anxiolytic, Semax may not be indicated for people with anxiety disorders. In a 1996 study, researchers noted an “anxiogenic [anxiety-worsening] component in the spectrum of Semax’s behavioral effects” and suggested that the peptide would be optimally useful in people without elevated anxiety levels.38

Other populations for whom Semax is contraindicated include people with diabetes (Semax may increase their blood sugar levels) and pregnant or breastfeeding women (there isn’t enough research to say whether Semax is safe for the developing fetus or child). 4

Currently, because Semax isn’t an FDA-approved drug, there are few to no reputable places to get it in the United States. While you can find online retailers selling Semax powder or spray, most of these right now are certain to be pushing research-grade products that (it must be reiterated) are not suitable for human use.

But the peptide landscape is ever-shifting, and Semax may one day become as readily accessible as the Ozempics and Mounjaros of the world. As this space evolves, we’ll make sure to update this guide accordingly.