Semax is a heptapeptide deriving from the adrenocorticotrophic hormone (ACTH). ACTH was first identified in the 1950s as having potential hormonal and cognitive effects. Although it itself does not demonstrate hormonal activity, semax does have similar neurotrophic effects as ACTH. Thus, the Russian Academy of Sciences developed semax for indications such as Parkinson’s stroke, ocular nerve atrophy, newborn neurological deficits, and dyscirculatory encephalopathy (DEP). It is taken intranasally via a dropper (1).
Semax works through a variety of mechanisms. When it comes to cerebral stroke therapy, semax supports neuron survival during hypoxia and glutamate neurotoxicity. Additionally, it exerts neuroprotective effects and helps to stabilize the mitochondria during stress caused by deregulation of calcium ion flow. It inhibits nitric oxide synthesis and supports neurotrophic supply of the brain (2).
A few preclinical studies have shown that semax can be neuroprotective. For example, in transgenic mice serving as a model for Alzheimer’s disease, semax treatment was evaluated in the context of amyloidosis development and behavioral characteristics. The study showed that semax improved cognitive functions in treated mice with regards to novel object recognition, open field, and maze tests. The histology results indicated that semax also decreased amyloid inclusions in the mice’s brains (3).
Semax was also evaluated in rat brain focal ischemia. This study evaluated gene expression following semax treatment in animals after permanent middle cerebral artery occlusion (pMCAO). It was found that the peptide increased gene expression related to the immune system and the vascular system. Such genes are associated with the functioning and formation of the vascular system, emphasizing potential neuroprotective effects (2).
A few studies in humans also exist that have been conducted in Russia, and findings include the following:
Though evidence in humans is limited, there are a few clinical studies that support the potential neurocognitive benefits of semax. In particular, individuals looking to improve cognitive function, including those with Alzheimer’s could see some advantages associated with use.
Semax is currently on the list of category 2 bulk substances nominated under sections 503A or 503B of the Federal Food, Drug, And Cosmetic Act. The FDA notes that as such, the substance could carry some safety risks. Semax will be discussed at an advisory committee meeting in July 2026 regarding its potential inclusion in the 503A bulks list (4).
The FDA notes that semax may carry a risk of immunogenicity due to the possibility of aggregation and peptide-related impurities. The FDA possesses little safety information on the current formulations of semax, and thus cannot draw conclusions regarding the safety of the substance (5).
Semax demonstrates potential neuroprotective effects in both animal models and human studies, however, its safety and efficacy must be further validated in well-controlled clinical studies in the US.
The information provided in this article is for educational purposes only and is not intended as medical advice. Many peptides are not FDA-approved for human use outside of limited clinical contexts. These compounds are often obtained through unregulated sources that lack quality control. Studies suggest 30–65% of products may be contaminated or mislabeled, with risks including endotoxins, heavy metals, and incorrect sequences. At Weight Loss & Vitality, we focus on evidence-based, medically supervised therapies.
As of April 21, 2026, regulatory status for many peptides remains under review and may change as additional data and guidance become available.
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