Semax

Semax is a neuropeptide and synthetic analog of adrenocorticotropin (ACTH 4-10) with established therapeutic applications in neuroprotection and cognitive enhancement¹. Primary clinical uses include treatment of acute ischemic stroke, where it has demonstrated improved neurological recovery and restoration of motor function when added to standard care¹,², and management of cerebrovascular insufficiency, where it reduces overall brain damage and may lower risk of subsequent stroke events³. The peptide functions through multiple mechanisms: modulation of dopaminergic and serotonergic neurotransmitter systems⁴, stimulation of brain-derived neurotrophic factor (BDNF) expression to promote neurogenesis and synaptic plasticity¹,⁴, and reduction of neuroinflammatory processes via suppression of pro-inflammatory cytokines⁴. Secondary indications supported by clinical or preclinical evidence include anxiety and depressive disorders through BDNF-mediated pathways¹, attention-deficit/hyperactivity disorder (ADHD) owing to its dopaminergic effects and neurodevelopmental impact⁵, and neuroprotection in neurodegenerative conditions such as Alzheimer's disease where BDNF depletion is implicated in disease progression¹. Semax is administered via intranasal application and has been associated with favorable tolerability in clinical trials³.

Semax is generally well-tolerated, with clinical trials employing intranasal administration often reporting no side effects at all, though long-term safety data remain limited⁶,⁷. The most commonly reported side effects are mild and transient, including nasal irritation (such as dryness, tingling, or burning sensations), headaches, and occasionally nausea or dizziness, which typically resolve with continued use or dosage adjustment⁸,⁹. Less common but potential side effects include increased anxiety or restlessness due to the peptide's stimulatory effects on the central nervous system, sleep disturbances if used close to bedtime, temporary increases in blood pressure (particularly concerning for those with hypertension), and rare digestive discomfort⁹,¹⁰. According to clinical data, discoloration of the nasal cavity has been reported in approximately 10% of patients, and blood glucose increases in around 7.4% of diabetic patients². Key safety considerations include starting with a low dose to assess individual tolerance, maintaining proper hydration to mitigate headaches, avoiding use near bedtime to prevent insomnia, and consulting a healthcare professional before use—particularly for elderly individuals (over 65), those with hypertension, diabetics, or anyone considering using Semax alongside other medications⁶,⁸,¹⁰.

Semax, a synthetic heptapeptide analog of adrenocorticotropic hormone (ACTH 4-10), has a complex and not fully elucidated mechanism of action.⁴,¹¹ It rapidly elevates brain-derived neurotrophic factor (BDNF) levels and its receptor TrkB expression in the hippocampus, promoting neurogenesis, synaptic plasticity, and neuroprotection, with specific binding sites identified in the rat basal forebrain.²,¹¹,¹² Semax modulates dopaminergic and serotonergic systems by enhancing neurotransmitter release and turnover, contributing to improved mood, cognition, and anxiolytic effects.⁴,¹¹,¹³ It may also interact with melanocortin receptors such as MC4 and MC5 as an antagonist or partial agonist, inhibit enkephalinase, exert anti-inflammatory and antioxidant effects, and regulate genes involved in immune response and neuronal survival.⁴,¹¹,¹⁴