--- title: "Modafinil vs Semax: Side-by-Side Comparison (2026)" url: https://www.bodyhackguide.co/compare/modafinil-vs-semax description: "Compare Modafinil vs Semax side by side. We earn a commission on some vendor links. Mechanism, half-life, dose range, side effects and prices." lang: en --- Skip to content Compare notes on r/BodyHackGuide (https://reddit.com/r/bodyhackguide) Compare notes with other researchers. Join r/BodyHackGuide (https://reddit.com/r/bodyhackguide) # Modafinil vs Semax Side-by-side comparison of Modafinil and Semax: mechanism, half-life, dose range, safety profile, and vendor pricing. Modafinil: no price on file Semax from $32.90 ## Price snapshot ### Modafinil Current low — 7-day low — not enough history yet 30-day low — not enough history yet 30-day change — not enough history yet ### Semax Current low $32.90 current listings 7-day low — not enough history yet 30-day low — not enough history yet 30-day change — not enough history yet ## Modafinil Modafinil is a prescription wakefulness-promoting agent approved by the US Food and Drug Administration in December 1998 under the brand name Provigil (Cephalon, now Teva) for the treatment of excessive daytime… No vendor price on file. Full Modafinil profile (https://www.bodyhackguide.co/compound/modafinil) ## Semax Semax is a synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro, MEHFPGP, 813 Da molecular weight) developed at the Institute of Molecular Genetics of the Russian Academy of Sciences in the 1980s. The compound is derived… **Lowest listed price:** $32.90 across 5 listings Full Semax profile (https://www.bodyhackguide.co/compound/semax) ## Side-by-side comparison | Attribute | Modafinil | Semax | | --- | --- | --- | | Category | Nootropics | Nootropics | | Research Stage | Preclinical | Approved in Russia; registered as a prescription intranasal solution | | Mechanism of Action | Modafinil's mechanism of action is genuinely incompletely understood despite more than two decades of clinical use and extensive preclinical research. It is not a classical stimulant — it does not produce the catecholamine surge of amphetamines, the direct… | Primary Mechanism: Multi-Pathway Neurotrophic Activation Semax produces its effects through coordinated activation of multiple neurotrophic, neurotransmitter, and neuroprotective pathways. Unlike conventional nootropics that target a single system (modafinil… | | Half-Life | — | ~2-3 minutes plasma half-life (functional neurological effects persist 12-24 hours due to BDNF/NGF gene expression changes) | | Typical Dose Range | — | 100-900 mcg intranasal daily (0.1% solution: 2-3 drops per nostril 2-3x daily); 1% solution used for acute stroke in Russian clinical protocols | | Dosing Frequency | — | Intranasal 1–3 times daily | | Administration | — | Intranasal | | Side Effects | Modafinil's side effect profile is relatively favorable compared to classical stimulants but is not negligible. The most common side effects, reported in 5-10% or more of users in clinical trials, are headache (dose-related, typically transient but… | Overall Safety Profile Semax has an excellent safety profile across 20+ years of Russian clinical use. In acute stroke trials, cognitive studies, and pediatric applications, Semax has demonstrated consistent tolerability with minimal adverse event burden. This… | | Molecular Weight | — | 813.9 Da | | Common Vial Sizes | — | 5mg, 10mg | ## Price History 5 data points - OF - Half Nattys - Ion Peptide - BHG Labs ### Modafinil: potential benefits - No structured benefit list published. ### Semax: potential benefits - Rapid BDNF/TrkB upregulation in the hippocampus, supporting synaptic plasticity and learning (PMID: 16996037) - Neuroprotective, immunomodulatory gene-expression changes in focal cerebral ischemia (middle cerebral artery occlusion) models (PMID: 28255762) - Cognitive enhancement including improved attention, working memory, and processing speed - Dopaminergic modulation that may support motivation and executive function (preclinical data) - Stroke recovery facilitation - accelerated functional recovery and improved Barthel Index in ischemic stroke patients; approved in Russia for ischemic stroke (PMID: 29798983) - Anxiolytic and anti-asthenic effects reported in Russian clinical use, attributed to neurotrophic and monoaminergic modulation - Non-addictive cognitive support without tolerance development or withdrawal at standard doses ## Frequently asked ### What's the difference between Modafinil and Semax? Modafinil is a nootropics that modafinil's mechanism of action is genuinely incompletely understood despite more than two decades of clinical use and extensive preclinical research. it is not a classical…. Semax is a nootropics that primary mechanism: multi-pathway neurotrophic activation semax produces its effects through coordinated activation of multiple neurotrophic, neurotransmitter, and neuroprotective…. The two differ in mechanism, half-life (not reported vs ~2-3 minutes plasma half-life (functional neurological effects persist 12-24 hours due to BDNF/NGF gene expression changes)), and typical dose range. ### Which has the longer half-life, Modafinil or Semax? Modafinil has a half-life of not reported. Semax has a half-life of ~2-3 minutes plasma half-life (functional neurological effects persist 12-24 hours due to BDNF/NGF gene expression changes). Longer half-lives generally mean less frequent dosing but slower on/off kinetics. ### Can you stack Modafinil and Semax? Stacking depends on mechanism overlap, safety profile, and goals. Modafinil and Semax should only be stacked after reviewing each compound's individual protocol page, side effect profile, and any published interaction data. Use the BodyHackGuide stack builder for a structured review before combining research compounds. ## See current vendor prices Listings from the vendors we track. Prices change often, so check the vendor before you buy. Modafinil prices: https://www.bodyhackguide.co/compound/modafinil?tab=prices Semax prices: https://www.bodyhackguide.co/compound/semax?tab=prices Compare all compounds: https://www.bodyhackguide.co/compare ### Before you buy Modafinil or Semax Check the vendor trust score. Every supplier we track is rated 0-100 on COA verification, payment transparency, shipping, reviews, and listings: one published, reproducible methodology, applied to every vendor. View Vendor Scorecard (https://www.bodyhackguide.co/vendors/scorecard) ## Related comparisons Selank vs Semax: https://www.bodyhackguide.co/compare/selank-vs-semax Modafinil vs Phenylpiracetam: https://www.bodyhackguide.co/compare/modafinil-vs-phenylpiracetam Bromantane vs Modafinil: https://www.bodyhackguide.co/compare/bromantane-vs-modafinil **Research use only.** BodyHackGuide is a research and price-comparison reference. The compounds discussed on this page are not approved by the FDA for human consumption and are sold strictly for laboratory research. Prices shown are pulled from vendor listings tracked on BHG and are subject to change. Every vendor is ranked on the same public, reproducible methodology. See editorial standards (https://www.bodyhackguide.co/editorial-standards) and affiliate disclosure (https://www.bodyhackguide.co/affiliate-disclosure). 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