--- title: "Phenibut vs Semax: Side-by-Side Comparison (2026)" url: https://www.bodyhackguide.co/compare/phenibut-vs-semax description: "Compare Phenibut vs Semax side by side. We earn a commission on some vendor links. Mechanism, half-life, dose range, side effects and prices. Semax from $32.90." 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) # Phenibut vs Semax Side-by-side comparison of Phenibut and Semax: mechanism, half-life, dose range, safety profile, and vendor pricing. Phenibut from $49.99 Semax from $32.90 ## Price snapshot ### Phenibut Current low $49.99 current listings 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 ## Phenibut Phenibut is the common Western name for β-phenyl-γ-aminobutyric acid (beta-phenyl-GABA; Russian trade names Phenibut/Фенибут, Noofen, Anvifen), a Soviet-era anxiolytic and nootropic developed in the 1960s at the Herzen… **Lowest listed price:** $49.99 across 1 listing Full Phenibut profile (https://www.bodyhackguide.co/compound/phenibut) ## 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 | Phenibut | Semax | | --- | --- | --- | | Category | Nootropics | Nootropics | | Research Stage | Prescription Medicine (Russia/CIS) / Unregulated Elsewhere | Approved (Russia, since mid-1990s for stroke and cognitive disorders) | | Mechanism of Action | Phenibut's pharmacology is dominated by activity at the GABA-B receptor, with secondary effects at GABA-A receptors and voltage-gated calcium channels. Understanding these three components is essential to understanding both its therapeutic effects and its… | 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 | 5-8 hours (plasma); central CNS effect 10-16 hours | ~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 | Oral | Intranasal | | Side Effects | Phenibut's side effects fall into three categories: acute-dose effects (largely dose-dependent sedation and impairment), withdrawal effects (physiologically similar to benzodiazepine/alcohol withdrawal), and interactions with other CNS depressants (additive… | 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 | 179.22 g/mol (free base); 215.68 g/mol (HCl salt) | 813.9 Da | | Common Vial Sizes | — | 5mg, 10mg | ## Price tracking Tracking Phenibut prices since September 5, 2026. Trend chart unlocks once we have price snapshots from more than one day. ## Price History 5 data points - OF - Half Nattys - Ion Peptide - BHG Labs ### Phenibut: 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 Phenibut and Semax? Phenibut is a nootropics that phenibut's pharmacology is dominated by activity at the gaba-b receptor, with secondary effects at gaba-a receptors and voltage-gated calcium channels. understanding these three…. 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 (5-8 hours (plasma); central CNS effect 10-16 hours 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, Phenibut or Semax? Phenibut has a half-life of 5-8 hours (plasma); central CNS effect 10-16 hours. 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. ### Which is cheaper, Phenibut or Semax? Lowest listed price on BodyHackGuide: Phenibut from $49.99, Semax from $32.90. Prices are pulled from the vendor listings tracked on BHG and change frequently. See the compare tables on each compound page for the current set of offers. ### Can you stack Phenibut and Semax? Stacking depends on mechanism overlap, safety profile, and goals. Phenibut 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. Phenibut prices: https://www.bodyhackguide.co/compound/phenibut?tab=prices Semax prices: https://www.bodyhackguide.co/compound/semax?tab=prices Compare all compounds: https://www.bodyhackguide.co/compare ### Before you buy Phenibut 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 Selank vs Phenibut: https://www.bodyhackguide.co/compare/selank-vs-phenibut **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). BodyHackGuide (https://www.bodyhackguide.co/) Your biohacking research hub: compound pricing, brain health protocols, dosing tools, and vendor reviews. support@bodyhackguide.co Join our Discord: https://discord.gg/Mhq5UdRYBA r/BodyHackGuide on Reddit: https://reddit.com/r/BodyHackGuide **Affiliate Disclosure:** We rank every vendor on the same public, reproducible methodology (https://www.bodyhackguide.co/vendors/methodology). Full details in our affiliate disclosure (https://www.bodyhackguide.co/affiliate-disclosure). **Research Disclaimer:** All compounds listed are for laboratory and research purposes only. Not for human consumption. This site does not sell or ship any products. Always consult a qualified healthcare professional and comply with local regulations. © 2026 BodyHackGuide. All rights reserved. - Terms: https://www.bodyhackguide.co/terms - Privacy: https://www.bodyhackguide.co/privacy ## Structured data ```json [ { "@context": "https://schema.org", "@type": "BreadcrumbList", "itemListElement": [ { "@type": "ListItem", "position": 1, "name": "Home", "item": "https://www.bodyhackguide.co/" }, { "@type": "ListItem", "position": 2, "name": "Compare", "item": "https://www.bodyhackguide.co/compare" }, { "@type": "ListItem", "position": 3, "name": "Phenibut vs Semax" } ] }, { "@context": "https://schema.org", "@type": "WebPage", "name": "Phenibut vs Semax: Side-by-Side Comparison (2026)", "description": "Compare Phenibut vs Semax side by side. We earn a commission on some vendor links. Mechanism, half-life, dose range, side effects and prices. 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