Semax vs GB-115
Comprehensive side-by-side comparison of mechanisms, dosing, side effects, and research
Also: SEMAX, Heptapeptide SEMAX
Semax is a synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) developed in Russia in the 1980s as an analog of the ACTH(4-10) fragment, with a Pro-Gly-Pro tail added to resist breakdown. It is researched and used as a neuroprotective and nootropic agent, typically intranasally, and keeps the cognitive and neurotrophic effects of the ACTH fragment without the parent hormone's cortisol-raising activity. It is used clinically and registered in Russia (including for ischemic stroke and cognitive disorders) but is not approved by the FDA or EMA, and Western evidence is limited.
Also: Ranquilon, N-phenylacetyl-L-prolylglycine ethyl ester
GB-115 is a synthetic dipeptide anxiolytic developed in Russia, chemically the amide of N-phenylhexanoyl-glycyl-L-tryptophan and described as a retro-analogue of cholecystokinin-4. Rather than acting like a benzodiazepine, it blocks cholecystokinin receptors, a different anti-anxiety route. It has been studied in animals and in a small pilot human study, but it is not an approved or widely available medication.
Key Comparison Insights
- Both peptides belong to the Cognitive category, suggesting similar primary applications.
Detailed Comparison
| Attribute | Semax | GB-115 |
|---|---|---|
| Category | Cognitive | Cognitive |
| FDA Status | Not FDA Approved | Not FDA Approved |
| Clinical Status | Pre I II III IV FDA | Pre I II III IV FDA |
| Mechanism of Action | Semax is derived from ACTH(4-10) but, unlike ACTH, does not stimulate the adrenal or cortisol axis; its main documented action is upregulating brain-derived neurotrophic factor (BDNF) and its receptor TrkB, especially in the hippocampus. In rats, a single dose increases BDNF protein and mRNA and raises TrkB phosphorylation, activating growth and survival pathways (such as MAPK/ERK and PI3K/Akt) that support neuron health and plasticity. It also modulates dopamine and serotonin signaling and influences genes tied to the immune and vascular response after brain ischemia. The combined effect in animal models is neuroprotection against insults like reduced blood flow and oxidative stress, plus enhanced learning and memory. The Pro-Gly-Pro extension makes it more stable than the bare ACTH(4-10) sequence, which is partly why it stays active intranasally. | Cholecystokinin (CCK) is a peptide that acts as a neurotransmitter in the brain, and activating its CCK-2 (also called CCK-B) and CCK-1 receptors tends to trigger anxiety and panic-like states. GB-115 works as an antagonist at these cholecystokinin receptors, meaning it occupies the receptor and blocks CCK from setting off that anxiety signaling. In animal work it specifically prevented anxiety provoked by CCK-4, which shares a pharmacological target with GB-115. This CCK-blocking mechanism is the proposed explanation for its calming effect, and it is distinct from the GABA system that classic sedatives act on. |
| Common Dosing | 200-600 mcg intranasal daily 1-3x daily, intranasal | 6 mg daily (2 mg three times daily) 2-3 times daily (morning, afternoon, evening) |
| Administration | Intranasal spray (most common) | Oral tablets or sublingual |
| Typical Duration | 10-30 days typical | 21+ days in clinical trials, effects noted by day 7 |
| Best Time to Take | Morning or early afternoon | Morning and throughout the day |
Possible Side Effects May vary by individual |
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| Research Summary | The mechanistic core is well documented preclinically: Dolotov et al. (2006, Brain Research) showed a single intranasal Semax dose raised hippocampal BDNF protein, TrkB phosphorylation, and BDNF and TrkB mRNA in rats, alongside improved learned behavior. Additional rat work shows neuroprotection and changes in immune- and vascular-related gene expression after experimental stroke. Human clinical use is real but the published trials are mostly Russian-language, small, and frequently non-randomized or open-label: studies in acute ischemic-stroke patients reported faster recovery of neurological function, and a 2018 study reported increased plasma BDNF with improvements on disability and motor scales. These results are promising but methodologically weaker than Western regulatory-grade trials and have not been replicated in large independent Western studies. Honest summary: solid animal mechanistic data and decades of Russian clinical use, but the human cognitive and stroke claims rest on small, mostly non-randomized studies and are not validated by FDA or EMA-grade trials. | The research record is real but thin and almost entirely from a single Russian group. In rodent studies (rats, BALB/c and C57Bl/6 mice), GB-115 reduced anxiety induced by CCK-4 and by yohimbine, with effects that varied by mouse strain, and it stayed effective after long-term dosing without producing tolerance or a withdrawal syndrome when stopped. Preclinical safety work has also been published. The only human data comes from a small pilot clinical study of 25 patients with generalized anxiety disorder given 6 mg daily for 21 days, where anxiety scores on the Hamilton scale fell substantially and fatigue scores improved. Importantly, that study was a single-arm pilot with no placebo or control group, so it cannot prove the drug caused the improvement. There are no large randomized controlled trials, no Western regulatory approval, and the evidence base remains preliminary. |
Frequently Asked Questions: Semax vs GB-115
What is the difference between Semax and GB-115?
Semax is a cognitive peptide that semax is a synthetic heptapeptide (met-glu-his-phe-pro-gly-pro) developed in russia in the 1980s as an analog of the acth(4-10) fragment, with a pro-gly-pro tail added to resist breakdown. it is researched and used as a neuroprotective and nootropic agent, typically intranasally, and keeps the cognitive and neurotrophic effects of the acth fragment without the parent hormone's cortisol-raising activity. it is used clinically and registered in russia (including for ischemic stroke and cognitive disorders) but is not approved by the fda or ema, and western evidence is limited. GB-115 is a cognitive peptide that gb-115 is a synthetic dipeptide anxiolytic developed in russia, chemically the amide of n-phenylhexanoyl-glycyl-l-tryptophan and described as a retro-analogue of cholecystokinin-4. rather than acting like a benzodiazepine, it blocks cholecystokinin receptors, a different anti-anxiety route. it has been studied in animals and in a small pilot human study, but it is not an approved or widely available medication. The main differences lie in their mechanisms of action and clinical applications.
Which is better, Semax or GB-115?
Neither is universally "better" - the choice depends on your specific goals. Semax is typically used for cognitive purposes, while GB-115 is used for cognitive. Always consult with a healthcare provider to determine which may be appropriate for your situation.
Can Semax and GB-115 be used together?
Some peptide protocols combine multiple compounds for synergistic effects. However, using Semax and GB-115 together should only be considered under medical supervision, as both compounds have their own side effect profiles and potential interactions. Research on their combined use may be limited.