Semax is a synthetic heptapeptide derived from the ACTH(4–7) sequence and extended with Pro-Gly-Pro. It has been investigated in neurological and neuroprotective research, including human studies, but it is not a component of an FDA-approved drug in the United States.
Because authoritative sources reviewed do not establish a universal Semax vial size or standardized BAC-water reconstitution protocol, the examples below are mathematical concentration examples only.
They are not manufacturer instructions, FDA-approved dosing, clinical dosing recommendations, or BacScience treatment advice.
| Illustrative Vial Quantity | 1 mL | 2 mL | 2.5 mL | 3 mL | 5 mL |
|---|---|---|---|---|---|
| 5 mg | 5 mg/mL | 2.5 mg/mL | 2 mg/mL | 1.67 mg/mL | 1 mg/mL |
| 10 mg | 10 mg/mL | 5 mg/mL | 4 mg/mL | 3.33 mg/mL | 2 mg/mL |
There is no single scientifically established answer such as “add exactly X mL” for all Semax products. A reconstitution volume should not be inferred from the name of the compound alone because concentration depends on the actual amount of Semax present and the final liquid volume.
Mathematically, 1 mL would produce 5 mg/mL, 2 mL would produce 2.5 mg/mL, 2.5 mL would produce 2 mg/mL, 3 mL would produce approximately 1.67 mg/mL, and 5 mL would produce 1 mg/mL.
These are concentration calculations, not instructions to use a particular volume.
Mathematically, 1 mL would produce 10 mg/mL, 2 mL would produce 5 mg/mL, 2.5 mL would produce 4 mg/mL, 3 mL would produce approximately 3.33 mg/mL, and 5 mL would produce 2 mg/mL.
These examples do not establish a preferred Semax concentration.
Increasing liquid volume decreases concentration. Decreasing liquid volume increases concentration, assuming the total amount of Semax remains unchanged.
Divide the total peptide quantity by the liquid volume. Keep the units consistent.
Semax is a synthetic heptapeptide commonly represented by the sequence Met-Glu-His-Phe-Pro-Gly-Pro. FDA substance records identify Semax with the molecular formula C37H51N9O10S and a molecular weight of approximately 813.92 g/mol.
Semax is structurally related to the N-terminal ACTH fragment ACTH(4–7) and includes a C-terminal Pro-Gly-Pro sequence. Scientific literature has investigated Semax in neuroscience, including cognition, neurotrophic signaling and ischemic brain research.
FDA's 2026 evaluation states that Semax free base and Semax acetate have no applicable USP/NF drug-substance monograph and that neither is a component of an FDA-approved drug.
The precise molecular mechanism of Semax is not fully established. Experimental research has investigated interactions with neurotrophic signaling and changes in expression of factors including BDNF and NGF.
In rat studies, intranasal Semax was associated with changes in BDNF protein and related signaling in brain regions involved in learning and memory. Other experimental studies reported changes in neurotrophin gene expression after Semax administration.
Synthetic ACTH-derived heptapeptide.
Experimental studies have examined neurotrophin-related signaling.
Published clinical studies exist, particularly in Russian medical literature.
Semax has been investigated in several neurological contexts. Published human studies include ischemic stroke, motor-neuron disease, cerebrovascular disorders and other neurological conditions.
Experimental literature has additionally examined cognition, neurotrophic signaling, hypoxia-related effects, inflammatory pathways and neuroprotection.
Human studies of Semax have been published, including controlled and comparative clinical research. However, the evidence base is not equivalent to an FDA-approved clinical indication in the United States.
For example, a 1997 clinical study examined Semax as part of treatment in patients with acute hemispheric ischemic stroke and reported study regimens of 12 mg/day or 18 mg/day over 5–10 days depending on stroke severity. :contentReference[oaicite:2]{index=2}
A later study involving 110 patients undergoing post-stroke rehabilitation reported a Semax regimen of 6,000 micrograms/day in two 10-day courses separated by 20 days. :contentReference[oaicite:3]{index=3}
These published regimens are historical research data. They are not universal dosing instructions and cannot be used to determine a reconstitution volume for an unspecified Semax vial.
| Study | Population | Dose Studied | Route | Frequency | Duration | Key Finding |
|---|---|---|---|---|---|---|
| Gusev et al., 1997 | 30 patients with acute hemispheric ischemic stroke | 12 mg/day or 18 mg/day | Intranasal | Daily | 5–10 days | Reported neurological recovery effects in the study population. |
| Serdiuk et al., 2007 | 27 patients with motor-neuron disease | 1% Semax solution; 12 mg/day | Intranasal | Daily | Two 10-day courses with a 2-week break | Quality-of-life measures improved, while the study did not show an effect on the course of chronic partial denervation. |
| Gusev et al., 2018 | 110 patients after ischemic stroke | 6,000 mcg/day | Intranasal | Daily | Two 10-day courses | The study reported increased plasma BDNF and improved rehabilitation-related outcomes. |
| Human research summarized in earlier Semax literature | Healthy men / neurological research populations | Approximately 0.015–0.050 mg/kg reported in historical literature | Intranasal | Study-dependent | Study-dependent | Historical reports investigated attention, memory and neurophysiological effects. |
Study-specific formulation, concentration, route and population matter. A published dose is not equivalent to a validated modern product specification or universal Semax reconstitution instruction.
Semax has also been investigated extensively in animal and cellular models. These studies provide mechanistic hypotheses but should not be interpreted as evidence of an established human therapeutic effect.
Rat studies reported increases in BDNF protein and changes in BDNF-related signaling following intranasal Semax administration.
Experimental research reported changes in NGF and BDNF gene expression in rat brain regions following Semax exposure.
Animal studies have examined Semax after experimentally induced cerebral ischemia and investigated neuroprotective and neurotrophic mechanisms.
In-vitro research has examined Semax-associated changes in neurotrophin gene expression in cultured neural/glial cells.
Reconstitution mathematics is separate from clinical dosing. If a research vial contains a known mass of Semax, the resulting concentration depends on the volume of liquid added.
| Liquid Volume | Calculation | Resulting Concentration |
|---|---|---|
| 1 mL | 5 mg ÷ 1 mL | 5 mg/mL |
| 2 mL | 5 mg ÷ 2 mL | 2.5 mg/mL |
| 2.5 mL | 5 mg ÷ 2.5 mL | 2 mg/mL |
| 3 mL | 5 mg ÷ 3 mL | 1.67 mg/mL |
| 5 mL | 5 mg ÷ 5 mL | 1 mg/mL |
| Liquid Volume | Calculation | Resulting Concentration |
|---|---|---|
| 1 mL | 10 mg ÷ 1 mL | 10 mg/mL |
| 2 mL | 10 mg ÷ 2 mL | 5 mg/mL |
| 2.5 mL | 10 mg ÷ 2.5 mL | 4 mg/mL |
| 3 mL | 10 mg ÷ 3 mL | 3.33 mg/mL |
| 5 mL | 10 mg ÷ 5 mL | 2 mg/mL |
BAC-water volume and peptide quantity describe two different variables. If the vial contains 5 mg of Semax, that vial still represents 5 mg of total peptide after dilution; changing the liquid volume changes the concentration expressed as mg/mL.
For the same vial quantity, increasing the liquid volume decreases the concentration.
Example:5 mg ÷ 5 mL = 1 mg/mL
For the same vial quantity, decreasing the liquid volume increases the concentration.
Example:5 mg ÷ 1 mL = 5 mg/mL
A concentration such as mg/mL describes how much compound exists per unit volume. A dose describes how much compound is administered in a particular experimental or clinical context.
The presence of a BAC-water calculation does not establish that BAC water is the appropriate diluent for every Semax formulation. Product-specific documentation and validated research procedures control that question.
Semax should not be described as an FDA-approved drug in the United States. FDA's July 2026 Pharmacy Compounding Advisory Committee materials state that Semax free base and Semax acetate have no applicable USP/NF drug-substance monograph and neither is a component of an FDA-approved drug.
FDA proposed that Semax free base and Semax acetate not be placed on the 503A Bulks List. The FDA evaluation cited concerns involving physicochemical characterization, selection and qualification of intranasal spray containers/pumps, historical compounding data, safety characterization, potential immunogenicity and insufficient evidence of effectiveness for the uses evaluated.
The July 24, 2026 PCAC meeting materials identify cerebral ischemia, migraine and trigeminal neuralgia as the uses FDA evaluated for Semax-related bulk substances.
Advisory committee recommendations are not themselves FDA approval decisions. Regulatory status should therefore be checked against the current FDA record before publication or commercial use of this page.
Published Semax literature includes different formulations, concentrations, routes, populations and study designs.
Semax free base and Semax acetate should not automatically be treated as interchangeable chemical forms for research calculations.
The existence of human studies does not establish an FDA-approved indication, standardized dosage or universal reconstitution protocol.
Identity, purity, peptide-related impurities, formulation, sterility and analytical characterization are separate questions from concentration mathematics.
| Concept | What It Means | Is It the Same as Reconstitution? |
|---|---|---|
| Mathematical concentration | Total peptide quantity divided by liquid volume. | No |
| Clinical dose studied | Amount used in a specific human study. | No |
| FDA-approved dosage | Dosing supported by an FDA-approved drug product/label. | No |
| Experimental research dose | A dose investigated under a defined experimental protocol. | No |
| Community protocol | User-generated or anecdotal practice. | No |
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Regulatory claims were prioritized from FDA materials. Scientific claims were prioritized from PubMed-indexed peer-reviewed literature. Vendor pages, forums, Reddit discussions and affiliate sources were not used as evidence for scientific or regulatory claims.