Semax: Reference Overview and Reconstitution Notes

Semax is a man-made chain of seven amino acids (the building blocks of proteins). It comes from a small piece of a natural hormone called ACTH. Researchers study it for possible effects on the brain and nervous system. In the United States, it is for research use only and is not approved by the FDA.

Semax

What it is

Semax is a synthetic heptapeptide (a man-made chain of exactly seven amino acids, the building blocks of proteins). It is based on a small section of a natural hormone called adrenocorticotropic hormone (ACTH). Scientists added a short extra piece to one end of the molecule to help it last longer before enzymes (proteins that break molecules down) can destroy it. Semax was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences. It belongs to a family of short protein fragments that researchers study for their effects on the nervous system.

Research context and categorization

Semax falls into the cognitive and neuroprotective (nootropic) research category. "Cognitive" refers to thinking and memory. "Neuroprotective" means possibly helping to shield brain cells from damage. In lab settings, researchers look at how Semax affects signaling in the nervous system. Animal model studies have examined its possible influence on two proteins that help brain cells grow and survive. These proteins are brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF). Think of BDNF and NGF like fertilizer for brain cells. Semax is also studied in models of cerebral ischemia (reduced blood flow to the brain), cell survival, attention, and memory-related outcomes.

All of these uses are investigational, meaning they are still being studied and are not proven. In the United States, Semax is not FDA-approved. The brain-protective, cognitive, or mood-related effects described in research papers are not confirmed or approved outcomes. Russia and some neighboring countries have registered Semax as a prescription drug for conditions like ischemic stroke and cognitive decline. That foreign approval does not mean these uses are proven or approved anywhere else.

Key point: Semax is not FDA-approved in the United States and remains restricted to research use only, even though it is a registered prescription drug in Russia.

Status

• Regulatory status: Research use only in the United States. Not FDA-approved. It has no U.S. drug approval or official U.S. drug standards listing, though it is approved and prescribed as a medication in Russia for certain conditions.
• Sport status: Semax is not listed by name on the WADA Prohibited List. However, as a non-approved substance it may fall under the S0 catch-all category (a rule that covers any drug not addressed elsewhere on the list and not currently approved by any government health authority for human therapeutic use). This category is banned at all times. Athletes should check the current status with their governing body, since classifications can change.

Reconstitution notes (general)

Semax typically comes as a lyophilized (freeze-dried) powder. Before lab use, researchers mix it with bacteriostatic water (sterile water with a small amount of preservative added to slow microbial growth). This mixing process is called reconstitution. The math is simple: divide the milligrams of peptide by the milliliters of water added to get the concentration. For example, 5 mg in 5 mL gives 1 mg/mL. You can work out any combination with the calculator at peptide calculator.

Dilution and handling notes (compound-specific)

Solubility and Ratios

Semax is a short, highly water-soluble peptide, meaning it dissolves easily in water. It forms a clear, colorless solution. You will not see the gelling or cloudiness that can happen with larger or more water-repelling peptides. A common reference range is 1 mL to 5 mL of bacteriostatic water per 5 mg vial, giving concentrations from roughly 5 mg/mL down to 1 mg/mL.

Using less water creates a more concentrated solution with a smaller volume to measure. Using more water makes small measurements easier to read on a syringe. You pick the water amount for measuring convenience, not because dissolving is a problem.

Reconstitution Best Practices

Follow these steps when working with short peptides like Semax at the bench:

• Add the water slowly down the inside wall of the vial instead of aiming it directly at the powder.
• Swirl gently instead of shaking. High-speed streams and vigorous shaking cause foaming and stress on the molecule, which can make the peptide clump together or break down.
• If the powder does not fully dissolve right away, let the vial sit and swirl it again gently rather than forcing it.
• If a properly mixed solution ever looks cloudy or has floating particles, discard it. This is a sign of a problem, not normal behavior.

Note that Semax also comes as a ready-to-use liquid (for intranasal research applications). That form is already in solution and does not require reconstitution.

Handling and storage

Store the reconstituted solution in a refrigerator at 2 to 8 degrees Celsius (standard fridge temperature) and keep it away from light. Wipe the rubber stopper with an alcohol swab before drawing from the vial, and label the vial with the date you mixed it.

A reconstituted, refrigerated solution is commonly referenced with an approximate 4-week window. Discard the vial if the contents become cloudy, change color, or show visible floating particles.

Related reading

• Sermorelin
• SLU-PP-332
• SNAP-8 (Acetyl Octapeptide-3)
• How Reconstitution Works
• How Long Does a Reconstituted Vial Last?

Tools and supplies

• peptide calculator
• Bacteriostatic Water 30 ml
• Gansulin Metal Reusable Pen
• 3 ml Glass Cartridges (10-pack)
• Complete Starter Kit

Reminder: research and educational reference only. Preppin Peppers sells hardware and materials, not peptides. Not medical, dosing, or health advice, not evaluated by the FDA, and not intended for human or animal use.

Frequently asked questions

What is Semax and how is it classified for research?

Semax is a synthetic seven-amino-acid peptide derived from ACTH, studied in animal models for effects on BDNF, NGF, cerebral ischemia, and cognitive outcomes. It is not FDA-approved; U.S. use is restricted to research only.

How do researchers reconstitute lyophilized Semax powder?

Add a measured volume of bacteriostatic water to the lyophilized powder vial. Divide the milligrams of peptide by milliliters of water added to obtain concentration in mg/mL (e.g., 5 mg ÷ 5 mL = 1 mg/mL).

Is Semax banned in competitive sport or approved as a drug anywhere?

Semax is not named on the WADA Prohibited List but may fall under the S0 catch-all category for non-approved substances. It is a registered prescription drug in Russia; that approval does not extend to the U.S. or other jurisdictions.

What the research community gets wrong about Semax

• Assuming a foreign approval makes it a proven or approved compound. Semax is a registered prescription drug in Russia, but that does not carry over. In the United States it is research use only, has no FDA approval, and has no official U.S. drug standards listing. The registration abroad says nothing about proof or approval at your bench.
• Treating high water solubility as a reason to shake the vial. Semax dissolves easily, so people assume vigorous shaking speeds things up. Fast streams, shaking, and foaming create air and liquid interfaces and shear that can stress short peptides and push them to clump (aggregate). Add the water down the vial wall and swirl gently instead.
• Confusing the ready-to-use liquid with the lyophilized powder. Semax is sold both as a freeze-dried powder and as a liquid form used in intranasal research. The liquid is already in solution and needs no reconstitution. Only the powder is reconstituted with bacteriostatic water, so check which form is in front of you before adding anything.
• Thinking a small peptide is stable enough to leave out. A reconstituted solution is not shelf stable at room temperature. Keep it refrigerated at 2 to 8 degrees Celsius, away from light, and discard it if it turns cloudy, changes color, or shows floating particles.
• Calling it ACTH or the same as the ACTH(4-10) analog. Semax is a synthetic seven amino acid fragment (ACTH 4-7) with an added Pro-Gly-Pro tail (PubChem CID 9811102, formula C37H51N9O10S). It is not the full hormone. The extra tail is there to slow enzyme breakdown of the molecule, not to do anything to the person handling the vial.

From our bench: If you reconstitute a lyophilized Semax vial, we would like your real observation on how the powder goes into solution. Time how many seconds of gentle swirling it takes to reach a clear, colorless solution with no visible particles, note the vial size (mg) and the volume of bacteriostatic water you added, and tell us whether any faint foam formed at the surface. Share your actual numbers, not an estimate, so other researchers can compare handling notes.

Sources

1. Bacteriostatic Water for Injection, USP , FDA/DailyMed label (0.9% benzyl alcohol)
2. Duerkop et al., Biotechnol J 2018 , Impact of Cavitation, High Shear Stress and Air/Liquid Interfaces on Protein Aggregation
3. Sigma-Aldrich (Merck) , Handling and Storage Guidelines for Peptides and Proteins
4. PubChem, Semax compound record (CID 9811102, ACTH(4-7)-Pro-Gly-Pro, C37H51N9O10S)