What semax is
Semax is a synthetic peptide of seven amino acids, Met-Glu-His-Phe-Pro-Gly-Pro. FDA's review gives its formula as C37H51N9O10S and its molecular weight as 813.93 g/mol, and describes the free base as a white lyophilized powder.
Where it stands with the FDA
Semax isn't approved by the FDA, and the agency says it isn't a component of any FDA-approved drug. It reached the FDA because pharmacies nominated it for compounding. Those nominations were later withdrawn, and FDA reviewed it on its own initiative.
That review looked at three uses: cerebral ischemia, migraine and trigeminal neuralgia. It concluded that the criteria weigh against putting semax on the list of substances pharmacies may compound with. The reasons it gives include gaps in how the substance is characterized and concern about immune reactions to it in an injection or a nasal spray.
FDA took the question to its Pharmacy Compounding Advisory Committee on July 24, 2026. Its meeting page had no minutes posted as of October 2026, so this page doesn't report a vote.
The strength in the record
The products described in the nominations were a nasal spray or an injection under the skin, at 1,000 mcg/mL or 7,500 mcg/mL.
| Strength in the record | Water for a 5 mg vial | One unit holds | 10 units hold |
|---|---|---|---|
| 1,000 mcg/mL | 5 mL | 10 mcg | 100 mcg |
| 7,500 mcg/mL | 0.6667 mL | 75 mcg | 750 mcg |
Add that much water to a 5 mg vial and it comes to that strength. Any other amount of water works too. It only changes how many units the same dose takes up.
Storing semax
FDA's review says semax free base is expected to be stable stored below -20°C. It also says that how stable a peptide stays depends heavily on how the finished product was made.
There's no approved label for semax, so nothing official says how long a mixed vial keeps.
Semax dosage calculator questions
How do I turn a semax dose into syringe units?
Divide the dose by the concentration to get millilitres, then multiply by 100. A 5 mg vial mixed with 5 mL is 1 mg/mL, so one unit on an insulin syringe holds 10 mcg and ten units hold 100 mcg.
How much bacteriostatic water goes in a 5 mg vial of semax?
There's no single right amount. The water only sets the concentration, and the amount of semax in the vial stays the same. With 5 mg, 1 mL makes 5 mg/mL, 2 mL makes 2.5 mg/mL and 3 mL makes 1.667 mg/mL. Choose the amount that puts your dose somewhere between about 10 and 40 units, where it's easiest to read.
Is semax approved by the FDA?
No. FDA says semax isn't a component of any FDA-approved drug. It reviewed semax for use in compounded drugs and concluded the criteria weigh against it, then took it to an advisory committee on July 24, 2026.
Does this page tell me how much semax to take?
No. There's no FDA-approved semax product, so there's no approved dose to point to. The dose box starts empty for that reason, and the chart only converts.
More peptide calculators by name
The same instrument, set up one peptide at a time. For any other vial, use the peptide reconstitution calculator.