Semax (10 mg)

At a Glance

Semax (MEHFPGP) is a synthetic ACTH(4-7)-PGP heptapeptide studied for BDNF induction, neuroprotection, and cognitive effects. The PGP C-terminal tail degrades to an independently active metabolite that extends the neurotrophic signal after proteolysis.[1]

• Reconstitute: Add 2.0 mL bacteriostatic water → 5 mg/mL (5,000 mcg/mL) concentration.
• Starting dose: 250 mcg once daily (5 units / 0.05 mL) subcutaneous for the first week.
• Easy measuring: At 5 mg/mL on a U-100 syringe, 1 unit = 0.01 mL = 50 mcg.
• Doses per vial: 20 doses at the 500 mcg maintenance level; use within 30 days of reconstitution.
• Storage: Lyophilised: freeze at −20 °C; reconstituted: refrigerate at 2–8 °C; use within 30 days.

Overview

• Goal: Induce BDNF expression and activate TrkB/MAPK cascades; modulate striatal monoamines; inhibit enkephalin-degrading enzymes; support neuroprotective signaling.[1]
• Schedule: Once-daily subcutaneous injection; intranasal administration is the primary route in most published efficacy studies.[1]
• Dose range: 250 mcg (initiation) → 500 mcg (maintenance).
• Reconstitution: 2.0 mL BAC water per 10 mg vial → 5 mg/mL.
• Storage: Lyophilised at −20 °C; reconstituted at 2–8 °C; use within 30 days.

What You'll Need

Plan based on an 8-week course titrated from 250 mcg to 500 mcg once daily (total ≈ 26,250 mcg / 26.3 mg).

• Semax Vials (10 mg each): 26.3 mg cumulative → 3 vials (with buffer).
• Insulin Syringes (U-100, 1 mL): 1 per injection → 56 syringes for the 8-week course.
• Bacteriostatic Water (10 mL bottles): 2.0 mL per vial → 1 × 10 mL bottle covers all three vials.
• Alcohol Swabs: 2 per injection → 112 swabs for the course.

How to Reconstitute

1. Allow frozen lyophilised vial to reach room temperature (10–15 minutes).
2. Draw 2.0 mL bacteriostatic water with a sterile syringe.
3. Inject slowly down the inner vial wall; do not inject directly onto the powder cake.
4. Gently swirl or roll until fully dissolved — do not shake. Solution should be clear and colourless.
5. Label with reconstitution date; refrigerate at 2–8 °C. Use within 30 days.

Dosing Schedule

Frequency: Inject once daily subcutaneously. The first week at 250 mcg establishes tolerability before advancing to the 500 mcg maintenance dose. At 500 mcg/day, a 10 mg vial (5 mg/mL, 2.0 mL total) yields 20 doses. Doses are calculated at 50 mcg per unit for convenient measurement on a standard U-100 insulin syringe.[1]

Protocol Details

• Week 1: 250 mcg (5 units / 0.05 mL) once daily — initiation and tolerability.
• Weeks 2–8: 500 mcg (10 units / 0.10 mL) once daily — maintenance.[1]
• Injection site: Abdomen, thigh, or upper arm. Rotate sites between injections.

Storage

• Lyophilised: Store at −20 °C (−4 °F) or below; protect from moisture and light.
• Reconstituted: Refrigerate at 2–8 °C. Do not freeze. Use within 30 days.
• Appearance: Clear and colourless. Discard if cloudy, coloured, or particulate.

How Semax Works

Semax is a synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro, MEHFPGP) built on ACTH residues 4-7 with a synthetic Pro-Gly-Pro C-terminal extension that replaces native ACTH residues 8-10. The PGP tail substantially extends metabolic stability and is itself biologically active: it degrades to the tripeptide Pro-Gly-Pro, which independently activates neurotrophic gene expression in cortical tissue.[1] Dolotov et al. (2006) showed Semax binds basal forebrain membranes with KD ~2.4 nM and induces BDNF mRNA and protein, activating TrkB and downstream MAPK/PI3K cascades — through a binding site distinct from classical melanocortin receptors (MC1R-MC5R), which remain an uncharacterized target.[1] Semax also inhibits enkephalin-degrading enzymes (IC₅₀ ~10 µM) and modulates striatal monoamines (serotonin turnover, dopamine potentiation).[2] For the full mechanism, evidence base, and safety profile, see What Is Semax?.

Good to Know

• Semax CAS: 80714-61-0; Molecular Weight: ~813.93 g/mol; Formula: C₃₇H₅₁N₉O₁₀S. Do not use CAS 4037-01-8, which is native ACTH(4-10), a different peptide.
• Most published efficacy studies use intranasal delivery. SC is used for research protocols requiring bioavailability control; the PGP metabolite is still produced after SC administration.[1]
• Russian pharmaceutical registration covers ischemic stroke and optic nerve disease. Human data originate entirely from Russian clinical literature; no Western RCTs have been published.
• The PGP degradation product independently activates neurotrophic genes, so total effect reflects both the intact Semax molecule and its metabolite.[1]
• Semax inhibits enkephalinases at IC₅₀ ~10 µM, somewhat more potent than Selank (~20 µM) in the same assay.[2]
• Semax shows a stronger dopaminergic signal than Selank, which is predominantly serotonergic — the basis for theoretical complementarity in combined research protocols. No published co-administration study exists.
• Mild injection site reactions are the predominant reported side effect.
• For mechanism and clinical evidence detail, see What Is Semax?.

Tips for Best Results

• Collect baseline cognitive or neurological measures before the first dose; BDNF peak (30–60 minutes post-dose) and 24-hour sustained elevation are the relevant pharmacokinetic windows for sampling.
• Time injections consistently; day-to-day variability in dosing window complicates tracking across the titration phase.
• Store reconstituted vials promptly and adhere to the 30-day use window.
• If tracking neuroprotection endpoints in an animal model, align tissue collection times to the BDNF and NGF peak windows mapped by Shadrina et al. (2010): ~30–60 min for peak, up to 24 h for BDNF.
• Include both Semax-treated and PGP-treated arms in mechanistic studies to separate metabolite contributions from intact-peptide effects.

Injection Tips

• Clean the vial stopper and injection site with separate alcohol swabs; allow both to air-dry fully before proceeding.
• Using a 29–31 gauge insulin syringe (5/16″ to 1/2″ needle), draw the calculated dose precisely.
• Pinch a fold of skin and insert the needle at 45° into subcutaneous fat (90° is acceptable with a short needle into a well-pinched fold).
• Inject slowly over 2–3 seconds; do not aspirate. Withdraw the needle, apply gentle pressure, and do not rub the site.
• Rotate injection sites (abdomen, thighs, upper arms) and dispose of each syringe in a sharps container immediately after use.[4]