Overview
Semax is a cognitive-focused compound. Synthetic ACTH analog (fragment 4–10).
With a half-life of ~3 minutes, Semax requires daily administration in most observed protocols. Taken orally, it has a bioavailability of approximately 95% via its primary route.
Half-life approximately 3 minutes, but downstream neurotrophin effects persist 8+ hours via BDNF pathway upregulation. Intranasal administration. N-Acetyl Semax Amidate is a modified variant. One-compartment model.
Mechanism of Action
Semax's pharmacological activity involves the following key pathways:
Neurotrophin Modulation
Semax interacts with central nervous system pathways involved in neuroplasticity and cognitive function.
CNS Penetration
Semax reaches the central nervous system via intranasal administration, bypassing the blood-brain barrier.
Dosing Protocols
The following protocols represent commonly observed dosing patterns. These are observational summaries, not recommendations.
Dose
200 mcg
Route
Intranasal
Frequency
2-3 times daily
Duration
4-12 weeks
Dose
600 mcg
Route
Intranasal
Frequency
2-3 times daily
Duration
4-12 weeks
Reconstitution Steps
Semax is supplied as a lyophilized (freeze-dried) powder and requires reconstitution before use. Common vial sizes: 2 mg, 5 mg, 10 mg.
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1
Gather Supplies
You will need your Semax lyophilized powder vial, bacteriostatic water, a 1 mL insulin syringe for transfer, a nasal spray bottle (0.1 mL per spray), and alcohol swabs. Nasal spray bottles typically hold 5–10 mL.
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2
Swab Both Vials
Clean the rubber stopper on the Semax vial and the bacteriostatic water bottle with separate alcohol swabs. Allow both to air dry for 30 seconds before proceeding.
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3
Draw Bacteriostatic Water
For a 5 mg vial, draw 5 mL of bacteriostatic water to achieve a concentration of 1 mg/mL (1,000 mcg/mL). Each 0.1 mL nasal spray will then deliver 100 mcg. For a 10 mg vial, use 10 mL for the same concentration.
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4
Add Water to Vial
Insert the syringe at an angle and drip the bacteriostatic water slowly down the inside wall of the vial. Do not inject directly onto the powder or shake the vial. Allow it to dissolve at room temperature for 5–10 minutes, gently rolling if needed.
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5
Transfer to Nasal Spray Bottle
Draw the reconstituted solution into your syringe and transfer into a clean nasal spray bottle. Prime the spray pump 3–4 times before first use to ensure a consistent 0.1 mL dose per spray.
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6
Label and Refrigerate
Label the spray bottle with the concentration, date of reconstitution, and expiry (28 days from today). Store upright in the refrigerator at 2–8°C and protect from light.
Quick Reconstitution Math
5 mg vial + 5 mL bac water = 1,000 mcg/mL. Each 0.1 mL nasal spray delivers 100 mcg. For a 300 mcg dose, administer 3 sprays (1–2 per nostril). Use the Milligram reconstitution calculator for custom vial sizes.
Lyophilized Semax should be stored frozen at −20°C. After reconstitution, refrigerate at 2–8°C and use within 28 days. Do not freeze the reconstituted solution or expose to light.
Frequently Asked Questions
What is Semax and how does it work?
Semax is a synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) derived from the ACTH(4–10) fragment of adrenocorticotropin. It is most commonly administered as an intranasal spray and has been observed to rapidly elevate levels of brain-derived neurotrophic factor (BDNF) and activate its signaling receptor TrkB in the hippocampus. It also appears to stimulate serotonergic and dopaminergic systems, which is thought to underlie its reported cognitive and neuroprotective effects.
What is the half-life of Semax and how often should it be dosed?
Semax has a very short plasma half-life of approximately 2–7 minutes for the parent compound, though functional effects are commonly reported for 2–4 hours after intranasal administration. Because of this rapid clearance, Semax is typically dosed 2–3 times daily in standard nootropic protocols. The N-Acetyl Semax variant has a longer functional half-life and is frequently used with once or twice daily dosing.
What is the difference between 0.1% and 1% Semax nasal spray?
The 0.1% solution (1 mg/mL) is the most widely used formulation for cognitive enhancement and general nootropic purposes, with typical doses of 200–600 mcg per day. The 1% solution (10 mg/mL) delivers a much higher concentration per drop and is associated with acute neurological applications such as stroke recovery in clinical settings. For most community protocols focused on focus and neuroprotection, the 0.1% formulation is the standard starting point.
How long does Semax take to work?
Subjective cognitive effects – including increased focus, mental clarity, and alertness – are commonly reported within 15–30 minutes of intranasal administration due to rapid nasal mucosal absorption. BDNF-driven neuroplastic changes are more gradual, with most community protocols reporting noticeable cognitive improvement over 5–14 days of consistent use. Full cumulative benefit from a standard cycle is typically observed within 2–4 weeks.
Can Semax and Selank be used together?
Semax and Selank are frequently combined in community protocols and clinical practice because they target complementary neurological pathways. Semax is primarily associated with cognitive stimulation and BDNF elevation, while Selank is associated with anxiolytic and calming effects via GABAergic modulation. The combination is commonly described as producing focused calm – enhanced cognitive output without the overstimulation that Semax alone can occasionally produce in sensitive individuals.
What does Semax do for cognitive performance?
Semax has been observed in clinical trials to improve attention, short-term memory, and information processing speed when administered intranasally at standard doses (200–600 mcg/day). Its mechanism involves upregulation of hippocampal BDNF and TrkB signaling, serotonin and dopamine system activation, and enkephalinase inhibition. Community reports commonly describe improvements in focus, mental drive, and verbal fluency during short cycles of 5–14 days.