Semax Calculator

What Is Semax?

Semax is a synthetic heptapeptide composed of seven amino acids with the sequence Met-Glu-His-Phe-Pro-Gly-Pro (MEHFPGP). It is derived from a fragment of adrenocorticotropic hormone (ACTH 4-10), to which the stabilizing tripeptide ending Pro-Gly-Pro has been attached at the C-terminus. This modification fully removes the hormonal — that is, corticotropic — activity of the original ACTH fragment while substantially extending the duration of biological action. What remains are the neurotropic and neuroprotective properties, without any stimulation of the adrenal axis. Semax is therefore classified as a pure neuropeptide rather than a hormone.

Semax was developed in the 1980s at the Institute of Molecular Genetics of the Russian Academy of Sciences in collaboration with Lomonosov Moscow State University. In Russia, the compound has since been studied intensively in neurological research, including in models of ischemic stroke, cognitive load, attention disorders, and optic neuropathy. A defining feature is its intranasal route: Semax is typically administered as an aqueous solution in the form of nasal drops or nasal spray, not by injection. Through the well-vascularized nasal mucosa, and in part via the olfactory nerve, the peptide reaches central nervous system compartments quickly.

In plasma, Semax has an exceptionally short half-life on the order of a few minutes, as it is rapidly degraded by peptidases. The biological effect, however, lasts considerably longer than the measurable plasma concentration would suggest. This is attributed to downstream signaling cascades — in particular the upregulation of neurotrophic factors, which remain detectable hours after administration. This decoupling of plasma half-life from duration of action is a hallmark of regulatory neuropeptides and shapes the dosing logic for Semax.

Mechanisms of Action

Semax does not act through a single receptor; instead, it modulates several neurochemical systems simultaneously. The mechanisms best documented in preclinical research are:

• Upregulation of BDNF and NGF: Semax increases the expression of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF), along with their receptors, particularly the TrkB receptor in the hippocampus. This neurotrophic effect is considered the central mechanism behind the observed effects on memory, learning, and neuronal plasticity.
• Neuroprotection under hypoxia and ischemia: In models of reduced cerebral blood flow, Semax reduces the extent of neuronal damage. It dampens oxidative stress, stabilizes cell membranes, and limits glutamate-mediated excitotoxicity. This property is why Semax has been researched in Russia in the context of acute stroke.
• Dopaminergic and serotonergic modulation: Semax influences the turnover of dopamine and serotonin in various brain regions. This modulation is linked to the reported effects on drive, motivation, mood, and the ability to concentrate.
• Modulation of the endogenous regulatory peptide system: Semax slows the enzymatic breakdown of the body's own regulatory peptides by inhibiting enkephalin-degrading enzymes, thereby indirectly reinforcing the activity of endogenous neuromodulatory systems.
• Anti-inflammatory and antioxidant effects: Semax dampens the release of pro-inflammatory cytokines within the central nervous system and influences the gene expression of enzymes involved in the defense against oxidative stress.
• Influence on gene expression in the brain's immune and vascular systems: Transcriptomic studies show that a single dose of Semax can alter the activity of hundreds of genes, including those in pathways governing neuroinflammation and vascular adaptation.

An important distinction from classic stimulants: Semax does not acutely increase catecholamine release the way an amphetamine does — it modulates signal processing. The reported effects are therefore better described as regulating and stabilizing rather than acutely activating.

Dosage Calculation

Because Semax is administered intranasally, dosing does not refer to an injection volume but to the amount of peptide delivered into the nose per application. The lyophilized powder is typically dissolved in water so that a defined concentration per drop is obtained. Dosing is individual and should begin at the lower end of the range.

Standard Dosing Parameters

• Conservative dose: 100-300 mcg (0.10-0.30 mg) per application
• Standard dose: 300-600 mcg (0.30-0.60 mg) per application
• Higher range: up to roughly 1 mg per day, split across several applications
• Frequency: one to three times daily, depending on the research protocol
• Form of administration: nasal drops or nasal spray, not intended for injection

Example Calculation: 5 mg Vial with 2 mL Water

A common vial size is 5 mg. Dissolving it in 2 mL of a suitable solvent (sterile or bacteriostatic water) gives a concentration of 2.5 mg/mL (2,500 mcg/mL). A typical drop from a standard dropper bottle is roughly 0.05 mL.

• Per drop (0.05 mL): 0.05 x 2500 = 125 mcg
• 300 mcg dose: 300 ÷ 2500 = 0.12 mL, or about 2-3 drops
• 600 mcg dose: 600 ÷ 2500 = 0.24 mL, or about 5 drops

The exact drop size varies with the pipette or spray head, so it is only a guideline. At a daily dose of 300 mcg, a 5 mg vial provides roughly 16 days of dosing on paper. Use the Semax calculator above to determine the concentration, volume per dose, and vial duration precisely for any vial size and solvent volume.

Preparation and Use

Semax is supplied as a lyophilized (freeze-dried) powder in sealed vials and must be brought into solution before use. For an intranasal solution used over several days, bacteriostatic water is sensible, as the benzyl alcohol it contains inhibits microbial growth. Cleanliness is especially important when handling anything applied to the nasal mucosa.

Step-by-Step: Preparing the Intranasal Solution

1. Gather supplies: the Semax vial, a vial of bacteriostatic or sterile water, alcohol swabs, a sterile draw needle, and a clean dropper bottle or nasal spray head.
2. Wipe the rubber septa of both vials with fresh alcohol swabs and allow them to air-dry for about 30 seconds. Do not touch the septa afterward.
3. Draw the desired volume of water (2 mL is standard for a 5 mg vial) and insert the needle into the peptide vial at an angle so the tip points toward the inner glass wall.
4. Slowly push the plunger so the water runs down the glass wall and gently wets the powder. A direct stream onto the powder cake can mechanically stress the peptide.
5. Gently roll or swirl the vial between your palms until the powder is fully dissolved. The solution should appear clear and colorless. Do not shake or vortex.
6. Transfer the finished solution into a clean nasal dropper or spray bottle, or fit the vial itself with a suitable spray attachment, provided it is sterile.
7. Label the vial with the preparation date and concentration (e.g., "Semax 2.5 mg/mL, prepared [date]").

Applying the Nasal Solution

Before use, gently blow the nose if needed. Tilt the head slightly back or to the side and deliver the calculated number of drops into each nostril without letting the pipette or spray head touch the nasal mucosa. After instilling the drops, remain in the tilted position for a few seconds so the solution can be absorbed by the mucosa, and do not blow the nose immediately afterward. If the daily dose is split, the applications should be spread across the day. If the solution becomes cloudy, discolored, or contains visible particles, discard the vial and do not continue using it.

Storage and Shelf Life

• Lyophilized powder (unprepared): Store at −20°C for long-term storage, where it remains stable for many months. Short-term storage at 2-8°C in a refrigerator is acceptable. Keep away from light and moisture, and do not store at room temperature for extended periods.
• Prepared nasal solution: Store in the refrigerator at 2-8°C. With bacteriostatic water the solution is generally usable for several weeks; with sterile water the window is much shorter and the solution should be used promptly. Keep the vial protected from light.
• Do not freeze after preparation. Freeze-thaw cycles promote aggregation of the peptide and loss of activity. Once prepared, the solution must remain refrigerated throughout its use window.
• Applicator hygiene: Because the nasal solution repeatedly contacts the mucosa, the dropper or spray attachment should be kept clean and not shared with other people to avoid contaminating the solution.
• Transport: For longer trips, use an insulated cooler with an ice pack and avoid temperatures above 25°C.

Side Effects and Safety Profile

Semax is regarded as well tolerated in preclinical research and in the limited clinical research conducted in Russia. Because the Pro-Gly-Pro modification removes the corticotropic activity of the original ACTH fragment, Semax does not stimulate the adrenal axis and causes no hormonal shifts. Robust long-term human data outside Russia is lacking, however, which is why use remains in the research domain.

Commonly Reported Observations

• Mild local irritation of the nasal mucosa, a brief stinging sensation, or an urge to sneeze immediately after instillation. This usually subsides quickly.
• Temporary changes in sleep patterns, particularly when Semax is used in the late afternoon or evening. Use during the first half of the day is often preferred.
• Mild headache or a feeling of mental over-stimulation at higher doses, which often improves when the dose is reduced.

Less Common or Theoretical Concerns

• Irritability or restlessness: Through modulation of dopaminergic pathways, sensitive users may experience restlessness or increased irritability, especially when the dose is too high.
• Blood pressure changes: Isolated reports describe minor effects on blood pressure. Individuals with pre-existing cardiovascular conditions should monitor this.
• Interaction with stimulants or antidepressants: Because Semax influences monoaminergic systems, an interaction with substances that also act on dopamine or serotonin is theoretically possible and not sufficiently characterized.

Contraindications

• Pregnancy and breastfeeding (insufficient safety data)
• Acute disease or injury of the nasal mucosa
• Known hypersensitivity to any component of the preparation
• Severe uncontrolled psychiatric or cardiovascular conditions (without medical supervision)

No serious adverse events have been described in the published research at standard doses. Given the absence of large-scale international trials, caution is warranted, and consultation with a qualified healthcare professional is strongly recommended.

Combinations and Stacks

Semax + Selank — The Focus-and-Calm Stack

The combination of Semax and Selank is one of the best-known neuropeptide stacks. Both peptides come from the same Russian research tradition and are administered intranasally, but they complement each other in profile: Semax leans toward drive and focus, while Selank, as an anxiolytic peptide, contributes a calming, anxiety-dampening component. Combined, the stack aims to support cognitive performance without the jitteriness often associated with stimulants. The two solutions are typically prepared separately and used one after the other, not mixed in a single vial.

Semax and N-Acetyl Semax

N-Acetyl Semax is an acetylated variant of the Semax molecule. The acetyl group at the N-terminus increases stability against peptidases and extends the duration of action, which is why N-Acetyl Semax is often described as a more potent and longer-acting version. In practice, the two compounds are usually viewed not as a stack but as alternatives to each other. Anyone switching from Semax to N-Acetyl Semax should recalibrate the dose, as effective potency differs.

Semax + DSIP for the Sleep-Wake Rhythm

Some research protocols combine daytime Semax with DSIP (Delta Sleep-Inducing Peptide) in the evening. The rationale is to confine the drive-oriented effect of Semax to the active part of the day and flank it with a sleep-supporting component in the evening. Because Semax can disrupt sleep when used late, this separation addresses the timing issue directly.

Research-grade Semax is available directly from BergdorfBio: Semax at BergdorfBio.

Frequently Asked Questions

Why is Semax administered intranasally rather than injected?

Semax is used almost exclusively as nasal drops or nasal spray. The nasal mucosa is richly vascularized, and a portion of the peptide can reach central nervous system structures relatively directly via the olfactory nerve. The intranasal route also bypasses first-pass metabolism in the liver. Because Semax is degraded very quickly in plasma, mucosal absorption offers a practical, non-invasive route of administration.

How quickly does Semax work?

Users often report a relatively rapid effect on alertness and concentration within the first one to two hours after application. The neurotrophic effects — the upregulation of BDNF and NGF — develop more slowly and are associated more with repeated use over days and weeks.

Does Semax have hormonal effects like ACTH?

No. Although Semax is derived from an ACTH fragment, the added Pro-Gly-Pro sequence removes the corticotropic, hormone-stimulating activity. Semax does not stimulate the adrenal glands and does not raise cortisol levels. It is therefore classified as a pure neuropeptide rather than a hormone, and no post-cycle therapy is required.

What is the difference between Semax and N-Acetyl Semax?

N-Acetyl Semax carries an acetyl group at the N-terminus, which makes the molecule more stable against enzymatic breakdown. As a result, N-Acetyl Semax tends to act more strongly and for longer than unmodified Semax. Both share the same mechanism of action through the upregulation of neurotrophic factors. Anyone switching between the two should adjust the dose.

How long should a Semax cycle last?

Research protocols often run for two to four weeks, followed by a break. Longer continuous use has been described, but cyclical use is preferred as a precaution, since robust long-term human data outside Russia is lacking. Breaks also provide an opportunity to assess one's actual baseline state without the peptide.

Can Semax affect sleep?

It can. Because of its drive- and alertness-oriented effect, Semax may make it harder to fall asleep when used in the late afternoon or evening. In practice, use is therefore usually scheduled in the first half of the day.

Is Semax a stimulant like caffeine or amphetamine?

No. Semax does not acutely increase catecholamine release the way a classic stimulant does; instead, it modulates signal processing within monoaminergic and neurotrophic systems. The reported effects are better described as regulating and stabilizing. A pronounced crash, as seen with stimulants, is typically not reported.

Where can I buy Semax?

BergdorfBio offers research-grade Semax with verified purity and concentration. View the product page: Buy Semax at BergdorfBio. All products are sold strictly for research purposes.

Medical Disclaimer: The information on this page is provided for educational and research purposes only. Outside its country of origin, Semax is not an approved drug or medical treatment and is sold strictly for research use. Nothing on this page constitutes medical advice, diagnosis, or a recommendation to use any specific compound. Always consult a qualified healthcare professional before beginning any peptide protocol. BergdorfBio assumes no liability for the use or misuse of the information presented here.