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ACTH(4-10) fragment analogue (nootropic, registered in Russia) · safety

Semax side effects

The semax study reported 1 safety findings, but it did not publish a list of common side effects or reliable frequency rates. The findings and source are below.

The findings were: bursts of abnormal electrical activity on brain recordings.

The sources describe these effects in relation to the dose and to the early weeks.

Semax is a peptide seven amino acids long, copied from a short stretch of a stress hormone. It carries none of that hormone’s own activity. It is sold as a nootropic, for focus, memory and recovery after a stroke.

In Russia it is a registered prescription medicine given as nasal drops. Stroke patients there have received it for thirty years. That work is Russian-language, and none of it was ever registered as a trial. The clearest published result is a negative one, in 27 people with motor neuron disease.

Further down: when to get medical help · questions

Medically reviewed by Jennifer Montecillo, MD · non-practicing medical reviewerReviewed 2026-08-13open the primary sources

At a glance

Common reactions listed

0

Serious reactions listed

1

Boxed warning

No label exists

Strongest source

limited human data

The counts show how many distinct reactions the cited trial report names. The percentages show how often a reaction appeared in a study group, not the chance that it will happen to you.

Serious reactions to watch for

These are rarer, and they are the ones clinicians monitor for. Seek medical care if you have symptoms.

Serious — monitorwarning/precaution
ReactionFrequency
Bursts of abnormal electrical activity on brain recordingsSeen in some of 73 patients followed up after oxygen starvation of the brain, fourteen of whom were in a persistent vegetative state. The report gives no rate, no denominator and no comparison group, so this is a signal rather than a frequency. Its authors drew one practical conclusion from it: the first injection should be given while the brain’s electrical activity is being recorded. That is the only monitoring instruction anywhere in this literature. No other reaction has a published rate, and no dose-ranging safety study of this peptide exists in people

limited human dataEvery reaction above comes from a cited trial. These are study findings, not instructions on what to take.

When to seek medical care

The trial report does not give a separate list of serious reactions. There is also no approved label. That gap does not mean serious reactions cannot happen. This compound has been studied in fewer people and for less time than an approved drug.

EmergencySome symptoms should not wait for an appointment. Call emergency services (911 in the US) if they are severe, getting worse fast, or involve trouble breathing, chest pain, fainting or confusion.

1Read deeperTiming, evidence limits, and product context

When these effects tend to occur

The cited evidence describes these effects in relation to the dose and to the early period of taking it, rather than as a constant background throughout.

When a study reports how side effects changed over time, it describes the group as a whole. It cannot predict one person’s experience.

Common questions

How long do semax side effects last, and do they go away?

The sources do not commit to a set number of days. What they describe is a pattern — reactions cluster after you start and after each increase, then ease while the dose is held steady. Any page quoting an exact number of days is quoting something the sources do not say.

What side effects were reported for semax?

The study reported bursts of abnormal electrical activity on brain recordings. It did not publish reliable frequency rates, so none can be called common.

Does semax have a boxed warning?

No, because a boxed warning is part of an FDA-approved label and semax has no approved label. That reflects what regulatory review has and has not covered, not a finding that serious risks were looked for and ruled out.

Can the semax dose be lowered if side effects are hard to tolerate?

That decision belongs to the prescribing clinician. No approved schedule exists for this compound, so there is no labeled framework for adjusting a dose. That leaves the prescriber as the only place the decision can sit.

Does semax cause hair loss?

Hair loss is not among the reactions listed on this page for semax, because the cited trial report cited here does not carry it. Anything missing from the tables is outside what can be sourced here rather than ruled out, and a symptom that worries you belongs with a clinician.

Is fatigue a listed semax side effect?

No — the cited trial report cited here does not list it. That describes what was reported, not proof that the symptom cannot happen.

Is constipation a listed semax side effect?

Not separately. If a source groups stomach and gut events together, this page keeps that group intact. It does not invent named reactions the source never listed.

What should someone do about a serious semax reaction?

Contact a clinician promptly, and emergency services if symptoms are severe or getting worse quickly. The section above describes what those reactions actually look like, so they can be spotted early rather than explained away.

Do the frequencies on this page mean the chance it happens to one person?

No. These figures describe groups in a study. A band shows how often a reaction appeared under that trial’s conditions. It cannot predict what will happen to one person.

Related

The schedule these reactions were recorded against, the comparisons, and the sourcing rules behind every grade on this page.

1primary source, each with the day we read it — open the documents used on this page