Adamax vs Semax: A Thin Literature and an Almost Empty One

Adamax is sold as a modified version of Semax, but the two sit at very different points on the evidence scale. Semax has a small clinical literature, almost all of it Russian-language. Adamax has almost nothing that can be checked, and Peptide Library's dosage review for it is still pending.

That gap is the most useful thing to understand about this comparison. It is not a contest between two established compounds; it is a comparison between a thinly documented one and a derivative that is barely documented at all.

What each one is

• Semax is a synthetic seven-residue peptide, Met-Glu-His-Phe-Pro-Gly-Pro, developed in Russia. It is described as an analogue of the ACTH(4-10) fragment of adrenocorticotropic hormone: the Met-Glu-His-Phe stretch of ACTH, followed by a Pro-Gly-Pro tail added to the end. In Russia it is used intranasally for stroke and cognitive indications. The Semax profile carries the full record.

• Adamax is sold as an adamantane-modified Semax analogue. Adamantane is a bulky, cage-shaped hydrocarbon group, and the stated purpose of adding it is to make the peptide more fat-soluble and more resistant to breakdown by enzymes. The Adamax profile records it as a designer peptide with inconsistent supplier identifiers.

If you are comparing Semax with its better-known Russian counterpart, the Semax vs Selank guide covers that pair.

How the two are related

Semax: an ACTH fragment without the hormone's main job

ACTH's main job is to make the adrenal glands release cortisol. Semax does not do that. The Pro-Gly-Pro tail markedly slows its enzymatic degradation, and the design removes the corticotropic activity of the parent hormone: Semax does not stimulate the adrenal cortex.

What it is reported to do instead centres on the neurotrophin system. Animal studies and small human studies describe increased expression of brain-derived neurotrophic factor (BDNF) and nerve growth factor in the hippocampus and cortex, alongside modulation of dopamine and serotonin signalling. The profile lists its targets as melanocortin-related pathways in the brain and BDNF.

The melanocortin link has a structural basis. The Met-Glu-His-Phe core that Semax takes from ACTH is the same stretch that sits at positions 4 to 7 of alpha-melanocyte-stimulating hormone; the afamelanotide profile shows that sequence, with norleucine substituted at position 4.

Adamax: the same core, plus a modification

According to the profile, Adamax keeps Semax's seven-residue core. The structure listed is Ac-MEHFPGP-Adam-NH2: Semax's sequence in one-letter code, with an acetyl group at the start and an adamantane group and an amide at the end. Its molecular formula is given as C50H69N11O11S, a mass of about 1033 g/mol, against Semax's C37H51N9O10S and 813.92 g/mol. That is roughly 220 g/mol added to a molecule of about 814, an increase of more than a quarter. On a peptide this small, a change of that size is not a cosmetic tweak, and its effect on how the molecule behaves has to be measured rather than assumed.

Its proposed mechanism is Semax's, carried over: the adamantane group is intended to improve stability and lipophilicity while retaining the melanocortin and neurotrophic activity seen with Semax in preclinical models. Every part of that sentence is design intent rather than measurement. There are no published data in the profile showing that Adamax is more stable than Semax, that it reaches the brain more readily, or that it keeps Semax's activity.

Side by side

The evidence behind each

Semax: clinical, but hard to verify from outside Russia

Semax's human evidence is clinical rather than purely preclinical. The problem is where that evidence sits. The indexed clinical publications are Russian-language, mostly in a single national neurology journal, and cover ischaemic stroke and optic nerve disease:

• a clinical and electrophysiological study in the acute period of hemispheric ischaemic stroke (Gusev 1997);

• a study in optic nerve disease (Polunin 2000);

• a study at different stages of ischaemic stroke (Gusev 2018);

• a 2024 paper on its place in the therapy and rehabilitation of ischaemic stroke (Spirin 2024).

None of these trials is registered on ClinicalTrials.gov, and the doses used are not available in the indexed English-language record, so the Semax profile does not state a dose as established. Independent replication outside Russia is limited. Its rodent work on neuroprotection and cognition is a separate, preclinical tier, and it does not establish effects in people.

Most of the clinical work is in acute stroke, a hospital setting. The focus and cognitive-enhancement uses Semax is sold for have no corresponding trial.

Adamax: nothing that can be graded yet

Adamax has no evidence level on this site, no established human dose and no dosage evidence record; its review is pending. The profile's risk list notes limited independent published research, and in practice we could not find an indexed study of the peptide at all. Searching PubMed for the name is not much help, because "AdaMax" is also the name of a machine-learning optimisation algorithm, and the records it returns concern that, not the peptide.

Everything said about Adamax's effects is therefore extrapolated from Semax. That is a hypothesis about a related molecule, not evidence about this one.

Known safety signals

Semax. The profile records nasal irritation and headache as side effects, with overstimulation and limited data as the main risks.

Adamax. Its human safety profile is not established. The profile lists possible headache or stimulation, based on reports for the peptide class rather than for Adamax itself, and possible irritation depending on the route. Long-term safety is not established, and because it is unregulated, products may be mislabelled or contaminated. The grey-market peptides guide covers why that matters.

What the evidence does not show

• That Adamax is a better Semax. The adamantane modification is designed to improve stability; no data in the profile show that it does, or that activity is retained.

• Any head-to-head comparison. No study has compared the two.

• An established human dose of either. Semax's clinical doses are not retrievable from the indexed record; Adamax has no human data.

• That Semax improves focus or cognition in healthy people. Its clinical work is in stroke and optic nerve disease.

• That rodent findings on BDNF or neuroprotection transfer to people. They are animal results.

• That Russian registration transfers anywhere else. Approval in one jurisdiction does not establish an approved use or dose in another.

Frequently asked questions

What is the difference between Adamax and Semax?

Semax is a seven-residue analogue derived from ACTH, registered as a medicine in Russia and studied there in stroke and optic nerve disease. Adamax is sold as the same peptide core with an adamantane group added, intended to make it more stable and fat-soluble. Semax has a small Russian-language clinical literature; Adamax has no indexed studies we could find.

Is Adamax stronger than Semax?

There is no evidence either way. The claim rests on the design intent behind the adamantane modification, and no published study has measured Adamax's stability, potency or effects against Semax.

Is Semax FDA-approved?

No. It is registered as a medicine in Russia, but it has no FDA-approved use and no regulator outside Russia has approved it. Adamax is not approved anywhere.

Does Semax affect cortisol like ACTH?

According to its profile, no. The design removes the corticotropic activity of the parent hormone, and Semax does not stimulate the adrenal cortex.

Is Semax the same as Selank?

No. They are different peptides, but both are Russian-developed and share the same evidence problem: registered as medicines in Russia, absent from ClinicalTrials.gov, and reported in a literature that is difficult to verify from outside. The Semax vs Selank guide compares them.

Why is there so little research on Adamax?

It is a designer peptide, described inconsistently between suppliers, and we could not find an indexed study of it. Its name is also shared with a machine-learning algorithm, which crowds out searches. Its dosage review on Peptide Library is pending.