Adamax

What it is

Semax is a short peptide from Russia, derived from the stress hormone ACTH, more precisely from the fragment ACTH(4-7), to which three further amino acids were attached. The hormonal effect is largely absent; what remains is a peptide that is registered as a medicine in Russia, where it comes in the form of nasal drops, and is traded as a nootropic in the West.

Adamax builds on this molecule. In the notation based on the New Zealand medicines authority Medsafe, it reads Ac-MEHFPGP^AG-NH2: the Semax chain, acetylated at the front, with an adamantylated building block and an amide at the back. On this basis the molar mass is around 1032 g/mol; accordingly, vendors sometimes list the product as Adamax 1032.

Adamantane is a small, fat-soluble carbon cage that has been used in medicinal chemistry for decades, for example in the Alzheimer’s medicine memantine. A 2013 review in Chemical Reviews calls it, in its title, the lipophilic bullet that hits the target.

Where it comes from

The end caps are not new. They come from P021, a peptide from the research group of Khalid Iqbal that was derived from the nerve growth factor CNTF. The group shrank a longer CNTF fragment down to four active amino acids and then attached an adamantylated glycine, explicitly to cross the blood-brain barrier more effectively. In mice, P021 improved learning and memory and promoted the formation of new nerve cells.

Who came up with the idea of putting exactly these caps on Semax is not known. There is no publication, no patent specification and no trial registry entry under this name. The earliest official mention that could be found is a Medsafe submission from June 2025 that lists Adamax alongside Semax as an ACTH analog marketed as a cognitive enhancer.

The confusion with Dihexa

In the scene, Adamax often comes up in the same breath as Dihexa, and at least one peptide vendor even lists it as a synonym: Adamax (Dihexa, PNB-0408), with the Dihexa structure and Washington State University as its origin. Chemically, that does not fit. Dihexa is a small molecule derived from angiotensin IV that targets the growth factor HGF and its receptor c-Met, whereas Adamax is a Semax derivative with an ACTH core. All the two have in common is the nootropic label and the gray market.

The Dihexa context is nonetheless instructive. The paper that was supposed to show the HGF mechanism of Dihexa appeared in the Journal of Pharmacology and Experimental Therapeutics in 2014, received a formal expression of concern in 2021 and was retracted in April 2025, together with two further papers from the same group. The company that emerged from this work, Athira, reached a settlement of just over 4 million dollars with the US Department of Justice in January 2025, without admission of liability. And the HGF approach itself failed in humans: in the LIFT-AD trial, the related compound fosgonimeton missed its primary endpoint in 287 Alzheimer’s patients over 26 weeks.

For Adamax this means two things. The Dihexa problems cannot be transferred to Adamax; it is a different molecule. But anyone buying Adamax should know that Dihexa is apparently also sold under that name.

How it is supposed to work

The vendors’ story is one of addition: Semax supplies the BDNF effect, adamantane makes the molecule more stable and better able to reach the brain, and the result is said to act longer and more strongly. Some speak of a hybrid of Semax and P21.

The first part has a real basis. In rats, a single dose of Semax raised BDNF protein in the hippocampus by up to 1.4-fold and increased activation of its receptor TrkB. The second part is plausible, because exactly this purpose was the reason for the adamantane cap on P021. Nobody has measured it for Adamax.

The third part, the hybrid, does not hold up. The developers of P021 attribute the neurotrophic effect to the CNTF core, the four amino acids DGGL. Adamax takes over only the caps, not this core. At best, then, it is a Semax with a protective shell, not Semax plus P21.

What users report

In an English-language forum in spring 2026, users describe Adamax as rocket fuel or as somewhat more energizing and focusing than NA-Semax. Others found no reason to prefer it to NA-Semax; the effect was similar, the price considerably higher. No side effects were mentioned in the exchange. These are individual reports without a comparison group and without any check of what was actually in the vial.

What the studies show

Semax and BDNF in rats (2006)

Rats received Semax a single time. In the hippocampus, BDNF protein rose by up to 1.4-fold, activation of the TrkB receptor also increased, and the animals learned an avoidance task better. This is the core study for the BDNF mechanism of Semax. For Adamax there is no comparable measurement.

Semax in the brain scan (2018)

In 24 healthy adults, 14 with Semax and 10 with placebo, functional magnetic resonance imaging 5 and 20 minutes after nasal administration showed an enlarged anterior subnetwork of the resting-state network. A surrogate finding without a performance test, but the only placebo-controlled human study on Semax that could be found.

P021 and the adamantane cap (2010, 2016)

The research group led by Khalid Iqbal developed P021 from a CNTF fragment and attached an adamantylated glycine to cross the blood-brain barrier. Normal adult mice then learned better, and more new nerve cells formed in the dentate gyrus. All data come from animal models of the developer group.

LIFT-AD, fosgonimeton (2025)

Randomized, placebo-controlled, phase 2/3, 287 patients with mild to moderate Alzheimer’s dementia in the main analysis, 26 weeks. Primary endpoint missed, p = 0.70. Not an Adamax finding, but the reason why the Dihexa route is considered tested and failed in humans.

Where the data stop

On Adamax itself there is nothing: no human study, no animal experiment, no cell culture, no registry entry. Claims such as longer-acting or stronger than Semax have not been measured anywhere, and the hybrid story contradicts the account of the P021 developers, according to which the neurotrophic effect depends on the CNTF core. Even with P021 the transfer is not smooth: in a mouse model of CDKL5 disorder, BDNF did not rise under continuous administration.

Then there is the question of what is actually being sold. Wikipedia places the adamantane group at the back end, a peptide encyclopedia from the scene at the front, a chemicals supplier lists a sequence of nine ordinary amino acids without any adamantane building block, and one vendor sells Dihexa under the name. The Semax foundation, too, is predominantly Russian; in 2026 the US Food and Drug Administration (FDA) saw insufficient evidence for the indications it reviewed.

Status, approval and legal

Adamax is not approved as a medicine anywhere; in Germany and the EU it is neither a medicine nor an authorized food supplement; it is sold as a research chemical. In New Zealand, Medsafe proposed in June 2025 to make ACTH analogs including Adamax and Semax prescription-only. The responsible committee deferred the decision on July 23, 2025; the secretariat subsequently recommended the classification. In sport, Adamax is not listed by name on the Prohibited List of the World Anti-Doping Agency, but as a non-approved substance it falls under group S0 and is therefore banned at all times.

Safety

No safety data exist for Adamax: no toxicology, no pharmacokinetics, no case reports, no information on interactions. For the parent substance Semax, the FDA is concerned about immune reactions due to aggregation and peptide-related impurities in poorly characterized products; for an even less well-described derivative this applies all the more. That adamantane is contained in approved medicines says nothing about the tolerability of this molecule. For pregnant and breastfeeding women, children and people with neurological or psychiatric conditions there is no data basis at all; problems with memory or concentration should be medically evaluated.

Sources

• Dolotov et al., Brain Research 2006 – Semax, BDNF and TrkB in the rat hippocampus
• Lebedeva et al., Bulletin of Experimental Biology and Medicine 2018 – Semax and the default mode network
• Li et al., FEBS Letters 2010 – neurotrophic peptides with adamantane (P021)
• Kazim and Iqbal, Molecular Neurodegeneration 2016 – development of P021
• Medsafe, Classification of Unscheduled Peptides, June 2025
• Medsafe, minutes of the 74th meeting of the Medicines Classification Committee, July 23, 2025
• FDA, briefing Pharmacy Compounding Advisory Committee 2026 – Semax
• Porsteinsson et al., Journal of Alzheimers Disease Reports 2025 – LIFT-AD, fosgonimeton
• Retraction Notice, Journal of Pharmacology and Experimental Therapeutics 2025 – Benoist et al. 2014
• US Department of Justice, settlement with Athira Pharma, January 6, 2025