The Psychoactive Substances Act and Why Peptides Fall Outside It

The Psychoactive Substances Act 2016, in force across the UK since 26 May 2016, makes it an offence to produce, supply, offer to supply, possess with intent to supply, import or export a psychoactive substance ^{[1] [6]}. It defines that target by effect — a substance capable of affecting mental functioning or emotional state by stimulating or depressing the central nervous system — and not by chemistry ^[2]. Most peptides fall outside it because they have no such effect in the Act's sense, not because they carry a research label.

The Act is often conflated with two neighbours. It is not the Misuse of Drugs Act, which controls named substances by class, and it is not medicines law, which turns on presentation and function. This article sets out what the 2016 Act covers, its exemptions, why its "research chemicals" were a different thing from laboratory reagents, and where the peptides marketed as nootropics actually sit.

What the Act covers

The Home Office announced the Act as a landmark law to tackle so-called legal highs, prohibiting production, supply and importation or exportation for human consumption, with prohibition and premises orders to close head shops and online dealers ^[6]. The offences sit in sections 4 to 9, and section 9 creates the only possession offence, confined to custodial institutions ^[1].

There is no general offence of simple possession. The Act's weight falls on the trade — producing, selling, importing — which is where its mental element, discussed below, does most of its work ^{[1] [5]}.

The psychoactive test

Section 2 defines a psychoactive substance as one that is capable of producing a psychoactive effect in a person who consumes it and is not an exempted substance. A substance produces a psychoactive effect if, by stimulating or depressing the person's central nervous system, it affects the person's mental functioning or emotional state. Consuming is defined broadly: causing or allowing the substance, or its fumes, to enter the body in any way ^[2].

Three features of that definition matter for peptides. It is about capability, not about intention or labelling. It requires an effect through the central nervous system on mental functioning or emotional state, which most peptides studied for metabolic, structural or tissue-level activity are not claimed to have. And it is evidential: whether a given substance meets it is a question of fact, which the courts have answered substance by substance ^[7].

The exemptions

Schedule 1 lists exempted substances: controlled drugs within the meaning of the Misuse of Drugs Act 1971, medicinal products as defined by reference to the Human Medicines Regulations 2012, alcohol and alcoholic products, nicotine and tobacco products, caffeine and caffeine products, and food ^[3]. The MHRA's guidance summarises the result: the Act makes it an offence to produce or supply any psychoactive substance, with the exemption of a small number of legitimate substances including medicinal products ^[8].

Schedule 2 lists exempted activities. Alongside healthcare activities it exempts any activity carried on in the course of, or in connection with, approved scientific research — and defines approved research as research approved by a relevant ethics review body, such as a research ethics committee, an NHS body, a research council, a research institution or a relevant charity ^[4].

The medicinal-products exemption is also narrower than it looks. When suppliers of nitrous oxide argued that their canisters were medicinal products and therefore exempt, the Court of Appeal in R v Chapman held that the question is decided case by case, and that canisters not made for medical purposes and supplied for recreational use were not medicinal products ^[7]. An exemption is about the product as it actually exists, not about the category its substance might belong to elsewhere. The Home Office's 2018 review recorded that the exemption list had not been amended since the Act came in ^[7].

"Research chemicals" under the Act are a different thing

The trade the Act was aimed at sold novel psychoactive substances under labels that denied consumption — among them "research chemical". Laboratory reagent suppliers use the same two words. The overlap in vocabulary is the root of much of the confusion, and it helps to know which authorities decide what counts as a research chemical, and why none of them treats it as a legal class.

The Act does not engage with labels at all. The supply offence in section 5 requires that the supplier knows, or is reckless as to whether, the substance is likely to be consumed by the person supplied, or by someone else, for its psychoactive effects ^[5]. A label saying otherwise is simply one piece of evidence about what the supplier knew, weighed against everything else about how the product was sold.

Where peptides actually sit

For most research peptides the analysis ends at section 2. Material studied for metabolic, structural, tissue or immune activity is not claimed to act on the central nervous system to change mental functioning or emotional state, and the Act's definition is not engaged ^[2].

The exceptions are the short peptides studied for neurological activity and sometimes marketed as nootropics, of which Semax and Selank are the names most often seen. For those, whether a given material is capable of a psychoactive effect is a question of evidence, not of marketing, and the reference literature is the place to test claims — for example, what the Semax literature does and does not show. This article draws no conclusion about any compound's effects.

The point a buyer can take from the structure of the law is simpler. Selling a peptide with claims about mood, focus or cognition does two things at once. It supplies evidence that the seller expects consumption for psychoactive effects, which is the mental element of the supply offence ^[5]. And it presents the product as affecting a physiological function, which is a route into medicines law ^[8]. The same sentence of marketing copy pulls in both directions, and neither pull depends on the research label printed beside it.

What the review found

The Home Office's statutory review, presented to Parliament in November 2018, found three types of legal challenge in the Act's first years — to the medicinal-products exemption for nitrous oxide, to the psychoactivity of nitrous oxide, and to the psychoactivity of synthetic cannabinoids — and that in every case the courts held the substances to be within the Act. It also found no known evidence that exempted activities, or the trade in exempted substances, had been adversely affected ^[7].

That last finding is the one relevant to laboratory supply. The Act was designed to leave legitimate trade alone, and the government's own review says that, by the measures it used, it did.

A buyer's reading

1. Ask the right statute the right question: effect on the mind is this Act; named substances are the Misuse of Drugs Act; presentation and function are medicines law ^{[1] [8]}.
2. Treat any seller's mood, focus or cognition language as a warning about that seller, not as information about the material ^[5].
3. Do not rely on the research exemption unless the work genuinely has approval from an ethics review body of the kind Schedule 2 names ^[4].
4. Keep the purpose of a purchase recorded in research terms that match what the material is and what your work does.