Is Linaclotide legal in the United Kingdom?

A 14-amino-acid peptide taken orally that works without being absorbed, acting entirely on receptors in the gut lining. Approved on randomised phase 3 trials for constipation.

Linaclotide is the most interesting design on this page and the reason is counterintuitive: it is an oral peptide that works precisely because it is not absorbed. Oral peptides are normally a pharmaceutical problem, because the gut destroys them and almost nothing reaches the bloodstream.

Mechanism: A 14-amino-acid peptide agonist at guanylate cyclase-C on the apical surface of intestinal enterocytes, mimicking the endogenous peptides guanylin and uroguanylin. Activation raises intracellular and extracellular cyclic GMP, which activates the cystic fibrosis transmembrane conductance regulator chloride channel, driving chloride and bicarbonate into the lumen with sodium and water following.

Regulatory history: FDA-approved as Linzess for irritable bowel syndrome with constipation and for chronic idiopathic constipation in adults, and for functional constipation in children. Carries a boxed warning against use in children under two years because of a risk of serious dehydration.

Licenses medicines for the UK market. A compound without a marketing authorisation is an unlicensed medicine, which can only lawfully be supplied for human use through a prescriber under the specials scheme, not sold as a research product.

The classification above is the The Longevity Archive reading of Medicines and Healthcare products Regulatory Agency listings for Linaclotide at the reviewed date, not a legal opinion. Rules change, and importing, prescribing and possessing a compound can each be treated differently. Check the regulator directly before acting on anything here.