A US compounding organisation is marketing an unlicensed, under-the-tongue form of semaglutide to private doctors in the UK, prompting a safety warning from Novo Nordisk, which makes the branded versions.
The Professional Compounding Centers of America (PCCA) is offering a sublingual semaglutide — a custom-made, unbranded preparation designed to dissolve under the tongue and be absorbed through the lining of the mouth. It is marketed as a way to reduce the stomach side effects associated with oral formulations.
Why the sublingual claim invites scrutiny
Semaglutide is a peptide, and peptides are difficult to absorb through any route other than injection. They are large, water-soluble and readily broken down by enzymes.
The approved oral version illustrates the difficulty. It requires an absorption enhancer, must be taken fasting with a small amount of water and no food for a set period afterwards, and even then only a small fraction of the dose reaches circulation.
Sublingual absorption is a recognised route for some drugs, and it works best for small, fat-soluble molecules that cross the mucous membrane readily. A large peptide is close to the opposite profile.
Whether a sublingual formulation delivers a therapeutic dose is therefore an empirical question — and one that pharmacokinetic testing would answer. In the absence of such testing, the marketing claim rests on nothing measurable.
Not approved, not tested
The product is not approved by the UK’s MHRA and has not been clinically tested for safety or effectiveness.
The consequences run in two directions. Under-delivery means a patient pays for and takes a medicine that does little, believing they are being treated. Over-delivery, if absorption is more variable than expected, produces the gastrointestinal effects the formulation is marketed to avoid, and at worst more serious dose-related problems.
Neither risk is quantifiable without data, which is the substance of the objection rather than a procedural complaint.
What compounding is meant to be
UK rules permit compounding to tailor a medicine for an individual patient but prohibit mass compounding — making unlicensed medicines at scale.
The legitimate purpose is narrow and genuine. A patient may need a liquid formulation because they cannot swallow tablets, or a version free of a dye or preservative they react to, or a dose not commercially available. Preparing that for a named patient on a prescription is established practice.
The exemption exists because such needs cannot be met by industrial manufacturing, and it deliberately does not require the testing a licensed medicine undergoes — on the reasoning that a one-off preparation for one patient is a different proposition.
Producing a standardised formulation and marketing it to clinics uses the exemption for something it was not designed to permit, which is the legal question here.
Why demand exists
The dispute highlights a two-tier system in UK weight-loss care, where private clinics move faster than the public system.
NHS access to weight-loss medication is tightly restricted by eligibility criteria and capacity, so most people seeking these drugs pay privately. That market is large, price-sensitive and competitive, which creates commercial pressure toward cheaper alternatives.
Supply has also been constrained for extended periods, and shortages of licensed products historically drove patients toward compounded versions in other markets. The conditions that generate demand for unlicensed alternatives are structural rather than incidental.
Novo Nordisk pushes back
“We do not condone mass compounding, which provides a significant risk to the safety of patients,” Novo Nordisk said. The company markets authorised versions including injectable Wegovy and an oral pill.
The commercial interest is obvious and does not make the safety argument wrong. A manufacturer objecting to unlicensed copies of its product is protecting revenue, and the absence of testing data is a real deficiency independent of who points it out.
The dispute echoes a running battle between manufacturers and compounders in the US, where compounded semaglutide proliferated during shortages and has been the subject of extended litigation and regulatory action.
What happened when this played out in the US
The American experience with compounded semaglutide is the closest available guide to how the UK situation may develop.
US law allows compounding pharmacies to prepare copies of a drug that is officially in shortage — an exemption intended to keep patients supplied when a manufacturer cannot meet demand. Semaglutide and tirzepatide were listed as in shortage for an extended period, and a large compounding industry grew around them, supplying telehealth platforms at a fraction of branded prices.
When the shortages were declared resolved, that legal basis disappeared, and manufacturers pursued enforcement and litigation against sellers who continued.
Two problems surfaced along the way. Some products contained semaglutide salt forms rather than the active base, chemically distinct and not the drug studied in trials. And dosing errors caused real harm, because patients drawing doses from vials with syringes miscalculated units in a way the branded pen prevents by design.
The UK exemption is narrower and there is no shortage-based provision of the same kind, but the demand conditions and the safety failure modes transfer directly.
This describes a regulatory dispute and is not a recommendation. Unlicensed compounded medicines have not been assessed by regulators for safety or effectiveness.