The pharmaceutical watchdog has reprimanded Wegovy maker Novo Nordisk for failing to correctly disclose dozens of payments to the UK health sector as it sought to boost sales of its slimming drugs.

The Danish drug giant – Europe’s most valuable listed company – systematically misreported, under-reported or did not disclose funding given over seven years to pharmacy firms, obesity charities, training providers, professional bodies and patient groups.

Even after admitting to errors and conducting an internal review, it failed to accurately report its spending. The company has now been formally reprimanded by the Prescription Medicines Code of Practice Authority (PMCPA), which said it had brought the industry into disrepute.

Finding 48 breaches of the industry code, it said serious compliance failings – committed while Novo Nordisk was already the subject of an audit after previous breaches – “raised questions about the culture of the company and demonstrated poor governance and a lack of care”.

It said that “by failing to publicly disclose payments, inaccurately reporting and misreporting payments to healthcare organisations and patient organisations over an extended period of time”, it “had brought discredit upon, and reduced confidence in, the pharmaceutical industry”.

The company was not referred for further sanctions because it has already been punished for similar breaches and is subject to an ongoing audit, the PMCPA panel said.

The undisclosed payments came to light after an investigation by academics in the UK and Sweden who cross-referenced transparency disclosures by Novo Nordisk with financial statements and other records from UK healthcare organisations.

The firm had previously admitted failing to correctly disclose payments, telling the PMCPA in 2023 that it had omitted more than 500 transactions worth £7.8m to more than 150 organisations between 2020 and 2022.

It was subsequently found to be in breach of industry code by the PMCPA which said in July that there had been “fundamental governance failures”.

But the investigation by researchers at Bath and Lund universities, which overlapped with the PMCPA probe, found that even after conducting an internal review and claiming to rectify the issue, Novo Nordisk failed to accurately record further payments totalling £635,000 to 30 organisations.

They submitted a 130-page complaint to the PMCPA which said in a ruling on Friday that Novo Nordisk repeatedly broke industry code over the payments, from 2015 to 2022.

These included £183,000 in undeclared funding to a weight-loss-coaching company that partners with pharmacies and the NHS and sponsorship of webinars provided by a medical training provider and grants to charities and a royal college. A £338,435 payment to a global obesity organisation was also incorrectly disclosed.

Dr Emily Rickard, who led the research at Bath, said it was “deeply concerning” that so many errors were not picked up in Novo Nordisk’s own review. This was “especially troubling”, given that they coincided with the UK launch of “blockbuster weight-loss drugs like Wegovy”. “This happened while the company was under audit – when compliance should have been a priority,” Rickard said. “It raises serious questions about transparency and accountability.”

Dr Piotr Ozieranski, a colleague of Rickard’s at Bath, said: “When a company as large as Novo Nordisk doesn’t disclose payments, it’s not just damaging to their reputation – it undermines trust in the entire healthcare system.”

Novo Nordisk said it was “dedicated to working transparently and ethically” and took the reporting of “these historical transfers of value extremely seriously”. It said it had voluntarily flagged most of the missed disclosures itself, and the others had now been accurately disclosed, adding that it was “committed to adhering to” industry code and maintaining the highest ethicalstandards.

The ruling against Novo Nordisk follows a series of investigations into tactics used by the Wegovy maker to promote its drugs.The Observer previously revealed how Novo Nordisk paid experts who went on to promote its drugs in media appearances without always making their financial interests clear. It has also funded the rollout of NHS weight loss services and provided hundreds of thousands of pounds’ worth of sponsorship to pharmacies including Boots and Lloyds.

The researchers said the latest findings showed the need for a “total overhaul” of systems for monitoring pharmaceutical spending in Britain.

There is no legal requirement for companies to disclose payments to the healthcare sector, but many subscribe to an industry code that requires them to report through a voluntary scheme called Disclosure UK.

Alleged breaches are assessed by the PMCPA, which can impose sanctions, including a public reprimand or requiring the company to publish a corrective statement. It can also report the company to the ABPI board, which may suspend or expel the firm from the association.

Critics say this is not enough. They are calling for a government run, centralised database for payment reporting, accessible to the public, with rigorous enforcement and penalties for non-compliance. “Transparency in the UK’s pharmaceutical industry is transparency in name only. A total overhaul is urgently needed,” Ozieranski said.

The Association of the British Pharmaceutical Industry, which represents drug firms, declined to comment, but Dr Amit Aggarwal, director of medical affairs, said the case was evidence the self-regulatory system was “holding companies to account”.

The Department of Health said: “We are considering options to increase transparency and will set out next steps soon.”