Nearly half of all slimming clinics offer unsafe care, with some leaner drugs that could put their health at risk, a report warned.
Some appetite suppressants prescribed to patients who should not have used them because they were not overweight enough or were already on therapy to lower blood pressure.
The Commission for the Quality of Assistance (CQC), the health inspectorate for England, has also expressed concerns that too many private doctors incorrectly prescribe painkillers and antibiotics or unauthorized drugs.
His findings, based on inspections in 2017-18, raise questions about safety standards in the independent health sector, which also includes clinics that offer travel services, allergy and circumcision.
CQC inspectors considered that the cure was not safe in 16 of the 38 weight-loss clinics and 32 of the 66 private medical services visited.
The report revealed: "Nearly a quarter of weight-loss clinics (nine out of 38 analyzed inspection reports) did not comply with the regulations for effective care, some found that they treated people with medicines not recommended by the National Institute for health and care excellence (Nice) or the Royal College of Physicians.
"The inspectors found examples of appetite suppressants prescribed to patients with a lower BMI (body mass index) than recommended, or to patients with hypertension."
Some clinics have prescribed and supplied slimmers with "medicines that were neither clinically nor economically effective," he added.
While some slimming clinics paid attention to CQC advice and made improvements, others did not. The regulator withdrew the operating license of a clinic which, when reinspected, was found not to have addressed the concerns raised during the first visit.
It has also raised the alarm about questionable and potentially risky practices involving the prescription of drugs by some private doctors. However, he pointed out that some patients ended up receiving drugs that could be dangerous because they didn't reveal to a private doctor appointment that they had already sought, or were already receiving, health care for a problem.
"This has implications for the safety of the prescription, particularly high-risk drugs including opioid painkillers and antibiotics," the report said.
"Some patients may choose to use a private service after refusing an NHS GP prescription because it is deemed inappropriate or dangerous." This can lead to antibiotic resistance, the CQC added, which said it had similar concerns about private doctors prescribing painkillers ignoring the fact that a patient was already receiving another treatment.
He also highlighted another problem, stating: "We have expressed concerns about prescribing medicines without a solid foundation of scientific evidence and prescribing unauthorized medicines. At a number of inspected services, the prescriber was unable to inform the patients that the medicine was not authorized. "
While some for-profit service providers offered excellent assistance, "too often we have seen poor practice and suppliers with a limited awareness of their responsibilities, not only for their patients but for the wider healthcare system", said Ursula Gallagher, deputy head of the watchdog inspector of general practice and guide for independent suppliers.
He reminded independent suppliers of "having the legal responsibility to offer a safe and high quality care that not only meets the needs of the people who use it, but also meets the existing legal requirements to protect patients".
. (tagToTranslate) Health (t) Diets and diet (t) Obesity (t) Assistance Quality Commission (CQC) (t) Drugs (t) Regulators (t) Company (t) News of the United Kingdom