The Medical Health Care Products Regulatory Agency (MHRA) has launched an investigation into the marketing of a number of detox products, including Gillian McKeith's 24 hour detox.
BBC ONE's Doctors on a Detox programme drew their attention to medical claims made by some of the most popular products on the market.
The programme found detox products that claimed to enhance the immune system, stimulate poor circulation, correct hormonal imbalances, relieve pain, benefit sufferers of Rheumatism, Gout or Arthritis as well as flush out harmful toxins.
Yet the products have not undergone proper medical tests and are not licensed to make medical statements.
Medical claims can only be made after rigorous testing.
It is a criminal offence against the Medicines (Advertising) Regulation Act 1994 to issue an advertisement relating to a relevant medicinal product without a licence.
A spokesman for the MHRA said: "Licenses will only be granted after the safety and efficacy of products have been shown in clinical trials.
"Any product making a medical claim has to prove that quality standard.
"The consumer has to be able to trust what they buy."
The MHRA is now writing to a number of detox product manufacturers to ask them to withdraw any unproven medical claims.
Gillian McKeith's 24 hour Detox claims to 'cleanse and normalise your body's vital organs, including liver, bowels, gall bladder, spleen and abdominal intestine system'.
According to the MHRA this is a medical claim that requires the product to be tested and licensed.
Gillian McKeith's company told the BBC that they believed the claims complied with current legislation and that "packaging is changed immediately if it is found to be out of line."
SlimLife Detox Foot Patches claim to 'flush harmful toxins from your body' and 'assists in boosting the immune system'.
SlimLife told the BBC they will be discussing the claims made for the product with the MHRA but an independent trial of 84 people had tried the product and the response was excellent.
Shapechangers'.Detox Wrap Deluxe Home Kit claims the clay wraps can detox and also 'soothes psoriasis and eczema'.
Manufacturers Sirius Blue said the medical claims are no longer made, although they acknowledged that old stock is still being sold.
Doctors on a Detox, a BBC ONE Real Story programme, will be broadcast on Monday 27 March on BBC ONE at 7.30pm.