The agency became aware of the products following an operation by the Consumer Affairs, Environment and Doping Section of the General Commissariat of the Judicial Police, after which it ordered their sale to be halted.

The products affected are Slim U, Slim U Pro, P57 Hoodia, Bikini Siluet Perfect, Slim 24, 14 Día, Fatzorb, AB Slim, Get Lean, Slimina, Burn and Slim, Body Slim, Black Panther, Aphrodite Thermoslim Coffee, Aphrodite Plus, Aphrodite LipoDetox, Aphrodite Green Plus, Aphrodite Forte Plus, Aphrodite Forte, Li Da Ultra, Pineapple Slimming Peptide and Pezo Mega.

According to the AEMPS, analyses carried out by its Official Medicines Control Laboratory (LOCM) found that all 22 products contained sibutramine. Seven products, namely Fatzorb, AB Slim, Get Lean, Slimina, Burn and Slim, Body Slim and Black Panther, also contained phenolphthalein.

The presence of these substances means the products are considered medicines, despite never having been assessed or authorised by the AEMPS. The agency said the substances were not declared on the labelling and that the products were presented as natural, concealing their true composition from consumers.

Sibutramine is an appetite suppressant that creates a feeling of fullness and also increases calorie expenditure by counteracting the body's adaptive reduction in its basal metabolic rate during weight loss.

Its main risk is that it can increase heart rate and blood pressure, which the AEMPS said may be clinically significant in some patients. Cases of arrhythmias, ischaemic heart disease and serious cerebrovascular events have been reported in association with its use.

Other possible side effects include dry mouth, headache, insomnia and constipation, while the substance can also interact with numerous other medicines.

Sibutramine was previously used in prescription medicines for the treatment of obesity. Its sale in the European Union was suspended after use of the substance was associated with serious cardiovascular side effects.

Phenolphthalein, meanwhile, is found in some laxatives. It stimulates bowel movements and prevents the intestine from absorbing water, helping to soften stools.

The main risks associated with its use include excessive loss of fluids and electrolytes, which can cause dehydration, as well as intestinal protein loss, low blood calcium levels and poor absorption of nutrients resulting from excessive bowel motility.