Today ANSES publishes its recommendations on dietary supplements for weight-loss containing p-synephrine

P-synephrine, a substance found in the skin of bitter oranges, is used as an ingredient in numerous so-called "weight-loss" food supplements. ANSES has received 18 reports of adverse reactions likely to be linked to consumption of food supplements containing p-synephrine. Following its assessment, ANSES considers that intake levels of p-synephrine through food supplements must remain below 20 mg/day and recommends not taking p-synéphrine with caffeine. It also recommends avoiding using products containing p-synephrine during physical exercise and discourages its use by sensitive individuals (people taking certain treatments, pregnant or breastfeeding women, children and adolescents). 

P-synephrine is found in the skin of bitter oranges (Citrus aurantium ssp. aurantium) and in other species of Citrus. P-synephrine, as well as other ingredients obtained from Citrus spp. fruits, is found in many food supplements which allegedly reduce body fat or alter body composition.                                 

Weight problems, whether objective or subjectively perceived, create fertile ground for use of these types of products, either alone or in combination with a diet or physical exercise.

Nutrivigilance: 18 adverse effect reports received by the Agency

Since the creation of its nutrivigilance system in 2009, ANSES has received 18 well-documented reports of adverse effects potentially linked to the consumption of food supplements containing an ingredient obtained from Citrus spp. fruits, which are a source of p-synephrine.

The thirteen cases with a very likely, likely or possible causal link include cardiovascular effects, liver damage, hyperphosphoremia and neurological damage. 

Isolated cases of severe adverse effects, mainly cardiovascular in nature, have also been reported in the literature. In these cases, it is rarely possible to unequivocally attribute the reported adverse effects to Citrus spp. due to the presence of other etiologies, co-morbidities, and especially to complex associations.

Intakes through food supplements should be distinguished from common food-based intakes of p-synephrine, through the consumption of citrus juices in particular. This type of intake through food is widespread, and a balanced diet which may include up to 20 mg/d of p-synephrine does not seem to expose the general public to any risks linked to the presence of this substance. The food supplements containing Citrus spp. extracts which have been to subject of declarations of cardiovascular effects within the context of the nutrivigilance scheme provide between 1 and 72 mg of p-synephrine per day, according to the doses recommended by the manufacturer, and all contain caffeine.

Agency conclusions and recommendations

Following its assessment, ANSES:

  • considers that a dose of 20 mg/day, corresponding to the dose ingested by consumers of large amounts of citrus fruit, may be a reference value representing the p-synephrine intake level not to be exceeded in food supplements (although it is not strictly speaking a safety limit as such); 
  • notes that many of the food supplements currently on the market provide a daily intake of this substance which surpasses the above reference value; these food supplements therefore should not be made available to the consumer;
  • recommends not combining p-synephrine with caffeine, preparations containing caffeine, or any substance possessing cardiovascular effects similar to those of caffeine, due to the cumulative, and possibly synergystic effects of these two substances. For these reasons, synephrine and caffeine should not be combined into a single food supplement;
  • strongly discourages the consumption of p-synephrine by individuals with heightened risks of adverse effects (people under treatment for high blood pressure, heart disease or depression in particular), pregnant or breastfeeding women, children and adolescents. This information should be made clearly available to consumers;
  • strongly discourages taking food supplements containing p-synephrine during physical exercise due to its possible effects on blood pressure. These effects could heighten cardiovascular risk in overweight or obese subjects, and reduce the beneficial effects of prolonged physical activity on blood pressure at rest.

Due to the contexts in which food supplements containing p-synephrine are commonly used, ANSES recalls the main recommendations it issued in 2001 following its risk assessment of dietary weight-loss practices. Weight-loss diets pose a risk to health, and may have harmful effects on the bones, kidneys, heart, as well as on behaviour and psychological well-being and may pose a risk of regaining the weight lost. Without monitoring by a healthcare professional, and in situations other than those where weight loss is medically justified, weight-loss diets are not recommended.