Some dietary products promoting weight loss commonly contain synephrine as one of the attributes. Synephrine is a naturally occurring alkaloid found in citrus fruits and is known for its long lasting adrenic effects compared to noradrenaline or epinephadrine. The main advantages compared to other adrenaline stimulating supplements is the weaker effect on raising arterial tension and heart rate, which means lower side effects.
Research published in the British Journal of Clinical Pharmacology investigated the effects of 3 mg per kg of body weight of p-synephrine on fat and carbohydrate metabolism during exercise on 18 subjects. The researchers reported an increase fat oxidation and decreased carbohydrate oxidation at low and moderate intensity. This research further reported that the maximal rate for burning fat was 0.7g/min, which would be 42g of fat per hour when taking the synephrine.
Getting the amount of synephrine used in this study would require consuming around 70 oranges depending on body weight, and therefore supplementation would be the better route.
Recommendations are ~10mg and a single dose of up to 50mg when taken in healthy individuals does not affect blood pressure or heart rate over 75 minutes and may increase calorie expenditure up to 65 kcal. (Haller, Benowaitz and Jacob, 2005).
Sign up below to get this research and others for free.