Synephrine is a substance that helps to stimulate the metabolism. It can produce effective weight loss and also boosts power and number of repetitions during a workout. The main effects of synephrine come from its ability to trick the body into increasing the rate of metabolism and energy use.
It works as a brain chemical similar to serotonin or norepinephrine. The body ‘eats’ synephrine using enzymes called Monamine Oxidase enzymes (MAOs). Unlike many similar compounds, synephrine supplements do not produce any negative side effects and it is regarded as being very safe.
Caffeine is possibly the most consumed stimulant on Earth today. It can be drunk in coffee from roasted beans, used in energy drinks, or taken as a powdered extract. Caffeine is also a stimulant and its effects are similar to the effects of synephrine. It is most commonly found in coffee beans, green tea, cocoa, and Yerba Mate.
Many studies have shown caffeine’s ability to increase running capacity, power output, adrenalin, focus, and concentration. It is also used to prevent drowsiness and sleep.
Side effects of caffeine include increased blood pressure, heart rate, and blood glucose levels, as well as anxiety and restlessness.
Interactions / safety
Caffeine and synephrine are both stimulants and using them together may increase the effects of both. Synephrine is regarded as a safe supplement for use in weight loss and weight management or as an effective pre-workout.
Caffeine is often used for the same effects but most commonly to increase focus and prevent drowsiness.
Many pre-workout supplement ‘stacks’ combine synephrine with caffeine. There is some debate about the safety of taking synephrine in combination with caffeine.
Studies have found that synephrine use is safe both alone and in combination with caffeine: see <here> and <here>. However, some government agencies in Europe have decided to remove supplements combining synephrine and caffeine from the market for safety reasons.
Both Finland and Germany produced health assessments saying that combining synephrine with caffeine could increase potentially harmful effects of increase blood pressure and heart rate.
However, these claims are at odds with the scientific research which appears to have found that synephrine does not produce cardiovascular effects.
Synephrine vs Caffeine
Synephrine and caffeine have similar effects but are also quite different.
Caffeine is a stimulant that mostly acts on the central nervous system, and also affects the digestive and circulatory systems. It produces effects of alertness, wakefulness and increased mood. However, caffeine also has some side effects. These can include irritability, anxiety, headaches and jitters.
Synephrine is a metabolic stimulant, meaning it acts mostly on the metabolism. The main effects of synephrine include metabolism boost, increased power, and increased energy expenditure. Synephrine is predominantly used as a weight loss supplement or a pre-workout.
So, synephrine boosts the metabolism while caffeine increases your alertness and wakefulness. It is difficult to compare the two because they have such different benefits.
Caffeine effects may include some of the same effects of synephrine, but if you are looking for a weight loss supplement, synephrine would be the one to choose! That’s because synephrine doesn’t have the negative side effects that caffeine produces and may be more potent at stimulating the metabolism and boosting power!
 Stohs SJ, Preuss HG, Shara M. A Review of the Human Clinical Studies Involving Citrus aurantium (Bitter Orange) Extract and its Primary Protoalkaloid p-Synephrine. Int J Med Sci 2012; 9(7):527-538. doi:10.7150/ijms.4446. Available from http://www.medsci.org/v09p0527.html
 Caffeine, Examine.com: https://examine.com/supplements/caffeine/ , retrieved June 20, 2016
 Health assessment of sports and weight loss products containing synephrine and caffeine BfR Opinion No. 004/2013, of 16 November 2012
 THE EFFECTS OF CAFFEINE ON THE BODY, Ann Pietrangelo, October 22, 2014, Healthline.com: http://www.healthline.com/health/caffeine-effects-on-body, retrieved June 20, 2016
 Synephrine, Examine.com: https://examine.com/supplements/synephrine/, retrieved June 20, 2016