By Summer Banks FNS, SPT on Jun 26, 2023

Various herbs and ingredients, including synephrine, are used in dietary supplements for health, fitness and weight management.

It is critical to gain a good understanding of each ingredient or supplement before you begin consuming it regularly. After all, you need to be fully aware of any benefits, potential side effects, clinical research and drug interactions.

One ingredient that is commonly found in over-the-counter weight-loss supplements and fitness products is synephrine.

In this article, we will take a close look at the details and clinical research regarding synephrine to help you better determine whether or not it is right for you and your goals/needs.

What is Synephrine?

To begin with, synephrine is a molecule or alkaloid that is found in bitter orange fruit, according to

It’s also known as citrus aurantium or the brand name Advantra Z. Sometimes called p-synephrine, this substance is a type of stimulant, as stated on the African Journal of Plant Science.

Experimental Biology and Medicine said that, typically synephrine is a key component used in diet products and workout supplements, which was a popular thermogenic used in over-the-counter diet pills as stated by PubMed. However, it was banned in 2004 due to serious side effects and health concerns, according to RxList.

According to WebMD, this alkaloid occurs naturally in some other plants and animals. It has been used in traditional Chinese medicine for many years.

Often synephrine is combined with herbal stimulants such as caffeine, yerba mate, green tea and guarana seed. This helps intensify its effect.

Put simply, synephrine is a natural alkaloid and stimulant that is found in bitter orange, according to the Journal of AOAC International.

What Does Synepherine Do?

An International Journal of Medical Sciences study have shown that synephrine elevates heart rate or elevates the body’s core temperature according. Another research published in the British Journal of Clinical Pharmacology analyses synephrine’s role in burning fat during rest and exercise.

Specifically, this alkaloid affects the central nervous system. It squeezes or constricts blood vessels, according to a study posted on the Journal of Pharmacological Sciences.

This chemical also helps improve focus and concentration, which can be beneficial for exercise.

According to a study published by the Journal of the International Society of Sports Nutrition, synephrine essentially impacts the nervous system, which in turn may help boost metabolism, increase energy expenditure during workouts and enhance focus.

How Much Synepherine Do You Need?

The amount of synephrine you need just depends on what you are trying to accomplish or what your fitness goals are. Your age, gender, and weight will also play a part in how this stimulant affects you. states that the recommended dosage is 32 milligrams, which can be taken daily.

However, some people do use as much as 50 milligrams, up to three times a day. It’s best to consult a licensed physician before taking a high dosage of this ingredient.

The amount of synephrine needed depends on your health and fitness goals. However, a dosage of 32 milligrams daily is considered safe and effective, as stated on Livestrong.

Effects of Synephrine

Some clinical studies have been conducted with synephrine.

One study published by the Journal of the International Society of Sports Nutrition involving 12 college-aged men revealed that a 100-milligram dose of synephrine provided more endurance for an increase in workout performance via repetitions and sets.

Another clinical study published by the Journal of the American College of Nutrition showed that p-synephrine when taken in combination with caffeine, can help increase cardiovascular response and lipolysis during resistance exercises.

It’s clear that synephrine can help intensify workouts, especially when taken in conjunction with a stimulant such as caffeine.

Synephrine and Weight Loss

There’s a wealth of research and studies connecting synephrine and weight-loss.

One clinical study published by Obesity Reviews showed that synephrine alkaloids could help treat obesity and aid with weight-loss.

Other research, including one study published by the British Journal of Clinical Pharmacology involving 18 healthy adults, has revealed that the acute ingestion of p-synephrine supplements can help increase fat oxidation and energy expenditure during workout.

Furthermore, some studies have shown that p-synephrine is similar to adrenergic agents, according to a journal by Molecules. More specifically, it can help improve liver metabolism, increase glycogenolysis and enhance calorie burning to aid with weight reduction.

Synephrine can help to some degree with weight-loss and treating obesity. It can reduce appetite, boost metabolism and improve fat oxidation, especially when taken in conjunction with stimulants like caffeine.

Additional Health Benefits of Synephrine

There are some additional health benefits that have been linked to synephrine as mentioned by WebMD. These include reducing glucose production (Journal of Medicinal Food), improving heart health (The Japanese Journal of Pharmacology), minimizing nasal congestion ( and treating constipation (University of Michigan Health Library).

First off, some research has shown that topical bitter orange oil can help treat fungal infections such as athlete’s foot, ringworm and jock itch.

Also, one clinical study published by Journal of Medicinal Food demonstrated that p-synephrine could help suppress glucose production.

There is also some research that ties this alkaloid to nasal congestion treatments. One study revealed that this ingredient is a decongestant and vasodilator, which means it can help clear the airways or sinuses, as stated on

Sometimes bitter orange or citrus aurantium is even used to treat digestive conditions such as constipation. In fact, this plant extract is often used in regions like South America and Mexico as a natural laxative, according to the University of Michigan Health Library.

Synephrine Side Effects

As with many herbs and ingredients, synephrine can lead to some unwanted side effects. These may include headaches (Livestrong), fainting, and nausea. The chances for adverse reactions are heightened when this ingredient is taken in combination with stimulants like caffeine.

One 24-year-old man experienced ST-segment-elevation myocardial infarction [STEMI] after taking an over-the-counter diet supplement for weight-loss that contains this substance, according to a study published by the Texas Heart Institute Journal.

Moreover, other clinical studies have presented some safety concerns regarding this stimulant, as stated on the Phytotherapy Research. However, the dosage consumed and the individual using the supplement are important factors when it comes to adverse reactions. It’s best to consult a licensed doctor before taking a supplement that contains this component.

There are some side effects that can occur while taking a synephrine product. However, these unpleasant adverse reactions are more likely to happen when this chemical is taken with stimulants such as caffeine, according to Mayo Clinic.

What Users Are Saying

“I take as a stimulant in addition to caffeine. Compared to caffeine, the CNS stimulation I get from it is low. But I work in physical labor in a cold climate and I’ve found it significantly helps me dealing with cold resistance – I believe it comes from its effects on increasing norepinephrine. It helps with insulin resistance and obviously I also take it for it’s fat burning capabilities – from what I’ve understood, something like 100 calories per day or a few kgs of fat per year.”

“I am interested in this as well! I took a supplement. With synephrine but it was a smartshop formula and I got headache the whole evening. Now I am going to try bitter orange and mandarin marmelade first and if I dont get headache from that I’ll try synephrine separately.”

“Synephrine is quite weak and does not cross the blood brain barrier like ephedrine does so you won’t really “feel” it. It’s more of a “true” thermogenic that burns a handful of extra calories in the background.”

The Bottom Line on Synephrine

It’s evident that synephrine, a chemical found in bitter orange or citrus aurantium, can assist with weight management and does have some health benefits. However, this substance appeared to be most effective for weight-loss and increased athletic performance when it is combined with stimulants such as caffeine.

Since there are certain side effects that can occur while using Synephrine, it’s best to fully understand the supplement, all of its ingredients, and your overall health before taking anything. It’s also prudent to avoid taking too much of this ingredient. This should help you avoid adverse reactions.

If you have any preexisting medical conditions or health problems, be sure to consult a licensed physician before taking any synephrine supplements. Overall, it may be best to go down a different avenue if you want to lose weight, like a comprehensive weight-loss program.

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Synephrine – A Replacement for Ephedra?

Is synephrine a fat burner?

Yes, synephrine is a type of naturally occurring plant-based compound that can help to boost metabolism and promote fat burning. It also helps to regulate hunger and cravings, which can lead to improved weight loss results over time.

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About the Author:

Summer Banks has researched over 5000 weight-loss programs, pills, shakes and diet plans. Previously, she managed 15 supplement brands, worked with professionals in the weight loss industry and completed coursework in nutrition at Stanford University.