3 Potential Benefits of Synephrine + Safety & New Research


Synephrine is a naturally occurring chemical that has been sought after by athletes and those looking to lose weight; some people believe that it increases the bodys energy production, but what does the science say? Read on to learn more about the potential benefits, mechanisms, and the safety of synephrine supplementation.


What is Synephrine?

Synephrine is a biogenic amine.


It is found at high levels in the peels of citrus plants, like bitter orange or Seville orange (Citrus aurantium). Extracts from fruits or peels of these plants have been used in traditional Chinese medicine to treat stomach problems and allergies for hundreds of years.


There is much confusion and controversy over whether synephrine is safe and what effects it has on the body. This is because many sources, and even some scientific journals, confuse synephrine with other substances including:


synephrine also stimulates neuromedin U2 receptors, molecules found mostly in the hypothalamus, which increases wakefulness.Anti-Inflammatory Activity

In cells, synephrine stops the production of eotaxin-1, a molecule that signals to eosinophils to move to an inflamed area. It also blocks the activity of the NADPH oxidase, an enzyme produced in neutrophils that creates many reactive oxygen species.


Synephrine also reduces the activation of NF-κB. Overactive NF-κB plays a role in many inflammatory diseases like asthma, inflammatory bowel disease, and psoriasis.


Oxidative Stress

Synephrine reduced the production of reactive oxygen species (ROS) released by neutrophils (a type of white blood cell found at sites of inflammation) by inhibiting the enzyme NADPH oxidase, which produces many types of free radicals.


Other Effects

Synephrine may also block acetylcholinesterase and butyrylcholinesterase, enzymes that are harmful in Alzheimers disease.


However, these effects have not been explored in animal or human studies, and this finding from cell studies may have no clinical relevance whatsoever.

Potential Benefits of Synephrine

Synephrine supplements have not been approved by the FDA for medical use and generally lack solid clinical research. Regulations set manufacturing standards for them but dont guarantee that theyre safe or effective. Speak with your doctor before supplementing with synephrine.

Possibly Effective For

1) Metabolic Rate & Fat Burning

A study of 10 subjects given 50 mg of p-synephrine showed that the subjects burned 65 calories more than participants given placebo in the first 75 minutes after taking the supplement.


Subjects given synephrine did not have increased blood pressure or heart rate .


A study of 17 people given p-synephrine before exercise showed that people given p-synephrine burned more fat as opposed to carbohydrates during exercise. No effect on heart rate was observed.


Another study of 23 people given a combination of caffeine and bitter orange extract (C. aurantium) showed higher amounts of fat being burned even while at rest than those given placebos. This study also found no difference in heart rate or blood pressure between the groups.


These results are supported by a study of 12 men that showed increased fat burning at rest and up to 30 minutes after exercise in men given synephrine, or a combination of synephrine and caffeine compared to placebo. In this study, only those men given caffeine showed increased heart rates.


Small doses of caffeine may be needed for synephrine to burn fat while the body is at rest, however. Another study of 18 people found that p-synephrine without caffeine did not burn more fat at rest, but did burn more during exercise.


The sizes of these studies are small, so more research is needed to confirm these effects. More research is also required to fully clarify the relative role of synephrine in studies on bitter orange or combinations with caffeine.


Insufficient Evidence For

While some clinical evidence has emerged for the potential benefits in this section, the available studies are too small, contradicted by other studies, or yet to be repeated. As such, the evidence is insufficient to recommend synephrine for these purposes, and there are better-studied alternatives available.


2) Athletic Performance

In a study of 12 men, p-synephrine taken 45 minutes before exercise increased the number of repetitions and maximum weight load when performing squats compared to placebo. Taking caffeine in addition to p-synephrine further increased the subjectsmaximal squat repetitions and weight load.


However, another study of 13 sprinters given p-synephrine failed to show improvement in sprint velocity or jumping heights compared to placebo.


3) Antifungal Activity

Bitter orange oil, which contains synephrine in addition to other active ingredients, in one study of 60 patients, improved fungal skin infections of the (feet, body/skin, or groin) in 2 to 3 weeks in over 80% of participants.


Animal and Cell Studies (Lacking Evidence)

No clinical evidence supports the use of synephrine for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies listed below should not be interpreted as supportive of any health benefit.


4) Irritable Bowel Syndrome

Synephrine reduced the movement of intestinal muscles in animals. Overactive intestinal muscles are linked to a number of stomach problems, like irritable bowel syndrome and constipation.


No studies directly link synephrine to the relief of stomach problems, but its ability to reduce intestinal muscle movement makes it a promising avenue of future research for these health issues.


  1. Mood and EnergyMice with classic signs of depression, including sleep problems and changes in eating habits, do worse in response to stressful events, like being forced to swim, than healthy mice do. 

    One study showed that mice fed synephrine were able to swim longer, indicating higher energy and mood levels.


    6) Inflammation

    In mice with lung injury, synephrine reduced the number of inflammatory cells and inflammatory cytokines TNF-alpha and IL-6, while increasing the anti-inflammatory IL-10.


    In addition, synephrine also reduced the activation of NF-κB. Overactive NF-κB plays a role in many inflammatory diseases like asthma, inflammatory bowel disease, and psoriasis.


    In cell studies, synephrine stopped the production of eotaxin-1, a molecule that signals to eosinophils to move to an inflamed area.


    It also blocked the activity of the NADPH oxidase, an enzyme produced in neutrophils that creates many reactive oxygen species.


    7) Allergy Symptoms

    A study performed using guinea pigs showed that synephrine reduced spasms of the smooth muscle in the trachea, a symptom that is associated with coughing. Synephrine also reduced asthma symptoms that occurred when the animals were given histamines.


    8) Antimicrobial Activity

    One laboratory study showed that synephrine prevented the growth of some bacteria including E. coli, which can cause food poisoning, as well as Staphylococcus aureus, which can cause skin infections.


    Side Effects & Precautions

    Serious side effects of supplements that contain synephrine have been reported. In many cases, these were reported for supplements that contain other active ingredients like caffeine in addition to synephrine. In order to avoid adverse effects or unexpected interactions, talk to your doctor before using synephrine.


    Reported side effects of synephrine-containing supplements include:


Post time: Oct-26-2020
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