Synephrine
STIMULANTAlso known as: p-Synephrine, Bitter orange extract, Citrus aurantium
What is Synephrine?
Synephrine has COMPLEX regulatory status: Natural p-synephrine from bitter orange fruit IS permitted in supplements. However, synthetic p-synephrine HCl is NOT permitted. WADA has synephrine in its Monitoring Program—under surveillance for potential future prohibition. Do NOT confuse with methylsynephrine (oxilofrine) which is completely banned.
Why is Synephrine Banned?
Synthetic form not permitted. WADA monitoring for potential ban. Athletes should avoid due to regulatory uncertainty.
Health Risks & Side Effects
Health Risk Level
This substance has a moderate risk of overdose and low addiction potential.
warningCommon Side Effects
- arrow_rightIncreased heart rate
- arrow_rightElevated blood pressure
- arrow_rightHeadache
- arrow_rightAnxiety
blockContraindications
- arrow_rightHeart conditions
- arrow_rightHypertension
- arrow_rightMAO inhibitors
- arrow_rightOther stimulants
How Does Synephrine Work?
Alpha-adrenergic receptor agonist causing vasoconstriction and modest increases in metabolic rate and blood pressure.
History
Natural component of bitter orange. Complex regulatory status emerged. WADA monitoring. Distinct from banned methylsynephrine.
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Research articles and educational resources
Overview
Synephrine
Synephrine, or, more specifically, p-synephrine, is an alkaloid, occurring naturally in some plants and animals, and also in approved drugs products as its m-substituted analog known as neo-synephrine. p-Synephrine and m-synephrine are known for their longer acting adrenergic effects compared to epinephrine and norepinephrine. This substance is present at very low concentrations in common foodstuffs such as orange juice and other orange products, both of the "sweet" and "bitter" variety. The preparations used in traditional Chinese medicine (TCM), also known as Zhi Shi (枳实), are the immature and dried whole oranges from Citrus aurantium. Extracts of the same material or purified synephrine are also marketed in the US, sometimes in combination with caffeine, as a weight-loss-promoting dietary supplement for oral consumption. While the traditional preparations have been in use for millennia as a component of TCM-formulas, synephrine itself is not an approved over the counter drug. As a pharmaceutical, m-synephrine (phenylephrine) is still used as a sympathomimetic, mostly by injection for the treatment of emergencies such as shock, and rarely orally for the treatment of bronchial problems associated with asthma and hay-fever.
Scientific Research
From PubMed • 2 peer-reviewed studies
Sexual Performance Anxiety.
Sexual performance anxiety (SPA) is one of the most prevalent sexual complaints; yet, no diagnosis is recognized for either gender. Thus, research into treatment has been minimal.
p-Synephrine, ephedrine, p-octopamine and m-synephrine: Comparative mechanistic, physiological and pharmacological properties.
Confusion and misunderstanding exist regarding the lack of cardiovascular and other adverse health effects of p-synephrine and p-octopamine relative to ephedrine and m-synephrine (phenylephrine) which are known for their effects on the cardiovascular system. These four molecules have some structural similarities. However, the structural and stereochemical differences of p-synephrine and p-octopamine as related to ephedrine and m-synephrine result in markedly different adrenergic receptor binding characteristics as well as other mechanistic differences which are reviewed. p-Synephrine and p-octopamine exhibit little binding to α-1, α-2, β-1 and β-2 adrenergic receptors, nor are they known to exhibit indirect actions leading to an increase in available levels of endogenous norepinephrine and epinephrine at commonly used doses. The relative absence of these mechanistic actions provides an explanation for their lack of production of cardiovascular effects at commonly used oral doses as compared to ephedrine and m-synephrine. As a consequence, the effects of ephedrine and m-synephrine cannot be directly extrapolated to p-synephrine and p-octopamine which exhibit significantly different pharmacokinetic, and physiological/pharmacological properties. These conclusions are supported by human, animal and in vitro studies that are discussed.