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Systematic (IUPAC) name
CAS number  ?
ATC code C01CA08
PubChem 7172
Chemical data
Formula C9H13NO2 
Mol. mass 167.205 g/mol
Pharmacokinetic data
Bioavailability  ?
Metabolism  ?
Half life  ?
Excretion  ?
Therapeutic considerations
Pregnancy cat.


Legal status
Routes  ?

Synephrine (or oxedrine) is a drug aimed at encouraging fat loss. While its effectiveness is widely debated, synephrine has gained significant popularity as an alternative to ephedrine, a related substance which has been made illegal or restricted in many countries due to concerns about potential problems with heart disease risk and its use in methamphetamine manufacture. Synephrine is derived primarily from the fruit of [Citrus aurantium], a relatively small citrus tree, of which several of its more common names include Bitter Orange, Sour Orange, and Zhi shi.


  • Burns fat
  • Increases energy levels
  • Increases metabolism
  • Promotes weight loss

There has been some confusion surrounding synephrine and phenylephrine (a.k.a. neosynephrine), one of its positional isomers. Both chemicals are similar in structure, with the only difference being the location of the aromatic hydroxyl group. In synephrine, the hydroxyl is at the para position, while in neosynephrine it is at the meta position. Each compound has differing biological properties. Phenylephrine acts primarily on alpha1 adrenergic receptors, so it has mainly vasoconstricting actions. Synephrine's pharmacology has not been thoroughly studied.

Associated risks

Many diet products such as Stacker 2 contain synephrine along with caffeine. Some reports have indicated that such diet pills cause numerous harmful effects. The Mayo Clinic published a report that suggested a link between Stacker 2 pills and increased risk of stroke, increased blood pressure, and cardiac infarcts.

Synephrine can also cause arrhythmias [1]. It similar to ephedrine [1] and can therefore show similar symptoms (see Ephedrine#Adverse effects).


  1. ^ a b Livsmedelsverket (Swedish FDA)
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Synephrine". A list of authors is available in Wikipedia.
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