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The mechanism of action of synephrine is relatively unique among weight loss aids. Synephrine is an agonist of the alpha(1) adrenoreceptor [1-2], which is involved in many physiological processes. This adrenoreceptor plays a variety of roles in adipose tissue, such as modulating intracellular Ca2+ and protein kinase C levels and glycogenolysis and lactate production [3]. Correspondingly, alpha(1) agonists increase lipolysis in a variety of experimental paradigms [3-6], including an in vivo increase in lipolysis in human white adipose tissue [4]. This effect is potentiated by beta receptor stimulation, adenosine antagonism, and elevated cAMP levels [5-7], so ephedrine, caffeine, and forskolin may all be synergistic with synephrine. The appetite suppression caused by some agents is also known to be due to alpha(1) agonism [8], so synephrine can also be expected to aid in a fat loss plan in this regard.
The dosage of synephrine typically used is 10-20 mg daily, although some use as much as 50 mg daily. It is recommended to start with a low dose and work up, and exercise caution when combining synephrine with stimulants. Synephrine should not be taken if one is taking an MAO inhibitor or blood pressure medication.
If you have any questions or comments regarding this article, please email dvdtlsn@bulknutrition.com.
1. Song DK, Suh HW, Jung JS, Wie MB, Son KH, Kim YH. Antidepressant-like effects of p-synephrine in mouse models of immobility tests. Neurosci Lett. 1996 Aug 23;214(2-3):107-10. [abstract]
2. Brown CM, McGrath JC, Midgley JM, Muir AG, O'Brien JW, Thonoor CM, Williams CM, Wilson VG. Activities of octopamine and synephrine stereoisomers on alpha-adrenoceptors. Br J Pharmacol. 1988 Feb;93(2):417-29. [abstract]
3. Flechtner-Mors M, Jenkinson CP, Alt A, Adler G, Ditschuneit HH. In vivo alpha(1)-adrenergic lipolytic activity in subcutaneous adipose tissue of obese subjects. J Pharmacol Exp Ther. 2002 Apr;301(1):229-33. [abstract]
4. Boschmann M, Krupp G, Luft FC, Klaus S, Jordan J. In vivo response to alpha(1)-adrenoreceptor stimulation in human white adipose tissue. Obes Res. 2002 Jun;10(6):555-8. [abstract]
5. Zhao J, Cannon B, Nedergaard J. alpha1-Adrenergic stimulation potentiates the thermogenic action of beta3-adrenoreceptor-generated cAMP in brown fat cells. J Biol Chem. 1997 Dec 26;272(52):32847-56. [Abstract]
6. Schimmel RJ, Elliott ME, Dehmel VC. Interactions between adenosine and alpha 1-adrenergic agonists in regulation of respiration in hamster brown adipocytes. Mol Pharmacol. 1987 Jul;32(1):26-33. [abstract]
7. Raasmaja A, Larsen PR. Alpha 1- and beta-adrenergic agents cause synergistic stimulation of the iodothyronine deiodinase in rat brown adipocytes. Endocrinology. 1989 Nov;125(5):2502-9. [abstract]
8. Cheng JT, Kuo DY. Both alpha1-adrenergic and D(1)-dopaminergic neurotransmissions are involved in phenylpropanolamine-mediated feeding suppression in mice. Neurosci Lett. 2003 Aug 21;347(2):136-8. [abstract]
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