Stimulants & Focus
Synephrine (Bitter Orange Extract)
Also known as: p-Synephrine · Bitter orange extract · Citrus aurantium
A mild adrenergic stimulant from bitter orange peel. Weaker than ephedrine but without the same cardiovascular risk profile. Most useful for thermogenesis and appetite suppression.
Effective Dose
10–30mg / day
per clinical evidence
Evidence Level
Moderate
Stimulants & Focus
Mechanism
Beta-3 adrenergic agonism, thermogenesis
primary action
Best For
Fat loss
Energy, Pre-workout stimulant
This profile is for informational purposes only and does not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation, especially if you have pre-existing conditions or take medications.
What Is Synephrine (Bitter Orange Extract)?
Synephrine (p-synephrine) is the primary alkaloid in bitter orange (Citrus aurantium), introduced widely as an ephedra replacement after ephedra was banned in 2004. It preferentially activates beta-3 adrenergic receptors, stimulating lipolysis and thermogenesis with less cardiovascular effect than ephedrine or adrenaline.
How It Works: The Science
Beta-3 receptor activation in adipose tissue and skeletal muscle increases cAMP, activating hormone-sensitive lipase (HSL) to mobilise stored triglycerides, and upregulating uncoupling protein (UCP-1) to increase heat production. Unlike ephedrine, synephrine has low affinity for alpha-1, beta-1, and beta-2 receptors — responsible for cardiovascular and CNS stimulant effects.
Primary Mechanism
Beta-3 adrenergic agonism, thermogenesis
Evidence-Based Benefits
Dosage Guide
Effective Dose
10–30mg / day
10–30mg p-synephrine per dose, up to 3× daily. Often combined with caffeine (synergistic thermogenesis). Bitter orange extracts vary widely in synephrine content — verify standardisation.
Safety Profile & Side Effects
Safe as a standalone at recommended doses in healthy individuals. Concern arises in combination with caffeine at high doses — elevated blood pressure and heart rate reported. Avoid in cardiovascular disease, hypertension, or with MAO inhibitors.
Who Should (and Shouldn't) Take It
Those in a fat loss phase wanting mild thermogenic support alongside a caloric deficit. Not a substitute for diet — effect size is modest (~65 extra kcal/day).
Frequently Asked Questions
Related Ingredients
Medical Disclaimer
Ingredient profiles are for informational purposes only and do not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation, especially if you have pre-existing conditions or take medications. Full disclaimer →