Bitter Orange Extract
Also known as: Citrus aurantium, p-synephrine, synephrine, zhi shi, Advantra Z (branded extract)
Bitter orange extract is made from the immature fruit or peel of Citrus aurantium and is standardized to p-synephrine, a protoalkaloid structurally related to ephedrine but with much weaker cardiovascular activity. It became a common weight-management and pre-workout ingredient after ephedra was banned. Systematic reviews and meta-analyses have examined both efficacy and safety, and adverse-event case reports, mostly involving multi-ingredient products, have been reviewed. Doses are usually expressed as milligrams of synephrine.
Research summary
p-Synephrine is studied for beta-3 adrenergic activity that may raise resting energy expenditure without large effects on heart rate.
Dosage
Daily amounts, of extract.
| Lowest studied | Typical range | Highest studied | Upper limit |
|---|---|---|---|
| 200 mg | 200–500 mg | — | — |
200 to 500 mg of a 6 to 10% extract supplies roughly 10 to 50 mg p-synephrine per day, the range used in most studies. Keep synephrine at or below 50 mg per day and total with caffeine sources. Not recommended during pregnancy or for people taking stimulant or MAO-inhibiting medications.
Standardization: 6–10% p-synephrine
Source material: immature fruit or peel extract
Format suitability
- Capsule
- Powder
- Tablet
- Softgel
- Gummy
- Liquid
Bitter; capsules preferred. Some sports bodies restrict synephrine.
Formulation notes
Stimulant; additive with caffeine. Some competitive-sport programs restrict synephrine, and it is prohibited in some countries.
- Stimulant
- Not for pregnancy
- Notable drug interactions
Sources
Related ingredients
Caffeine Anhydrous
Sports performancePurified, dehydrated caffeine — the standard stimulant in pre-workouts, energy, and focus products.
Typical: 100–200 mg
Green Tea Extract (50% EGCG)
BotanicalA leaf extract of Camellia sinensis concentrated for catechins, especially EGCG, with a small amount of naturally occurring caffeine.
Typical: 300–500 mg
MCT Oil
Fatty acidMCT oil is a clear, flavorless oil made by fractionating coconut or palm kernel oil to isolate the medium-chain fatty acids caprylic (C8) and capric (C10) acid as triglycerides.
Typical: 5–15 g
L-Carnitine L-Tartrate
Amino acidA stable, highly soluble salt of L-carnitine with tartaric acid, the form most used in exercise-recovery research.
Typical: 1,000–2,000 mg
Guarana Extract
BotanicalGuarana is the seed of Paullinia cupana, an Amazonian vine whose seeds contain more caffeine by weight than coffee beans, along with theobromine and tannins.
Typical: 100–400 mg