Ingredient · Updated 2026-08-17
Synephrine
p-synephrine · bitter orange · Citrus aurantium
Isolated p-synephrine has Grade C evidence for a small bump in metabolic rate at roughly 10–50 mg. The interesting — and riskier — use is inside multi-stim fat burners. If milligrams are hidden, do not guess.
- Study-dose band
- 10–50 mg p-synephrine
- Typical bottle
- Often undisclosed inside bitter orange 6% extracts
Evidence by outcome
| Outcome | Grade | Note |
|---|---|---|
| Energy expenditure | C | Stohs reviews describe modest thermogenic effects for p-synephrine alone. |
| Fat loss in free-living adults | D | Standalone weight-loss RCTs are not compelling. |
Safety
- Bitter orange plus caffeine is the combination regulators worry about — blood pressure and heart rhythm.
- Not interchangeable with ephedrine, but not a candy either.
Unknowns
- 6% synephrine on an extract line is meaningless without the extract weight.
Questions
Is synephrine banned?
p-Synephrine is sold in many markets as a supplement. Sport and some regulators treat stimulant stacks differently. Check your rules.
Sources
Formulas on this desk
- Fat Burn Active — Eleven named actives, including forskolin, EGCG, synephrine, and caffeine — with almost no milligrams on the public label.