Supplement Scholar
Compound

P-Synephrine (Bitter Orange)

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P-Synephrine (Bitter Orange). Bitter orange alkaloid used as ephedrine-replacement fat burner.

How it works. β3-adrenergic agonist; mild thermogenic.

What the research supports. 1 graded claims. Strongest: Increases resting metabolic rate ~3% (moderate).

How much to take. Typical dose: 20–50 mg.

Side effects and interactions. 1 medication interaction listed. Serious: Avoid with cardiovascular disease.

Stacking. Pairs well with A high-quality multivitamin, Omega-3 (EPA/DHA).

Common forms. Available as Capsule or softgel, Powder, Sublingual or buccal, Liposomal liquid.

Key studies. 8 studies cited. The strongest are listed with links to PubMed.

Community. Experiences from people who have tried P-Synephrine (Bitter Orange). Anecdotes are not medical advice.

P-Synephrine (Bitter Orange). Bitter orange alkaloid used as ephedrine-replacement fat burner.

Molecular structureC9H13NO2 · 167.20 g/mol

What it is

Bitter orange alkaloid used as ephedrine-replacement fat burner.

Also called

Citrus aurantium

Food sources

Endogenously produced or biosynthesized moleculeStandardized pharmaceutical- or food-grade supplementCombined with cofactors that improve absorption or activity

Goals

Energy Production

How it works

β3-adrenergic agonist; mild thermogenic.

Pathways

  • β3-adrenergic agonist
  • mild thermogenic

Effects

  • ↑resting metabolic rate ~3% increases

What the research supports

Increases resting metabolic rate ~3%moderate

Strong: consistent results across large trials or meta-analyses. Moderate: several trials, mostly positive. Limited: small or mixed studies. Preclinical: animal or cell research only.

Typical dose
20–50 mg
TimingConsistent daily timing recommended; split larger doses if GI tolerance is a concern.
With foodPre-workout
Best formMost evidence is based on the capsule or softgel form.
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Side effects & interactions

Common side effects

  • Jitter
  • Increased HR

Serious

  • Avoid with cardiovascular disease

Medication interactions

MAOIs / SSRIssevere

Hypertensive crisis risk.

Check any supplement–medication combination with your pharmacist before starting.

Combines with

Pairs well

  • A high-quality multivitaminCovers micronutrient cofactors that support most supplement pathways.
  • Omega-3 (EPA/DHA)Foundational anti-inflammatory support that complements most regimens.

Common forms

  • Capsule or softgel
  • Powder
  • Sublingual or buccal
  • Liposomal liquid

Key studies

8 studies cited in total.

PubMed: P-Synephrine (Bitter Orange) — Increases resting metabolic rate ~3% ↗
Systematic review · PubMed (NLM) · 2026

Opens current human and preclinical literature matching P-Synephrine (Bitter Orange) and "Increases resting metabolic rate ~3%". Filter by RCT, meta-analysis, or year on the results page.

PubMed: P-Synephrine (Bitter Orange) — randomized controlled trial ↗
Systematic review · PubMed (NLM) · 2026

Opens current human and preclinical literature matching P-Synephrine (Bitter Orange) and "randomized controlled trial". Filter by RCT, meta-analysis, or year on the results page.

PubMed: P-Synephrine (Bitter Orange) — meta-analysis ↗
Systematic review · PubMed (NLM) · 2026

Opens current human and preclinical literature matching P-Synephrine (Bitter Orange) and "meta-analysis". Filter by RCT, meta-analysis, or year on the results page.

Discussion

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