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1.5/5 Very weak evidence

Fat loss evidence brief

Synephrine / bitter orange

Used in thermogenic and pre-workout products, but weight-loss and performance evidence is weak while cardiovascular and interaction concerns matter.

Poor risk-reward focus / health 6 linked sources Content audit 2026-05-04

Headline Finding

Reviews show weak efficacy evidence and recurring cardiovascular, stimulant-stacking, and interaction concerns.

Dose Context

Avoid stacking with high caffeine or other stimulants; product labels often make attribution difficult.

Important Caveat

Stimulant-sensitive users, medication users, and people with cardiovascular risk need caution.

Source Drawer

Linked Research

6 papers and evidence links - audit 2026-05-04
  1. Meta-analysis Safety/efficacy meta-analysis
  2. Safety NCCIH bitter orange safety
  3. Review Exercise narrative review
  4. Trial Resistance exercise trial
  5. Review Adverse-event case review
  6. Review Weight-loss supplement fact sheet

How To Read This Rating

The score reflects evidence that the supplement does its stated job. Some jobs are direct, such as strength, endurance, or recovery; others are indirect, such as sleep, mood, appetite, or health support. A real effect can still receive a cautious practical rating when dose, safety, product quality, or audience fit remain uncertain.

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