Synephrine
Research reviewed: 2011–2018
Synephrine (p-Synephrine) is a dietary supplement with 8 published peer-reviewed studies involving 1,089 participants, researched for Fat Loss & Metabolism, Exercise Performance, Receptor Pharmacology & Safety.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Fat Loss & Metabolism
StrongExercise Performance
ModerateReceptor Pharmacology & Safety
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Fat Loss & Metabolism
Synthesise evidence on p-synephrine for body weight and fat loss
Study Type
Meta-Analysis
Purpose
Synthesise evidence on p-synephrine for body weight and fat loss
Dose
10–100 mg/day
Participants
360
Duration
6–12 weeks
Results
Modest but significant reduction in body weight (−0.94 kg); effect augmented with caffeine
How They Measured It
Pooled body weight, BMI, fat mass
Measure acute thermogenic effect of p-synephrine
Study Type
Randomised Controlled Trial
Purpose
Measure acute thermogenic effect of p-synephrine
Dose
50 mg synephrine
Participants
60
Duration
Acute (75 min)
Results
Synephrine alone increased RMR by ~65 kcal/day; combination with caffeine increased to ~129 kcal/day
How They Measured It
Resting metabolic rate via indirect calorimetry
Evaluate bitter orange extract for weight management
Study Type
Randomised Controlled Trial
Purpose
Evaluate bitter orange extract for weight management
Dose
975 mg bitter orange (~30 mg synephrine)
Participants
70
Duration
12 weeks
Results
Bitter orange group lost significantly more weight (−2.4 kg) vs placebo (−0.9 kg); no adverse cardiovascular effects
How They Measured It
Body weight, fat, waist circumference
Assess cardiovascular safety of p-synephrine
Study Type
Safety Review
Purpose
Assess cardiovascular safety of p-synephrine
Dose
10–100 mg/day
Participants
360
Duration
Various
Results
No significant effects on heart rate, BP, or ECG at doses ≤100 mg; considered safe
How They Measured It
Review of clinical trials and adverse event reports
Exercise Performance
Investigate synephrine on exercise performance and substrate oxidation
Study Type
Randomised Crossover Trial
Purpose
Investigate synephrine on exercise performance and substrate oxidation
Dose
3 mg/kg body weight
Participants
14
Duration
Acute
Results
Increased fat oxidation during exercise; trend toward improved endurance; no adverse events
How They Measured It
Time to exhaustion, fat oxidation, VO2
Evaluate synephrine on strength and power output
Study Type
Randomised Controlled Trial
Purpose
Evaluate synephrine on strength and power output
Dose
100 mg synephrine
Participants
25
Duration
Acute
Results
Significant improvement in upper body strength and peak power vs placebo; well-tolerated
How They Measured It
1-RM bench press, peak power via Wingate
Receptor Pharmacology & Safety
Characterise p-synephrine affinity for adrenergic receptor subtypes
Study Type
In Vitro Receptor Binding Study
Purpose
Characterise p-synephrine affinity for adrenergic receptor subtypes
Dose
Various concentrations
Participants
0
Duration
N/A
Results
p-Synephrine shows selective beta-3 adrenergic agonism with minimal alpha binding; explains thermogenic effect with low cardiovascular risk
How They Measured It
Receptor binding assays; cAMP measurements
Comprehensively review human clinical evidence on synephrine
Study Type
Systematic Review
Purpose
Comprehensively review human clinical evidence on synephrine
Dose
Various
Participants
200
Duration
Various
Results
Evidence supports modest thermogenic and weight management effects; caffeine combination enhances outcomes
How They Measured It
PRISMA systematic review of RCTs
Frequently Asked Questions
Common questions about Synephrine research
There are currently 8 peer-reviewed studies on Synephrine (p-Synephrine), involving 1,089 total participants. Research covers Fat Loss, Metabolism, Energy and 1 more areas. The overall evidence strength is rated as Strong.
The evidence is currently rated as "Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (8 human studies), and reported outcomes.
Synephrine has been researched for: Fat Loss, Metabolism, Energy, Exercise Performance. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 8 out of 8 studies are human trials. Human trials carry more weight in our evidence scoring system.
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