Synephrine

Best for

Lower your resting heart rate

Not enough research · 3–214 mg/day · 1 meta-analysis , n=247

6 papers · 11 claims · 37 outcomes scored · 6 positive

Outcomes

What synephrine actually does, by outcome

Each row is one outcome with effect size, evidence base, the dose that worked in trials, and time to first effect. Magnitude tiers come from native-unit MCID where available, Cohen's d otherwise.

Outcome Effect size Evidence Dose Weeks Rank

Lower your resting heart rate Not enough research

Each beat pushes more blood, so your heart needs fewer beats per minute.

3 meta-analyses n=247 3–214 mg — #1/20

21537493·36235672·36297036

moderate

3 meta-analyses n=247 Meta-analyzed

3–214 mg

—

#1 /20

Boost cardiovascular exercise output Promising early signal

Your heart pushes more blood per beat and sustains higher intensity longer.

1 RCT n=36 3 mg/kg — #2/16

36297036

moderate

1 RCT n=36

3 mg/kg

—

#2 /16

Burn more fat for fuel Faint early signal

Your body favors fat as fuel, sparing stored carbs for intense efforts.

2 meta-analyses n=377 3–60 mg/kg — #5/18

36297036·36235672

small

2 meta-analyses n=377 Meta-analyzed

3–60 mg/kg

—

#5 /18

Lose body fat Not enough research

Body fat percentage drops and the mirror shows it before the scale does.

1 meta-analysis n=94 10–54 mg —

36235672

small

1 meta-analysis n=94 Meta-analyzed

10–54 mg

—

Feel full longer and crave less Faint early signal

Genuine satiety replaces the constant urge to snack or overeat.

1 RCT n=36 3 mg/kg —

36297036

small

1 RCT n=36

3 mg/kg

—

Sharpen focus and mental stamina Faint early signal

Concentrate longer, resist distraction, and stay mentally sharp through demanding tasks.

1 RCT n=20 50 mg —

21537493

small

1 RCT n=20

50 mg

—

Lower your blood pressure Not enough research

Brings down both systolic and diastolic, especially when baseline runs high.

3 meta-analyses n=247 3–50 mg 8 wk

21537493·36297036·36235672

small

3 meta-analyses n=247 Meta-analyzed

3–50 mg

8 wk

—

Blunt blood pressure spikes Probably doesn't help

Keeps your numbers steadier when stress, caffeine, or exertion hits.

1 meta-analysis n=191 10–214 mg 8 wk

36235672

trivial

1 meta-analysis n=191 Meta-analyzed

10–214 mg

8 wk

—

Lose weight on the scale Not enough research

Less weight on your joints, better blood markers, easier movement.

1 meta-analysis n=94 10–54 mg —

36235672

trivial

1 meta-analysis n=94 Meta-analyzed

10–54 mg

—

Stay cooler longer during exercise Not enough research

Better sweat regulation keeps you performing before heat forces a slowdown.

1 RCT n=36 3 mg/kg —

36297036

—

1 RCT n=36

3 mg/kg

—

Boost your resting metabolic rate Not enough research

Burns more calories at rest and after meals without extra exercise.

1 RCT n=— 50 mg —

21537493

—

1 RCT n=—

50 mg

—

Outcome	Effect	Evidence	Dose	Weeks	Rank
Lower your resting heart rate Not enough research	moderate	3 meta-analyses n=247 Meta-analyzed	3–214 mg	—	#1/20
Boost cardiovascular exercise output Promising early signal	moderate	1 RCT n=36	3 mg/kg	—	#2/16
Burn more fat for fuel Faint early signal	small	2 meta-analyses n=377 Meta-analyzed	3–60 mg/kg	—	#5/18
Lose body fat Not enough research	small	1 meta-analysis n=94 Meta-analyzed	10–54 mg	—	—
Feel full longer and crave less Faint early signal	small	1 RCT n=36	3 mg/kg	—	—
Sharpen focus and mental stamina Faint early signal	small	1 RCT n=20	50 mg	—	—
Lower your blood pressure Not enough research	small	3 meta-analyses n=247 Meta-analyzed	3–50 mg	8 wk	—
Blunt blood pressure spikes Probably doesn't help	trivial	1 meta-analysis n=191 Meta-analyzed	10–214 mg	8 wk	—
Lose weight on the scale Not enough research	trivial	1 meta-analysis n=94 Meta-analyzed	10–54 mg	—	—
Stay cooler longer during exercise Not enough research		1 RCT n=36	3 mg/kg	—	—
Boost your resting metabolic rate Not enough research		1 RCT n=—	50 mg	—	—

Buy well

Recommended Synephrine products

Real products that dose Synephrine where the research does, in a clean formulation, from brands we've audited. We only list ones we'd stand behind.

Chosen for adequate Synephrine dosing vs. the studied range, a clean formulation (grade A–C), and independent brand-quality audits. Not sponsored.

Risk profile

Adverse events and known drug interactions

Safety events

myocardial infarction severe

stroke (cerebral infarction/vasospasm) severe

rhabdomyolysis severe

acute coronary syndrome severe

cardiac arrhythmia severe

stroke severe

seizure severe

QT prolongation severe

Drug interactions

other major additive

Isoprenaline major additive

Ephedrine major increases toxicity

Caffeine moderate decreases concentration

Dapsone moderate decreases concentration

Nebivolol moderate decreases effect

Caffeine moderate increases effect

Gliclazide moderate increases effect

Chlorzoxazone minor unknown

Metformin minor unknown

Sources

Generated August 14, 2026

Synephrine

What synephrine actually does, by outcome

Recommended Synephrine products

Adverse events and known drug interactions

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Focus & memory: evidence map across 45 supplements

Metabolic health: evidence map across 82 supplements

Capsaicinoids

Fucoxanthin

Caffeine

Garlic