Supplement interactions
93 supplement pairs checked against published research. Every interaction cites at least one source.
1
Avoid
9
Warning
39
Caution
44
Info
Check your own stack
Select what you take and see every interaction instantly.
Risk of serotonin syndrome
Calcium blocks iron absorption significantly
Stacking two serotonin precursors is redundant and risky
Charcoal adsorbs NAC and blocks its absorption
Guarana is caffeine — risk of double-dosing
Both are strong GABAergic sedatives
Grapefruit compound dangerously boosts red yeast rice potency
Two stimulants with dangerous cardiovascular synergy
Charcoal kills probiotics on contact
Aspirin-like herb plus clot dissolver — significant bleeding risk
Iron and zinc compete for absorption
Calcium may reduce zinc absorption
Long-term zinc can deplete copper
High-dose retinol may antagonise Vitamin D
Calcium and magnesium compete at high doses
Both promote relaxation — additive sedation possible
Calcium may reduce manganese absorption
Iron and manganese share the same transporter
Calcium carbonate may interfere with chromium
High-dose Vitamin C may degrade B12
Vitamin C can neutralise selenite in the gut
Both promote sleep through sedative mechanisms
Additive sedation from two calming compounds
St. John's Wort may lower CoQ10 levels
Green tea sharply reduces iron absorption
Curcumin chelates iron
Possible absorption competition
High-dose magnesium may reduce zinc absorption
SJW may alter DHEA hormone conversion unpredictably
Both raise acetylcholine — excess causes side effects
Coffee polyphenols sharply reduce iron absorption
High caffeine intake modestly increases calcium loss
Two sedatives with overlapping mechanisms
Kava's sedation adds to melatonin's sleep effect
Additive cholesterol lowering — monitor for muscle symptoms
Both thin blood through different mechanisms
Both have anticoagulant activity
Vitamin E adds mild blood-thinning on top of nattokinase
Serotonin and dopamine precursors can imbalance each other
L-DOPA chelates iron, reducing absorption of both
Both amplify GABAergic calming — excessive drowsiness possible
Two sleep promoters through different receptor systems
Poorly studied neurochemical overlap
SJW may reduce melatonin effectiveness
Both affect monoamine neurotransmitters
Additive blood sugar lowering — watch for hypoglycaemia
Two sleep aids with additive sedation risk
Stacking two hormone precursors is unpredictable
Glucomannan's gel traps iron in the gut
D3 and K2 direct calcium to bone
Vitamin C boosts iron absorption
Magnesium activates Vitamin D
NAC may enhance zinc bioavailability
Curcumin and omega-3s target inflammation differently
Folate and B12 are interdependent
Both are fat-soluble with no meaningful conflict
Vitamin D is essential for calcium absorption
Piperine dramatically increases curcumin absorption
Complementary calm through different pathways
Two adaptogens with complementary stress pathways
Milk thistle may boost berberine absorption
Citrulline sustains arginine levels better than arginine alone
Complementary energy systems for exercise
CoQ10 and PQQ target mitochondria from different angles
The classic joint health combination
Complementary joint support compounds
The two macular pigments, always taken together
Fish oil provides the fat D3 needs for absorption
Complementary sleep support through different systems
Potassium may actually help preserve calcium
Complementary antioxidant recycling
Berberine may deplete CoQ10 like statins do
B6 may enhance magnesium cellular uptake
No conflict — magnesium creatine chelate is a supplement form
Caffeine does not negate creatine's benefits
The most studied nootropic combination
Red yeast rice depletes CoQ10 like a statin
A traditional Ayurvedic pairing for cognition and stress
Two cognitive supports through different pathways
Vitamin C is essential for collagen synthesis
Vitamin C recycles oxidised quercetin
Quercetin slows EGCG breakdown
Two flavonoid senolytics with overlapping targets
Complementary cardiovascular support
Astaxanthin protects omega-3s from oxidation
Complementary hormonal support through different mechanisms
Both support oestrogen metabolism
Yeast probiotic complements bacterial probiotics
Both activate the Nrf2 antioxidant defence system
Complementary liver support — popular for alcohol recovery
Immediate plus sustained ketone elevation
Copper is required for iron metabolism
Quercetin may extend resveratrol's short half-life
Check your full stack for interactions
This information is for educational purposes only. It is not medical advice and does not diagnose, treat, cure, or prevent any disease. Always consult a qualified healthcare professional.