This index lists every ingredient we have profiled, with a separate evidence rating for each use it is studied for, sorted from strongest to weakest. Ratings reflect human trials only, using the scale described in how we research: strong, moderate, limited, mixed or insufficient. The "note" column gives the dose or population the rating applies to; the interaction column names the concern most relevant to people on medication.
Two things to keep in mind. An ingredient rated moderate for one use may be unstudied for another, and a rating for an ingredient is not a rating for any product that contains it — finished products are rarely tested, and their doses are often below those trials used.
| Ingredient | Use | Evidence | Note | Key interaction concern |
|---|---|---|---|---|
| Benfotiamine | Correcting thiamine deficiency | Strong | Reliably raises thiamine | No significant interactions known |
| Beta-sitosterol | LDL cholesterol (plant sterols 2 g/day) | Strong | 8–10% reduction | Reduces carotenoid absorption; avoid in sitosterolemia |
| Creatine | Strength/power and lean mass (with resistance training) | Strong | Hundreds of RCTs; the best-evidenced performance supplement | Very safe in healthy people at 3–5 g/day; established kidney disease needs medical advice; water-weight gain of ~1–2 kg is expected; hydrate normally |
| Glucomannan | Constipation | Strong | Established bulk laxative effect | Take all medications 1 hour before or 4 hours after (absorption delay); swallow only with a full glass of water — choking/obstruction risk with dry tablets; may add to glucose-lowering drugs |
| Magnesium | Constipation | Strong | Established laxative | Separate from tetracyclines, quinolones, bisphosphonates, levothyroxine; caution in kidney disease |
| Vitamin C | Correcting deficiency / scurvy | Strong | Rapid, complete response | High doses: GI upset, oxalate kidney-stone risk in formers; interferes with some glucose meters and lab tests; large doses reduce with kidney disease; splits absorption above ~200 mg |
| Vitamin D | Correcting deficiency (bone, muscle symptoms) | Strong | Deficiency causes real disease; repletion treats it | Fat-soluble — toxicity possible at sustained very high doses (hypercalcemia); interacts with thiazides (calcium), steroids and some seizure/weight-loss drugs; take with a meal |
| Zinc | Correcting deficiency (immunity, taste, healing, growth) | Strong | Deficiency is consequential and repletion works | Long-term >40 mg/day depletes copper (anemia, neuropathy); binds quinolone/tetracycline antibiotics and penicillamine (separate hours); nasal zinc destroyed smell — never intranasal; nausea on empty stomach |
| Alpha-lipoic acid | Diabetic neuropathy symptoms (intravenous) | Moderate | 600 mg/day for 3 weeks | Insulin and sulfonylureas (hypoglycemia); may interfere with levothyroxine; avoid during chemotherapy |
| Ashwagandha | Perceived stress and anxiety | Moderate | 300–600 mg/day root extract, 6–12 weeks; consistent small-to-moderate effects | Sedatives (additive), thyroid medication (may raise hormone levels), immunosuppressants; avoid in pregnancy; rare liver-injury reports |
| Berberine | Blood glucose in type 2 diabetes | Moderate | 900–1,500 mg/day; short trials, mostly from China | Insulin and sulfonylureas (hypoglycemia); CYP3A4/2D6/2C9 substrates incl. cyclosporine; avoid in pregnancy and infants |
| Berberine | LDL cholesterol and triglycerides | Moderate | Same trial populations | Insulin and sulfonylureas (hypoglycemia); CYP3A4/2D6/2C9 substrates incl. cyclosporine; avoid in pregnancy and infants |
| Creatine | Older adults preserving muscle (with training) | Moderate | Meta-analyses: added lean mass and strength vs training alone | Very safe in healthy people at 3–5 g/day; established kidney disease needs medical advice; water-weight gain of ~1–2 kg is expected; hydrate normally |
| Glucomannan | LDL cholesterol | Moderate | Consistent ~10% reductions in meta-analyses | Take all medications 1 hour before or 4 hours after (absorption delay); swallow only with a full glass of water — choking/obstruction risk with dry tablets; may add to glucose-lowering drugs |
| Lutein and zeaxanthin | Slowing intermediate AMD (in AREDS2 formula) | Moderate | 10 mg + 2 mg within the full formula; ~25% progression-risk reduction, condition-specific | Very safe at studied doses; harmless skin yellowing at high intake; smokers should use AREDS2-type (no beta-carotene) formulas |
| Magnesium | Blood glucose in people with low magnesium | Moderate | 250–400 mg/day | Separate from tetracyclines, quinolones, bisphosphonates, levothyroxine; caution in kidney disease |
| Magnesium | Blood pressure | Moderate | About 2 mmHg systolic | Separate from tetracyclines, quinolones, bisphosphonates, levothyroxine; caution in kidney disease |
| Magnesium | Migraine prevention | Moderate | 400–600 mg/day | Separate from tetracyclines, quinolones, bisphosphonates, levothyroxine; caution in kidney disease |
| Melatonin | Jet lag | Moderate | 0.5–5 mg at destination bedtime; the best-supported use | Drowsiness additive with sedatives/alcohol; caution with warfarin, immunosuppressants, epilepsy, and diabetes meds; US OTC products notoriously mislabeled — content 83–478% of label in testing |
| Melatonin | Delayed sleep phase (night-owl body clocks) | Moderate | Low dose taken hours before target bedtime shifts the clock | Drowsiness additive with sedatives/alcohol; caution with warfarin, immunosuppressants, epilepsy, and diabetes meds; US OTC products notoriously mislabeled — content 83–478% of label in testing |
| Melatonin | Children (autism/ADHD sleep, clinician-guided) | Moderate | Prescription-grade evidence in these groups | Drowsiness additive with sedatives/alcohol; caution with warfarin, immunosuppressants, epilepsy, and diabetes meds; US OTC products notoriously mislabeled — content 83–478% of label in testing |
| Vitamin C | Iron absorption aid | Moderate | Enhances non-heme iron uptake with meals | High doses: GI upset, oxalate kidney-stone risk in formers; interferes with some glucose meters and lab tests; large doses reduce with kidney disease; splits absorption above ~200 mg |
| Vitamin D | Fracture/fall prevention (with calcium, deficient elderly) | Moderate | Benefit concentrates in low-status, institutionalized groups | Fat-soluble — toxicity possible at sustained very high doses (hypercalcemia); interacts with thiazides (calcium), steroids and some seizure/weight-loss drugs; take with a meal |
| Zinc | Age-related macular degeneration (in AREDS2) | Moderate | 80 mg zinc within the formula; condition-specific | Long-term >40 mg/day depletes copper (anemia, neuropathy); binds quinolone/tetracycline antibiotics and penicillamine (separate hours); nasal zinc destroyed smell — never intranasal; nausea on empty stomach |
| Alpha-lipoic acid | Diabetic neuropathy symptoms (oral) | Limited | 600–1,800 mg/day; clinical relevance debated | Insulin and sulfonylureas (hypoglycemia); may interfere with levothyroxine; avoid during chemotherapy |
| Alpha-lipoic acid | Blood glucose / A1C | Limited | Small, inconsistent | Insulin and sulfonylureas (hypoglycemia); may interfere with levothyroxine; avoid during chemotherapy |
| Ashwagandha | Sleep quality | Limited | Modest improvements, clearest in people with insomnia | Sedatives (additive), thyroid medication (may raise hormone levels), immunosuppressants; avoid in pregnancy; rare liver-injury reports |
| Ashwagandha | Testosterone | Limited | 10–17% rises in small trials of stressed/overweight men | Sedatives (additive), thyroid medication (may raise hormone levels), immunosuppressants; avoid in pregnancy; rare liver-injury reports |
| Ashwagandha | Strength and recovery | Limited | Small gains alongside resistance training | Sedatives (additive), thyroid medication (may raise hormone levels), immunosuppressants; avoid in pregnancy; rare liver-injury reports |
| Bacopa monnieri | Memory (delayed recall) in adults | Limited | 300–450 mg/day standardized extract, 8–12 weeks; consistent small effects in small trials | Cholinergic additive effects — caution with dementia drugs; may potentiate thyroid hormone; GI upset common; avoid in pregnancy |
| Benfotiamine | Diabetic neuropathy symptoms | Limited | 300–600 mg/day; short trials positive, 2-year trial negative | No significant interactions known |
| Berberine | Insulin resistance / prediabetes | Limited | No prevention trials | Insulin and sulfonylureas (hypoglycemia); CYP3A4/2D6/2C9 substrates incl. cyclosporine; avoid in pregnancy and infants |
| Berberine | Weight | Limited | About 1–2 kg in some trials | Insulin and sulfonylureas (hypoglycemia); CYP3A4/2D6/2C9 substrates incl. cyclosporine; avoid in pregnancy and infants |
| Berberine | Polycystic ovary syndrome | Limited | Small trials | Insulin and sulfonylureas (hypoglycemia); CYP3A4/2D6/2C9 substrates incl. cyclosporine; avoid in pregnancy and infants |
| Beta-sitosterol | Urinary symptoms of BPH | Limited | 60–130 mg/day; four 1990s trials, unreplicated | Reduces carotenoid absorption; avoid in sitosterolemia |
| Cinnamon | Cholesterol and triglycerides | Limited | Inconsistent | Additive with glucose-lowering drugs; cassia coumarin — liver caution at gram doses |
| Collagen | Skin hydration / elasticity | Limited | 2.5–10 g/day hydrolyzed, 8–12 wks; small effects in small, mostly industry-funded trials | Benign for most; it is incomplete protein (no tryptophan) — a supplement, not a protein replacement; marine-collagen fish allergy; quality/heavy-metal testing worth checking |
| Collagen | Joint comfort (athletes, OA) | Limited | Small trials of hydrolyzed 10 g and UC-II 40 mg; modest signals | Benign for most; it is incomplete protein (no tryptophan) — a supplement, not a protein replacement; marine-collagen fish allergy; quality/heavy-metal testing worth checking |
| Creatine | Cognition in vegetarians/sleep-deprived states | Limited | Brain stores lower/stressed; small positive trials | Very safe in healthy people at 3–5 g/day; established kidney disease needs medical advice; water-weight gain of ~1–2 kg is expected; hydrate normally |
| Fenugreek | Libido / sexual function scores (men) | Limited | Standardized extracts 500–600 mg/day; more consistent than hormone changes | Additive with glucose-lowering drugs; possible interaction with warfarin; avoid medicinal doses in pregnancy; maple-syrup odor is harmless |
| Fenugreek | Testosterone | Limited | Small, inconsistent rises across trials | Additive with glucose-lowering drugs; possible interaction with warfarin; avoid medicinal doses in pregnancy; maple-syrup odor is harmless |
| Fenugreek | Blood glucose in type 2 diabetes | Limited | 5–25 g/day seed powder in small, older trials | Additive with glucose-lowering drugs; possible interaction with warfarin; avoid medicinal doses in pregnancy; maple-syrup odor is harmless |
| Ginkgo biloba | Intermittent claudication (leg circulation) | Limited | Small walking-distance gains, less than exercise therapy | Bleeding risk with warfarin, DOACs, aspirin, NSAIDs; stop 2 weeks pre-surgery; seizure caution; raw seeds toxic |
| Glucomannan | Post-meal blood glucose | Limited | Slows carbohydrate absorption; modest effects | Take all medications 1 hour before or 4 hours after (absorption delay); swallow only with a full glass of water — choking/obstruction risk with dry tablets; may add to glucose-lowering drugs |
| Glucosamine and chondroitin | Severe-pain knee OA subgroup (combination) | Limited | GAIT secondary finding; unconfirmed | Well tolerated; caution with warfarin (INR-rise case reports); shellfish-allergy note usually tolerable but check; chondroitin quality varies widely |
| Green tea extract | Weight loss | Limited | ~0.5–1.5 kg vs placebo in meta-analyses; less in caffeine users | High-dose EGCG linked to rare liver injury — take with food, cap EGCG ~<800 mg/day, stop if jaundice/dark urine; caffeine interactions; reduces folate and iron absorption; avoid with liver disease |
| Green tea extract | LDL cholesterol | Limited | Small reductions (~5 mg/dL) in meta-analyses | High-dose EGCG linked to rare liver injury — take with food, cap EGCG ~<800 mg/day, stop if jaundice/dark urine; caffeine interactions; reduces folate and iron absorption; avoid with liver disease |
| Green tea extract | Blood pressure | Limited | 1–2 mmHg in pooled trials | High-dose EGCG linked to rare liver injury — take with food, cap EGCG ~<800 mg/day, stop if jaundice/dark urine; caffeine interactions; reduces folate and iron absorption; avoid with liver disease |
| Green tea extract | Exercise fat oxidation | Limited | Acute lab effects; performance translation inconsistent | High-dose EGCG linked to rare liver injury — take with food, cap EGCG ~<800 mg/day, stop if jaundice/dark urine; caffeine interactions; reduces folate and iron absorption; avoid with liver disease |
| Gymnema sylvestre | Blood glucose in type 2 diabetes | Limited | 200–400 mg/day extract; old, mostly uncontrolled trials | Additive with insulin and oral diabetes drugs (hypoglycemia) |
| Gymnema sylvestre | Sweet food intake (short-term) | Limited | Taste-blocking effect under an hour | Additive with insulin and oral diabetes drugs (hypoglycemia) |
| L-citrulline | Mild erectile dysfunction | Limited | 1.5 g/day, 1 month: 50% improved erection hardness vs 8% placebo; 24 men, single-blind | Additive with PDE5 inhibitors, nitrates and blood-pressure drugs — hypotension risk; discuss with prescriber |
| L-citrulline | Blood pressure | Limited | 3–6 g/day; small reductions in some trials, mainly in hypertension | Additive with PDE5 inhibitors, nitrates and blood-pressure drugs — hypotension risk; discuss with prescriber |
| L-citrulline | Muscle soreness | Limited | Modest reductions in several small studies | Additive with PDE5 inhibitors, nitrates and blood-pressure drugs — hypotension risk; discuss with prescriber |
| Lutein and zeaxanthin | Visual performance / glare in healthy adults | Limited | Small trials show raised macular pigment, modest contrast/glare effects | Very safe at studied doses; harmless skin yellowing at high intake; smokers should use AREDS2-type (no beta-carotene) formulas |
| Magnesium | Blood glucose with normal magnesium | Limited | Small or absent | Separate from tetracyclines, quinolones, bisphosphonates, levothyroxine; caution in kidney disease |
| Magnesium | Sleep | Limited | Small trials in older adults | Separate from tetracyclines, quinolones, bisphosphonates, levothyroxine; caution in kidney disease |
| Melatonin | Ordinary chronic insomnia | Limited | Meta-analyses: ~7 min faster onset on average — modest | Drowsiness additive with sedatives/alcohol; caution with warfarin, immunosuppressants, epilepsy, and diabetes meds; US OTC products notoriously mislabeled — content 83–478% of label in testing |
| Melatonin | Tinnitus-related sleep disruption | Limited | Small trials; treats the sleep side | Drowsiness additive with sedatives/alcohol; caution with warfarin, immunosuppressants, epilepsy, and diabetes meds; US OTC products notoriously mislabeled — content 83–478% of label in testing |
| Saw palmetto | Urinary symptoms of BPH (hexane lipidosterolic extract) | Limited | Mostly sponsored European trials | No major interactions; stop two weeks before surgery; does not affect PSA |
| Saw palmetto | Male pattern hair loss | Limited | Small trials | No major interactions; stop two weeks before surgery; does not affect PSA |
| Tongkat ali | Total testosterone | Limited | Significant rise in 5-trial meta-analysis; clearest in older/hypogonadal men; 100–400 mg/day | Caution with diabetes and blood-pressure medication (limited data); avoid in hormone-sensitive cancers and pregnancy; quality/adulteration concerns |
| Tongkat ali | Libido / sexual wellbeing | Limited | Small improvements in several trials | Caution with diabetes and blood-pressure medication (limited data); avoid in hormone-sensitive cancers and pregnancy; quality/adulteration concerns |
| Tribulus terrestris | Libido | Limited | Some improvement in small trials of men and women with low desire | Possible additive effect with glucose-lowering and blood-pressure drugs; avoid in pregnancy and hormone-sensitive cancers; rare toxicity reports at high/prolonged doses |
| Turmeric / curcumin | Knee osteoarthritis pain | Limited | 500–1,500 mg/day curcumin extracts, 8–12 weeks; repeatedly better than placebo in small trials, one NSAID-comparable result | Antiplatelet effect — caution with warfarin/DOACs/aspirin, stop pre-surgery; avoid with gallstones; rare but rising liver-injury reports (esp. enhanced-absorption piperine products); iron absorption reduced |
| Turmeric / curcumin | Inflammatory markers (CRP etc.) | Limited | Reductions in meta-analyses of small trials | Antiplatelet effect — caution with warfarin/DOACs/aspirin, stop pre-surgery; avoid with gallstones; rare but rising liver-injury reports (esp. enhanced-absorption piperine products); iron absorption reduced |
| Vitamin C | Shortening colds (regular daily use) | Limited | ~8% adults / ~14% children shorter duration; taking it only at onset does little | High doses: GI upset, oxalate kidney-stone risk in formers; interferes with some glucose meters and lab tests; large doses reduce with kidney disease; splits absorption above ~200 mg |
| Vitamin C | Preventing colds under heavy physical stress | Limited | Marathoners/soldiers subgroup: ~50% fewer colds | High doses: GI upset, oxalate kidney-stone risk in formers; interferes with some glucose meters and lab tests; large doses reduce with kidney disease; splits absorption above ~200 mg |
| Vitamin D | Respiratory infection prevention | Limited | Meta-analysis: small effect, mainly in the deficient on daily dosing | Fat-soluble — toxicity possible at sustained very high doses (hypercalcemia); interacts with thiazides (calcium), steroids and some seizure/weight-loss drugs; take with a meal |
| Xylitol | Tooth decay prevention (gum/lozenges, ~5 g/day) | Limited | Reviews find reduced decay, esp. in children; quality of trials moderate; saliva stimulation contributes | Dose-dependent gas/diarrhea above ~10–20 g; 2024 research links high blood levels to cardiovascular questions (unsettled); EXTREMELY toxic to dogs — hypoglycemia and liver failure |
| Xylitol | Ear infections in children | Limited | Regular dosing reduced episodes in daycare trials; adherence impractical | Dose-dependent gas/diarrhea above ~10–20 g; 2024 research links high blood levels to cardiovascular questions (unsettled); EXTREMELY toxic to dogs — hypoglycemia and liver failure |
| Xylitol | Plaque reduction | Limited | Less and less-adhesive plaque vs sucrose and sorbitol comparisons | Dose-dependent gas/diarrhea above ~10–20 g; 2024 research links high blood levels to cardiovascular questions (unsettled); EXTREMELY toxic to dogs — hypoglycemia and liver failure |
| Xylitol | Dry mouth relief | Limited | Saliva stimulation; symptomatic benefit | Dose-dependent gas/diarrhea above ~10–20 g; 2024 research links high blood levels to cardiovascular questions (unsettled); EXTREMELY toxic to dogs — hypoglycemia and liver failure |
| Zinc | Shortening colds (lozenges, started <24h, frequent dosing) | Limited | Meta-analyses: ~1–2 days shorter; acetate/gluconate ≥75 mg/day dissolved slowly | Long-term >40 mg/day depletes copper (anemia, neuropathy); binds quinolone/tetracycline antibiotics and penicillamine (separate hours); nasal zinc destroyed smell — never intranasal; nausea on empty stomach |
| Bacopa monnieri | Attention / processing speed | Mixed | Some trials show gains, others none | Cholinergic additive effects — caution with dementia drugs; may potentiate thyroid hormone; GI upset common; avoid in pregnancy |
| Chromium | Blood glucose in type 2 diabetes | Mixed | 200–1,000 mcg/day; benefit mostly with poor control | May add to glucose-lowering drugs; absorption reduced by antacids and PPIs |
| Chromium | Cholesterol | Mixed | Small, inconsistent | May add to glucose-lowering drugs; absorption reduced by antacids and PPIs |
| Cinnamon | Fasting glucose in type 2 diabetes | Mixed | 1–6 g/day; high heterogeneity | Additive with glucose-lowering drugs; cassia coumarin — liver caution at gram doses |
| Cinnamon | A1C | Mixed | Small or non-significant | Additive with glucose-lowering drugs; cassia coumarin — liver caution at gram doses |
| Fenugreek | Breast milk supply | Mixed | Traditional use; trials small and conflicting | Additive with glucose-lowering drugs; possible interaction with warfarin; avoid medicinal doses in pregnancy; maple-syrup odor is harmless |
| Ginkgo biloba | Preventing dementia / cognitive decline | Mixed | GEM trial: 3,069 adults, 6 years, 240 mg/day — no effect; leaning negative | Bleeding risk with warfarin, DOACs, aspirin, NSAIDs; stop 2 weeks pre-surgery; seizure caution; raw seeds toxic |
| Ginkgo biloba | Cognition in existing dementia | Mixed | European trials of EGb 761 modestly positive; US trials negative | Bleeding risk with warfarin, DOACs, aspirin, NSAIDs; stop 2 weeks pre-surgery; seizure caution; raw seeds toxic |
| Ginkgo biloba | Tinnitus | Mixed | Overall negative in reviews; possible signal alongside dementia | Bleeding risk with warfarin, DOACs, aspirin, NSAIDs; stop 2 weeks pre-surgery; seizure caution; raw seeds toxic |
| Glucomannan | Weight loss | Mixed | 3 g/day before meals: ~1–2 kg in some trials, null in others | Take all medications 1 hour before or 4 hours after (absorption delay); swallow only with a full glass of water — choking/obstruction risk with dry tablets; may add to glucose-lowering drugs |
| Glucosamine and chondroitin | Knee OA pain (overall) | Mixed | Independent trials/meta-analyses: small-to-no effect vs placebo; sponsored trials larger | Well tolerated; caution with warfarin (INR-rise case reports); shellfish-allergy note usually tolerable but check; chondroitin quality varies widely |
| L-citrulline | Exercise performance | Mixed | 6–8 g citrulline malate pre-exercise; small or no effects across trials | Additive with PDE5 inhibitors, nitrates and blood-pressure drugs — hypotension risk; discuss with prescriber |
| Phosphatidylserine | Age-related memory complaints (bovine form, discontinued) | Mixed | 1990s trials positive; form no longer sold | Possible additive effects with anticholinergic and cholinergic drugs and blood thinners (theoretical); generally well tolerated to 300 mg/day |
| Saw palmetto | Urinary symptoms of BPH (typical extracts) | Mixed | Largest trials negative; pooled effect below clinical significance | No major interactions; stop two weeks before surgery; does not affect PSA |
| Vitamin C | Preventing colds (general population) | Mixed | Cochrane: no reduction in incidence | High doses: GI upset, oxalate kidney-stone risk in formers; interferes with some glucose meters and lab tests; large doses reduce with kidney disease; splits absorption above ~200 mg |
| Vitamin D | General population supplementation (bones, cancer, heart) | Mixed | VITAL and peers: no major-outcome benefit in the replete | Fat-soluble — toxicity possible at sustained very high doses (hypercalcemia); interacts with thiazides (calcium), steroids and some seizure/weight-loss drugs; take with a meal |
| Alpha-lipoic acid | Weight | Insufficient | About 1 kg | Insulin and sulfonylureas (hypoglycemia); may interfere with levothyroxine; avoid during chemotherapy |
| Alpha-lipoic acid | Diabetic retinopathy | Insufficient | Large trial negative | Insulin and sulfonylureas (hypoglycemia); may interfere with levothyroxine; avoid during chemotherapy |
| Ashwagandha | Thyroid function | Insufficient | One small trial in subclinical hypothyroidism | Sedatives (additive), thyroid medication (may raise hormone levels), immunosuppressants; avoid in pregnancy; rare liver-injury reports |
| Bacopa monnieri | Anxiety | Insufficient | Secondary outcomes only, inconsistent | Cholinergic additive effects — caution with dementia drugs; may potentiate thyroid hormone; GI upset common; avoid in pregnancy |
| Bacopa monnieri | Children / ADHD | Insufficient | Small trials, promising but inadequate | Cholinergic additive effects — caution with dementia drugs; may potentiate thyroid hormone; GI upset common; avoid in pregnancy |
| Bacopa monnieri | Dementia | Insufficient | No adequate trials | Cholinergic additive effects — caution with dementia drugs; may potentiate thyroid hormone; GI upset common; avoid in pregnancy |
| Benfotiamine | Diabetic kidney disease | Insufficient | 12-week trial negative | No significant interactions known |
| Beta-sitosterol | Prostate size | Insufficient | No effect shown | Reduces carotenoid absorption; avoid in sitosterolemia |
| Chromium | Insulin resistance / prediabetes | Insufficient | Trials largely negative | May add to glucose-lowering drugs; absorption reduced by antacids and PPIs |
| Chromium | Weight loss | Insufficient | Under 1 kg; not clinically meaningful | May add to glucose-lowering drugs; absorption reduced by antacids and PPIs |
| Cinnamon | Prediabetes | Insufficient | Few trials | Additive with glucose-lowering drugs; cassia coumarin — liver caution at gram doses |
| Collagen | Wrinkle depth | Insufficient | Instrument-measured changes of uncertain visibility | Benign for most; it is incomplete protein (no tryptophan) — a supplement, not a protein replacement; marine-collagen fish allergy; quality/heavy-metal testing worth checking |
| Collagen | Nails / hair | Insufficient | One small uncontrolled nail study; hair essentially untested | Benign for most; it is incomplete protein (no tryptophan) — a supplement, not a protein replacement; marine-collagen fish allergy; quality/heavy-metal testing worth checking |
| Collagen | Bone density | Insufficient | One 5 g/day postmenopausal trial awaiting replication | Benign for most; it is incomplete protein (no tryptophan) — a supplement, not a protein replacement; marine-collagen fish allergy; quality/heavy-metal testing worth checking |
| Creatine | General cognition in healthy omnivores | Insufficient | Mostly null so far | Very safe in healthy people at 3–5 g/day; established kidney disease needs medical advice; water-weight gain of ~1–2 kg is expected; hydrate normally |
| Creatine | Endurance performance | Insufficient | Not its mechanism; weight gain can hinder | Very safe in healthy people at 3–5 g/day; established kidney disease needs medical advice; water-weight gain of ~1–2 kg is expected; hydrate normally |
| Fenugreek | Menopausal symptoms | Insufficient | A few small extract trials | Additive with glucose-lowering drugs; possible interaction with warfarin; avoid medicinal doses in pregnancy; maple-syrup odor is harmless |
| Garcinia cambogia | Weight loss | Insufficient | Pooled effect <1 kg, unreliable across trials | Avoid with SSRIs/serotonergic drugs (case reports incl. serotonin syndrome), bipolar disorder (mania reports), liver disease (injury case series); additive with diabetes medication |
| Garcinia cambogia | Appetite | Insufficient | Inconsistent self-report findings | Avoid with SSRIs/serotonergic drugs (case reports incl. serotonin syndrome), bipolar disorder (mania reports), liver disease (injury case series); additive with diabetes medication |
| Garcinia cambogia | Cholesterol / triglycerides | Insufficient | Scattered small changes | Avoid with SSRIs/serotonergic drugs (case reports incl. serotonin syndrome), bipolar disorder (mania reports), liver disease (injury case series); additive with diabetes medication |
| Ginkgo biloba | Memory in healthy adults | Insufficient | Trials show no meaningful enhancement | Bleeding risk with warfarin, DOACs, aspirin, NSAIDs; stop 2 weeks pre-surgery; seizure caution; raw seeds toxic |
| Glucosamine and chondroitin | Slowing joint-space narrowing | Insufficient | Small, conflicting X-ray studies | Well tolerated; caution with warfarin (INR-rise case reports); shellfish-allergy note usually tolerable but check; chondroitin quality varies widely |
| Glucosamine and chondroitin | Hip OA | Insufficient | Trials negative | Well tolerated; caution with warfarin (INR-rise case reports); shellfish-allergy note usually tolerable but check; chondroitin quality varies widely |
| Green tea extract | Cancer prevention | Insufficient | Observational tea data; trials inadequate | High-dose EGCG linked to rare liver injury — take with food, cap EGCG ~<800 mg/day, stop if jaundice/dark urine; caffeine interactions; reduces folate and iron absorption; avoid with liver disease |
| Gymnema sylvestre | Weight | Insufficient | Combination products only | Additive with insulin and oral diabetes drugs (hypoglycemia) |
| Lion's mane | Cognition in older adults with mild impairment | Insufficient | One 30-person, 16-week trial; scores improved, faded after stopping | Possible additive effect with antiplatelet/anticoagulant drugs and glucose-lowering medication (limited data); mushroom allergy |
| Lion's mane | Memory / focus in healthy adults | Insufficient | Tiny short studies with mixed results | Possible additive effect with antiplatelet/anticoagulant drugs and glucose-lowering medication (limited data); mushroom allergy |
| Lion's mane | Mood and anxiety | Insufficient | One 4-week trial in 30 women; menopause-symptom scale | Possible additive effect with antiplatelet/anticoagulant drugs and glucose-lowering medication (limited data); mushroom allergy |
| Lion's mane | Nerve regeneration | Insufficient | Laboratory and animal data only | Possible additive effect with antiplatelet/anticoagulant drugs and glucose-lowering medication (limited data); mushroom allergy |
| Lutein and zeaxanthin | Preventing AMD in healthy eyes | Insufficient | No trial support; observational diet data only | Very safe at studied doses; harmless skin yellowing at high intake; smokers should use AREDS2-type (no beta-carotene) formulas |
| Lutein and zeaxanthin | Digital eye strain | Insufficient | Few small industry trials | Very safe at studied doses; harmless skin yellowing at high intake; smokers should use AREDS2-type (no beta-carotene) formulas |
| Lutein and zeaxanthin | Cognition | Insufficient | Early small studies | Very safe at studied doses; harmless skin yellowing at high intake; smokers should use AREDS2-type (no beta-carotene) formulas |
| Phosphatidylserine | Age-related memory complaints (soy form) | Insufficient | Few small trials, inconsistent | Possible additive effects with anticholinergic and cholinergic drugs and blood thinners (theoretical); generally well tolerated to 300 mg/day |
| Phosphatidylserine | Dementia | Insufficient | Old small trials, modest transient effects, bovine form | Possible additive effects with anticholinergic and cholinergic drugs and blood thinners (theoretical); generally well tolerated to 300 mg/day |
| Phosphatidylserine | Sports stress / cortisol | Insufficient | Small studies at high doses | Possible additive effects with anticholinergic and cholinergic drugs and blood thinners (theoretical); generally well tolerated to 300 mg/day |
| Phosphatidylserine | Children / ADHD | Insufficient | A couple of small trials | Possible additive effects with anticholinergic and cholinergic drugs and blood thinners (theoretical); generally well tolerated to 300 mg/day |
| Saw palmetto | Prostate size | Insufficient | No reduction shown | No major interactions; stop two weeks before surgery; does not affect PSA |
| Tongkat ali | Erectile function | Insufficient | 2-trial meta-analysis: no significant improvement | Caution with diabetes and blood-pressure medication (limited data); avoid in hormone-sensitive cancers and pregnancy; quality/adulteration concerns |
| Tongkat ali | Stress and mood | Insufficient | One small trial (cortisol, mood) | Caution with diabetes and blood-pressure medication (limited data); avoid in hormone-sensitive cancers and pregnancy; quality/adulteration concerns |
| Tongkat ali | Sports performance | Insufficient | Small, inconsistent studies | Caution with diabetes and blood-pressure medication (limited data); avoid in hormone-sensitive cancers and pregnancy; quality/adulteration concerns |
| Tribulus terrestris | Testosterone | Insufficient | Repeated trials in athletes and healthy men: no rise | Possible additive effect with glucose-lowering and blood-pressure drugs; avoid in pregnancy and hormone-sensitive cancers; rare toxicity reports at high/prolonged doses |
| Tribulus terrestris | Athletic performance / muscle | Insufficient | Trials negative | Possible additive effect with glucose-lowering and blood-pressure drugs; avoid in pregnancy and hormone-sensitive cancers; rare toxicity reports at high/prolonged doses |
| Tribulus terrestris | Erectile function | Insufficient | Mixed small trials; best result in mild ED with a specific extract | Possible additive effect with glucose-lowering and blood-pressure drugs; avoid in pregnancy and hormone-sensitive cancers; rare toxicity reports at high/prolonged doses |
| Tribulus terrestris | Blood sugar | Insufficient | One small trial in women with type 2 diabetes | Possible additive effect with glucose-lowering and blood-pressure drugs; avoid in pregnancy and hormone-sensitive cancers; rare toxicity reports at high/prolonged doses |
| Turmeric / curcumin | Indigestion / IBS symptoms | Insufficient | A few small mixed trials | Antiplatelet effect — caution with warfarin/DOACs/aspirin, stop pre-surgery; avoid with gallstones; rare but rising liver-injury reports (esp. enhanced-absorption piperine products); iron absorption reduced |
| Turmeric / curcumin | Depression adjunct, metabolic markers | Insufficient | Pilot-scale only | Antiplatelet effect — caution with warfarin/DOACs/aspirin, stop pre-surgery; avoid with gallstones; rare but rising liver-injury reports (esp. enhanced-absorption piperine products); iron absorption reduced |
| Vitamin D | Mood / depression | Insufficient | Trials in the non-deficient negative | Fat-soluble — toxicity possible at sustained very high doses (hypercalcemia); interacts with thiazides (calcium), steroids and some seizure/weight-loss drugs; take with a meal |
| Zinc | Preventing colds | Insufficient | Routine supplementation shows little in the replete | Long-term >40 mg/day depletes copper (anemia, neuropathy); binds quinolone/tetracycline antibiotics and penicillamine (separate hours); nasal zinc destroyed smell — never intranasal; nausea on empty stomach |
| Zinc | Testosterone / tinnitus | Insufficient | Deficiency-only signals; nothing in the replete | Long-term >40 mg/day depletes copper (anemia, neuropathy); binds quinolone/tetracycline antibiotics and penicillamine (separate hours); nasal zinc destroyed smell — never intranasal; nausea on empty stomach |
Updated whenever an ingredient profile is added or revised. Suggest a correction via the contact page.