Single-Ingredient Supplement Database

Also known as: Withania somnifera, KSM-66, Sensoril

Commonly studied dosage

Commonly studied: 300-600 mg extract/day

Known interactions

May interact with sedatives, thyroid medications, and immunosuppressants.

An adaptogenic herb studied mostly for stress and sleep-related outcomes. Evidence quality varies by trial.

Also known as: B1/B2/B3/B5/B6/B7/B9/B12 blend

Commonly studied dosage

Commonly studied: around 100% DV per B vitamin

Known interactions

High-dose B6 over time can cause nerve symptoms; B vitamins can mask B12 deficiency diagnosis.

Often discussed for energy metabolism; excess is excreted but megadoses are discouraged.

Also known as: Berberis extract

Commonly studied dosage

Commonly studied: 500 mg 2-3x/day

Known interactions

May interact with blood sugar and blood pressure medications, and drugs metabolized by CYP3A4.

A plant alkaloid studied for metabolic outcomes. Frequently flagged for drug interactions.

Also known as: β-alanine

Commonly studied dosage

Commonly studied: 3.2-6.4 g/day

Known interactions

Causes harmless tingling (paresthesia) at higher single doses.

Studied for high-intensity exercise performance; tingling is a known benign side effect.

Also known as: Caffeine/theanine stack

Commonly studied dosage

Commonly studied: 100 mg caffeine + 200 mg theanine

Known interactions

Caffeine interacts with many stimulants and some medications.

A popular combination in attention research; individual caffeine sensitivity varies widely.

Also known as: Calcium

Commonly studied dosage

Commonly studied: 500-1000 mg/day in divided doses

Known interactions

May interfere with absorption of thyroid medication, iron, and some antibiotics.

Citrate form is often chosen by people with low stomach acid.

Also known as: Alpha-glycerophosphocholine

Commonly studied dosage

Commonly studied: 300-600 mg/day

Known interactions

Few well-documented interactions.

A choline source studied for cognitive outcomes; evidence base is still small.

Also known as: L-citrulline

Commonly studied dosage

Commonly studied: 6-8 g/day

Known interactions

May lower blood pressure; caution with ED medications.

Studied for exercise performance via nitric oxide pathways.

Also known as: Hydrolyzed collagen, collagen protein

Commonly studied dosage

Commonly studied: 10-20 g/day

Known interactions

Few known interactions; source (bovine/marine) matters for allergies.

Evidence is growing but still limited compared to whey; studied for skin, joint, and bone outcomes.

Also known as: Coenzyme Q10, ubiquinone/ubiquinol

Commonly studied dosage

Commonly studied: 100-300 mg/day

Known interactions

May interact with warfarin and blood pressure medications.

Studied in the context of statin-associated muscle symptoms and heart failure adjunct therapy.

Also known as: Creatine

Commonly studied dosage

Commonly studied: 3-5 g/day maintenance

Known interactions

May interact with diuretics; people with kidney conditions are usually advised to consult a clinician first.

One of the most studied sports supplements. Most research focuses on strength and power output.

Also known as: Echinacea purpurea

Commonly studied dosage

Commonly studied: 300-500 mg 3x/day

Known interactions

May interact with immunosuppressants.

One of the most popular herbal cold remedies; trial results are mixed.

Also known as: Sambucus nigra

Commonly studied dosage

Commonly studied: 300-600 mg/day during cold season

Known interactions

Raw elderberry can be toxic; commercial extracts are processed.

Popular in cold-season wellness; evidence is preliminary.

Also known as: L-methylfolate, vitamin B9

Commonly studied dosage

Commonly studied: 400-800 mcg/day

Known interactions

High folate intake can mask B12 deficiency.

The active form of folate; often discussed in prenatal contexts.

Also known as: Zingiber officinale

Commonly studied dosage

Commonly studied: 1-2 g/day

Known interactions

High doses may interact with blood thinners.

Most studied for nausea-related outcomes, including motion sickness and pregnancy-related nausea.

Also known as: Aminoacetic acid

Commonly studied dosage

Commonly studied: 3 g before bed

Known interactions

Few known interactions.

An amino acid studied for sleep quality in small trials.

Also known as: Myo-inositol

Commonly studied dosage

Commonly studied: 2-4 g/day

Known interactions

May interact with diabetes medications.

Studied most in PCOS-related research.

Also known as: Potassium iodide

Commonly studied dosage

Commonly studied: 150 mcg/day

Known interactions

Excess can disrupt thyroid function; interacts with thyroid medications.

Essential for thyroid hormone production; both deficiency and excess are concerns.

Also known as: Chelated iron, ferrous bisglycinate

Commonly studied dosage

Commonly studied: varies by deficiency status; clinician-guided

Known interactions

Take separately from calcium, coffee/tea, and thyroid medication.

Iron supplementation is usually guided by blood tests; excess iron can be harmful.

Also known as: Theanine

Commonly studied dosage

Commonly studied: 100-400 mg/day

Known interactions

Few known interactions; may lower blood pressure slightly.

An amino acid from tea, studied for calm focus, often combined with caffeine in trials.

Also known as: Magnesium bisglycinate, chelated magnesium

Commonly studied dosage

Commonly studied: 200-400 mg elemental magnesium/day

Known interactions

May interact with certain antibiotics, bisphosphonates, and blood pressure medications.

A chelated form of magnesium often chosen by people who find other forms hard on the stomach. Research on magnesium and sleep quality is ongoing.

Also known as: N-acetyl-5-methoxytryptamine

Commonly studied dosage

Commonly studied: 0.5-5 mg before bed

Known interactions

May interact with blood thinners, immunosuppressants, and diabetes medications.

Evidence is strongest for jet lag and delayed sleep phase; less clear for general insomnia.

Also known as: Citrucel (brand), soluble fiber

Commonly studied dosage

Commonly studied: per label, with water

Known interactions

Take separately from medications.

A non-fermenting soluble fiber; often chosen by people who get gas from psyllium.

Also known as: N-acetylcysteine

Commonly studied dosage

Commonly studied: 600-1800 mg/day

Known interactions

May interact with blood pressure medications and nitroglycerin.

A glutathione precursor with a long history as a mucolytic drug.

Also known as: EPA/DHA, marine omega-3s

Commonly studied dosage

Commonly studied: 1000-3000 mg combined EPA+DHA/day

Known interactions

May increase bleeding risk at high doses; can interact with blood thinners such as warfarin.

EPA and DHA are long-chain omega-3 fatty acids. Algal oil is a plant-based alternative.

Also known as: Lactobacillus / Bifidobacterium blends

Commonly studied dosage

Commonly studied: 10-50 billion CFU/day

Known interactions

Strain-specific effects; immunocompromised individuals are usually advised to consult a clinician.

Effects are highly strain-specific, so results from one product do not transfer to another.

Also known as: Ispaghula, Metamucil (brand)

Commonly studied dosage

Commonly studied: 5-10 g/day with plenty of water

Known interactions

Take separately from medications (2+ hours) as it can slow absorption.

A soluble fiber supplement with substantial evidence for regularity. Must be taken with adequate water.

Also known as: Flavonoid

Commonly studied dosage

Commonly studied: 500-1000 mg/day

Known interactions

May interact with blood thinners and some antibiotics.

A plant flavonoid studied for allergy-season and exercise outcomes.

Also known as: Trans-resveratrol

Commonly studied dosage

Commonly studied: 150-500 mg/day

Known interactions

May interact with blood thinners.

Famous from red-wine headlines; human evidence remains preliminary.

Also known as: Golden root, arctic root

Commonly studied dosage

Commonly studied: 200-400 mg/day

Known interactions

May interact with diabetes and blood pressure medications.

An adaptogen studied for fatigue-related outcomes; trial sizes are generally small.

Also known as: Selenomethionine

Commonly studied dosage

Commonly studied: 55-200 mcg/day

Known interactions

Excess intake can cause selenosis (hair loss, nail changes); narrow safety margin.

An essential trace mineral; Brazil nuts are a famously concentrated food source.

Also known as: Prunus cerasus

Commonly studied dosage

Commonly studied: 480-960 mg/day

Known interactions

May interact with blood thinners at high doses.

Studied for sleep quality and exercise recovery; trials are small.

Also known as: Curcuma longa

Commonly studied dosage

Commonly studied: 500-1000 mg curcumin/day, often with piperine

Known interactions

May interact with blood thinners, diabetes medications, and iron absorption.

Curcumin has poor bioavailability on its own, which is why formulations add piperine or lipids.

Also known as: Valeriana officinalis

Commonly studied dosage

Commonly studied: 300-600 mg before bed

Known interactions

May interact with sedatives and alcohol.

A traditional herbal sleep aid with modest modern evidence.

Also known as: Cobalamin

Commonly studied dosage

Commonly studied: 25-2500 mcg/day depending on deficiency

Known interactions

May interact with metformin and acid-reducing medications (absorption).

Deficiency is more common in older adults, vegans, and metformin users.

Also known as: Cholecalciferol

Commonly studied dosage

Commonly studied: 1000-4000 IU/day

Known interactions

May interact with thiazide diuretics, digoxin, and some seizure medications.

Often discussed in the context of bone health and deficiency correction, especially in low-sunlight regions.

Also known as: Menaquinone-7

Commonly studied dosage

Commonly studied: 90-200 mcg/day

Known interactions

May interact with warfarin and other vitamin K antagonists — medical supervision typically advised.

Often discussed alongside vitamin D in bone-health contexts.

Also known as: Benefiber (brand), soluble fiber

Commonly studied dosage

Commonly studied: per label, dissolves clear

Known interactions

Take separately from medications.

A soluble fiber that dissolves fully in liquids; studied for regularity.

Also known as: Whey protein

Commonly studied dosage

Commonly studied: 20-40 g/day

Known interactions

Generally well tolerated; people with dairy allergy should avoid.

A complete protein source widely studied for muscle protein synthesis.

Also known as: Zinc

Commonly studied dosage

Commonly studied: 15-30 mg/day

Known interactions

High doses can interfere with copper absorption; may interact with certain antibiotics and penicillamine.

Zinc is involved in immune function. Long-term high-dose use is generally discouraged without supervision.