Supplements

Each page shows every benefit that studies measured, the studies behind it and the doses that study groups took.

22 supplements
VitaminCalciumThe main mineral of bones and teeth, from dairy, fortified foods and supplements. Most studied for bone density and fractures, with small effects in trials.Most studied for fitness (64 studies)2 of 4 goals have studiesOpen Calcium ›VitaminCollagenCollagen is the main protein of skin, bone, tendons and cartilage. Supplements are most studied for knee osteoarthritis pain and for skin hydration.Most studied for fitness (34 studies)1 of 4 goals have studiesOpen Collagen ›Fatty acid or lipidDHA (docosahexaenoic acid)DHA is an omega-3 fat from fish and algae that builds up in the brain and retina. Most studied for lowering triglycerides and for pregnancy and infant growth.Most studied for cognition (118 studies)3 of 4 goals have studiesOpen DHA (docosahexaenoic acid) ›Other / not yet classifiedElectrolytesElectrolytes are minerals such as sodium, potassium and magnesium. They are most studied for rehydration in diarrhea and during long exercise.Most studied for fitness (95 studies)2 of 4 goals have studiesOpen Electrolytes ›Other / not yet classifiedFiberPlant carbohydrates the gut cannot digest, from food or powders such as psyllium. Clearest results for LDL cholesterol and constipation. It can add gas and bloating.0 of 4 goals have studiesOpen Fiber ›Fatty acid or lipidFish oilAn oil from fatty fish, rich in the omega-3 fats EPA and DHA. Most studied for triglycerides, which it lowers by about 15%, and for heart disease.Most studied for cognition (187 studies)3 of 4 goals have studiesOpen Fish oil ›Amino acid or proteinGlutathioneAn antioxidant that every cell makes from three amino acids. As a supplement, it has been tested for oxidative stress and for lighter skin.Most studied for fitness (25 studies)4 of 4 goals have studiesOpen Glutathione ›Chemical compoundHyaluronic acidA substance the body makes to hold water in skin and joint fluid. As a supplement, it is most studied for skin moisture and wrinkles, and for knee pain.Most studied for fitness (91 studies)1 of 4 goals have studiesOpen Hyaluronic acid ›VitaminIodineAn essential mineral that the thyroid needs to make its hormones. Most studied in pregnancy, in children with low iodine, and for goiter.Most studied for cognition (22 studies)2 of 4 goals have studiesOpen Iodine ›VitaminIronA mineral the blood needs to carry oxygen. Most studied for preventing anemia, including in pregnancy, and for tiredness and fitness in people low in iron.Most studied for fitness (359 studies)3 of 4 goals have studiesOpen Iron ›MineralMagnesiumA mineral in nuts, seeds, beans and greens that more than 300 enzyme systems need. As a supplement, best supported for constipation, blood pressure and migraine.Most studied for fitness (88 studies)3 of 4 goals have studiesOpen Magnesium ›Fatty acid or lipidOmega-3 fatty acidsFats the body needs from food: ALA from plants, EPA and [DHA](/supplements/docosahexaenoic-acid) from fish and algae. Most studied for triglycerides, the heart and pregnancy.Most studied for cognition (206 studies)4 of 4 goals have studiesOpen Omega-3 fatty acids ›MineralPotassiumAn essential mineral in fruit, vegetables, beans, potatoes and milk that cells, nerves and muscles need. Most studied for blood pressure and kidney stones.Most studied for fitness (45 studies)1 of 4 goals have studiesOpen Potassium ›Other / not yet classifiedPrebioticsCarbohydrates that gut microbes use as fuel, such as inulin and GOS. Studied for gut bacteria, bloating, constipation and markers of inflammation.Most studied for stress & mood (19 studies)2 of 4 goals have studiesOpen Prebiotics ›Other / not yet classifiedProbioticsLive bacteria and yeasts. Results depend on the strain. Studied for diarrhea after antibiotics, irritable bowel syndrome, colds and more.Most studied for stress & mood (154 studies)2 of 4 goals have studiesOpen Probiotics ›VitaminVitamin B12A vitamin from animal foods that the body needs for red blood cells and nerves. Most studied for preventing and treating a low B12 level.Most studied for cognition (24 studies)3 of 4 goals have studiesOpen Vitamin B12 ›Other / not yet classifiedVitamin B9Folate, a B vitamin in leafy greens, beans and fortified grain. Folic acid is the usual supplement form. Most studied for preventing birth defects of the spine and brain.Most studied for cognition (73 studies)2 of 4 goals have studiesOpen Vitamin B9 ›VitaminVitamin CVitamin C is a nutrient from fruit and vegetables. In trials, daily doses made colds a little shorter and lowered blood pressure a little.Most studied for stress & mood (15 studies)2 of 4 goals have studiesOpen Vitamin C ›VitaminVitamin DA fat-soluble vitamin that the skin makes in sunlight and a few foods contain. Most studied for bones, fractures and respiratory infections.Most studied for fitness (86 studies)4 of 4 goals have studiesOpen Vitamin D ›VitaminVitamin EA fat-soluble antioxidant from nuts, seeds and plant oils. Most studied for the heart, fatty liver disease and the eyes.Most studied for cognition (25 studies)2 of 4 goals have studiesOpen Vitamin E ›VitaminVitamin KA fat-soluble vitamin from leafy greens (K1) and fermented foods (K2). The body needs it for blood clotting. Most studied for bones and arteries.Most studied for cognition (5 studies)1 of 4 goals have studiesOpen Vitamin K ›MineralZincAn essential mineral in meat, seafood and supplements. Most studied for colds, diarrhea and growth in children, and macular degeneration.Most studied for cognition (22 studies)2 of 4 goals have studiesOpen Zinc ›