This section explains the ingredients found in supplements, from vitamins and minerals to herbs, amino acids and probiotics.Each guide covers what the ingredient is, the doses used in human research, how strong that evidence is, common side effects and known interactions. We use these guides as the base for every product review.Many ingredients interact with medicines. Ask your doctor or pharmacist before use if you take medication, are pregnant or have a chronic condition.Does the FDA approve supplement ingredients before they are sold?No. The FDA does not approve dietary supplements for safety or effectiveness before they go on sale. Companies are responsible for making sure their products are safe and labeled correctly. That is why it helps to look for third party quality seals and to check each ingredient against independent sources such as NIH. Ask your pharmacist about interactions.Source: Using Dietary Supplements Wisely, NCCIH
Vitamin D helps your body absorb calcium and keep bones strong, and that is where its benefits are best proven. Most people age 1 to 70 need 600 IU (15 mcg) a day and adults over 70 need 800 IU. A blood level of 20 ng/mL is enough for most people. Large trials of 2,000 IU a day found no drop in cancer, heart events or fractures.
Psyllium husk is a soluble fiber from Plantago ovata seeds. Its best evidence is for constipation and for lowering LDL cholesterol, by about 13 mg/dL in 28 trials at around 10 grams a day. Effects on IBS, blood sugar and blood pressure are smaller or less certain. Take each dose with at least 8 ounces of liquid, and ask your doctor first if you take daily medicine.
Magnesium glycinate is magnesium bound to glycine, also sold as magnesium bisglycinate. In the only sleep trial of this form, 155 adults who took 250 mg of magnesium a day for 4 weeks slept a little better than with placebo, but the effect was small. Adults should keep supplement magnesium at or under 350 mg a day, and people with kidney disease should ask a doctor first.
Read the label first. Then decide.
Slow, plain-language supplement reviews. We read the label, compare each dose with the research and work out the real cost. Edited by Maya Ellison.
The Well Brew is general information, not medical advice. Dietary supplements are not reviewed by the FDA for safety or effectiveness before they are sold. Talk to your doctor before you start, stop or combine supplements. Some links are affiliate links: if you buy through them we may earn a commission at no extra cost to you, and it never changes what we report.