Zinc supplement benefits and side effects explained: real evidence for immunity, colds and skin, the 40 mg upper limit, and the copper problem most people miss.

Magnesium citrate and glycinate cause very different side effects. Here's what each one does to your gut, sleep and meds, plus how to pick the right form.

Magnesium glycinate is gentle, well absorbed and popular for sleep and stress. Here's what the evidence says on benefits, side effects, dosing and safety.

Jitters, nausea, yellow urine or kidney stones: the real side effects of men's multivitamins, which ingredients trigger them, and how to pick a formula that works.

The best multivitamin for women can still cause nausea, constipation, and interactions. Learn which side effects matter and how to choose a formula safely.

Antioxidant supplements side effects range from nausea and bleeding to drug interactions and, in some cases, higher cancer risk. Here’s what the evidence shows.

Electrolyte powders can help hydration, but excess sodium, potassium, and magnesium can cause bloating, cramps, and worse. Here's what to know before you sip.

Iron pills for anemia side effects: why constipation and nausea happen, which symptoms are red flags, and the practical fixes that make iron tolerable.

Vitamin K2 supplements are usually well tolerated, but they can interact with blood thinners and cause digestive upset. Here's what to know before you buy.

Most vitamin D side effects are mild, but too much can raise blood calcium. Here's what the evidence says about doses, warning signs and who's at risk.

Vitamin C supplements are mostly safe, but high doses can trigger diarrhea, kidney stone risk, iron overload, and drug interactions. Here's what to watch.

Vitamin B12 supplements are mostly safe, but nausea, acne-like rashes, and rare allergic reactions can happen. Here’s what to expect and who needs care.