Tag

Supplement safety

Page 5 of 8

Grey capsules spilled from a clear bottle onto a yellow background

NAC: uses, evidence, dosing and safety

NAC is a hospital antidote sold as a supplement, and the two are not the same claim. It saves lives in paracetamol overdose. For almost everything it is marketed for, the evidence is thin or uncertain.

Aug 5, 2026

White powder being weighed on an antique brass apothecary balance

verdict

NMN and NR: uses, evidence, dosing and safety

These reliably raise NAD+ in humans, and that is the strongest thing anyone can say. Trials that then measured whether people got better have mostly found they did not.

Aug 5, 2026

Two cupped hands holding dark soil above a field

verdict

Selenium: uses, evidence, dosing and safety

Selenium is essential, and supplementing it when you are not short of it is the clearest honest-no in the supplement aisle. Cochrane found no cancer benefit at high certainty, plus signals of harm.

Aug 5, 2026

A yellow St Johns wort flower with long radiating stamens

verdict

St Johns wort: uses, evidence, dosing and safety

The one herbal with real antidepressant evidence, and the one with the most dangerous interaction profile. It can make prescription medicines stop working, including contraceptives and transplant drugs.

Aug 5, 2026