Tag

Supplement safety

Page 5 of 8

White powder being weighed on an antique brass apothecary balance

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

A heap of pale dried ashwagandha roots on a patterned market cloth

verdict

Ashwagandha: uses, evidence, dosing and safety

Ashwagandha has real evidence for stress and sleep, thinner evidence for strength, and a liver problem that arrived in 2017. The list of people who should avoid it is unusually long, and now includes thyroid patients.

Aug 3, 2026