Cell Protection

Selenium is the one people most often get wrong. It carries an authorised role in cell protection at a modest intake, and UK soils are low in it, so a supplement is reasonable. But the gap between a useful amount and too much is narrower than with most minerals, which is why reputable products sit around 100–200mcg rather than going higher.

Yeast-bound selenium and sodium selenite are the two common forms. If you already take a multivitamin, check what is in it before adding a standalone – the totals add up quickly.

Glutathione is the body's own compound, and swallowing it is not straightforward – standard capsules are broken down before much arrives. This is why liposomal and reduced forms exist and cost more, and Well Actually, Coyne and Balanced all sell them for that reason.

NAC takes the other route: it supplies a building block rather than the finished compound. Both approaches are legitimate and neither is proven superior, so buy on format and price rather than on which sounds more advanced.

NMN and nicotinamide riboside are precursors – raw material the body converts. The research is genuinely active but it is early, most of it is not in humans, and no health claim is authorised in the UK. Anyone telling you otherwise is ahead of the evidence.

Purity and dose are where these products differ. BioTech Life Sciences state a purity figure and sell by the gram; KIKI Health, Phytoceutics and Feel Supreme sell capsules, sometimes paired with resveratrol or astaxanthin. Compare cost per gram rather than cost per bottle, because bottle sizes vary enormously.