Does taking vitamin E have any proven benefit?
For the most widely studied application, the heart, vitamin E demonstrably does not work; for skin and fertility the evidence is too thin to say it helps, so there is no clear reason to take it.
Vitamin E has no proven benefit for the most widely studied applications. An analysis of 884 studies involving more than 880,000 participants showed that vitamin E provides no statistically significant benefit for cardiovascular disease or type 2 diabetes. Vitamin E supplements, whether a pill or capsule labelled 'Vitamin E' or 'alpha-tocopherol', are not recommended for this purpose: the evidence is unambiguously negative, regardless of which dose or form you choose.
For skin health the picture is slightly less clear. A broad literature review describes possible positive effects, such as protection against UV damage and some benefit in eczema. However, there is no consensus on the right amount, there is no high-quality evidence, and the authors themselves state that further research is needed. Here too, proven benefit cannot be claimed, and a supplement is not recommended.
In women with fertility problems, an analysis of 63 studies involving 7,760 women examined whether antioxidants as a group are helpful. The probability of pregnancy rose from roughly 19% to between 25 and 30%, but the quality of the evidence was low to very low. Vitamin E was one of the substances within that group and was not analysed separately; whether vitamin E itself does anything has not been established. In the research, women received vitamin E as part of a combination of antioxidants, but which amount is effective is unknown. Discuss this with your doctor.
Four claims used: one large meta-analysis (PMID 36480969), one large RCT (PMID 10465172), one narrative review on skin (PMID 38256329), one Cochrane review on antioxidants/fertility (PMID 32851663).
Does taking iron help, or is it actually a risk?
Taking iron clearly helps if you have a deficiency or anaemia, but is pointless and potentially risky if that is not the case. Have your iron levels checked before starting supplements.
Does taking resveratrol make sense as an anti-ageing supplement?
Research shows that resveratrol does not activate the mechanism behind the anti-ageing theory in people. There are small indications of benefit for muscle function in people who exercise, though that evidence is thin.
Do you have enough vitamin D, and should you take a supplement?
For healthy adults under 75, the evidence for supplementation is weak, but for people aged 75 and older, those with pre-diabetes, or those with an infant at home, there are good reasons to supplement.
Does taking glutathione make sense, or is it broken down in your gut?
Oral glutathione measurably raises levels in blood and cells, so it is not entirely pointless. Whether that rise translates into tangible health benefits has not yet been properly studied.
Does echinacea really work against the common cold?
Whether echinacea helps with the common cold depends strongly on which preparation you use. Standardised products made from Echinacea purpurea (herb and root) showed a modest reduction in symptoms in some studies, but root extracts and non-standardised products did not improve outcomes, and what you buy in a shop rarely corresponds to the products used in positive studies.
Does ergothioneine work as a longevity supplement?
Ergothioneine shows a positive signal in a small study of older adults with memory complaints, but it is too early for firm recommendations. Eating mushrooms is a risk-free way to obtain the compound; a supplement is worth considering only once larger studies provide greater clarity.