What does NRV mean on a supplement label?

NRV stands for Nutrient Reference Value — the EU and UK daily reference intake for vitamins and minerals used for labelling purposes. NRVs reflect the approximate daily amount needed to prevent deficiency in a healthy general population. They are not the same as the doses used in clinical intervention trials. Evaluate doses against clinical trial evidence, not NRV percentages alone.

What is the difference between a branded and generic supplement ingredient?

A branded ingredient — citicoline (CDP-choline), research-selected nutrients root extract, saffron extract, French maritime pine bark extract — specifies the exact source, processing method, standardisation, and clinical trial programme. A generic name carries none of this. Trials conducted on a specific branded form cannot be assumed to extend to an unstandardised generic equivalent.

How to read a supplement label: a research-led guide

Q: What certifications should I look for on a UK supplement?

Look for GMP certification from a named auditor, and where possible Informed Sport or NSF Certified for Sport certification — both involving independent laboratory testing of the finished product. A Certificate of Analysis from a third-party laboratory is the most granular form of verification. A self-declaration of 'manufactured to GMP standards' without a named certifying body is not equivalent.

How do I verify that a supplement is dosed correctly?

Go to PubMed (pubmed.ncbi.nlm.nih.gov), search the ingredient name plus "randomised controlled trial", filter for clinical trials, and note the dose in the treatment arm of the best-designed study. Compare that dose to what the label shows. For each ingredient where the label dose is below 50% of the studied dose, the product is underdosed relative to the evidence — and if the ingredient is inside a proprietary blend with no individual amount stated, the dose is entirely unknown.

Why does magnesium form matter on a supplement label?

Magnesium oxide is cheap and common but poorly absorbed. A randomised, double-blind study by Walker et al. (2003) found it produced no significant difference from placebo in serum magnesium over 60 days, while magnesium citrate showed significantly superior absorption. If a label states only "magnesium 300mg" without specifying form, or specifies "as oxide", the amount your body can actually use may be very small. Better-absorbed forms include citrate, glycinate, malate, and bisglycinate.

What certifications should I look for on a UK supplement?

Look for GMP (Good Manufacturing Practice) certification from a named auditor, and where possible Informed Sport or NSF Certified for Sport certification — both of which involve independent laboratory testing of the finished product against its label. A Certificate of Analysis from a third-party laboratory is the most granular form of verification. Brands confident in their manufacturing make these available. A self-declaration of "manufactured to GMP standards" without a named certifying body is not the same thing.

How to read a supplement label: a research-led guide

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