%NRV on a supplement label shows how much a serving provides against the Nutrient Reference Value, a fixed labelling figure set in law for that vitamin or mineral. It is a common reference point that lets you compare products, not a personal daily target, and a higher percentage is not automatically a better product.
NRV is one of the few numbers on a supplement label that means the same thing on every pack, which makes it genuinely useful once you know what it is doing. This article covers where the figure comes from, why some ingredients have no percentage at all, and the compound-versus-elemental trap that makes two magnesium products look very different when they are not.
What is a Nutrient Reference Value?
An NRV is a reference amount for a vitamin or mineral, fixed in labelling law and applied to everybody. Manufacturers do not choose it. When a label says a serving provides a given percentage of the NRV, that percentage is calculated against the same legal figure any other brand has to use.
That is the whole purpose of it: comparability. Two products can use different serving sizes, different units and different ingredient forms, but their %NRV figures are calculated against a common reference, so the percentages can be compared directly.
Is the NRV a personal target?
No, and this is the most common misreading. The NRV is a single labelling figure for a general adult population. It is not tailored to your age, your build, your activity level, your diet or anything else about you.
Requirements genuinely differ between people, and food contributes too. So "I hit 100% NRV" is not a statement about whether your own intake is adequate — it is a statement about what one serving of one product contains relative to a reference point. If you want personal advice on your intake, that is a conversation for a doctor, pharmacist or registered dietitian rather than a label.
Why do some ingredients show no %NRV?
Because NRVs only exist for vitamins and minerals that have been assigned one in law. Plenty of supplement ingredients have not been assigned one, and for those the label can only tell you the amount present.
- Botanicals and plant extracts — ashwagandha, lion's mane, sea moss, ginseng and similar have no NRV, because they are not vitamins or minerals with an assigned reference value.
- Other substances — things like creatine, collagen, fulvic acid or live cultures have no NRV either.
- Nutrients without an assigned value — a small number of nutrients are declared by weight only, because no reference figure has been set for them.
An asterisk or dagger next to an ingredient, with a footnote reading "NRV not established", is not the brand hiding something. It is the correct declaration. Our guide to reading a supplement label goes through the rest of the panel line by line.
Is more than 100% NRV better?
Not automatically, and treating the percentage as a score to maximise is how people end up paying for numbers rather than nutrition. A high figure tells you the serving is generous relative to the reference point. It does not tell you the nutrient is better absorbed, better tolerated or more useful to you.
Three things worth holding in mind:
- Some nutrients are water-soluble and largely excreted when intake is high; others are stored, so intake accumulates over time. More is not a neutral choice for the second group.
- Percentages stack across products. If you take a multivitamin, a separate vitamin, a greens blend and a fortified drink, you are adding percentages you may not be tracking.
- Regulated wording such as "source of" and "high in" is defined by law against the NRV, so those phrases have fixed meanings and are not marketing adjectives.
Very high figures usually appear in a handful of nutrients where they are common and unremarkable, and a sensible label will not present them as an achievement. If you are combining several products, our piece on building a supplement routine covers how to keep track of what overlaps.
Compound weight versus elemental weight
This is the single most useful thing on this page. Minerals are not supplied as pure metal. They are supplied as a compound — magnesium citrate, magnesium bisglycinate, magnesium oxide, zinc picolinate, iron bisglycinate and so on. The compound weight is the weight of the whole molecule. The elemental weight is the weight of the mineral itself within it.
The magnesium worked example
Take two magnesium products. One front label shouts a large milligram figure for magnesium citrate. The other states a much smaller figure for magnesium. It looks like a landslide until you notice the two numbers are measuring different things.
Magnesium citrate is magnesium bound to citric acid, and the citrate part makes up a substantial share of that total weight. So the amount of actual magnesium in a magnesium citrate serving is considerably lower than the compound figure printed on the front. The same logic applies to every mineral form: bisglycinate, oxide, carbonate and citrate all carry different amounts of the mineral per gram of compound.
The exact proportions differ by form and by product, so we are not going to invent percentages here — the label is the source. What matters is that you compare like with like. Our article on magnesium forms covers how the forms themselves differ.
How %NRV lets you compare two products honestly
Because %NRV must be calculated on the elemental amount of the mineral, it cuts straight through the compound-weight confusion. A percentage on one pack and a percentage on another are describing the same thing, even when the front-of-pack milligram figures are not.
A practical sequence when comparing two products:
- Find the nutrition panel, not the front label. The front is marketing; the panel is regulated.
- Check the serving size each panel is based on — one capsule, two capsules, a scoop — and normalise to the same serving.
- Compare the %NRV figures rather than the compound milligrams.
- Then look at the ingredient form named in the ingredients list, since two products at the same %NRV can still use different forms.
- Finally, work out servings per pack and cost per serving, which is where apparent bargains often reverse.
Where no NRV exists, as with most botanicals, you fall back on comparing the stated amount and the extract description — and accepting that comparison is harder there. You can see how the panels differ in practice across our everyday wellness range.
Common questions
Does %NRV tell me how much I absorb?
No. It describes what is in the serving relative to a reference figure, not what your body takes up. Absorption varies by nutrient, by form and between people.
Why do two magnesium products with similar milligrams show very different %NRV?
Almost always because one figure is compound weight and the other is elemental. The %NRV is the honest comparison, since it is calculated on the mineral itself.
Is an ingredient with no %NRV lower quality?
No. It usually means no reference value has been set for it in law, which is common for botanicals and other non-vitamin, non-mineral ingredients.
Should I add up %NRV across all my supplements?
It is a reasonable habit if you take several products, particularly where the same nutrient appears in more than one. If a total looks high and you are unsure about it, ask a pharmacist.
Are NRVs the same as the old RDA figures?
They serve the same labelling purpose and replaced that terminology on packs. You may still see "RDA" informally, but the regulated declaration on a UK label is %NRV.
Food supplements should not be used as a substitute for a varied and balanced diet or a healthy lifestyle. If you are pregnant, breastfeeding, taking medication or under medical supervision, speak to your doctor or pharmacist before starting any supplement. We are not able to give medical advice.