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What 'gluten-free' means on a label

'Gluten-free' is a voluntary claim, but one with a precise FDA definition behind it. Here is exactly what it means, the 20-ppm threshold, and why 'wheat-free' is not the same thing.

Updated June 19, 2026 · 3 min read · Sourced from FDA guidance

The FDA definition

Before 2013 there was no U.S. standard for 'gluten-free.' The FDA's gluten-free labeling rule (21 CFR 101.91) changed that. To bear the claim, a food must either be inherently gluten-free or must not contain:

  1. an ingredient that is a gluten-containing grain — wheat, rye, barley, or a crossbred hybrid such as triticale;
  2. an ingredient derived from such a grain that has not been processed to remove gluten (for example, wheat flour); or
  3. an ingredient derived from such a grain that has been processed to remove gluten (for example, wheat starch), if it leaves 20 ppm or more gluten in the food.

On top of that, any unavoidable gluten in the food must be below 20 parts per million (ppm) — about 20 milligrams per kilogram. The same standard applies to the equivalent claims 'no gluten,' 'free of gluten,' and 'without gluten.'

Note

Why below 20 ppm and not zero? The FDA set the limit at the lowest level that can be reliably detected by validated testing methods, and the level most people with celiac disease can tolerate.

It's voluntary — and testing isn't required

Using 'gluten-free' is optional, but if you use it, you must meet the standard. Notably, the rule does not require manufacturers to test their food; they are responsible for ensuring compliance by whatever means — sourcing, process controls, or testing. The claim covers FDA-regulated foods; alcohol and USDA-regulated meat, poultry, and egg products fall under other agencies.

'Gluten-free' is not 'wheat-free'

These are different claims. 'Wheat-free' only tells you there is no wheat — the product could still contain barley or rye, and therefore gluten. 'Gluten-free' addresses all gluten-containing grains and the 20-ppm limit. If you have celiac disease, 'gluten-free' is the claim that matters; see how wheat is handled among the nine major allergens.

The wheat-derived ingredient rule

If a 'gluten-free' food contains a wheat-derived ingredient that has been processed to remove gluten (such as some wheat starch), the word 'wheat' in the 'Contains wheat' allergen statement must carry an asterisk pointing to a note: 'The wheat has been processed to allow this food to meet the FDA requirements for gluten-free foods.' That keeps the allergen declaration and the gluten-free claim from appearing to contradict each other.

Frequently asked questions

What does 'gluten-free' legally mean?
Under FDA rule 21 CFR 101.91, a 'gluten-free' food must not contain wheat, rye, barley, or their crossbreeds, or any ingredient derived from them that has not been processed to remove gluten — and any unavoidable gluten must be below 20 ppm. The same applies to 'no gluten,' 'free of gluten,' and 'without gluten.'
How much gluten is allowed in a gluten-free food?
Less than 20 parts per million (about 20 mg per kg). The FDA chose this because it is the lowest level reliably detectable by validated methods and is tolerated by most people with celiac disease.
Is 'wheat-free' the same as 'gluten-free'?
No. 'Wheat-free' only means no wheat; the product could still contain barley or rye and thus gluten. 'Gluten-free' covers all gluten-containing grains and the under-20-ppm limit.
Do manufacturers have to test for gluten?
No. The rule sets the standard but does not require testing. Manufacturers are responsible for ensuring their 'gluten-free' foods comply, whether through sourcing, process controls, or testing.

Sources

Related tools & guides

This guide is general educational information, not legal advice, and labeling rules can change. Your obligations depend on your specific products, claims, sales, and state. Verify your situation against the current FDA guidance and eCFR linked above, or consult a qualified food-labeling professional, before printing a label.