Best Gluten-Free Protein Bars

What "gluten-free" legally has to mean

In the United States, a food can only be labeled gluten-free if it contains less than 20 parts per million of gluten, a threshold set by the FDA because it is the lowest level that can be reliably detected using validated testing methods. That is a legal standard, not a marketing claim, and every bar we call gluten-free here meets it.

Cross-contact is the main risk beyond the label itself. A facility that also processes wheat can introduce trace gluten even into a product whose ingredients are naturally gluten-free, which is part of why the 20 ppm rule exists in the first place rather than requiring zero gluten.

We check both the gluten-free claim and the ingredient list for every bar in this ranking.

What to check before you buy

• Look for the gluten-free claim itself, not just the absence of wheat in the ingredient list, since a shared facility can still introduce cross-contact.
• Oats are naturally gluten-free but are frequently cross-contaminated during growing and processing. Look for certified gluten-free oats specifically if that is a concern for you.
• If you have celiac disease rather than a general sensitivity, the 20 ppm threshold matters to you in a stricter, medical sense than it does to someone avoiding gluten by preference.