How do I tell if a product is gluten-free? A Comprehensive Guide

October 28, 2025 •

4 min read

According to the U.S. Food and Drug Administration (FDA), a product can only be labeled 'gluten-free' if it contains less than 20 parts per million (ppm) of gluten. For those with celiac disease or gluten sensitivity, knowing how do I tell if a product is gluten-free goes far beyond simply looking for the label, requiring careful attention to ingredients and potential cross-contamination risks. This guide will provide the tools for confident and safe grocery shopping.

Quick Summary

This guide outlines the critical steps for identifying gluten-free products, from understanding FDA regulations to scrutinizing ingredient lists for common and hidden gluten sources. It details the significance of third-party certification symbols and provides a comparison of labeling reliability to assist with safe food choices.

Key Points

Check for Certified Labels: Look for third-party certifications like the GFCO or Crossed Grain symbol, which often have stricter standards than the FDA's.
Understand the FDA Rule: A product labeled 'gluten-free' in the U.S. must contain less than 20 ppm of gluten, a legally enforced standard.
Read the Full Ingredients List: Go beyond the allergen statement to identify obvious sources like wheat, barley, and rye, as well as hidden sources such as malt and hydrolyzed vegetable protein.
Beware of Cross-Contamination: Products with 'may contain' warnings pose a risk for highly sensitive individuals and are not guaranteed to be gluten-free.
Be Cautious with Oats: Unless specifically labeled and certified gluten-free, oats are at high risk for cross-contamination and should be avoided.
Focus on Naturally Gluten-Free Foods: Prioritize unprocessed, whole foods like fresh produce, meat, and rice, which are inherently gluten-free.

Decoding the 'Gluten-Free' Label: What the Law Says

The most straightforward method for identifying a gluten-free product is to look for the prominent claim on the packaging. However, understanding what this label legally signifies is paramount for ensuring safety.

The FDA's 20 ppm Standard

In the United States, the FDA has set a clear legal definition for the term "gluten-free". The rule dictates that any food product bearing this claim must contain less than 20 parts per million (ppm) of gluten. This standard applies to foods that are naturally gluten-free (like produce) as well as processed products that have been specifically manufactured to remove gluten. Other claims, such as "no gluten," "free of gluten," and "without gluten," are also held to this same 20 ppm benchmark. This regulation provides a reliable baseline, but it is not the full story for meticulous label readers.

The All-Important Allergen Warning

Underneath or next to the ingredients list, many food products include an allergen statement, often starting with "Contains:" or "May Contain:". Since wheat is one of the major allergens, if a product contains wheat, it will be listed in the "Contains" section and is definitively not gluten-free. However, it is vital to remember that not all gluten-containing grains (like barley and rye) are required to be listed in this specific allergen statement. A lack of a wheat warning does not guarantee a product is safe for someone with celiac disease.

Expert-Level Label Reading: The Ingredients List

For products that don't carry an explicit "gluten-free" label, or for those who want an extra layer of assurance, a thorough scan of the ingredients list is necessary.

Obvious Sources of Gluten

Start by checking for the most common sources of gluten, which include:

Wheat (including varieties like spelt, durum, and farina)
Barley
Rye
Malt (often derived from barley)
Brewer's yeast
Triticale (a cross between wheat and rye)
Oats, unless explicitly certified as gluten-free, due to a high risk of cross-contamination during harvesting and processing

Hidden Sources of Gluten

Many processed foods contain ingredients that are less obviously derived from gluten-containing grains. These hidden sources require careful attention:

Maltodextrin: Often derived from corn, but can sometimes be from wheat. When derived from wheat in the U.S., the FDA requires it to be listed as "wheat maltodextrin".
Modified Food Starch: Can come from corn, potato, or wheat. If from wheat, it must be specified.
Hydrolyzed Vegetable Protein (HVP): A common flavor enhancer that can be derived from wheat.
Flavors and Colorings: Some can contain grain-based alcohol or barley derivatives. Look for descriptors like "malt flavor" or "smoke flavor from barley".
Dressings and Sauces: Many salad dressings, marinades, and barbecue sauces use flour as a thickener or malt vinegar for flavor.
Soy Sauce: Traditional soy sauce is brewed with wheat. Opt for tamari, but only if it's labeled gluten-free.

The Gold Standard: Third-Party Certification

Beyond the FDA's regulatory definition, several independent organizations offer third-party certification programs for manufacturers. These programs impose stricter standards and auditing processes, providing an extra level of confidence for consumers.

Key Certification Marks to Look For

GFCO Symbol: The Gluten-Free Certification Organization (GFCO) is a program by the Gluten Intolerance Group (GIG). Products with this symbol are tested to contain 10 ppm of gluten or less, a stricter standard than the FDA's.
Crossed Grain Symbol: Administered by various national celiac societies, such as Coeliac UK, this internationally recognized symbol also indicates that products meet strict, independently verified gluten-free standards.

Comparison of Gluten-Free Labeling Reliability


Labeling Type	Description	Reliability	Oversight	Key Considerations
Third-Party Certified	Bears a symbol like GFCO or the Crossed Grain.	Highest	Independent third-party audit, testing, and verification.	Often stricter standards (e.g., <10 ppm) and covers cross-contamination.
FDA-Regulated	States "Gluten-Free" (or similar) on packaging.	High	Adheres to the legal standard of <20 ppm; subject to FDA enforcement.	Manufacturers self-regulate; no independent audit required. Check ingredients for assurance.
Naturally Gluten-Free	Unprocessed whole foods like fruits, vegetables, and plain meat.	Assumed High	No formal oversight; inherent to the food itself.	Safe unless contaminated during handling or preparation.
Advisory Statement	Contains warnings like "May Contain Wheat" or "Made in a facility..."	Unreliable	Voluntary, not regulated by the FDA.	Indicates potential cross-contamination risk. Best avoided by individuals with celiac disease.

Taking Control of Your Shopping Trip

Prioritize Certified Products: If your sensitivity is high or you have celiac disease, certified products are the safest option and remove most of the guesswork.
Verify Labeled Products: For items with a simple "gluten-free" label, quickly scan the ingredients list to ensure no obvious sources have been overlooked.
Read Ingredients for Unlabeled Items: With unprocessed or un-labeled items, a careful read of the ingredients is essential. When in doubt, leave it out.
Beware of Advisory Warnings: If a product has a "May contain" statement, it's a warning about potential cross-contamination. Most experts recommend that people with celiac disease avoid these products.
Use Digital Tools: Organizations like Coeliac UK and the Celiac Disease Foundation offer online food databases and apps to help identify safe products.

Conclusion: Navigating Your Gluten-Free Journey with Confidence

For anyone on a gluten-free diet, becoming a diligent label reader is a non-negotiable skill. Learning how do I tell if a product is gluten-free involves a layered approach: starting with a reliable certified product, understanding the FDA's regulatory minimum, and scrutinizing every ingredients list for both obvious and hidden sources of gluten. By staying informed about labeling nuances, trusting third-party verification, and remaining vigilant against potential cross-contamination, you can navigate the grocery store with confidence and maintain a safe diet.

For more detailed information on living a gluten-free lifestyle, resources like the Celiac Disease Foundation offer extensive guides and support.

Frequently Asked Questions

In the United States, the FDA defines 'gluten-free' as a product containing less than 20 parts per million (ppm) of gluten. This standard applies to foods naturally free of gluten and those with gluten removed during processing.

No, 'wheat-free' does not mean 'gluten-free'. A product can be free of wheat but still contain other gluten-containing grains like barley or rye. Always check the full ingredients list for all potential gluten sources.

Third-party certification symbols, like those from GFCO or the Crossed Grain organization, indicate that a product has been independently tested and audited to meet even stricter standards than the FDA's minimum. This provides a higher level of safety assurance.

For individuals with celiac disease or high gluten sensitivity, it is best to avoid products with 'may contain' or 'processed in a facility...' warnings. These are voluntary statements indicating a risk of cross-contamination that isn't legally regulated.

To identify hidden gluten, you must read the ingredients list carefully. Look for terms like malt, brewer's yeast, modified food starch (unless sourced), and hydrolyzed vegetable protein, which can be derived from gluten-containing grains.

No, most oats are not gluten-free due to the high risk of cross-contamination from being grown, harvested, or processed alongside wheat. Only oats specifically labeled and certified gluten-free should be considered safe for a gluten-free diet.

Gluten can hide in many processed condiments and sauces. For example, some salad dressings and marinades use wheat flour as a thickener, and traditional soy sauce is brewed with wheat. Always check the labels for these products.