Standard powdered sugar (also called confectioners’ sugar) is gluten-free. It contains just two ingredients: finely ground sugar and a small amount of anti-caking agent, most commonly cornstarch or tricalcium phosphate. Neither of these contains gluten. However, there are a few situations where powdered sugar could be a concern for people with celiac disease or gluten sensitivity.
What’s Actually in Powdered Sugar
Powdered sugar is granulated sugar that has been milled into a very fine powder. On its own, pure sugar contains no gluten. The potential issue comes from the anti-caking agent added to prevent clumping. In the United States, that agent is almost always cornstarch, which is naturally gluten-free. Some brands use tricalcium phosphate instead, which is also gluten-free.
The concern arises with products from certain international markets, where wheat starch is occasionally used as the anti-caking agent. If you’re buying powdered sugar imported from Europe or another region, check the ingredients list carefully. Wheat starch will be listed as an ingredient and is also required to be called out as an allergen on the label in the U.S.
Cross-Contamination in Processing
Even when the ingredients themselves are gluten-free, shared manufacturing equipment can introduce trace amounts of gluten. The FDA notes that manufacturing facilities using shared production equipment for foods both with and without gluten can result in cross-contact. For sugar specifically, the risk is low because sugar refineries typically don’t process wheat products. But some brands package their sugar in facilities that also handle flour or other wheat-based ingredients.
If you have celiac disease, look for powdered sugar that either carries a “gluten-free” label or a third-party certification like the GFCO (Gluten-Free Certification Organization) seal. Under FDA rules, any product labeled “gluten-free” must contain fewer than 20 parts per million of gluten. Some store brands, like Great Value, include a gluten-free claim on their packaging. A product can carry both a “gluten-free” claim and an advisory statement like “made in a facility that also processes wheat,” so read both carefully and decide based on your own level of sensitivity.
Why Wheat Starch Matters for Celiac Disease
If you do encounter powdered sugar made with wheat starch, it’s worth taking seriously. A study published in PubMed found that wheat starch labeled as “gluten-free” still contained a measurable amount of gluten (0.75 mg per 100 grams). Of 17 celiac patients who consumed a product containing that wheat starch, 11 developed symptoms, and two of three patients with a related skin condition (dermatitis herpetiformis) experienced a relapse of skin lesions. The researchers concluded that the long-term safety of wheat starch in products marketed to celiac patients remains unproven.
This doesn’t mean all wheat starch will cause a reaction in every person with celiac disease, but it does mean that cornstarch-based powdered sugar is the safer choice by a wide margin.
How to Check a Label
Flip the package over and look at the ingredients. You should see something like “sugar, cornstarch” or “cane sugar, corn starch (3%).” That’s it. If you see wheat starch, tapioca starch, or potato starch listed, those tell you exactly what you’re dealing with. Tapioca and potato starch are both gluten-free. Wheat starch is not safe for people avoiding gluten.
Major U.S. brands like Domino, C&H, and store-brand powdered sugars all use cornstarch. If you’re unsure about a lesser-known brand, the ingredients list is your most reliable tool.
Making Your Own at Home
If you want complete control over what goes into your powdered sugar, you can make it in about 30 seconds with a blender or food processor. The ratio is simple: 1 cup of granulated sugar plus 1 tablespoon of your preferred starch. Blend on high until the sugar is a fine powder.
Potato starch, tapioca starch, and arrowroot starch all work well and are naturally gluten-free. Cornstarch is the most common choice and produces results closest to store-bought. This is a particularly good option if you’re also avoiding corn, since it lets you swap in a different starch entirely. Homemade powdered sugar works the same way in frostings, glazes, and baked goods.