Cornstarch is a thickening agent most often used to make marinades, sauces, dressings, soups, gravies, and some desserts. It’s derived entirely from corn.

If you follow a gluten-free diet for personal or health reasons, you may wonder whether this product contains any gluten.

This article tells you whether cornstarch is gluten-free.

Most cornstarch is gluten-free

Cornstarch is a fine, white powder processed from the endosperm of corn. The endosperm is the nutrient-rich tissue inside the grain.

Corn is a gluten-free grain, and no other ingredients are typically required to make cornstarch. As a result, pure cornstarch — which contains 100% cornstarch — is naturally gluten-free.

However, cornstarch may be made in a facility that also manufactures gluten-containing foods.

If so, it may be cross-contaminated with traces of gluten. In this case, a disclaimer on the label should note the factory status.

How to make sure your cornstarch is gluten-free

The best way to ensure that your cornstarch is gluten-free is to check the label for appropriate certification.

To be certified, a food must be tested and confirmed to contain fewer than 20 parts per million (ppm) of gluten. This is a very small amount that’s unlikely to trigger symptoms in people with gluten intolerance (1).

A gluten-free seal means that the product has been independently tested by a third party, such as NSF International, to ensure it meets these requirements.

The Gluten Intolerance Group’s gluten-free label goes one step further, requiring fewer than 10 ppm (2, 3).

Furthermore, you can quickly check to verify that the ingredients list includes only corn or cornstarch.

SUMMARY

Most cornstarch is naturally gluten-free, as it’s made by extracting the starch from corn. All the same, you should look for gluten-free certification to minimize the risk of gluten cross-contamination.

Substitutes for cornstarch

If you don’t have cornstarch on hand, several other gluten-free ingredients make good replacements — though you may need to use a little more or less to get the same effect. These include:

  • Rice flour. Made from finely ground rice, rice flour replaces cornstarch in a 3:1 ratio.
  • Arrowroot powder. Derived from the tropical arrowroot plant, this powder replaces cornstarch in a 2:1 ratio. Be sure to whisk it well, as it can become clumpy.
  • Potato starch. This can replace cornstarch in a 1:1 ratio but should be added toward the end of a recipe to ensure thickness.
  • Tapioca starch. Extracted from the root vegetable cassava, tapioca starch replaces cornstarch in a 2:1 ratio.
  • Flaxseed gel. Mix 1 tablespoon of ground flax seeds with 4 tablespoons (60 mL) of water to make a gel. This replaces 2 tablespoons of cornstarch.
  • Xanthan gum. This vegetable gum is made by fermenting sugar with certain bacteria. A little bit goes a long way, so it’s best to start with a small amount like 1/4 teaspoon and add more as needed.
  • Guar gum. Like xanthan gum, this vegetable gum made from guar beans should be used in very small amounts.

To minimize any risk of gluten cross-contamination with these products, look for gluten-free certification on the packaging.

SUMMARY

Several gluten-free thickening agents are neutral in flavor and can replace cornstarch in most recipes.

The bottom line

Cornstarch is derived from corn, a naturally gluten-free grain. As no other ingredients are required to make it, it’s generally gluten-free.

However, some cornstarch may harbor trace amounts if it was manufactured in a facility that also makes gluten-containing products.

To determine if your cornstarch is gluten-free, make sure the ingredients list contains nothing but corn or cornstarch. You should also choose products that are certified gluten-free.

Alternatively, you can use other gluten-free thickening agents like flaxseed gel or arrowroot powder in place of cornstarch. If you’re sensitive to gluten, it’s best to look for a gluten-free label on these products as well.