Quick answer
Rice flour is finely milled rice, about 80% carbohydrate by weight. In supplements it is usually a filler: on capsule labels it appears under Other ingredients, the list FDA requires for fillers, binders and other ingredients that are not dietary ingredients. Rice is not one of the gluten-containing grains in FDA's rules.1,2,3,4
Key facts
- USDA lists white rice flour at 80.1 g of carbohydrate, 5.95 g of protein and 1.42 g of fat per 100 g.1
- FDA requires fillers, binders and other non-dietary ingredients to appear in a supplement's ingredient list.3
- NIH's Dietary Supplement Label Database lists more than 11,000 labels that mention rice flour.2
- FDA's gluten-free rule names wheat, rye and barley, and their crossbreeds, as the gluten-containing grains.4
Why rice flour is in a capsule
FDA groups fillers with carriers, binders and other formulation aids: substances used to give a product the physical form or texture it needs. Rice flour is a common choice. In 50 of the database labels that mention it, 37 listed rice flour among the other ingredients, and most of those were capsules.2,5
Researchers have also tested rice flours as a base for pressed tablets. In a 2013 study, rice flours flowed and packed well and were less affected by magnesium stearate than a standard starch excipient.6
What is in rice flour
| Component | Amount |
|---|---|
| Carbohydrate | 80.1 g |
| Protein | 5.95 g |
| Fat | 1.42 g |
| Fiber | 2.4 g |
| Water | 11.9 g |
A capsule label does not give the amount of rice flour. Ingredients outside the Supplement Facts panel are listed by name only, in descending order of weight, so its position in the list is the only clue to how much is there.7
Rice flour and gluten
Under FDA's gluten-free rule, the gluten-containing grains are wheat, rye, barley and their crossbreeds. Rice is not on that list. A product that claims to be gluten-free must also contain less than 20 parts per million of gluten.4
Questions people ask
Is rice flour in supplements bad for you?
Rice flour is an ordinary food ingredient, and in supplements it is there as a filler. None of the sources we used raised a concern specific to it. If you avoid rice, the Other ingredients list will show whether a product contains it.1,3
Does rice flour contain gluten?
Rice is not a gluten-containing grain under FDA's rule, which lists wheat, rye and barley. A supplement that carries a gluten-free claim must contain less than 20 parts per million of gluten.4
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Sources
- U.S. Department of Agriculture, Agricultural Research Service. FoodData Central: Rice flour, white, unenriched (SR Legacy, FDC ID 169714). Opened 2026-10-07.
- Office of Dietary Supplements, National Institutes of Health. Dietary Supplement Label Database: search for rice flour, and a review of 50 matching labels, October 7, 2026. Opened 2026-10-07.
- Code of Federal Regulations, Title 21, Section 101.4: Food; designation of ingredients. eCFR, current as of October 2026. Opened 2026-10-07.
- Code of Federal Regulations, Title 21, Section 101.91: Gluten-free labeling of food. eCFR, current as of October 2026. Opened 2026-10-07.
- Code of Federal Regulations, Title 21, Section 170.3: Definitions (food additives). eCFR, current as of October 2026. Opened 2026-10-07.
- Ahmad MZ, Akhter S, Dhiman I, Sharma P, Verma R. Evaluation of material properties and compression characteristics of Assam Bora rice flours as a directly compressible vehicle in tablet formulation. Expert Opin Drug Deliv. 2013;10(2):163-171. Opened 2026-10-07.
- U.S. Food and Drug Administration. Dietary Supplement Labeling Guide: Chapter V. Ingredient Labeling. April 2005. Opened 2026-10-07.
This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.