From the Research
No, lactose monohydrate does not contain gluten. Lactose monohydrate is a sugar derived from milk and is completely unrelated to gluten proteins, which are found in wheat, barley, and rye. Lactose is a disaccharide composed of glucose and galactose molecules with one water molecule attached (hence "monohydrate"). It's commonly used as a filler or inactive ingredient in many medications and food products. People with celiac disease or gluten sensitivity can safely consume lactose monohydrate, though those with lactose intolerance may have difficulty digesting it since it contains lactose. If you're taking medications that contain lactose monohydrate and have lactose intolerance, you might experience digestive symptoms, but this is not related to gluten content. The distinction is important because lactose intolerance and gluten-related disorders are completely different conditions with different biological mechanisms, as discussed in a review of gluten-related disorders 1.
The FDA has established a definition of "gluten-free" for food labeling, which requires that the food does not contain an ingredient that is a gluten-containing grain, or an ingredient that is derived from a gluten-containing grain and has not been processed to remove gluten 2. Lactose monohydrate does not meet these criteria, and therefore, it is considered gluten-free. Additionally, a study on malabsorption syndromes notes that lactose intolerance and celiac disease are two distinct conditions, and lactose monohydrate is not a source of gluten 3.
In terms of the quality of life, it is essential to distinguish between lactose intolerance and gluten-related disorders, as the treatment and management of these conditions differ significantly. A gluten-free diet is the primary intervention for celiac disease, while a lactose-restricted diet is recommended for lactose intolerance 3. Lactose monohydrate is a safe ingredient for individuals with gluten-related disorders, but those with lactose intolerance should be cautious when consuming products containing lactose monohydrate. A recent study on the tableting performance of lactose monohydrate also supports its use as a pharmaceutical excipient, without any mention of gluten content 4.