These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

While HPMC is generally considered safe, some people may experience mild side effects, especially when consumed in high doses. These side effects may include gastrointestinal discomfort, bloating, or diarrhea. However, these effects are usually mild and short-lived and disappear once supplementation is stopped or the dose is reduced.