Can Too Much Turmeric Cause Side Effects?

There haven’t been many studies looking at the negative long-term side effects associated with taking a turmeric or curcumin supplement.

“Most of the current published information for long-term complications of turmeric supplementation are related to liver injury,” says Gradney. Beyond that, there’s some evidence of potential interactions, as well as a few small studies showing short-term side effects.

Turmeric May Lead to Liver Injury

The researchers noted that some of the damage may be associated with taking turmeric with black pepper, which increases the amount you absorb. The study also found a possible genetic connection: Most of the people studied had a specific gene variant that may make them more susceptible to turmeric-related liver damage.

While this research does establish a rise in liver-injury reports and that this gene variant may play a role, it falls short of explaining exactly why, says Ana Pruteanu, RDN, LDN, owner of Be Well Nutrition Counseling in Chicago.

“This study doesn’t describe doses of turmeric that were consumed to understand total intake that may have been linked to liver injury,” she says. “It confirms that individuals with [a certain genetic makeup] are more likely to experience liver injury, but it’s not clear what percentage of the population has this genetic makeup.”

Turmeric May Limit Iron Absorption

That said, Pruteanu notes that this was an observational study of one person who had low iron levels even before taking a turmeric supplement, so the link between turmeric and low iron levels can’t be determined. “While his iron levels improved after discontinuing the turmeric supplementation, it is difficult to conclude that turmeric was the reason for low iron absorption,” she says. “More studies are needed to confirm this phenomenon.”

Turmeric May Interact With Blood Thinners and Other Medications

If you’re taking blood thinners like warfarin (Coumadin), clopidogrel (Plavix), or aspirin, turmeric can strengthen the effects of these medications, which may raise your risk of bleeding, says Gradney.

Turmeric May Lower Blood Sugar Too Much

However, turmeric can lower your blood sugar and may also magnify the effects of certain diabetes medications, increasing your risk of low blood sugar (also known as hypoglycemia), says Gradney, so check with your doctor before taking any turmeric supplements for diabetes.

Turmeric May Cause Kidney Stones

Turmeric supplements may increase your risk for kidney stones, especially if they run in your family, says Gradney. Turmeric is high in oxalate, a chemical that your body releases through urine.

Turmeric May Lead to Nausea, Diarrhea, and Headache

While this review was based on older studies, Gradney notes that turmeric spice and related supplements can cause abdominal pain, nausea, and diarrhea when taken in high dosages.