Short answer

We found no direct interaction between NAC and Vitamin C in the sources below, but they share a caution.

Both have a note about cancer treatment; check with your care team.

NAC (N-acetylcysteine)

What it is: An antioxidant that's both a hospital medicine (for acetaminophen overdose) and a supplement.

What the research says: As a medicine it treats acetaminophen poisoning. As a supplement, results for lung conditions and as an add-on for depression are mixed.

Cautions

• It can cause stomach upset, nausea, diarrhea, tiredness or rash; less often low blood pressure or headache.

Medicines to check

• Nitroglycerin: don't combine (severe headaches, lower blood pressure)
• Antidepressants: animal studies suggest NAC may strengthen their effect
• Cancer treatment: check with your care team

In Holitro: NAC (600 mg per capsule)

Source: Memorial Sloan Kettering Cancer Center, About Herbs: N-Acetylcysteine (updated October 2022)

Vitamin C

What it is: An antioxidant vitamin the body needs to make collagen, absorb iron from plant foods and support the immune system.

What the research says: Vitamin C is essential; supplements make sure you get enough if your diet falls short.

Cautions

• Adults shouldn't exceed 2,000 mg a day; too much can cause diarrhea, nausea and cramps.
• People with hemochromatosis should avoid high doses.

Medicines to check

• Chemotherapy and radiation: check with your care team first
• In one study, antioxidants including vitamin C reduced the benefit of a statin plus niacin

In Holitro: Vitamin C (1000 mg per capsule)

Source: NIH Office of Dietary Supplements: Vitamin C: Fact Sheet for Consumers (updated March 2021)

Check with your doctor or pharmacist, especially if you take medication.

Check your stack — free

Educational information only, not medical advice. This reflects general ingredient overlap, not a personalized safety review. Always check with your doctor or pharmacist before combining supplements, especially if you take medication, are pregnant or nursing, or manage a health condition. These statements have not been evaluated by the FDA.