Short answer

We found no documented interaction between Biotin and Vitamin C in the sources below. That isn't proof the combination is right for you: check each one's cautions, and ask your pharmacist if you take medication.

Biotin

What it is: A B vitamin that helps turn the food you eat into energy.

What the research says: It's widely sold for hair, skin and nails, but there's little evidence for that. A few small studies found harder nails in people with brittle nails.

Cautions

• High-dose biotin can make some lab tests wrong, including thyroid hormone tests. Tell your clinician before a blood test.

Medicines to check

• Long-term anti-seizure medicines can lower biotin levels

In Holitro: Biotin 5000mcg (5000 mcg per capsule)

Source: NIH Office of Dietary Supplements: Biotin: Fact Sheet for Consumers (updated January 2021)

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.