None.
Vegan - Gluten Free.
Made Without: GMOs, milk, soy, eggs, yeast, wheat, rose hips, peanuts, tree nuts, fish, crustacean shellfish, animal products, fillers, binders, excipients, lubricants, starch, sweeteners, colorings, flavorings, and preservatives.
Our Promise and Guarantee: We use only 100% pure pharmaceutical grade L-ascorbic acid USP-FCC†(C6H806), which contains no corn residue, plant antigens, or protein impurities.†United States Pharmacopoeia - Food Chemical Codex