NutriBiotic Ascorbic Acid Vitamin C Powder, 16 Oz | Pharmaceutical Grade L-Ascorbic Acid, 2000 Mg Per Serving | Essential Immune & Antioxidant Collagen Support Supplement | Vegan, Gluten & GMO Free

Customers find this vitamin C powder effective for immune support, reporting it helps fight off sickness and the flu. The product receives positive feedback for being pharmaceutical grade, dissolving well in drinks, and lasting a long time. Customers appreciate its benefits for skin, making it softer and improving nail health, while also noting it's excellent value. The taste receives mixed reactions, with some finding it very mild while others describe it as very sour.