(Water-free suspension, tube format) This format is a suspension of very fine L-Ascorbic Acid powder and, as such, provides the most direct exposure of extremely high concentrations of Vitamin C topically. With such format, there are 2 important things to consider: 1) A very strong tingling but non-irritating sensation is expected during the first 1-2 weeks of use until the skin’s tolerance to such high exposure is elevated; 2) The powder exposure to the skin disallows the formula to feel like a serum, lotion or cream and each application requires a few seconds to feel absorbed by the skin. If desired, this formula can be diluted in a cream base per application to allow the skin to build tolerance over time. This formula feels gritty on the skin for a few seconds. If this feeling is not desirable, we would suggest Vitamin C Suspension 30% in Silicone.