Buttah Vitamin C Serum It is a 1 fl. oz (30ml) serum packaged in a black and orange box. The serum is formulated with 15% Vitamin C and Ferulic Acid to help brighten skin, fade dark spots, and defend against environmental damage. It is recommended for daily use, particularly in the morning, and can be paired with other Buttah Skin products like their Even Tone Retinol Oil and Invisible, Matte SPF 30. While the product may discolor over time due to the L-ascorbic acid, its effectiveness is said to remain. You can find more information about the product and purchase it on the Buttah Skin website.