Hi - this is one of the best brands to get (just my opinion) : Lypo–Spheric Vitamin C – 3 Cartons (90 Packets) – 1,000 mg Vitamin C & 1,000 mg Essential Phospholipids Per Packet – Liposome Encapsulated for Improved Absorption – 100% Non–GMO https://www.amazon.com/dp/B00DH30638/ref=cm_sw_r_cp_api_i_MYGJMWH3S3YABB09YSXA

You want to make sure you are buying Liposomal Vitamin C as it has a much higher absorption rate than regular vitamin C. It’s quite expensive but worth it. Hope this helps.