What is the difference between ProxUp2 and ProxUp3? ProxUp2 ready-to-use already contains serum, whereas ProxUp3 must be supplemented with 0.5% FBS. By Giulia Corso|2024-09-20T12:22:51+00:00September 20th, 2024|ProxUp3| Share This Story, Choose Your Platform! FacebookXLinkedInWhatsApp About the Author: Giulia Corso