Can I add casein to my blend? Elena M. February 27, 2020 01:04 Updated Absolutely! If you'd like a blend that contains casein protein, send us a note at firstname.lastname@example.org. Related articles Can I get a different mix of protein sources? What should I mix my protein powder with? Do you offer a longer lasting form of protein? Why isn't there any casein in my blend? Comments 0 comments Please sign in to leave a comment.