My skin can be pretty sensitive on the account that I have rosacea and KP so I wanted to try an alternative to Vit C because I noticed Vit C tends to leave me more red more often than other serums. I absolutely adored this serum. I used it at night rather than during the day simply because I was using too many other serums during the day at that time. This serum lasted me over 4 months! And my skin looked so dewy afterwards. I also wasn't as red as when I use Vit C. I'm excited to try other Mary&May serums.