Vitamin C Active balance doesn’t work and tan my skin ?

Perhaps it is because It is a stand alone serum ?

I use it in the morning and sunscreen every 2 hours, no going outside at all

I need to know if I change to another serum where C is just a secondary ingredient it may work for me ?

This serum has two Vitamin C derivatives: SAP and Ascorbyl Glucoside. You may consider LAA or EAA for skin brightening.