The timing of supplementation with creatine for improving training adaptations has only been investigated in a small number of trials.
One 10-week trial looked at the effect of supplementation with creatine together with protein and carbohydrates both before and after resistance training (i.e., in close proximity to the workout) compared to the same supplement taken in the morning and evening (i.e., further away from the workout).[1] The researchers found that taking the supplement in close proximity to the workout increased lean mass, the cross sectional area of type 2 muscle fibers, strength, and intramuscular creatine and glycogen stores more than taking the supplement further away from the workout. This potential benefit of creatine taken in close proximity to the workout, relative to other times, may be related to an upregulation of creatine transport secondary to muscle contraction.[2]
A handful of trials have also looked at the effect of supplementation with creatine before compared to after the workout.[3][4][5][6][7] In these trials, no differences were observed between groups for changes in body composition or strength.
In summary, because only one trial examined the effect of taking creatine (together with protein and carbohydrate) in close proximity to, compared to further away from, resistance training sessions, it remains unclear whether there is an optimal time to supplement with creatine. At the very least, it doesn't seem to matter whether creatine is taken before vs. after resistance training sessions.