Vit. C vs. Alpha Arbutin vs. Niacinamide vs. Trazenamic Acid

None of those are good acne prevention. They are not made for that, plus acne itself is dependent on the individual as to the trigger. As for fading pigments. All will assist with that, fading pigment is hard especially with person off color as you need to treat and stop multiple pigment pathway. Vitamin C is your skin can tolerate it would be good, vit c derivative Sodium Ascorbyl Phospate or MAP has studies to assist in acne as they have anti microbial properties and anti inflammatory but still may not address acne especially if its hormonal related.

Niacinamide for sure - it helps with sebum control as well as brightens the skin - so really it is the only one that targets both of your concerns (acne control+brightening)

niacinamide for sure

I’m a combination skin dealing with hyperpigmentation, I’ll pick tranexemic acid.

the first setw