Every person's skin needs are different, but both salicylic acid and niacinamide can treat acne. The pro of using niacinamide is that it can hydrate the skin and help with oil. Salicylic acid targets acne and blemishes. These two ingredients can also be used together, but you would have to give yourself time to adjust and be aware of your skin's pH levels. Before starting any acne treatment, it is always advisable to consult a dermatologist.