Best Niacinamide Serum in India is known for its ability to help heal acne scars. To achieve this benefit, apply the serum every day before bedtime. Apply a small amount of serum to your hands, and gently massage it into your skin. You can also apply the serum using a Q-tip or cotton ball. Be sure to avoid contact with your eyes. Because niacinamide is a vitamin, it may cause mild irritation if applied excessively or in high concentrations. If this occurs, gradually reduce the amount of niacinamide you are using until the irritation subsides.