When we use nicotinamide, we can use a low concentration of nicotinamide in combination with a high concentration of nicotinamide, or we can use a high concentration of nicotinamide in a toner or cream. Because the high concentration of nicotinamide whitening skin can not be directly applied to the facial skin, it needs to be used with some other skin care products to achieve the effect of whitening skin.
The use of nicotinamide whitens skin first to build up skin tolerance. For the first time, 2 drops can be applied, and 4 drops can be applied the next day if there is no abnormal skin reaction. If there is a slight reaction, you can reduce to 1 drop, and then gradually increase or decrease the dosage, until the skin reaches a stable state, and you can use it normally.
On the first day of use, take a small drop of nicotinamide and apply it behind the ear to see if there are allergic symptoms such as redness and swelling. If not, apply 10% of nicotinamide behind the ear on the second day. If there are still no symptoms, it means that you are not allergic to nicotinamide and can use it normally.
On days three and four, apply a low concentration of nicotinamide to the forehead and face to see if the face is allergic to nicotinamide. If it is normal, it can be used normally from the fifth day. Note that the direct effect on the skin is limited to low concentrations of nicotinamide. High concentrations of nicotinamide should be used with other skin care products. It is not recommended to apply directly to the face.