It is generally not recommended to use niacinamide and hydroquinone at the same time. Niacinamide is a form of vitamin B3 that offers various benefits for the skin, including reducing inflammation, improving skin barrier function, and reducing the appearance of hyperpigmentation. On the other hand, hydroquinone is a skin-lightening agent commonly used to treat hyperpigmentation and melasma.

The concern with using niacinamide and hydroquinone together is that they may interact and reduce the effectiveness of each other. Hydroquinone works by inhibiting the production of melanin in the skin, while niacinamide can potentially interfere with this process. Therefore, using them together may diminish the desired effects of hydroquinone.

Additionally, combining these two ingredients may increase the risk of skin irritation or other adverse reactions. Both niacinamide and hydroquinone can be quite potent, and using them simultaneously may overwhelm the skin and lead to sensitivity or inflammation.

If you are considering using both niacinamide and hydroquinone, it is best to consult with a dermatologist or skincare professional who can provide personalized advice based on your specific skincare needs and concerns. They can help you develop a suitable regimen that addresses your concerns effectively without compromising the health and integrity of your skin.