How Do I Use Hydroquinone 4% and Tretinoin 0.025% to Treat Melasma?

Typically you would wash the face and apply the medications at night prior to retiring to bed. You should be religious about the daily use of sunscreen and avoid sun-exposure. You may experience irritation and redness and for this reason most prescribers advise combining this regimen with a topical steroid.

Thanks for your question.  Both medications are useful for helping with melasma.  You will want to start more slowly with the tretinoin (retin-a) cream, maybe all over the face every other night, or every third night.  The hydroquinone can be combined with the tretinoin, and can also be used every night.  It does not tend to cause much irritation or peeling, but the tretinoin can be a bit tricky as far as dryness.  Use an excellent sunscreen, like the Elta MD products, every day, and we love a gentle cleanser such as ZO gentle cleanser or an Elta Foaming Facial Cleanser which will get the skin ready for product use.

Hello anastasia1965, yes, the two products are largely recommend together by most physicians and skin specialists. The instructions for application are very specific, I ensure my patients know exactly how to go about the routine. Wash your hands, your face with a deep cleanser, then apply the HQ to the dark spots and the tretinoin to the rest of your face.  Tretinoin helps Hydoquinone penetrate better which yields better outcomes. You can also apply a moisturizer over the two when you are done to help moisturize your skin. It is important you adhere to strict sun care and avoid direct sunlight this is because tritenoin will really irritate your skin in the sun.  
This answer has been solicited without seeing this patient and cannot be held as true medical advice, but only opinion.The information provided should not be relied upon as a substitute for consultations with a qualified health professional.