Can I Mix Hydroquinone with Tretinoin and a Moisturizer?

Yes, mixing hydroquinone gel and tretinoin cream with your moisturizer is a great treatment for your melasma.  However, they should not be used on the neck or other body areas due to increased likelihood of irritation.  With this said, I would recommend starting slowly with the face (initially 3 times per week) as gels can be more irritating, and then work up to nightly if no redness or flaking occurs.  I would consult your physician on how long they recommend you use this regimen.  In my practice, I recommend patients use hydroquinone for 6-8 weeks and then take a break. And during this break, I recommend using a natural lightener, such as kojic acid, to maintain the initial results achieved by the hydroquinone.

There are many options for melasma treatment. I advise my patients to begin Melarase AM and Melarase PM for melasma as they contain natural, non-HQ, and HQ skin lighteners. Raffy Karamanoukian Los Angeles

One should avoid mixing topical medications in absence of supervision of a board-certified dermatologist. There is always a concern about possible self-dilution and pH incompatibility. On the other hand, it may be appropriate to use a light thin-coat of moisturizer 30 minutes prior to topical tretinoin or hydroquinone to minimize irritation.