With acne medications
According to the manufacturer, it is ok to use Hydroderm with other acne medications in general. As with all medications, they recommend consulting your doctor before combining.
With other face creams or serums
According to the manufacturer, Hydroderm can be used along with moisturizers, but it is recommended that you let the Hydroderm dry for 10 minutes before applying any other product, including makeup. Do not use Retin-A products with Hydroderm since it could cause irritation. Consult with your physician is always recommended.