It gives a nice brown color, so you may need to get a new foundation color. I would not use it under moisturizer, as it needs time to set and develop on the skin. It does dry right away, but if you add moisturizer too soon on top you will just re-wet it and create thin spots or streaks in the tanner. I use it on clean skin before bed 1-2 times per week, in the morning it has developed and you can then use serum, moisturizer, etc. The color seems to last well by only applying 1-2x per week.
The is no SPF so I would not use it in the day. I put it on at night and wash off in the morning.