Thanks for your question. First of all, you should get some benefit and decrease in the oiliness even with the lowest strength of tretinoin, which is what you have, so I would encourage you to try it. Some people with really oily skin do not need to use moisturizer on top of retin-a or any of the retinoids, but you probably will want to use a gentle moisturizer either mixed in a sunscreen, or separately under sunscreen every morning. The retinoids can make your skin sensitive to sunlight and you might get more sun damage if you aren't really consistent with sunscreen. You can try going without moisturizers over the retin-a at night, but don't hesitate to use something light if you need it. Best of luck!