You can try drinking peppermint tea which helps treat oily skin. Alternatively you may try B5 Pantothenic Acid supplements. Personally I would look at incorporating a BHA exfoliator to help get deep inside your pores. It will penetrate the oil and help clean your pores.
Make sure to drink the recommended amount of water daily.
Be careful with this, but I've had some success with vitamin D supplements. Thing is, I stopped because I couldn't find a good balance. It's a fat-soluble vitamin so it stays in your system for a while. It would dry me out so much that I'd be thirsty and my skin would flake. So, in my experience, it zaps oily skin but in turn leaves you bone dry. I'm still trying to find a happy medium here. Right now, I'm not too upset with the appearance of my skin. I use a mild cleanser and moisturize with Neutrogena's facial moisturizer for combination skin. It doesn't leave my face too shiny but it also doesn't moisturize very well. That's the only trade off. Good luck with your search! Finding balance with oily skin is quite the challenge. I can relate for sure!
How long did vitamin D tablets take to work? I've been taking them for over a month. My skin is clear (recently cleared my acne) but still oily! @tea rex