I am in my late 20s and never had acne growing up. About 5 years ago, I started getting really bad acne on one side of my face, gradually spreading to my forehead. I tried so many topical creams, gels - both prescription and over-the-counter. I quit eating meat, drank more water, none of this helped.
I finally started drinking one squeezed lemon in warm water every morning before work, so 5 times a week. This has almost completely cleared my acne in just on month. I still get occasional hormonal breakouts, but the lemon water has helped greatly.
I also use a cleansing pad every morning and Clinique Dramatically Different moisturizer. This, combined with the lemon juice, has done wonders for my skin.
The reason I think the lemon juice does so well is that it is cleansing of the liver and kidneys. Cleansing your liver is one of the best things you can do for your skin. If you want to go one giant step further, try Andreas Golitz Amazing Gall Bladder flush. I have yet to try this, but plan to very soon.