Kellogg's Special K2O Protein Water

K2O is a health beverage released in September 2006 by the Kellogg Company. It is available in several flavors, including Strawberry Kiwi, Lemon Twist and Tropical Blend. Marketed as low-calorie alternative protein drink, a 16-ounce bottle of K2O contains 5 grams of protein, 10% DV of calcium, and 50 calories.

On August 15th, 2007, the company will re-launch the product with enhanced graphics and a new flavor, Mixed Berry. In addition to the 5 grams of protein, the product now has 5 grams of soluble fiber, from polydextrose, and 20% DV each of vitamins B3, B6, and B12, while maintaining 50 calories.

Potassium oxide also bears the chemical symbol K2O. Although the name "Special K2O" is a play on both the Special K brand name and the H2O (water) reference.