I just need to lose 15-20 pounds. what diet pills work, are available over the counter?

No pills: Simple sugars and processed carbs should be avoided or limited. This includes any flour product. The fine grind makes absorption quick, and spikes your blood sugar which increases Insulin and promotes weight gain. Good fats such as olive oil and coconut oil are fine in sensible amounts. Eat a rainbow of organic vegetables and just enough protein.