As of the start of 2023 the most frequently prescribed diet pill in the United States is Phentermine, an FDA approved appetite suppressant. Phentermine 37.5 mg is not available or suitable for everyone, it can only be obtained by prescription, it can also cause several side effects. For these reasons a thriving market has evolved for over the counter Phentermine alternatives. This article is a comprehensive guide and compares, reviews and rates the best phentermine over the counter brands for 2023.