Phentermine is a popular prescription medication for weight loss, yet some individuals may experience weight gain while taking it. This paradox can be attributed to several factors. First, phentermine can influence metabolism and appetite regulation, leading to changes in eating habits. Additionally, individuals might engage in compensatory behaviors, such as overeating or consuming high-calorie foods, as they feel more energetic. Stress, hormonal fluctuations, or underlying health issues can also play a significant role. It’s crucial to consult a healthcare professional if weight gain occurs while on phentermine, as they can provide tailored advice and support for effective weight management.