As autumn approaches, the first chills remind us that viruses are waiting for us. Vitamins, dietary supplements, and detox cures are making a comeback, but the immune system does not stimulate itself on simple demand. The solution to strengthen our defenses may be simpler than it seems. While there is no quick fix, there are practical, everyday habits that can support our body’s natural defenses. The immune system is a complex network of cells, tissues, and mechanisms that protect the body against infectious agents such as viruses and bacteria. It does not have a "turbo" button that can be activated with a few days of treatment. However, certain habits contribute to its proper functioning. For example, a varied and balanced diet plays a crucial role in maintaining overall health and supporting immune function. Vitamins and minerals are essential for many biological processes, including those involved in the immune system. Our intestinal microbiota—the community of bacteria living in the gut—also plays a significant role in immune responses. Fortunately, diet can help modulate this microbiota, offering a good reason to focus on balanced eating habits. This does not mean that one should start taking multiple dietary supplements in September. For people who do not have a specific deficiency, the benefits of systematic supplementation are not well proven. The French Agency for Food, Environmental and Occupational Health Safety (Anses) warns against products marketed as "immunity boosters" and advises focusing on identifying the causes of fatigue or health issues rather than automatically turning to supplements. Sleep and regular physical activity are also key factors in maintaining a strong immune system. Poor sleep quality or insufficient sleep duration can negatively affect both physical and mental functions. As winter approaches, regaining regular sleep patterns and ensuring enough rest are more reasonable preventive measures than relying on detox cures. Similarly, regular exercise—whether it's walking, cycling, or swimming—can contribute to overall health. The goal is to reduce sedentary behavior and engage in physical activity that is appropriate for one's abilities. Prevention against viruses also includes limiting exposure to them. Simple measures such as hand washing, ventilating rooms, coughing or sneezing into the elbow, and avoiding close contact when sick can significantly reduce the risk of transmission. Santé publique France also emphasizes the importance of vaccination for infections for which vaccines are available, such as the flu and COVID-19. These measures, when combined with healthy lifestyle choices, can help support the immune system and reduce the risk of illness.