As a general rule, if you begin to see lines and wrinkles that are visible when your facial muscles are relaxed, it’s probably time to start BOTOX treatments. For some, this may be as early as the mid-20s, while for others, the lines and wrinkles become evident in the mid to late 30s. The effects of aging appear at various times based on genetics, ethnicity, and environmental factors such as wind, cold weather, and sun exposure.