Wellbutrin (bupropion) typically starts to take effect within 1 to 2 weeks, with some small improvements in symptoms like mood, energy, and motivation noticeable during this period. However, it usually takes about 4 to 6 weeks to feel a more significant benefit, and up to 6 to 8 weeks or sometimes even a few months to experience the full therapeutic effect, including major improvements in depression symptoms and overall well-being. The exact timeline can vary depending on the individual, dosage, and the condition being treated, so consistent use and communication with a healthcare provider are important for best results.