The best supplements for sore muscles after a workout are the ones that support the actual recovery process: protein for muscle repair, creatine for strength and recovery capacity, omega-3s or tart cherry for exercise-related muscle stress, and magnesium plus electrolytes for mineral support and relaxation. But soreness is not just a supplement problem. If you are sore for days after every workout, the bigger issue may be training load, poor sleep, low protein intake, dehydration, or not enough active recovery. Start with the basics, then use supplements to fill the gaps.