Common nutritional supplements used for fitness enhancement include protein powders, creatine, BCAAs (branched-chain amino acids), and pre-workout formulas. Protein powders, derived from whey or plant sources, help meet protein needs for muscle recovery and growth. Creatine is known for its ability to improve strength and high-intensity performance. BCAAs can reduce muscle soreness and promote recovery. Additionally, consuming pre-workout formulas can increase energy and focus during workouts. It's essential to consult a healthcare professional before starting any supplementation regimen to ensure proper usage.