Yes, washing hair with hot or cold water affects hair and scalp health in different ways. Hot water opens the hair cuticles, helping to cleanse dirt and oil more deeply, but using it too often may dry out the scalp and damage the hair. Cold water, on the other hand, helps close the cuticles, which can reduce frizz, add shine, and even stimulate the scalp, though it may not remove oil as effectively. The best approach is to wash your hair with warm water and finish with a cold rinse to lock in moisture. Adjust the temperature based on your hair type and scalp sensitivity, and avoid very hot water. If you experience persistent dryness, irritation, or hair loss, please consult a dermatologist for personalized advice.