Premature greying of the beard is often due to genetics, stress, or nutritional deficiencies, and unfortunately, fully turning grey hair back to black naturally is difficult. However, you can slow further greying by maintaining a healthy diet rich in protein, iron, and Vitamin B12 (like green vegetables, nuts, milk, and eggs), managing stress, and getting good sleep. Some home remedies, like applying coconut oil with curry leaves or amla (Indian gooseberry), may help improve hair health, but results are usually gradual.