A lack of folate or vitamin D can make you feel tired, weak, or achy, and may even affect your hair. While grey hair is usually caused by genetics and ageing, things like poor nutrition, stress, anaemia, thyroid problems, or low vitamin B12 can sometimes make hair turn grey earlier. Getting better often means fixing these deficiencies and looking for any other issues that might be making you feel worse. If your symptoms do not improve with treatment, doctors might suggest tests for vitamin B12, iron, thyroid function, calcium, haemoglobin, and blood sugar. Eating balanced meals with protein, green vegetables, nuts, fruits, and eggs, getting sunlight, sleeping well, and managing stress can help you recover and boost your energy. It can take several weeks for vitamin D and folate supplements to make a difference, so improvement is usually slow. If you notice rapid hair loss, severe weakness, numbness, significant weight changes, or ongoing tiredness, it is important to get checked for other possible deficiencies or hormone problems.