1. You Keep Getting Ill
Vitamin D supports the normal function of your immune system.¹ Research suggests people with lower vitamin D levels may experience more frequent respiratory infections like pneumonia, bronchitis.³ The lack of sunlight in the winter may well help to explain why we’re all more prone to illness in the darker winter months.

2. Cuts and Injuries Are Slow to Heal
Your body needs vitamin D to help manage inflammation in response to injury.⁴ If you've noticed that small cuts or bruises seem to hang around longer than they should, low vitamin D could be playing a part.

3. Aches in Your Back or Bones
Vitamin D helps your body absorb calcium - the mineral that keeps your bones strong.¹ Without enough of it, you might notice a dull ache in your lower back or joints.

4. Weak Bones
This one is especially important as you get older. Without enough vitamin D, your body can't use calcium properly. Over time, this can weaken your bones and make fractures more likely.⁶