If you have diabetes, your body doesn’t produce insulin, doesn’t use it effectively, or both. The hormone insulin moves the sugar from the foods you eat from your bloodstream into your cells, where it can be stored or used as energy.

When you don’t have insulin or it’s not used effectively, sugar can build up in your blood.

That excess sugar can damage organs throughout your body, including your eyes and kidneys. It can also damage your nerves and blood vessels.

Your blood vessels carry oxygen around your body to nourish your organs and tissues. Damaged blood vessels may not be able to deliver enough oxygen to nourish your hair follicles. This lack of oxygen can affect your normal hair growth cycle.

How diabetes affects the hair growth cycle ??

Hair usually goes through four phases.

The active growing phase lasts for 2 years or more. During it, hairs grow 1 centimeter (cm) each month. After a transition period, hair then goes into a resting phase. This lasts for up to 4 months. After this phase, some resting hair falls out.

Diabetes can interrupt this process, slowing down hair growth. Having diabetes can also cause you to lose more hair than usual.

That hair loss doesn’t only affect your head. You can lose hairs on your arms, legs, and other body parts, too. When the hair regrows, it does so at a slower than usual rate.

People with type 1 diabetes are more likely to have a condition called alopecia areata. With alopecia areata, the immune system attacks the hair follicles, leading to the loss of patches of hair on the head and other parts of the body.

Other possible causes of hair loss include:

1 the stress of living with a chronic condition like diabetes .

2 thyroid disease, which affects some people with diabetes and can contribute to hair loss .

3 side effects of your diabetes medications .

Read more - https://www.healthline.com/health/does-diabetes-cause-hair-loss#effect-on-hair-growth-cycle