Does the sun help regrow eyebrow hair?

No quite frankly it is likely to have just the opposite effect. Prolonged exposure of your eyebrows (and all of your hair for that matter) to excessive sun rays can be quite damaging and could even lead to hair loss.

Exposure to the sun's ultra-violet A and B (UVA and UVB) rays can damage your hair from its cuticle to its inner structure the cortex. The outermost layer of your hair is made up of overlapping scales, as on a fish. Healthy hair cuticles lie down smoothly and reflect light, giving hair its shine. This is the only protecting layer for your hair. But when the hair shaft is exposed to the sun those scales dry out and begin to flare and become brittle. It is in this state that the hair shaft is in its most vulnerable condition and is subject to breakage. Or in extreme cases the hair follicle will dry to the point that it actually dies and falls out.

A key principle to remember is that hair damage occurs from the outside in and hair growth occurs from the inside out. So protection from the environment with sun blocking strategy is essential. Keep dryness at bay with an occasional moisturizing treatment to those scales which will help them to lay flat and smooth. This will help protect your hair from damage and hair loss.

But if you are looking for hair growth then your strategy needs to be inside out. Your most beautiful, fast growing hair is accomplished through good health, nutrition, exercise and of course, a good hair care routine. A large number of nutritionist's agree taking a daily multiple vitamins may help in achieving healthier hair, if you are not getting what nutrients you need from your daily diet. Other vitamins and minerals that come up often in regards to growing a healthy head of hair are; B-complex vitamins, especially biotin, PABA, and vitamin E. Your hair is mostly protein. Nutritionists are praising the high-protein/low-carbohydrate diets for good health.

Good Luck