Is Sun Good for Your Hair?

The sun is an absolute powerhouse. Responsible for everything from the avocados on your toast to the ZZ plant on your windowsill, the earth’s closest star is, well…a real star. But although the sun may be good for produce and plants, how does it get along with your locks? Is sun good for your hair?

The sun has a more complicated relationship with the human body than organisms that grow from the ground. It offers protection from seasonal depression while simultaneously posing a threat of skin cancer. Too little and you get bummed out — too much and you get burned up.

You can probably tell where we’re going with this: Things aren’t so simple when it comes to the helio-head of hair questions. There are reasons to see the sun as both a protector and a destroyer of hair follicles.

Here’s a rundown of how the sun can both benefit and damage your hair.

Sunlight can be good for your hair — vitamin D seems to help with hair growth on the head. However, excessive exposure to sunlight can also damage your hair in more ways than one.

When is sunlight good for hair — and when is it not good for hair? Here’s a snapshot.

So, while you do want to get some sun exposure up top, there’s definitely a case in which too much of a good thing becomes a bad thing. If you’re going to be in the sun for long periods, you need to protect your hair from damage.

Let’s dive into some hair and sun questions in more detail, along with how you can protect your hair from excessive sunlight.

Like that plant on your windowsill, the sun might help your hair grow.

Most people already have a general idea that the sun provides vitamin D — and that vitamin D is crucial for health.

Indeed, vitamin D is vital for maintaining calcium levels in your bones. It’s also essential for musculoskeletal health. Your skin supplies a substantial amount of it by using the sunlight that touches it to convert 7-dehydrocholesterol (7-DHC) into vitamin D.

What’s more, vitamin D helps regulate the immune system and works as an anti-inflammatory. But the relationship between hair and vitamin D is a little more complicated.

The Connection Between Sunlight and Hair Growth

We don’t fully understand vitamin D’s role in the complete hair growth cycle, except that it’s a modulator of healthy growth. The nutrient is also frequently deficient in people with the autoimmune condition alopecia areata (which causes round patches of hair loss).

But while studies have found that vitamin D deficiency is prevalent in alopecia areata, the relationship between the two is still murky. At this point, all researchers know is that the severity of the nutrient deficiency is associated with the severity of the disease.

That’s hardly a substantial connection. And although lots of folks do get a majority of their vitamin D from the sun, you can also get it from some foods and vitamin D supplements if necessary.

The TL;DR? Sunlight might be connected to healthy hair growth, but we don’t have much research on that topic.

See our guide to hair vitamins and supplements for more on essential nutrients that support growth.

In short, yep. Though the positive connection between sun and hair is situational at best, the negative side of this relationship has a far more direct set of causes and effects.

The sun can:

• Bleach your hair color or cause color fading if your hair’s dyed

• Weaken the hair follicle, exposing it to other types of damage

• Break down hair proteins, causing dry, frizzy, brittle hair

• Weaken the hair shaft, causing hair breakage (like split ends) and hair loss

• Cause oxidative stress and premature hair aging

• Burn your scalp

Here’s how.

Sunlight effectively does to hair what bleach does — it damages melanin and, therefore,  pigment over time, essentially bleaching the color out of the hair follicle. The natural highlights might be a welcome side effect, but that effect is permanent to the exposed hair — it’ll only return to your natural color when it begins to grow out.

Likewise, sunlight can damage the keratin (the main protein in hair) and cuticle of a hair follicle, which weakens the follicle and removes significant protections from other sources of hair damage (think heat styling, overbrushing, or using chemicals to color or relax your hair).

The sun can also damage hair proteins, which can cause dryness, frizz, and brittle hair that’s prone to breakage.

The effects of the sun can be worse for people with certain hair types and hair colors. Hair that’s finer and lighter is more vulnerable to sun damage than darker and coarser hair strands.

Research on UV Damage to Hair

A 2008 study found that sunlight damages keratin, and melanin offers some protection against the sun’s free radicals. People without much melanin (those with lighter hair) don’t get the same added security.

Over time, sun exposure damage can weaken the hair shaft. In a person with curly hair or black hair, this might look like more breakage. For someone with blonde hair, UV light could more quickly lead to breakage and, over time, increase the risk of hair loss.

That’s right: Hair loss in summer is even more of a threat.

Sun exposure can cause oxidative stress as well, which can lead to premature hair aging. Just like the skin on the rest of your body, the sun can also burn your scalp — and an unhappy scalp leads to unhappy hair.

This is where we have to make an important point: Hair is arguably there to get damaged by the sun — at least if the other option is sun damage to your skin.

A 2015 study showed that hair actually provides a protective barrier against UVA and UVB rays — radiation sources that have been linked over and over again to skin cancer. To put it bluntly, hair doesn’t get cancer, and that’s why sacrificing it to protect your scalp, ears, and anything else it covers might be worth the dry locks.

The study found that the darker, coarser, and thicker your hair is, the more protection it provides. But you don’t actually have to choose between healthy hair and healthy skin.

While your hair can protect your scalp, you don’t have to put up with sun-damaged hair. Here’s how you can safeguard your hair from sunlight: 

• Wear a hat. An easy one. Hats can protect your hair, scalp, and face from damaging UV light. And they look cool, too (well, depending on your hat choice). A scarf or umbrella can also work as sun protection.

• Use UV protection. The American Academy of Dermatology Association recommends using a leave-in conditioner with zinc oxide — like sunscreen for your hair and scalp. You can also find shampoos, sprays, and powders with UV protection.

• Avoid peak sunlight hours. Try to minimize your hair’s sun exposure when UV light is at its strongest from 10 a.m. to 4 p.m. Head inside, seek shade, or grab that hat.

Is sun good for your hair? Here’s what to keep in mind:

• The sun does some critical things for hair health (and overall health), mostly in the form of vitamin D production.

• And while sunlight probably isn’t making you lose all your hair, it could be damaging it more than you know.

• Direct sunlight can harm hair proteins and weaken the hair shaft, leaving your mane dry, reducing elasticity, and increasing your risk of hair breakage.

• Sunlight may be the culprit of damage to the hair on your head — but sun-damaged hair isn’t the only potential cause of hair loss.

If you’re looking for answers, you can take our free hair quiz to connect with a healthcare professional online.

You can also get hair loss treatments and hair care products to improve your hair health, rain or shine.