Medically reviewed by Kristin Hall, FNP
Written by Our Editorial Team
Last updated 1/4/2023
Our sun is an absolute unit. Responsible for everything from the avocados on our toast to the ZZ plants on our window sills, our closest star is, well…a real star. But while the sun may be good for the health of our food and apartment furnishings, how does it get along with our locks? Is sun good for your hair?
The sun has a more complicated relationship with our bodies than with plants. It offers protection from seasonal depression while simultaneously posing a threat of skin cancer. Too little and we get bummed out; too much and we 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 question. There are reasons to see the sun as both a protector and a destroyer of our follicles.
So, does sunlight help your hair grow?
The best way to break down this topic is to do it one question at a time, so let’s start with what might be the easiest one to answer.
One of the easiest questions to answer is about the relationship between hair growth and sunlight. Most of us already have a general idea that the sun provides us with vitamin D and that vitamin D is important for our health.
Vitamin D is vital for maintaining calcium levels in your bones. It’s also essential for musculoskeletal health, and your skin supplies a substantial amount of it by using the sunlight that touches your skin to convert dehydrocholesterol into vitamin D.
What’s more, vitamin D helps regulate your immune system and works as an anti-inflammatory.
But is sunlight good for your hair? It turns out the relationship between hair and vitamin D is a little more complicated.
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 the autoimmune condition alopecia areata.
But while studies found that vitamin D deficiency is prevalent in alopecia areata, the relationship between the two is still murky. All researchers know is that the severity of the deficiency is associated with the severity of the disease.
That’s hardly a substantial connection. And while we do get a majority of our vitamin D from the sun, you can also get it with vitamin D supplements if necessary.
While 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.
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. That effect is permanent to the exposed hair — it’ll only return to your natural color when it begins to grow out.
Likewise, sunlight has the effect of damaging the keratin and cuticle of a hair follicle, which weakens the follicle and removes significant protections from other sources of hair damage.
And it gets worse for people with fair hair and lighter hair colors. According to the Cleveland Clinic, hair that’s finer and lighter is more vulnerable to sun damage than darker and coarser strands.
A 2008 study found that sunlight damages keratin, and melanin offers some protection against the sun’s free radicals. People without much melanin 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 (from the sun’s ultraviolet rays) could more quickly lead to breakage and, over time, increase your risk of hair loss.
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 radiation — something that’s 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 is well worth the dry locks.
Similar to other research, the study found that the darker and coarser your hair is, the more protection it provides.
In the end, sunlight is neither good nor bad for your hair, even with the dangers we mentioned earlier. The reality is your hair and skin need some sunlight to stay healthy (and so does your mental health).
But there’s definitely a case in which too much of a good thing becomes a bad thing.
Planning and protection are crucial elements of your hair health. If you’re going to be in the sun for long periods, you need to protect your hair from damage.
The American Academy of Dermatology recommends covering your hair with a wide-brimmed hat or scarf before heading outside. Honestly, this is a great way to look stylish in a convertible on a cross-country road trip.
You should also prioritize going out in the early morning or late afternoon if possible, and consider hair protection like a swim cap when spending time in a chlorinated pool (which can exacerbate summertime hair damage).
Rinsing your hair of chlorine after swimming can also lessen the effects and remoisturize your strands.
There’s not much to say about so-called hair sunscreen at the moment. The research on it is in its infancy, according to experts, so hair products probably aren’t the way to go when it comes to prevention.
That said, products that deliver vitamins and essential minerals (like our biotin hair multivitamin gummies) to your hair may be a great way to protect, as well as repair and reinforce when damage does occur. To learn more, check out our page on vitamins for hair loss.
Let’s look at the sun and hair question from a galactic view — with a ton of perspective.
In the big picture, the sun does some important things for hair health, mostly in the form of vitamin D production. Meanwhile, sunlight probably isn’t causing you to lose your hair, but it may be damaging it more than you know. Direct sunlight could harm hair proteins, leaving your mane dry and increasing your risk of hair breakage.
Safeguarding your hair from excess ultraviolet radiation is important, as is protecting it from other things that may cause female-pattern baldness.
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, consult a healthcare professional with your questions today.
You can start here. Our hair health resources are a great way to learn more about hair types, the causes of hair loss and what’s happening to your otherwise healthy head.