Why Does Brown Hair Look Red in the Sun?

6 October 2022 | Tincture and Colour

It’s safe to say that every brunette has experienced their hair looking on the warmer side during summer. But if you’ve ever had a mini heart attack after catching a glimpse of your, now red, strands in the mirror, this one’s for you.

So if you’ve ever panicked, thinking, “Why does my brown hair look red in the sun?” it’s time to put that baby to bed and get some answers.


How Does Hair Get Its Colour?

Close up of brown hair

Are you ready for a quick science lesson? So we want to know why brown hair looks red in the sun but before we get to that particular burning question, it’s important to understand how hair gets its colour in the first place.

The colour of your hair (and your skin) is determined by the pigment melanin. The darker your hair, the more melanin it contains. The lighter your hair, the less melanin you have. All pretty straightforward so far.

There are two types of melanin that dictate the tone and colour of your hair. These are called eumelanin and pheomelanin.

What do eumelanin and pheomelanin do?


  • The concentration of eumelanin pigment determines how dark your hair is
  • The amount of pheomelanin pigment determines how red your hair is


The amount of eumelanin and pheomelanin that your hair contains is dependent on your genes. And did you know that your genes can, in effect, switch on and off? If they’re turned off, the pigments won’t be produced and if they’re switched back on, production will start again.

Now, depending on the genes that are turned on, your body will either start producing more eumelanin or more pheomelanin. And if you’re producing more pheomelanin your hair will start to subtly redden.

So, if you’ve always thought of yourself as a brunette but have ever wondered “Why does my brown hair look red?” there’s your answer. Blame it on your pheomelanin!

But if it all comes down to genetics, why does the sun seem to have an effect on the colour of your hair too?


Why Does Brown Hair Look Red in the Sun?

Woman with brown hair that looks red in the sun

To put it simply, brown hair can look red in the sun due to the UV rays having a “bleaching” effect on your locks, revealing the underlying red tones in your hair.

When we think of the sun and its UV rays and the effect they have upon us, particularly during our all-too-brief British summer, we primarily think of our skin. 

Whether you’re an avid sunbather who loves to tan or you slap on factor 50 all year round, we don’t often stop to think about what effect the sun has on our hair.

Both your hair and your skin react to the sun. And in much the same way that the sun destroys the melanin in your skin when it’s exposed to UV, it also bleaches and destroys the melanin in your locks. 

And because those UV rays are stronger in summer compared to other times of the year, some strands will turn a copper red colour due to the underlying warmer tones in your brunette hair being revealed as it’s bleached by the light. 

Suffice it to say, until new hair grows through, the reddish tint will remain.


How Can I Stop My Brown Hair Going Red in the Sun?

Let’s say for whatever reason you don’t want your brown hair to turn red in the sun. Is there anything you can do to stop it?

In a nutshell, no, not really. Due to the aforementioned genetics and the sun’s bleaching properties, your hair will take on that reddish hue if it wants to, thank you very much!

Having said that, you can give your brown locks a helping hand by using a protective product such as Davines’ SU Milk which is infused with UV protective filters that protect colour and hydrate the hair while you’re in the sun. 

However, without UV protection, the only real way around it is to wear a hat on sunny days. Which, let’s face it, isn’t a bad idea anyway as it will protect, not only your hair, but your scalp and face too.


How to Care for Sun-Damaged Hair

Just like your skin, your hair needs protection from the sun and if your hair has been overexposed to harmful UV rays, you should consider treating it with a weekly mask to keep it in tip-top condition.

A good moisturising shampoo and conditioner will also help to restore your locks to their former glory and, of course, your friendly local hair salon (hello!) can trim your hair to get it looking and feeling healthier, happier and bouncier in no time! 


Happy, Healthy Hair Courtesy of Tierney Salons Hertford, UK

Why let the sun have all the fun zhooshing up your hair when we can give you the colour you actually want?

Whether you want a fresh new colour or need some colour maintenance, you should consider visiting the best hairdressers in Hertford (psst…that’s us). 

If you have any questions, don’t hesitate to contact us. Or feel free to jump straight in by booking an appointment today.