Here’s Why Your Blonde Hair Is Turning Brown

2 June 2023 | Hair Care

If you’re reading this blog post, we’re going to jump to (a fairly obvious) conclusion and assume that you’re asking yourself “Why does blonde hair turn brown?” Are we right? Thought so…

But, seriously, blonde hair turning brown is a question that many fair-haired people have thought about and there is, of course, an explanation for it. And if you’re a regular reader of the Tierney Salons blog, firstly, thank you very much, and secondly, you’ll know by now that we love ourselves some science.

Call us nerds if you want, but we firmly believe that understanding the why behind some of the most commonly asked hair care conundrums is the only way to properly care for your hair and deal with any issues you might have.

So let’s take a look at a few of the reasons why blonde hair turns brown and what you can do to maintain your lighter locks.


Why does blonde hair turn brown?

First of all, it helps to know why you’re (naturally) blonde in the first place. 

The colour of our hair – and our eyes and skin – is created by the distribution of melanin throughout our bodies. Each of us is unique in this regard, which is why there are so many different hair, skin and eye colour combinations.

Furthermore, melanin can be broken down into two main types: eumelanin and pheomelanin. And it is eumelanin which is calling the shots on dark hair, eye and skin tones. All of us have eumelanin but we have different amounts of it. 

This means that those who have dark hair and skin have greater quantities of eumelanin, whilst blue-eyed, fair-skinned blondes have a lot less. And how much melanin our bodies produce is determined by our genes.

So that’s why you’re blonde (or dark – or somewhere in-between) but that hasn’t answered our original question of why does blonde hair turn brown? Surely our genes and melanin levels don’t change, do they? 

Or do they?!


Reasons for blonde hair turning brown

If you’ve noticed that your blonde hair is turning brown, what are some of the causes? Let’s take a look.

  1. Your pigment genes have turned on or off

Let’s take a closer look at melanin and the role it has to play in determining your hair colour. Now, the genes that are responsible for the melanin levels in your body and therefore the colour of your hair can turn on and off.

Weird, right? Well, not so much actually, as your pigment genes can be activated – or deactivated – and this is in fact a fairly common occurrence. 

So what causes this switching off and on of your pigment genes?

The biggest contributing factor is your hormones. 

Generally speaking, blonde hair usually turns brown – or at least darker – as we age. We’ve all seen photos of relatives or friends who were so fair as a child that their hair was almost white. And then wondered how on earth they went from that ethereal fairness to their current light, mid or even dark brown tone.

So it’s an age thing. But in actuality, your pigment genes may activate or deactivate at any age, sparking a change in colour.

As well as children’s hair darkening around the age they start school, think of how grey hairs start to creep in as we get older. And as we know, greys can start appearing at any age.

Pregnancy is another hormone game changer – both during and after, and this too can trigger a hair colour change that sees your blonde hair turning brown.

  1. You’ve overdone the heat

Heat – such as that from your styling tools – can be one of the reasons why blonde hair turns brown. 

The solution? You don’t have to give up your tongs, curlers or straighteners for good but do be aware of how often you use them and try to use a lower temperature setting if possible. 

And of course, use a heat protectant. For natural, and colour-treated blondes, we adore Sheer Glaze by Davines which is a brightening thermal leave-on fluid for blondes that provides hydration, shine, and heat protection.

Plus, don’t forget to look after your hair in summer and protect your hair from the sun’s harmful UV rays too, as these can also damage and discolour your hair. 

Product, hat, scarf – pick your anti-poison and enjoy the sunshine knowing that you’re doing all you can to preserve your blondeness!

Oh, and you should also avoid washing and rinsing your hair in super-hot water too. (And that goes for any colour!) 

  1. You have product build-up

The classic build-up of product. Now we all know that using the right products for our hair type, colour and goals is important. Blonde hair does need maintaining, but when you know how it will be easier to do so.

But back to lotions and potions. The products we use on our hair can build up, no matter whether they’re spray, gel, dry shampoo or conditioner.

Product build-up coats the hair shaft which dulls it and makes it look darker. That’s why a deep cleansing shampoo that removes the residue of styling products, such as Davines’ SOLU Shampoo is a great weapon in your hair care arsenal. 

  1. Your water is too hard

If you live in an area with hard water, this could be the root cause (sorry…) behind your fair hair turning darker.

This is because the mineral count in hard water is higher than softer water and these minerals can soak into the hair shaft which makes your locks appear darker.

And while the East and South of England have the hardest water (you have the proliferation of chalk and limestone in the regions which let more minerals through to thank for this) don’t think that just because you reside in the West or North, which have foundations of granite, you might have escaped the blonde hair turning dark issue.

That’s because if you live in an older house or flat that has plumbing made from lead (eek!) or copper pipes, the minerals from those pipes can still darken your light hair. 

You might find that investing in a water filter is your best bet in either scenario.


Why does blonde hair turn brown? The conclusion

Blonde hair turns brown for any number of reasons. Some you can do something about (limit the usage of heated styling tools and use the right products) and some you can’t (here’s looking at you, genes.)

 So, our thoroughly scientific conclusion is, don’t sweat the gene stuff, but do do your best to maintain and nourish your blonde hair, whether it’s natural or chosen.


Stop your blonde hair from turning brown at Tierney Salons, Hertford

Whether you’re worried about keeping your blonde hair the shade that you love, you want to know which is the right shade of blonde for you, or you’re concerned that your fair locks are losing their lustre, get in touch.

Why does blonde hair turn brown? If this blog post hasn’t convinced you of the answers, give us a call or drop us a message and we’ll be pleased to explain in person!

Our friendly and knowledgeable hairdressers in Hertford are happy to talk and would love to chat while you’re in the salon. Book an appointment now and let’s get you looking and feeling fabulous – whatever your hair colour.