Hair dye use is incredibly common — one survey on hair dye use in the UK found that 69% of people have used hair dye at some point [1]. Many hair dyes contain bleach, a chemical used to permanently lighten hair colour.
Unfortunately, bleach is linked to hair breakage and damage, especially when used regularly. But why does bleach damage your hair, and what can you do about it? In this article, we’ll explore:
To lighten your hair, bleach strips away the natural pigment (melanin) from your hair shafts. This weakens the cuticle (the outer layer of hair) and can even damage the cortex (the inner structure made of proteins).
Several studies have explored exactly how this works:
It’s easy to spot bleach-damaged hair. If you regularly use bleach on your hair, there’s a good chance you experience some of the following:
The image above shows what happens to hair as it becomes damaged and porosity increases. Larger gaps between cuticles also leave the inner layers of your hair vulnerable to damage, leading to the loss of important lipids and amino acids from your hair shaft [5].
If your hair is severely damaged by bleach, the best way to prevent further damage is to stop bleaching your hair — you can try adding colour to your hair without the use of chemicals. If that’s not an option, try to spread out the time between bleaching sessions. The American Academy of Dermatology advises waiting at least 8-10 weeks between bleaching sessions [6].
Certain types of bleach may be less damaging than others, so speak to your hairdresser or barber about gentler bleach treatments. A 2019 study found that smaller bleach particles cause less damage to the hair’s outer layer and result in brighter hair colour. Researchers suggest that using bleach with fine particles could be a safer, more effective way to lighten hair while reducing damage [7].
To treat bleach-damaged hair and help it recover as soon as possible, your hair needs:
Heat-damaged hair has similar characteristics to bleach-damaged hair, so combining the two can be a recipe for a frizzy nightmare. Let your hair dry naturally when possible, and use heat tools on a lower heat or use a heat protection spray if you must heat style your hair.
Use gentle detangling tools like a wide-tooth comb, and gently detangle from root to tip. Avoid excessively tight hairstyles that tug on your locks, like tight ponytails and buns, as these can stress your fragile shafts and lead to bleach hair loss from further breakage. Very tight hairstyles can also cause a type of hair loss called traction alopecia over time.
There’s research to support the effectiveness of hair repair products like K18® and Olaplex®: a 2024 study developed a realistic bleaching method to test how well K18® and Olaplex® work on damaged hair. It found that both products improved hair brightness and structure in different ways [8].
Structural damage to your hair can’t actually be repaired, as hair shafts are dead structures with no biological repair mechanisms. However, there are ways to mask the structural damage and prevent further loss of hair integrity.
Below, we’ll go through several methods to do this so your hair can start looking its best again. How long this will take depends on how badly damaged your hair is, as well as many other factors and aspects of your hair care routine.
Mildly bleach-damaged hair will likely recover within several weeks of stopping bleach treatments. Deep conditioning masks, protein treatments, and avoiding heat styling can all help to speed the process along.
Recovery from moderate damage is likely to take several months. Trimming damaged ends, using regular masks, and proven repair treatments like Olaplex and K18 can improve results.
If your hair’s badly damaged by bleach, you may need to gradually grow out and cut off the damaged parts. Full recovery can take 6 months to over a year, depending on how long your hair is and how high the damage extends along your hair shafts.
Hair itself doesn’t “heal” like skin, since it’s not living tissue, but with the right routine, you can improve its strength, softness, and appearance. New, healthy hair should grow back over time as bleach doesn’t damage the follicles when used correctly.
According to The Trichological Society, the average rate of hair growth is 0.5 cm–1.7 cm per month (depending on your ethnicity) [9]. This gives you an idea of how long you may need to wait until your hair regrows to its previous length after damaged sections are cut away.
It’s understandable if you want your hair to look its best when you’ve got a sunny holiday coming up. But experienced hair stylists often advise leaving several weeks between a bleaching session and going away somewhere hot, because freshly bleached hair is more vulnerable to damage.
UV rays from the sun can fade colour and dry out your hair — this dehydrated hair may be more prone to breakage. Too much sun exposure is not good for your hair, but bleached hair is already vulnerable and can find it especially tough.
If you’ve got bleach-damaged hair and you’re going away somewhere sunny, there are steps you can take. Bring a hat to protect your locks or use hair products with UV protection if you plan to be outdoors for the day.
Bleached hair is more porous, so it’s more likely to absorb chemicals, including chlorine from swimming pools. This can lead to dry, discoloured hair and further damage to your hair structure. Even salt water can cause dry hair.
The best way to protect your hair is to wear a swim cap to keep the chlorine out. If that’s not an option, wet your hair with clean water and apply a protective conditioner before you leap in the pool.
Getting your hair back on track after bleach damage can feel overwhelming, particularly if your hair is badly damaged. Fortunately, you don’t have to go it alone.
Trichologists are experts in identifying the causes of hair damage and helping you get it healthy again. It’s definitely worth seeking a professional opinion if you haven’t used much bleach, but your hair appears badly damaged — sometimes dry, brittle hair can be a sign of underlying conditions, such as thyroid problems, which can also cause thyroid-related hair loss [10].
Without professional help, it can be hard to identify whether hair thinning and breakage is due to bleach damage or something else. Our hair doctors use diagnostic trichology tests to identify the cause of your symptoms and rule out medical conditions.
They then work with you to create a comprehensive treatment plan to get your hair looking vibrant as soon as possible. If you want shiny, strong hair, book a consultation at your nearest clinic location to learn how we can help.
There is no way to bleach your hair without damaging it. Bleach strips away pigment from your hair, which weakens its structure. However, you can limit side effects like dryness, frizziness and breakage by spacing out bleach sessions, using deep conditioning treatments, and having a quality hair care routine.
Home bleaching can sometimes go wrong, leading to orange hair. This is particularly true if you started as a brunette. Blue or purple toning shampoos can help neutralise the orange tones, or a professional hair stylist will be able to sort out your orange locks in no time.
It’s possible to go blonde without bleach, but only if your starting hair colour is light enough. High-lift bleachless dyes can lighten natural hair a few shades, especially if your hair is already a light brown or dark blonde. For hair that’s darker or has been previously dyed or treated, bleach is usually needed to go blonde.
If you bleach your hair and it doesn’t turn out how you hoped, it’s tempting to jump straight back in for another try or head to the salon. Unfortunately, most experts recommend waiting at least two weeks before bleaching your hair again. This gives you hair time to recover and reduces damage.
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