If you’re constantly in a battle with your split ends, scientists might finally have the answer.
Experts have revealed that after using straighteners you should let your hair ‘recover’ before brushing it.
Heat makes hair temporarily much weaker and more brittle, they explained, which in turn makes it more likely to break under pressure.
However, this effect is reversible – and all it requires a little bit of patience.
In their study, the researchers found that hair fully recovered when it was allowed to ‘rest’ for two hours after being straightened.
But for those who don’t have that much time to spare, waiting half an hour is also likely to be beneficial.
‘Application of heat causes a dramatic reduction in performance…which is completely restored by a period of resting,’ they wrote in the Journal of the Mechanical Behavior of Biomedical Materials.
‘This well–known effect, presumably due to dehydration and rehydration, is clearly and quantifiably demonstrated.’
Scientists closely analysed how strands of hair split and cracked during the experiment, eventually leading to failure
Hair prone to splitting was found to ‘fail’ first, while typically strong hair lasted longer. Overall, straight hair lasted more cycles than curly hair
For the study the team, from the University of Dublin, made a machine to reproduce what happens when you brush tangled hair.
‘The individual hair strands are very thin and flexible, so they can literally tie themselves in knots – that’s a tangle,’ Professor David Taylor told the Daily Mail.
‘When you brush your hair you force the tangle to move along the hair, down to the end. This puts huge stresses on the hairs, which can cause them to break or split.’
His team tested a range of different hair types including straight, curly, strong, treated hair prone to breakage and natural hair prone to breakage.
Instead of pulling hair straight until it snaps, they used a ‘moving loop fatigue test’ to bend hair repeatedly and force it through a tight loop, simulating the repeated stress of tangled hair being brushed.
Analysis revealed that heat makes hair temporarily much weaker.
When hair was heated with straighteners at 150°C, the number of cycles it could withstand before breaking dropped dramatically – for example from 234 cycles to just 38.
The team attributed this breakage mainly to dehydration, caused by the hair being heated.
For the study the team, from the University of Dublin, made a machine to reproduce what happens when you brush tangled hair
They discovered that straight hair which had been wet, dried using heat and then left to rest lasted the most amount of cycles
However, they also discovered that this effect is reversible – if the hair is given time to rehydrate.
‘There’s enough water in the air to rehydrate dry hair, though it varies a lot depending on the humidity of the air around you,’ Professor Taylor said.
‘We need to do more tests to find out how long it takes for the hair to come back to full strength, but I suspect that even a few minutes will make a difference.’
The team also found that ‘strong’ hair resisted splitting the longest, while split–prone hair formed internal cracks early.
Both curly and wet hair were affected by heat, but both also recovered almost completely in the two–hour time frame.
When asked for advice on how to prevent split ends, Professor Taylor said: ‘Some people have hair which is just naturally prone to splitting, so there’s not much they can do about that.
‘For the rest of us, be aware that any kind of treatment – colouring, straightening, etc – could be detrimental.
‘But the good news is that it’s not for ever, so if a certain treatment causes problems, don’t do it again.’
The team also found that ‘strong’ hair resisted splitting the longest, while split–prone hair formed internal cracks early
He added that long hair is more likely to split than short hair, because the ends of our hair are naturally more brittle.
Keeping these regularly trimmed could help prevent cracks from running up the length of the hair, causing breakage.
Scientists have previously revealed the key to freeing tangles is by beginning with brushing at the end and moving upwards.
Harvard researchers created a model that simulated two entwined filaments to represent a tangle of hair, and analysed different ways of ‘brushing’ it so the hairs became free.
Their results, published in the journal Soft Matter, revealed short brush strokes that start at the ‘free’ end of the hair and move towards the ‘clamped’ end are most effective.
