The 6 surprising ways straighteners can damage your hair.

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It should come as no surprise that styling your hair with heat — straightening irons in particular — can potentially damage it.

Yet if you’re anything like me, the only time you give this any thought is when you apply your straightener to a section of your hair, forgetting you just got out of the shower, and tssss! You hear that telltale sizzle.

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As Chief Technical Officer at ghd’s Research and Development Facility in Cambridge, Dr Tim Moore knows rather a lot about the havoc styling tools can inflict on hair.

Dr Moore and his team spend a lot of time figuring out how to overcome the potentially damaging features common among many heat stylers available on the market. Their efforts have culminated in the creation of platinum, ghd’s very swish new straightener. Dr Moore was in Sydney recently for platinum’s launch, and talked The Glow through the many ways heat stylers can damage your hair if not made or used carefully:

1. Getting hot ‘n heavy

Hands up if you've ever cranked up the temperature dial because it felt like your straightener wasn't having any effect? It seems logical that adding more heat will make your hair respond and style better, but it can actually really harm it.

"A lot of irons on the market have temperature dials up to 230 degrees centigrade, which is very bad for hair ... it literally melts it," Dr Moore explains. Ongoing styling at such a high temperature can permanently change the colour of your hair and dramatically reduce its 'tensile strength' — this can cause your strands to break halfway down and then fall off when you brush. (Post continues after gallery.)

That's not to say your hair can't withstand any heat; it just has a threshold. "What you really want to do is style it below the 'denaturation temperature', which is the temperature where it starts getting damaged, but above the glass transition phase temperature so you can style the hair," Dr Moore says.

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So what's the magic temperature? Research points to 185 degrees. Platinum operates constantly at this heat with no option to go higher. It sounds unbelievable, but in their research ghd found this temperature actually improved the health of hair.

"Platinum had 54 per cent less breakage than 230 degree [irons], and 45 per cent less breakage than virgin [i.e. untreated] hair. It’s actively conditioning the hair because it’s not cooking it," Dr Moore says.

2. Going hotter for thickness

Any woman with thick or very curly hair will tell you it takes quite a lot of effort (and elbow grease) to style it. But again, adding more heat isn't going to help — the structure of hair doesn't change according to its thickness, so even the bushiest mane is susceptible to the perils of too much heat. However, thicker hair does have slightly different requirements to fine hair.

"This is a physics thing - there’s a difference between temperature and heat," explains Dr Moore. "When you’ve got really thick hair, you need to pump in more energy, but you don’t need any more temperature." A styler than maintains constant temperature and responds quickly will help you here.

RELATED: 22 problems only girls with thick hair will understand

If you want an example, Dr Moore likens the difference between styling different types of hair to heating up different volumes of water: "Thick hair is like heating up 10L of water, as opposed to thin hair which is like heating up 1L of water. You don’t need more temperature, but you need more energy."

3. Losing heat

If you've ever experienced snagging while straightening, chances are this was a result of the plates cooling off by the time they reached the tip of your hair.

"With a lot of other products, they don’t maintain the temperature — when you put the plate to your hair, unless it’s got a technology like the ghd irons, the temperature will drop and the hair will become more difficult to style," Dr Moore explains. Naturally, if your hair's not styling as well as you'd like it to, you're probably going to turn up the heat. Although this will seem to work better, it'll start damaging your hair in the long run (see point 1).

RELATED: How to get beach hair (without going anywhere near the beach).

Dr Moore says the inconsistent heat of many stylers results from there only being one sensor per hot plate, which can only detect hair when it's in a certain position — if the hair slips to one side, for instance, the sensor might not realise and won't adapt the heat accordingly. The ghd team uses a technology called tri-zone, whereby each plate has a number of sensors to detect the hair and maintain a constant 185 degrees.

4. Clamping down too hard

Excessive heat isn't the only way a straightener can damage your hair — brute strength will also do it.

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"One thing we discovered thought testing is that if you apply too much pressure while styling hair, or you pull your hair too much, it causes more damage," Dr Moore says. Often this happens because we assume it'll make for more effective straightening; or because we're trying to compensate for unstable heating plates that can slip as they're pulled or twirled through a section of hair.

5. Uneven, rough heat plates

The last thing you want when you're running a straightener through your hair is friction — this can cause (painful!) snagging and potentially breakage. Dr Moore says this friction typically results from the straightener plates being either uneven, poorly aligned or a bit rough on the surface.

To overcome this, the hot plates on ghd platinum (pictured above) have a low-friction coating that contains natural oils, which smooth the hair as you're using it. However, Dr Moore was not forthcoming with the exact combination of oils — it's like ghd's equivalent of the KFC 11 herbs and spices.

6. Straightening damp hair

Repeat after me: dry it, or you'll fry it. Although some stylers on the market claim to have 'wet to dry' straightening abilities, Dr Moore warns this technology actually doesn't exist yet.

"The temperature at which damage to your hair occurs actually drops with wetness. The glass transition phase temperature does the same thing. So for instance, if hair is 50 per cent wet, the temperature at which you can damage it has dropped to around about 100 degrees celcius," he explains.

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"So if you put a styler, even one of ours at 185 degrees, onto wet hair you’ll cause considerable damage. Essentially, water in the hair is suddenly expanding, it’s basically exploding the hair."

EXPLODING YOUR HAIR. Styling sprays, even heat-protectant ones, can also have this effect as they contain a small amount of water. Dr Moore recommends waiting five minutes after spritzing one on before using a straightener — this will allow the water to evaporate.

Healing heat damage

Here's a bit more bad news: the only way to truly repair heat-damaged hair is to let it completely grow out, which can take aeons.

In the interim, Dr Moore says there's an easy way to give your crispy strands a bit of TLC: when you condition your hair, leave it on for a good five minutes before you rinse, dry and style your hair. The key is to restore the lipids (naturally-occurring fats) that have been stripped from the hair.

RELATED: Sorry to break it to you, but you’re washing your hair all wrong.

"You need the fats to make you hair feel good and smooth and to get the shine. This won't fix the damage that's already there, but it'll make your hair more manageable and make your style last longer. As time passes your hair will grow out and it'll go back to full health," Dr Moore says.

ghd platinum (RRP: $315) is on sale from this month in approved salons, Mecca Maxima and Kit stores, and online: ghdhair.com/au