'Even if it’s just on the ends or you feel that it’s been a 'long time,' those chemicals are still in there and can have devastating effects, basically making the hair melt-think Nair hair removal,' says Dunning. Once you've tried either one of these solutions to get the straightened hair you've always longed for, Dunning warns you should never try the other formula.

'Then there's a sodium hydroxide formula, which is the better option for types 3b (curly/coily) to 4c (kinky/coily).' The hair tends to be springy and achieves natural, springy ringlets with wash-and-go’s. One formula that's 'thio'-based, 'is ideal for those with type 2a (wavy/curly) to 3c (curly/coily) hair,' Dunning explains. Type 3 hair has a curl pattern with clearly defined spiral curls when the hair is wet.

'There are two main types of straight perms,' she says, noting that their differences lie in the type of chemical formula that's used. 'A straight perm is great for someone with curly or frizzy hair who wants it to be straight and smooth,' says Dunning. 'They tend to do a keratin treatment or Brazilian blowout instead.' While a keratin treatment or a Brazilian blowout is a semi-permanent option with a shorter lifespan that smoothes over the cuticle, a straight perm is actually entering the hair shaft and altering the bonds of the hair for a longer-lasting effect. 'This isn’t something people normally ask for anymore,' says Lara. The catch that differs a straight perm from other straightening treatments? Well, it's permanent.

Small spiral curls