What effects does it have?

What is it?

Using heat to straighten hair strands.

How long does it last?

The effects last until the hair becomes wet, but will gradually wear off over time.

More information


A common cause of serious injuries to children is burns from home use of hair straighteners. If you are in a home containing children pay particular care to keep children away until the straighteners have completely cooled, which may take several minutes. Accidental contact with hot hair straighteners can cause permanent disfigurement and require skin grafting 1.

Hair straighteners (also known as straightening irons) use a pair of plates which are heated up to approximately 200°C. The heat and tension from moving the plates through the hair breaks chemical bonds in the hair proteins, causing them to straighten 2.

To reduce the amount of damage to the hair caused by straightening, it is important to use straighteners on dry hair, and to use a heat-protection spray 3.

As your hair straightening will be undone if your hair becomes wet, it may be useful to invest in a shower cap, which will keep your hair dry while you wash the rest of your body in the shower.

Hair straighteners come in a large range of prices, from £10 to over £100.

An alternative to hair straightening using heat is permanent hair straightening using chemicals. This approach lasts around 12 weeks between applications, instead of needing to be reapplied after each wash.


  1. 1 Jones, N Wilson, Wong, P and Potokar, T (2008) “Electric hair straightener burns an epidemiological and thermodynamic study.” Burns, 34(4), pp. 521–524.
  2. 2 Bryant, Harold, Dixon, Felicia, Ellington, Angela and Porter, Crystal (2015) “Hair straightening,” in Draelos, Z. D. (ed.), Cosmetic Dermatology: Products and Procedures, John Wiley & Sons, pp. 262–269.
  3. 3 Christian, Paul, Winsey, Nigel, Whatmough, Marie and Cornwell, Paul A (2011) “The effects of water on heat-styling damage.” Journal of cosmetic science, 62(1), p. 15.

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Page last updated: August 2017