Hair can be affected by several factors (friction, hair dying, heat…etc.), but let us tell you why heat could extremely affect your hair health over time.
Hair has two major layers; the outer layer is made of dead skin (cuticle) and the inner layer is made of fibers, mainly keratin and lipids (cortex) (1). Heat damages the cortex making the hair weak, brittle, and easier to break. this is because the cuticle has drastic damage which reduces hair’s ability to reflect light since the outer layer is not smooth enough and has pores that will scatter light in all directions, overall this affects the shine.
The heat causes loss of water content (dehydration) in hair strands between 25‐170°C and breaking downs (decomposition) of hair components including keratin and another cortex compartment starting from 200°C and above. (1)
These data evidenced the proper use of thermal hairstyle tools are important, so always observe the temperature and contact time with the hair. In this sense, the protection of the hair surface can ensure the integrity of the cuticle and play an important role in its anti- breaking effect in addition to protecting the cortex protein from thermal damage. (1)
How to protect your hair from heat damage?
1- Dry your hair first using a microfiber towel
Microfiber is a synthetic fabric created from threads with a very small diameter so it’s highly absorbable will dry your hair fast, so it decreases the amount and the contact time of water with hair fortunately this prevents hair shaft swelling that affects cell membrane complex (CMC) the hair lipids present in the cuticle & cortex (3) and since microfiber extremely gentle on your hair the friction kept at a minimum.
2- Use protective hair product before using heat
The protection of hair decreases water loss and breakage while combing, this contributes to heat control on repeated heat styling and drying. Hair breakage can be reduced significantly when hair is pretreated with selected ingredients you can find in special hair serums and creams such as:
polymers of VP/acrylates/lauryl methacrylate copolymer
polyelectrolyte complex of PVM/MA copolymer
In addition, polymeric pretreatments provide thermal protection against thermal degradation of keratin in the cortex as well as hair surface damage. The improvement in cuticle integrity and smoothness with the polymer pretreatment plays an important role in their anti-breakage effect and increasing hair shine. (2)
3- Use heat in the proper way
Although using a hair dryer causes more surface damage than natural drying, using a hairdryer at a distance of 15cm with continuous motion causes less damage than drying hair naturally. (3)
1- Lima CRRC, Couto RAA, Freire TB, Goshiyama AM, Baby AR, Velasco MVR, Constantino VRL, Matos JDR. Heat-damaged evaluation of virgin hair. J Cosmet Dermatol. 2019 Dec;18(6):1885-1892. DOI:
10.1111/jocd.12892. Epub 2019 Mar 12. PMID: 30861299.
2- Zhou Y, Rigoletto R, Koelmel D, Zhang G, Gillece TW, Foltis L,
Moore DJ, Qu X, Sun C. The effect of various cosmetic pretreatments on
protecting hair from thermal damage by hot flat ironing. J Cosmet Sci. 2011
Mar-Apr;62(2):265-82. PMID: 21635854.
3- Lee Y, Kim YD, Hyun HJ, Pi LQ, Jin X, Lee WS. Hair shaft damage from heat and drying time of hairdryer. Ann Dermatol. 2011 Nov;23(4):455-62. DOI: 10.5021/ad.2011.23.4.455. Epub 2011 Nov 3. PMID: 22148012; PMCID: PMC3229938