Why am I losing my hair - the facts on cosmetic over-processing

There are many reasons for hair loss, some of which have been discussed throughout this blog: pattern baldness, alopecia areata, shedding (telogen effluvium) and even rare hair disorders. Likewise we have also mentioned possible treatment options, the evidence supporting them, as well as the possible side effects. There are some cases however where improving your hair loss can be as easy as recognizing the behavior that can exacerbate it.

You have probably already heard that regular everyday styling can lead to over-processing. Moreover over-processing is a leading cause of physical hair damage. Heat processing tools such as curling and straightening irons as well as harsh chemicals found in hair dyes can significantly affect the integrity of the hair fiber1. Daily styling can compound the damage, further weakening the hair fiber and increasing the likelihood that it will break off.

The hair cuticle is an outer layer of the hair fiber which protects the inner layer, the cortex, from damage. To function properly, bleaches, dyes, and processing chemicals such as those used in straightening treatments must reach the inner cortex layer. If these chemicals are applied for too long, in high concentrations, or too often, the cuticle can be damaged or lost, exposing the cortex. An exposed cortex may then lead to the splitting and breaking related to cosmetic over-processing.

The cuticle can also be damaged through rough styling techniques including aggressive brushing and back combing. Regularly using a blow dryer on high heat is another good example of how to damage the cuticle.

While over-processed and damaged hair is difficult to treat, perhaps very obviously, relaxing your hair care routine can allow the hair fiber to recover. For instance, experts have recommended leaving a minimum of eight weeks between treatments 2. Overall, generally limiting harsh treatments will help to encourage the regrowth of healthy, undamaged hair3.

Article by: Dr. J.L. Carviel, PhD, Mediprobe Research Inc.


  1. Marsh J, Gray J, Tosti A. Root-to-Tip Hair Health. In: Healthy Hair [Internet]. Cham: Springer International Publishing; 2015 [cited 2016 Feb 29]. p. 29–44. Available from: http://link.springer.com/10.1007/978-3-319-18386-2_2
  2. Ahn HJ, Lee W-S. An ultrastuctural study of hair fiber damage and restoration following treatment with permanent hair dye. Int J Dermatol. 2002 Feb;41(2):88–92.
  3. Khumalo NP, Jessop S, Gumedze F, Ehrlich R. Determinants of marginal traction alopecia in African girls and women. J Am Acad Dermatol. 2008 Sep;59(3):432–8.