Since the waves in deep wave hair extensions are created artificially through chemical and/or heat treatment, these hair extensions are more susceptible to damage. The damage can either be directly due to the overuse of chemical or heat, or it may result in a weakening of the deep wave hair extensions due to the processing. As a result of the latter, the deep wave hair extensions become susceptible to damage even from regular grooming. The hair in deep wave hair extensions is cut away from its natural source of sebum oils which provide nourishment and moisture. This helps the hair to repair itself in case of regular wear and tear. The chemical styling also makes the fibers in deep wave hair extensions become brittle, causing the hair to break when combed or brushed. Some chemical treatments cause the hair in the deep wave hair extensions to swell due to over-saturation of the hair fibers with liquid and the consequent breakage of the bonds in the hair fibers. Proper conditioning of deep wave hair extensions before combing them reduces instances of loss of hair due to damage and swelling. Studies have shown that damage due to protein loss is reduced by about 20% and liquid retention (which causes swelling) is reduced by about 40% through the use of proper conditioners in deep wave hair extensions.