J. Cosmet. Sci., 62, 203–207 (March/April 2011) 203 Hair breakage index: An alternative tool for damage assessment of human hair SUDHAKAR MHASKAR, BHARGAVI KALGHATGI, MADHAVI CHAVAN, SURYAMANI ROUT, and VAISHALI GODE, Marico R & D Centre, Bombay College of Pharmacy, CST Road, Kalina, Santacruz (E), Mumbai, India 400098. Synopsis Improper hair care, mechanical abrasion, sun damage and chemical treatment changes the physical and mor- phological characteristics of hair. Several methods involving microscopic techniques, protein loss and assess- ment of tensile properties of the hair are generally used to evaluate the extent of damage caused. These are also used to determine the protective effect of hair care products. In the present investigation, the hair break- age index (HBI) was used as an alternative tool to determine the change in the properties of hair on weather- ing. HBI is a measure of the diameter of hair in a given cross sectional area of a marked region of hair on the scalp. The hair diameter changes as we progress towards the tip of the hair due to breakage. The ratio of the diameter of hair bundle in the distal region to the diameter of hair bundle in the proximal region from the scalp is used as an indicator of hair breakage. Higher HBI value is an indicator of hair damage. A study was conducted for duration of 16 weeks to assess the effect of weathering due to grooming practices on HBI values. The HBI and break stress for a group of 30 subjects were measured at baseline and at the end of 16 weeks (NU). Since Coconut oil (CNO) is known to have a positive benefi t on tensile properties of hair, another matched group of 30 subjects who oiled their hair daily with CNO was used as a positive control (CNO). The HBI and break stress for this group were also measured at the baseline and after 16 weeks. It was observed that the HBI signifi cantly increased in the NU group versus the CNO user group. The break stress also signifi cantly decreased in the NU group suggesting its correlation with the HBI data. This study dem- onstrates the usefulness of HBI as a simple and effective tool for determining hair damage and its protection by different hair care products. INTRODUCTION Human hair is a keratin containing appendage that grows from the hair follicle. It pre- dominantly contains 65-95% of proteins, the remaining constituent being water, lipids (sterol, free fatty acids and polar lipids), sugars, pigments and nucleic acids (1,2). The human hair is a reactive substrate, whose structure and physio-chemical properties are of great interest in relation to environmental factors and cosmetics applied to it. Several factors like improper hair care, mechanical abrasion, solar radiation and chemical treat- ments, change the physical and morphological characteristics of hair. A variety of methods have been used for the assessment of hair damage, including mea- surement of tensile property and chemical changes like protein loss (3). Most of the methods

JOURNAL OF COSMETIC SCIENCE 204 are time consuming and are performed in vitro. In the present study, the extent of hair damage was determined by a cross-sectional trichometer which allowed a quick and non invasive assessment of hair and is time saving. The cross-sectional trichometer is a new device that enables the measurement of hair loss and hair growth, or simply measures the quantity of hair that is present in a particular area of scalp. It works on the principle that there is a change in hair diameter in the se- lected area of scalp due to breakage by different practices like washing and combing. These grooming practices damage more to the distal portion of the hair strand as com- pared to the proximal end of hair. Therefore, the diameter in the distal end will be lower as compared to the proximal end. This difference is represented by HBI which is mea- sured as follows HBI = (distal cross-sectional area / proximal cross-sectional area) × 100 In the present investigation, the HBI was used as an alternative tool to determine the extent of protection offered by the application of CNO versus the NU group. Increase in HBI value is an indicator of hair damage. Two groups of female volunteers in the age group of 20-30 years (30 each) were included in the study. One group received daily ap- plication of CNO for 16 weeks and the other group did not receive any oil application. The subjects continued with their normal hair maintenance regimen of shampooing and combing their hair during the study period. The subjects assigned to the coconut hair oil group used the oil before shampooing as a pre-wash conditioner. The effectiveness of this method was evaluated by comparing the HBI values with the changes in tensile parameters and a correlation between these two techniques was drawn. MATERIALS AND METHODS STUDY DESIGN Sixty volunteers (female) in the age group of 20-30 years were included in this study. These were subjects who did not use hair oil but used a shampoo for cleansing hair. They also did not use any other conditioners or styling products. These subjects were divided into two groups of 30 each. One group applied coconut oil daily while the other group did not apply any product. The primary assessments included measurement of HBI at the baseline and after 16 weeks of treatment. Few hair fi bers were collected during each visit to determine the break stress of hair. DETERMINATION OF HBI HBI was measured using a hair check instrument, which is a mechanical device that pre- cisely measures the cross-sectional area of a bundle of hair on the scalp. During this study, the HBI of a specifi c area of the scalp was determined using a marking template in order to measure the HBI of same area after treatment. Initially, the hair fi bers around the marking template were separated carefully and then the measurement was taken 1 cm