title: Effects of hard water on hair.
abstract: BACKGROUND
  Hardness of water is determined by the amount of salts (calcium carbonate [CaCO3] and magnesium sulphate [MgSO4]) present in water. The hardness of the water used for washing hair may cause fragility of hair.
  
  
  OBJECTIVE
  The objective of the following study is to compare the tensile strength and elasticity of hair treated in hard water and hair treated in distilled water.
  
  
  METHODS
  10-15 strands of hair of length 15-20 cm, lost during combing were obtained from 15 volunteers. Each sample was cut in the middle to obtain 2 sets of hair per volunteer. One set of 15 samples was immersed in hard water and the other set in distilled water for 10 min on alternate days. Procedure was repeated for 30 days. The tensile strength and elasticity of the hair treated in hard water and distilled water was determined using INSTRON universal strength tester.
  
  
  RESULTS
  The CaCO3 and MgSO4 content of hard water and distilled water were determined as 212.5 ppm of CaCO3 and 10 ppm of CaCO3 respectively. The tensile strength and elasticity in each sample was determined and the mean values were compared using t-test. The mean (SD) of tensile strength of hair treated in hard water was 105.28 (27.59) and in distilled water was 103.66 (20.92). No statistical significance was observed in the tensile strength, t = 0.181, P = 0.858. The mean (SD) of elasticity of hair treated in hard water was 37.06 (2.24) and in distilled water was 36.84 (4.8). No statistical significance was observed in the elasticity, t = 0.161, P = 0.874.
  
  
  CONCLUSIONS
  The hardness of water does not interfere with the tensile strength and elasticity of hair.
authors.affiliation: Department of Dermatology, Venereology and Leprology, PSG Institute of Medical Science and Research, Coimbatore, Tamil Nadu, India.
authors.forename: Gautham
authors.initials: G
authors.lastname: Srinivasan
authors.affiliation: Department of Dermatology, Venereology and Leprology, PSG Institute of Medical Science and Research, Coimbatore, Tamil Nadu, India.
authors.forename: Chakravarthi Rangachari
authors.initials: CR
authors.lastname: Srinivas
authors.affiliation: Department of Dermatology, Venereology and Leprology, PSG Institute of Medical Science and Research, Coimbatore, Tamil Nadu, India.
authors.forename: Anil C
authors.initials: AC
authors.lastname: Mathew
authors.affiliation: Department of Dermatology, Venereology and Leprology, PSG Institute of Medical Science and Research, Coimbatore, Tamil Nadu, India.
authors.forename: Divakar
authors.initials: D
authors.lastname: Duraiswami
keywords: Calcium carbonate; hair; hardness of water; magnesium sulphate; tensile strength and elasticity