Hair strength is a desirable claim and many products on the market claim to ‘strengthen hair’, ‘make hair x times stronger and ‘prevent damage for stronger hair’. At Dia-Stron, we offer two types of single fibre test methods to evaluate hair strength.
Single fibre tensile testing
Single fibre tensile testing is a well-established technique within the cosmetics industry to evaluate hair strength. Using our automated tensile testing system, we can evaluate the mechanical properties of hair in both the wet and dry states. Typically testing 50-100 fibres per test group, we obtain the elastic modulus (Young’s Modulus), break stress, and break strain, parameters which can be used to support elasticity and strength claims.
Cyclic fatigue testing
An alternative and complementary method to evaluate hair strength and resistance to break is cyclic fatigue testing. In the last 10 years, there has been a growing use of hair fatigue testing within the cosmetic industry. In this test, single hair fibres are repeatedly extended by a small amount and the number of cycles for the fibre to break is recorded. The fatigue behaviour of the hair is influenced by cracks and flaws within the fibre. Damage treatments such as bleaching and heat lead to the formation of cracks and flaws, making cyclic fatigue an ideal method to measure the effect of damage on hair and the subsequent effect of product treatment. From this test, we obtain the median cycles to break as well as the elastic modulus. At Dia-Stron, we have extensive expertise and knowledge in cyclic fatigue testing.
Our team of experts can advise on which is the best suited test method for your product and the claim you want to make.