In Vitro Methodologies to Evaluate the Effects of Hair Care Products on Hair Fiber

Abstract

Consumers use different hair care products to change the physical appearance of their hair, such as shampoos, conditioners, hair dye and hair straighteners. They expect cosmetics products to be available in the market to meet their needs in a broad and effective manner. Evaluating efficacy of hair care products in vitro involves the use of highly accurate equipment. This review aims to discuss in vitro methodologies used to evaluate the effects of hair care products on hair fiber, which can be assessed by various methods, such as Scanning Electron Microscopy, Transmission Electron Microscopy, Atomic Force Microscopy, Optical Coherence Tomography, Infrared Spectroscopy, Raman Spectroscopy, Protein Loss, Electrophoresis, color and brightness, thermal analysis and measuring mechanical resistance to combing and elasticity. The methodology used to test hair fibers must be selected according to the property being evaluated, such as sensory characteristics, determination of brightness, resistance to rupture, elasticity and integrity of hair strain and cortex, among others. If equipment is appropriate and accurate, reproducibility and ease of employment of the analytical methodology will be possible. Normally, the data set must be discussed in order to obtain conclusive answers to the test.

Development of hair care formulations containing Spirulina platensis and Ascophyllum nodosum extracts

“…This way, the increase of hair shine indicates that there was an improvement of hair fibers surface conditions and cuticle alignment after the application of the formulation with microalgae. 14,17 Hair care formulations with Spirulina platensis and Ascophyllum nodonsum extratcs Clinical Efficacy According to the obtained results, there was not significant difference between basal and after 28 days of treatment with vehicle and microalgae formulations. It is possible to observe a decrease in sebum content in both treatments, but there was not a statistical significance among them ( Figure 5).…”

Protective effect of conditioner agents on hair treated with oxidative hair dye

“…This is directly related to the forces that oppose the action of combing the hair. This is an important attribute of the conditioned of the hair and in consumer perception; its improvement reflects the easing of combing the hair . The analysis measures the resistance, in mJoule (mJ), required to comb hair.…”

“…Then, the hair stretches quickly, about 25%‐30% in its length, with a moderate increase in load (plastic property). Maintaining constant the value of the force applied, the fibers stretch proportionally to the load until rupture occurs . The lower the value of breaking strength is related to a more damaged cortex.…”

“…This assay was based on the reduction in the Folin reagent by protein previously treated with copper in alkaline medium . The complex between copper amino acid bonds reduces the Folin reagent, becoming a blue solution.…”

“…The physical and mechanical proprieties of hair depend on its geometry, and it regards the characteristics such as elasticity, smoothness, volume, shine, and softness. These are referred to the adhesion of the cuticle scales and the motion control (malleability), as easily as the facility of combing, as they cut down the fibers static electricity or negative direction of hair …”