Skin measurements can accomany a product along its complete life cycle, from development, through official approval to point of sale and finally to the consumer. Diana Khazaka & Christiane Uhl chart their importance each step of the way
In the last two decades many bioengineering methods have been established to assess a lot of different parameters of the skin. Such equipment is used not only in clinical dermatology to accompany the course of several diseases and determine the efficacy of treatment, but also in the research and development of cosmetic products to substantiate their claims.
From simple moisturising claims a couple of years ago, today most of the cosmetic claims are about such aspects as cell protection, barrier function renewal, anti-ageing, wrinkle reduction, elasticity and increased firmness.
Even a recent ISS space mission included devices to assess skin hydration (Corneometer), the quality of the barrier function (TEWL with the Tewameter) and the skin's structure and surface (Visioscan). The devices were taken on board to monitor the effect of skin exposure to the special environment of a space mission. This indicates how important those methods have become in the last couple of years and shows that they are indispensable in many ways.
Fortunately this type of equipment is relatively easy and economical to use so not only the big companies but also small and middle sized ones can perform such tests in all kinds of development stages. However, the development of a useful testing protocol is very important. Bearing in mind that the skin is a living organ constantly reacting with the environment and the body, and that all in vivo measurements are performed on that living organ, it becomes clear that in an appropriate testing protocol as many influencing factors as possible have to be controlled.
It is important to choose the volunteers from a meaningful target group in relation to gender and age (eg not to test anti-ageing products on a group of 20 year olds) and to have certain exclusion criteria (general health state, skin disorders etc).
Since the skin is especially sensitive to temperature and relative humidity, keeping those conditions constant in the testing environment is essential (best at 20-22°C and 40-60% rh). The test person should be acclimatised to the laboratory conditions for a minimum of 15-30 minutes prior to the test.
Short-term studies are generally chosen whenever it involves a single application of a product (eg application of a moisturiser and taking readings from 30 minutes after application, every hour for the next 12 hours to see how long the moisture level of the skin is kept up). The product must always be applied in a standardised manner (same amount, same area, same cleansing beforehand) and a control area must be measured in the same way.
Long-term tests are generally for use in studies where the efficacy is measured after certain time periods during which the volunteer has repeatedly applied the product under standardised conditions. In this case it is important to teach the participating volunteers the exact use of the product (how to prepare/cleanse skin, when and where and how much product should be applied etc). Control areas also need to be taken into account.
When studies are performed using bioengineering instruments, it is important to check their accuracy before a study or to have them perfectly calibrated.
Guidelines are available from different organisations (eg Colipa, the European cosmetics association, or EEMCO, the European group of efficacy measurements and other topically applied products).
In addition to the long established clearly defined laboratory testing conditions, the product effects in use in daily life can be monitored by providing those being tested with special home testing equipment measuring, for example, the skin surface moisture in order to record the product performance over the day during different daily actions and conditions. After a certain trial period such data loggers can be collected by the laboratories and the effect of the product under daily conditions can be studied.
Most studies involving skin measurements are performed on the efficacy of cosmetic products. With the different measuring methods available, product claims can be easily proven, not only for the finished product, but the product effects can also be tested during the product development process. In this way, the development process can be steered in the desired direction at its different stages. Ultimately the finished product can be forwarded to the testing institutes for its final documentation prior to launch onto the market.
The most commonly used measurement parameters for such studies are skin surface moisture, sebum content and transepidermal water loss (TEWL). For testing anti-ageing products the measurements of visco-elasticity and skin surface roughness provide very important information on product efficacy. Redness, pigmentation and pH-measurements are also often used to study special product performance. Other studies deal with the effect of medication on the skin, like the contraceptive pill’s effect on acne and other skin problems. The resulting skin changes can involve changes in the skin sebum as well as in skin moisture, pH-value and TEWL.
There are also studies conducted on nutritional effects where skin parameters can be important, for example changes in skin elasticity and skin surface moisture as an effect of malnutrition, or contrary to this special nutrients to improve skin and hair parameters. This category also includes skin changes caused by such parameters as smoking and working outdoors.
In recent years there has also been a move towards the development of educational aspects of skin measurements. One area for using this educational effect is in problematic work places where skin protection is an issue. Work related skin diseases are quite common for certain working areas and professions and can cause immense financial damage for insurance companies. For example, in several working areas in the metal industry workers come into close contact with lubricants that cause skin irritation. With constant contact this can lead to serious skin diseases that may even result in early retirement of such workers. Hairdressers and many other professions also have to deal with irritating or dangerous materials and employees here can often be affected by contact eczema and skin diseases.
To persuade employees in potentially damaging working environments to use skin protection like wearing gloves or applying suitable skin protection products, the demonstration of skin conditions by measurements such as skin moisture and showing the damaged skin surface with special cameras can have a very beneficial effect. When people see for themselves the damage done to their skin, they usually tend to improve their skin protection and skin care. Of course there are also medical doctors for occupational health who can use the measurements to evaluate and document work related skin problems.
Despite the fact that it has been an issue in all kinds of media for years, many people continue to underestimate the power of the sun. To educate these people about the proper use of sun protection products, there are roadshow events where melanin measurement is used to determine the skin pigmentation and to recommend suitable sun protection factors. People are frequently astonished to learn quite how short the natural self protection time of their skin is.
Skin measurements are also often performed where cosmetic products are offered to the consumer. Such products are sold in all price ranges and at all kinds of points of sale – from drugstores and supermarkets, through pharmacies up to high end perfumeries and aesthetic institutes. Skin measurements to establish objectively a customer's skin type and recommend the best individually suited set of products are a good way for a brand to differentiate itself from its competition.
Measurement of skin hydration and sebum level, the state of the elastic properties of the skin, pigmentation measurements to recommend sunscreen products or skin whitening treatments accompanied by impressive camera images of skin and hair not only increase the professionalism of the beauty advisers but also offer an ideal starting point for sales discussions. By demonstrating the individual needs of the customer's skin, it is possible to convince the customer of the need to use a complete product portfolio consisting of the best suited cleanser, the ideal day and night care and specialist products to achieve the best possible results. Personalised printouts or skin passports with the recommendations help the customer to understand that the best day care will not reach its optimum performance if the other care products are not equally suited to the skin type.
Such skin tests at point of sale help brands gain customer loyalty. In fact, experiences at all kinds of points of sale using such equipment to promote products show increases in turnover of up to 30% and the development of strong customer loyalty.
Skin measurements can accompany a product along its complete life cycle, from development stages, through the official approval to point of sale and finally to use by the consumer.