In vitro (meaning in glass) describes an alternative method of animal testing and clinical trials on living subjects in which samples are tested on cultured models of skin and tissues resembling human skin. This method, using cell culture models, has revolutionized the way in which safety and efficacy of products are assessed, providing an alternative method live methods using living objects. This approach uses a controlled environment such as Petri dishes or test tubes and is an indispensable method in the cosmetics and personal care industry, where understanding how products interact with biological systems is crucial. In vitro These methods can also be used to enhance other testing strategies by complementing them live AND live tests and cosmetogenomics.

In vitro methods are widely used because of their controlled, repeatable and ethically sound testing procedures. The primary reason in vitro methods to eliminate the need for animal testing are becoming increasingly popular. These methods comply with ethical standards and regulatory requirements, especially in regions such as the European Union, where animal testing of cosmetics is prohibited. Cultured cells can simulate some of the biological processes that occur in animals, providing an alternative way to observe how products interact with these living organisms.

Testing in living subjects using in vivo testing methods can be expensive and logistically difficult, requiring extensive recruitment and multiple meetings. Relying on human subjects carries many risks, including difficulties in recruitment, such as the risk of person-to-person transmission, highlighted by COVID-19, and personal circumstances, meaning that recruitment quotas are not always met. In vitro methods do not rely on live subjects and therefore provide a faster, more streamlined process, making these testing methods cost-effective and time-efficient. Variables in in vitro Test environments can also be precisely manipulated, enabling reproducible results. This is essential for validating product claims and understanding the mechanisms of action of active ingredients, raw materials, and cosmetic products.

Many cosmetics markets have strict regulatory standards, such as those set by the OECD and Good Laboratory Practice (GLP), which set high standards for product safety and efficacy. In vitro testing encompasses a wide range of tests, each designed to assess specific aspects of safety and effectiveness. Some common types in vitro tests include:

Safety tests

A range of safety tests can be performed using in vitro testing methods. Cytotoxicity tests assess the potential toxicity of a substance on isolated cells. They are key to determining the safety of cosmetic ingredients and other products. Advanced models, such as three-dimensional reconstructed epithelial models, provide deeper insight into cytotoxicity in tissues such as oral, gingival and vaginal epithelium. Irritation tests are also commonly used safety tests that assess the potential of a substance to cause irritation. Eye irritation tests, based on OECD standards (e.g. OECD 491, 492), assess the potential to irritate ocular tissues, while skin irritation tests (e.g. OECD 439) focus on skin irritation. Eurofins offers a comprehensive range in vitro tests, including skin irritation tests (OECD 439, OECD 431) and can determine the irritation potential of various substances.

Phototoxicity tests conducted according to guidelines such as OECD 432 or OECD 498 determine whether a substance becomes toxic when exposed to light, an important factor for products such as sunscreens and photosensitizing preparations. Sensitization methods are also common in vitro testing method. These tests, including methods such as Keratinosens and h-CLAT, assess whether a substance can cause allergic reactions. They are essential to ensure that cosmetics and personal care products do not cause allergies in consumers. Recently, in vitro tests are commonly used for micronucleus tests and AMES tests (for the detection of chromosomal aberrations), which are crucial for assessing genetic toxicity and ensuring that products do not cause harmful mutations.

Efficacy tests

In vitro Efficacy tests evaluate the functional benefits of a product. For example, barrier function tests evaluate protection against environmental stressors such as pollutants. Eurofins can conduct microbiome tests and test for related acne pathologies. These tests can assess inflammation of the scalp and skin and measure the anti-aging and regenerative properties of cosmetic products. Transepidermal Water Loss (TEWL) measurements provide information on skin barrier integrity and hydration. TEWL is often used to support claims about the barrier-restoring and barrier-enhancing properties of skin care products.

In vitro Research on sun protection

In vitro testing methods are also commonly used for sunscreen products. These methods may measure SPF, UVAPF, or critical wavelength to support claims of broad-spectrum protection. Other related factors, such as HEV and IR, may also be measured in vitro.

Using different in vitro tests, companies can better understand how their products interact with biological systems, ultimately providing safer and more effective solutions to consumers. Eurofins Cosmetics and Personal Care goes beyond providing these tests to ensure your products meet regulatory requirements, also offering the option of fully vegan versions of selected safety tests.