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4 days ago8 min read

Introduction to Product Evaluation for Cosmetic & Personal Care Products – Bite-Sized Learning

Filipa De Castro, Intern at TRI Princeton




Filipa de Castro, Intern, TRI Princeton, NJ, USA


Paul Cornwell from Director of Business Development at TRI Princeton




Paul Cornwell, Director of Business Development, TRI Princeton, NJ, USA


Fact checked by:

“When you cannot measure (...what you are speaking about…), when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind” - Lord Kelvin, 1883


“A fool with a tool is still a fool” - Prof Albert Kligman, and many others





Introduction


Cosmetic scientists have a critical role in ensuring that cosmetic and personal care products are safe, efficacious and pleasing to use, and that claims made to consumers about these products are fully substantiated. Product evaluation is a fundamental part of delivering all these objectives. 


This short article introduces readers to the principles of product evaluation for cosmetic and personal care products. It also provides suggestions for further reading in the TRI Library and other literature sources. This guide is designed for anyone new to product evaluation, including students and those starting work in the cosmetics industry. It only covers the regulations in the EU (including the UK*) and the US, although the general principles are similar in other parts of the world.


Summary of the Key Points ⬇️



Overall Definition


Product evaluation, in the cosmetics and personal care industry, is defined by the International Federation of Societies of Cosmetic Scientists (I.F.S.C.C.), as the “assessment of one or more of the attributes, characteristics or qualities of a product” [1].  This very wide definition covers both product development and claims support studies.  Examples of product evaluation tests could include the measurement of the skin moisturization effects of a skin cream, the measurement of the conditioning properties of a hair treatment, or the measurement of consumer preferences between different hand wash formulations.



Uses of Product Evaluation


Product evaluation, as defined by the IFSCC Monograph [1], is performed for a range of purposes including (i) new product development (NPD), (ii) formula changes of existing products, (iii) competitor benchmarking, and (iv) in the validation of claims.  Product evaluation is also used for safety and tolerance testing.


Of course, many other types of technical measurements are performed during the development of cosmetic and personal care products. However, these are usually covered by different specialist teams within a business and are not classified as product evaluation.  Examples might include the formulation and manufacture of products (formulation science), stability testing of products (formulation science), quality control testing of both raw materials and finished products (QC, analytical chemistry), packaging testing and packaging compatibility testing (packaging technology).



Categories of Product Evaluation


The IFSCC Monograph [1] categorizes different types of product evaluation for all cosmetic products (Figure 1).   Objective tests are procedures using either instrumental [2] or sensory methods [3,4] that produce reproducible and quantifiable results. They either use specific instrumentation or trained panels, which perform as if they were a calibrated instrument.


Figure 1: Categories of Product Evaluation [1]


Subjective tests involve sensory test methods carried out using consumer panels. Results of subjective evaluation are usually influenced by personal preferences and are related to the panelists’ likes and dislikes. 


Tests can be performed in vitro (in a laboratory, on model systems) or in vivo (on live volunteers).  

Sensory evaluation is a key aspect of product evaluation of cosmetic and personal care products.  Sensory evaluation methods assess a product's appearance and performance through the senses (sight, touch, smell) of naïve consumers or trained experts.  Expert clinical grading can be used, for example, for measures such as skin dryness, skin redness, fragrance strength, hair combability and hair shine.  Great care needs to be exercised in the design of sensory studies, as they are suspectable to experimental bias.  For general information on sensory test methods, see the textbooks by Kemp et al [3] and Meilgaard et al [4].


Regulations and Guidelines for Product Evaluation


Products defined solely as cosmetic products, unlike medical products, do not need to be licensed before being sold in Europe (including the UK*) and the US. As a result, product evaluation protocols for cosmetics do not usually need to be pre-approved by regulators, ahead of license submissions, as they do with medicinal products. There are no pharmacopeial monographs instructing on how to perform particular tests, and virtually no regulated test methods for cosmetic product evaluation.  There are also no inspections of testing facilities by government agencies, such as the European Medicines Agency (EMA) or the U.S. Food & Drug Administration (FDA).  Instead, cosmetic and fair-trade regulations in Europe and the US provide general guidance to companies on the standard of testing expected for the support of cosmetics claims [5-8].  There is also guidance on green claims in Europe and the US that covers more than just cosmetic products [9,10].  Claims regulations will be covered in more detail in a later article in this series.


In some limited cases and some legal territories, however, evaluation test methods for cosmetic products are pre-defined.  For example, in Europe, brands making SPF claims must test product performance using SPF testing methods prescribed by EU regulations [11].  In another example, in the US, some cosmetic products are also designated as medicinal products.  These are known as ‘OTC drug-cosmetic Products’ [12], and include sunscreens, medicated toothpastes, and anti-dandruff shampoos.  As these are designated as medicinal products manufacturers must apply for product licenses from the Food and Drug Administration (FDA), and the evaluation tests required for these license applications need FDA approval.


Most testing for cosmetic products involves human volunteers and any study that is performed on human volunteers, regardless of whether the agent being tested is defined as a food, cosmetic or medicine, must comply with the Declaration of Helsinki [13], an important international agreement that outlines the ethical conduct of clinical trials. In the US the ethical procedures required for the protection of human subjects in clinical trials are also detailed in what is known as the Common Rule [14]. 


Clinical trials for medicinal products must also be undertaken in accordance with rules agreed by the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH), known as ICH Good Clinical Practice (ICH GCP) [15].  Whilst full compliance with ICH GCP is not mandatory for cosmetics, the spirit of the ICH GCP is expected to be followed during the testing of cosmetic items.  To help provide guidance on implementing ICH GCP, the WHO has issued a Handbook of Good Clinical Research Practice [16]. Some of the principles covered by the GCP include ethics, risk-vs-benefit analyses, safety considerations, defined protocols, ethical committee (also known as Institutional Review Boards IRB’s) clearances, medical support from physicians, panelist consent, staff training, confidentiality, sample preparation, and quality assurance systems (including SOPs).  All of these are also important for cosmetics testing because they ensure the protection of human subjects, the reliability of test results, and the integrity of the research process.  Adherence to these standards should be considered when choosing where to have studies on human volunteers conducted, to ensure these principles and your corporate social responsibility objectives are adhered to.


To help define best practice in product evaluation for cosmetics manufacturers in Europe, Cosmetics Europe produce Guidelines for the Evaluation of the Efficacy of Cosmetic Products [17].  This guide gives practical advice on protocol design for all types of cosmetic product evaluation and is intended to help companies seeking to comply with EU cosmetic regulations, particularly those related to claims.  Whilst developed for use in Europe, this guide is very useful for cosmetic scientists all around the world.


In addition to the Cosmetics Europe guide, there are also many other detailed guides for effective study design, including those created by the European Group for Efficacy Measurements on Cosmetic and Other Topical Products (EEMCO) [for example papers see references 18 & 19].  Although these guides are not legally binding, they do provide very useful advice based on the experiences of the experts in the group.  In a similar vein, ASTM International, formerly known as the American Society for Testing and Materials, have also published guidance notes on sensory test methods [20,21].  Finally, guidance on test methods can also be found in ISO standards.  ISO standards are not legally binding but are very useful and built on the advice of industry experts. Good examples include ISO/TR 26369:2009 (sun protection test methods) [22] and ISO 11132:2021 (sensory analysis) [23].


Finally, it is worth noting that some large retail chains and TV marketing platforms (HSN, QVC etc) are now starting to develop their own guidelines for product claim substantiation.  It is important to consult these businesses well in advance of any testing, if they are sales channels that you intend to use.


Conclusions


Product evaluation is essential for the development of cosmetics and personal care products and can be used in many different settings, such as screening prototypes, making formula changes, benchmarking and claims support.  Test methods are split into objective and subjective tests, with objective tests either being performed by instruments or on panelists.  Methods for product evaluation of cosmetics and personal care products must comply with cosmetics regulations, but usually do not follow standardized methods.  Guidance on best practice for product evaluation is provided by many sources, including the Cosmetics Europe Guidelines for the Evaluation of the Efficacy of Cosmetic Products and the various EEMCO guides, ASTM publications, and ISO standards.  Being familiar with best practice will help you make better informed choices and will ensure that any testing undertaken meets good ethical and scientific standards.


* Note - For purposes of simplicity, we have assumed in this article that UK cosmetic regulations, after Brexit, remain broadly in line with EU regulations with respect to the requirements product evaluation and claims testing.


More information in the TRI Library



Test Your Knowledge with Our Multiple Choice Quiz ⬇️


 

References

  1. International Federation of Societies of Cosmetic Chemists. (1987). Principles of product evaluation: Objective sensory methods. (I.F.S.C.C. Monograph Number 1) https://ifscc.org/monographs/monograph-no-1-principles-of-product-evaluation-objective-sensory-methods/

  2. Piérard, G.E. (2002). Instrumental non-invasive assessments of cosmetic efficacy. Journal of Cosmetic Dermatology, 1: 57-58. https://doi.org/10.1046/j.1473-2165.2002.00013.x

  3. Kemp, S.E., Hollowood T., Hort, J. (2009). Sensory evaluation: A practical handbook. John Wiley & Sons.

  4. Meilgaard, M.C., Civille, G.V, Carr, B.T. (2006). Sensory evaluation techniques, Fifth Edition.  Taylor & Francis Group.

  5. European Union (2024) Regulation (EC) No. 1223/2009 Cosmetic products.  Retrieved September 29, 2024, from  https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=CELEX%3A32009R1223 

  6. U.S. Food & Drug Administration. (2024). Federal food, drug, and cosmetic act​. Retrieved September 29, 2024, from https://www.fda.gov/regulatory-information/laws-enforced-fda/federal-food-drug-and-cosmetic-act-fdc-act

  7. European Union. (2024). Directive 2005/29/EC Unfair business-to-consumer commercial practices in the internal market. Retrieved September 29, 2024, from https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=celex%3A32005L0029 

  8. Federal Trade Commission. (2024). Federal trade commission act. Retrieved September 29, 2024, from https://www.ftc.gov/legal-library/browse/statutes/federal-trade-commission-act 

  9. European Commission. (2024). Green claims: New criteria to stop companies from making misleading claims about environmental merits of their products and services. Retrieved September 29, 2024, from https://environment.ec.europa.eu/topics/circular-economy/green-claims_en

  10. Federal Trade Commission. (2024). Green guides. Retrieved September 29, 2024, from https://www.ftc.gov/news-events/topics/truth-advertising/green-guides

  11. European Commission. (2024). Sunscreen products. Retrieved September 29, 2024, from https://single-market-economy.ec.europa.eu/sectors/cosmetics/cosmetic-products-specific-topics/sunscreen-products_en 

  12. Baki, G. (2022). Basic definitions. Claims. Classifications of cosmetics and OTC drug-cosmetic products. In Baki, G. (Ed.), Introduction to cosmetic formulation and technology, 2nd Edition (pp 3-32). John Wiley & Sons.

  13. World Medical Association (2024) WMA declaration of Helsinki- Ethical principles for medical research involving human subjects.  Retrieved September 29, 2024, https://www.wma.net/policies-post/wma-declaration-of-helsinki-ethical-principles-for-medical-research-involving-human-subjects/

  14. U.S.  Department of Health and Human Services (2024) Federal policy for the protection of human subjects (‘Common Rule’).  Retrieved September 29, 2024, https://www.hhs.gov/ohrp/regulations-and-policy/regulations/common-rule/index.html

  15. International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH). (2016, November 9). Guideline for Good Clinical Practice E6(R2). https://database.ich.org/sites/default/files/E6_R2_Addendum.pdf

  16. World Health Organization. (2005). Handbook for good clinical research practice (GCP). https://iris.who.int/bitstream/handle/10665/43392/924159392X_eng.pdf

  17. Cosmetics Europe. (2008, May). Guidelines for the evaluation of the efficacy of cosmetic products. https://www.cosmeticseurope.eu/files/4214/6407/6830/Guidelines_for_the_Evaluation_of_the_Efficacy_of_Cosmetic_Products_-_2008.pdf

  18. Berardesca, E. (1997). EEMCO guidance for the assessment of stratum corneum hydration: electrical methods. Skin Research and Technology, 3(2), 126-132. https://doi.org/10.1111/j.1600-0846.1997.tb00174.x

  19. Rogiers, V., & EEMCO Group (2001). EEMCO guidance for the assessment of transepidermal water loss in cosmetic sciences. Skin Pharmacology and Applied Skin Physiology, 14(2), 117–128. https://doi.org/10.1159/000056341ASTM

  20. Danker, W.H. (Ed.) (1968) Basic principles of sensory evaluation. American Society for Testing and Materials.

  21. Chambers IV, E., & Wolf, M.B. (1996) Sensory testing methods, 2nd edition. American Society for Testing and Materials.

  22. International Organization for Standardization (ISO). (2009). Cosmetics – sun protection test methods – review and evaluation of methods to assess the photoprotection of sun protection products. ISO/TR 26369:2009

  23. International Organization for Standardization (ISO). (2009). Sensory analysis – methodology – guidelines for the measurement of the performance of a quantitative descriptive sensory panel.  ISO 11132:2021



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