The cosmetic market is currently flooded with terms like “Microbiome-Friendly,” “Probiotic-infused,” or “Postbiotic-powered.” However, as the European Commission and the FTC (USA) increase their scrutiny over greenwashing and scientific claims, the burden of proof for brands has never been higher. Substantiating these claims requires more than a simple “before and after” test; it demands a robust clinical strategy.
1. Defining the Different Types of Claims
Before launching a testing protocol, it is vital to categorize the intended claim:
- Microbiome-Friendly / Respectful: The goal is to prove neutrality. The product must not alter the natural diversity or the pH of the skin, nor should it inhibit the growth of beneficial bacteria like S. epidermidis.
- Probiotic Skincare: Legally, most cosmetics do not contain live bacteria (due to preservation challenges). These claims usually refer to lysates or tyndallized bacteria.
- Prebiotic & Postbiotic: Claims focused on “feeding” the good bacteria or providing the metabolic byproducts (like lactic acid) that improve the skin environment.
2. The Clinical Protocol: A Step-by-Step Approach
To satisfy both scientific rigor and regulatory bodies, a standard evaluation follows this rigorous workflow:
A. Volunteer Selection & Recruitment
The cohort must be homogeneous. For a microbiome study, factors like age, gender, and even geographical location are critical, as the “normal” microbiota varies significantly between a teenager in New York and an elderly person in Tokyo.
B. The “Wash-out” Phase: A Mandatory Constraint
Technical Note: To observe the true impact of a product, volunteers must undergo a “wash-out” period of 7 to 14 days. During this time, they use a neutral, fragrance-free soap provided by the lab to eliminate the “noise” of their previous cosmetic routines.
C. Controlled Sampling (T0, T-Final, and Follow-up)
- T0: Mapping the baseline microbiota.
- T-Treatment: Sampling at various intervals (e.g., Day 7, Day 28) to observe the evolution of species richness and Shannon Index (diversity).
- T-Persistence: Checking if the changes last after product cessation.
3. Key Biodiversity Indicators to Monitor
When reviewing the data from your CRO, three metrics are essential:
- Alpha Diversity: The richness and evenness of species within a single sample. A “friendly” product should maintain or increase this.
- Beta Diversity: The variation in species composition between different volunteers or different time points.
- The S. aureus / S. epidermidis Ratio: Often used as a marker for skin health, especially in atopic skin studies.
4. Comparison of Certification vs. Clinical Data
| Approach | Objective | Methodology | Pros/Cons |
| Labelling / Certification | Marketing “Seal of Approval” | Standardized in-vitro or in-vivo tests | High consumer trust, but less specific to the formula. |
| Bespoke Clinical Trials | Scientific Proof of Efficacy | Custom in-vivo sequencing (16S/Shotgun) | Unique IP, strong scientific backing, but higher cost. |
Conclusion
Substantiating microbiome claims is a journey from microbiology to marketing. The key to success lies in the ability to translate complex sequencing data into clear, transparent, and honest claims for the consumer.
Do you need a CRO that specializes in specific microbiome certifications? Register on Skinobs and use our advanced filters to find the perfect testing partner for your claims.
