Do You Need 100 Participants
As more brands position their products for sensitive or eczema-prone skin, expectations around safety testing are increasing. While standard Human Repeat Insult Patch Test (HRIPT) studies are widely used to support claims like “dermatologist tested,” some programs and endorsements require more robust clinical data.
One of the most common questions brands ask is whether a 100-participant HRIPT study is necessary. The answer depends on the type of claims being made and whether third-party endorsements are being pursued.
What Is Standard HRIPT
HRIPT is a clinical study used to evaluate the potential for irritation or allergic reactions after repeated exposure to a product.
A typical HRIPT study includes:
- Approximately 50 participants
- Repeated application to the same skin site over several weeks
- A rest period followed by a challenge phase
- Evaluation by trained professionals
This type of study is generally sufficient to support:
- Dermatologist tested
- Dermatologically tested
- Skin tested
- Non-irritating
When Standard HRIPT May Not Be Enough
For products marketed toward sensitive skin or eczema-prone consumers, expectations are higher.
Claims such as:
- Suitable for sensitive skin
- Safe for eczema-prone skin
- Gentle or non-irritating for compromised skin
may require stronger supporting data, particularly when:
- Submitting to third-party endorsement programs
- Working with major retailers
- Building premium or clinical brand positioning
HRIPT Requirements for Eczema-Focused Programs
Some third-party programs, including the National Eczema Association Seal of Acceptance, emphasize the need for more robust clinical testing.
In these cases, HRIPT studies may be expanded to include:
- A minimum of 100 participants
- Inclusion of individuals with self-perceived sensitive skin
- A defined panel structure, such as:
- At least 50 participants with sensitive skin and 50 with normal skin
- Or a full panel of sensitive skin participants
Additional requirements may also apply depending on product type, such as dilution conditions or ingredient restrictions.
These enhanced study designs are intended to better evaluate product tolerability in populations that are more likely to experience irritation.
Why Larger HRIPT Studies Matter
Increasing the number of participants and including sensitive skin subjects provides several advantages:
- Greater confidence in product safety across different skin types
- Stronger support for sensitive skin positioning
- Improved acceptance in endorsement and certification programs
- Reduced risk of claim challenges
While no study can guarantee zero irritation, larger and more targeted panels improve the reliability of the data.
Standard vs Enhanced HRIPT
Brands can think of HRIPT in two tiers:
Standard HRIPT
- Approximately 50 participants
- General population
- Supports basic safety and dermatologist tested claims
Enhanced HRIPT
- 100 or more participants
- Includes sensitive skin populations
- Supports stronger claims and third-party endorsements
- Aligns with expectations for eczema-focused positioning
Do You Always Need 100 Participants
No. A 100-participant HRIPT is not required for most cosmetic products or claims.
However, it may be beneficial if:
- You are targeting sensitive or eczema-prone consumers
- You plan to pursue third-party endorsements
- You want to strengthen product credibility in a competitive market
Choosing the right study design depends on your claims strategy, target audience, and commercial goals.
Final Thoughts
HRIPT remains one of the most widely used tools for supporting cosmetic safety claims. While standard studies are sufficient for many products, enhanced HRIPT designs with larger and more targeted panels can provide stronger evidence for sensitive skin and eczema-related positioning.
For brands looking to differentiate and build trust, investing in more robust testing can be a valuable step.
50 Subject HRIPT Testing – Normal Skin
50 Subject HRIPT Testing – Sensitive Skin
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