Human Repeat Insult Patch Testing (HRIPT)

The human repeat insult patch test (HRIPT), which is the standard human clinical test used for personal care and pharmaceutical products, is used to help predict the likelihood for induced allergic contact dermatitis (ACD) of topically applied products. Under highly controlled conditions, small amounts of test product are applied to patches, which are then repetitively applied to the backs of volunteers. At specified intervals during the course of the study, our expert clinical graders closely examine the patch application sites for any reactivity.

RCTS has performed thousands of standard and customized HRIPT tests for dermatological and cosmetic products.

At RCTS, we conduct HRIPTs according to two study designs:
  • Modified Jordan and King (used primarily for products designed to be submitted to the FDA)
  • Modified Draize (used primarily for cosmetic products)

However, we also have the ability to conduct customized patch test protocols.

Cumulative Irritation Test (CITs)

CITs are used primarily as a comparative dermal irritation test to determine the irritation potential of a test product versus that of a competitive product and moderate irritant and low irritant controls. Comparative products are commonly chosen within the same category (e.g., bar soap, shampoo). While a CIT can be of any time period, they are typically of either 14- or 21-day duration.


Comedogenicity assays are back patch safety studies designed to test the potential of a test product to cause micro-comedone (non-inflammatory acne lesions formation). This test is used to help support non-comedogenic claims and involves the repeated application of products, including a positive and negative control, over a four-week time point. At the conclusion of the four week time point cyanoacrylate biopsies are taken of each site and microscopically examined for the presence of micro-comedones.