Photo Patch Test

Ingredients in cosmetics may cause skin reactions such as irritation or sensitization. Evaluating the compatibility of cosmetic products with the skin is essential to ensure consumer safety and product quality.

Protheragen-ING offers a cosmetic photo patch test service, a reliable and comprehensive solution to help customers evaluate the potential of cosmetic formulations to cause adverse skin reactions and make informed decisions to protect your customers and your brand.

Principles of Photo Patch Test

The purpose of photopatch testing is to determine whether photoallergic contact dermatitis is caused by sensitization to certain chemicals that come into contact with the skin, sensitization to UV light, or sensitization to sunlight-activated chemicals.

Light energy sensitizes photoallergens, turning them from half-antigens to full-antigens that attach to skin proteins and trigger the body's production of antibodies or a cellular immune response.

The body produces a series of degenerative reactions, with erythema, papules, blisters, and other reactions visible to the unaided eye, when the sensitized individual is re-exposed to the same sensitizing factor or cross-sensitizing substance. This process identifies the photo-reactive photoallergens of the skin.

Our Testing Methods

Control Skin Exposure

Cosmetic spot testing involves controlled exposure of the skin being evaluated to a cosmetic product. We apply a small, diluted chemical sample (photoallergen) to a patch or area of skin, expose it to a certain wavelength of light, and monitor the skin's reaction for a specified period of time.

This allows us to assess the potential for skin irritation, redness, or other adverse reactions that may occur from use of the product.

Reactions to each allergen are graded on a spectrum:

• Negative
• Irritating
• +/- Suspicious
• + Weak positive
• ++ Moderate response
• +++ Strong reaction

Irradiation Light Source and Dose

• Irradiation light source: mainly long-wave ultraviolet (UVA) with a wavelength of 320~400 nm.
• Irradiation dose: After removing allergens, UVA 5 J/cm² is given to the irradiated side. If the minimum erythema dose (MED) is < 5 J/cm², reduce the UVA radiation dose to 2.5 or 1 J/cm².

Comprehensive Evaluation

Our experienced professionals carefully analyze the skin's reaction to cosmetics in cosmetic spot testing.

Protheragen-ING evaluates various factors, including the degree of erythema (redness), edema (swelling), and other signs of irritation or allergy. By checking these indicators, we can determine the compatibility of your cosmetic formula with your skin and identify any potential issues.

Customized Testing

Every cosmetic product is unique, with different ingredients and formulas. Protheragen-ING works closely with you to develop a customized test plan that reflects the specific characteristics of your product.

Whether you have a cream, lotion, serum or any other cosmetic formula, we can tailor our testing methods to meet your specific needs.

Benefits of Cosmetic Photo Patch Test Service

Cosmetic light spot testing can help identify potential skin reactions caused by cosmetic formulas. Our testing services provide valuable insights into the compatibility of your cosmetic formulations with your skin.

If any adverse reactions are observed during testing, our experts can provide recommendations for formulation optimization to help improve the overall skin compatibility of the cosmetic product.

Contact Protheragen-ING today to discuss how we can help you conduct effective skin compatibility testing of your cosmetics. We will respond within 2-4 working days.