Hydroquinone Test Kit and Alpha Arbutin Cross-Reactivity

Subject: Re: Inquiry about testing for prohibited substances in cosmetics

Hello,

Thank you for your question regarding the Hydroquinone test kit and Alpha Arbutin.

You are correct that Alpha Arbutin is chemically related to Hydroquinone; it is a glycosylated form of Hydroquinone. This chemical similarity is likely why Mahidol University suggested the possibility of cross-reactivity.

However, whether Alpha Arbutin will cause a positive result on a Hydroquinone test kit depends entirely on the specific reagents and detection method used in that particular kit. Some test kits are designed to be highly specific to free Hydroquinone molecules, while others might react with related phenolic compounds or derivatives.

Based on your experience, where your test kit did not show a positive result when testing a formula containing Alpha Arbutin (and presumably no Hydroquinone), it suggests that your specific test kit is likely designed to detect free Hydroquinone and does not significantly react with Alpha Arbutin under the test conditions.

So, while cross-reactivity is theoretically possible depending on the test kit's chemistry, your result indicates that your kit is likely specific enough not to be affected by Alpha Arbutin.

For the most accurate and definitive testing, especially for regulatory purposes, sending samples to a certified laboratory like the Department of Medical Sciences (กรมวิทยาศาสตร์การแพทย์) remains the gold standard, as mentioned by the staff.

We hope this clarifies the situation.