When conducting a patch test, how long should it be left on the skin?

When conducting a patch test, leaving the test substance on the skin for 10-15 minutes is typically recommended. This duration allows for adequate skin reaction observation while minimizing potential irritation or discomfort for the client.

The short time frame is sufficient to gauge the skin’s sensitivity and reaction to a cosmetic product or ingredient, which is especially important for ensuring the safety of further treatments or applications. Testing for a longer period, such as 30 minutes or 1 hour, may increase the likelihood of irritation or reactions that could skew the results, making it less effective for a preliminary assessment. A duration of just a few minutes, like 5 minutes, may not provide enough time for the skin to react appropriately, which is why the 10-15 minute window is the standard practice.