How should a product be tested for sensitivity before a full application?

Testing a product for sensitivity is crucial to ensure skin compatibility and to prevent adverse reactions. Applying a small amount of the product on a discrete area of the skin, typically known as a patch test, allows for observation of any immediate or delayed allergic reactions such as redness, itching, or irritation. This method is effective because it provides insight into how the skin will react to the product without exposing a large surface area.

Using the product for an extended period—such as a week—doesn't help identify immediate sensitivities and could lead to a significant reaction that would be more difficult to manage if it occurred over a larger area. Mixing the product with another before testing can alter the formulation's effects and mask potential sensitivity issues. While consulting a dermatologist can provide guidance, it does not directly assess the product's effect on the individual’s skin in a practical manner. The patch test remains the most reliable initial approach to ensure safety.