What should be done first when trying a new hair product on a client?

Performing a patch test is crucial when trying a new hair product on a client because it helps to identify any potential allergic reactions or skin sensitivities the client may have to the product's ingredients. By applying a small amount of the product to a discreet area of the skin, usually behind the ear or on the inner forearm, you can monitor for any adverse reactions, such as redness, swelling, or irritation, before applying the product more broadly. This step ensures the safety and comfort of the client, making it a standard best practice in the cosmetology field.

While consulting the product label is important to understand the ingredients and any specific instructions or precautions, it does not provide immediate information about the client's individual reactions. Applying the product directly to the hair or researching its reviews may lead to negative experiences if there's an undetected allergy or sensitivity. Thus, starting with a patch test is a responsible approach to ensure client safety.