Can tretinoin cream be applied over a large area?

Tretinoin cream is generally not recommended for large-area application. The specific analysis is as follows:

The active ingredient in tretinoin cream is highly irritating. After skin absorption, it may cause local reactions such as dryness, flaking, redness, and stinging. Applying it over a large area can spread these irritations, worsen damage to the skin barrier, and increase the risk of adverse effects due to excessive absorption—such as heightened skin sensitivity, fragility, and increased susceptibility to heat or sunburn. Since tretinoin works effectively at the deeper layers of the skin, targeted application on affected areas alone is sufficient. There is no need to extend coverage; overuse contradicts proper skincare principles and imposes additional burden on the skin.

During use, enhanced moisturization is necessary. Choose gentle, non-irritating moisturizers to relieve dryness and discomfort. Strict sun protection must be practiced during daytime—apply sufficient sunscreen and combine with physical sun protection measures (e.g., hats, umbrellas) to prevent UV exposure from exacerbating skin irritation. When applying the medication, use only a small amount and apply thinly to localized areas. If severe discomfort occurs, discontinue use immediately and consult a healthcare professional to ensure safe and effective skincare.