How is benzoyl peroxide used?

The benzoyl peroxide is an active ingredient commonly used to combat acne. The frequency of use depends on the formulation of the product and the concentration applied, as well as the sensitivity of the skin. It is often recommended to start with an application once a day, in the evening, then gradually increase the frequency if the skin tolerates it well, up to twice a day. Indeed, an application of benzoyl peroxide in the evening helps to limit photosensitivity reactions induced by sun exposure. This is a phototoxic substance that can induce undesirable reactions such as red patches, burns similar to sunburn, erythema or hyperpigmentation. For sensitive skin, it can be used every other day to avoid irritations, redness or excessive peeling that it can cause.

It is strongly recommended to consult a dermatologist to understand the correct frequency of use for benzoyl peroxide, depending on the treatment and the issue at hand.

For cleansing products based on benzoyl peroxide, it is generally advised to use them morning and evening. Indeed, it is beneficial to start the morning routine with a skin cleanse before moisturising. In the evening, cleansing is essential to remove dirt and other pollutants accumulated by the skin throughout the day. Rinsing off the product allows for a temporary application, an application twice a day is less problematic for sensitive skin.

Benzoyl peroxide, found in various types of products, is formulated in different concentrations depending on the galenic formulation and the specific needs of the patient. Cleansers, creams, and lotions are typically used to treat mild to moderate acne and are available over the counter. These products contain benzoyl peroxide concentrations ranging from 2.5% to 5%. For cases of moderate to severe acne, targeted gels and serums are often recommended. Although some of these products are available without a prescription, they are frequently prescribed by dermatologists, as they are generally combined with antibiotics and have higher concentrations of benzoyl peroxide, ranging from 5% to 10% to maximise the effectiveness of the treatment. It is important to note that the use of benzoyl peroxide at concentrations higher than 10% is very rare.

The benzoyl peroxide is often combined with other active ingredients such as antibiotics, retinoids or niacinamide, each combination offering specific benefits. When used with antibiotics, this combination enhances the effectiveness of the treatment while reducing the risk of bacterial resistance development. The alternating use of benzoyl peroxide and retinoids (one in the morning, the other in the evening) significantly improves the effectiveness on acne. Finally, the combination of benzoyl peroxide and niacinamide, known for its anti-inflammatory properties, provides complementary and synergistic effects: it increases effectiveness while reducing skin irritations often induced by benzoyl peroxide.

The National Agency for the Safety of Medicines and Health Products (ANSM) advises to adhere to the prescribed dosages in order to minimise the risk of side effects such as skin irritations , a photosensitivity and, in some cases, allergic reactions. These adverse effects can be exacerbated by a high concentration of benzoyl peroxide. Therefore, it is important to follow the information provided on the manufacturer's instructions. Additionally, it is recommended to perform a patch test, which involves applying a small amount of the product to a patch of skin and waiting 24 hours to check for the absence of an allergic reaction. It is also advised to moisturise your skin after using benzoyl peroxide to limit the risk of skin dryness. Finally, it is essential to avoid using other irritating active ingredients simultaneously (such as AHA, retinol, etc.) to limit the risk of skin reactions.