What type of reaction can occur from using expired cosmetic products?

Using expired cosmetic products can lead to skin irritation or allergic reactions primarily due to the breakdown of active ingredients and preservatives, which can compromise the product's safety and efficacy. Over time, cosmetics can change in chemical composition, leading to the growth of bacteria or other pathogens. This increase in microbial load can irritate the skin or provoke allergic responses, especially in individuals with sensitive skin or known allergies.

In addition to irritation and allergic reactions, the expired products may not provide the intended benefits, and instead can trigger adverse effects, reinforcing the need for awareness about product expiration and proper storage. Other options, while potentially harmful, do not specifically align with the risks associated with using expired cosmetics. For instance, while hair loss can be a concern for other reasons, it is not a direct consequence of using expired cosmetics. Enhanced effectiveness and reduction of skin oiliness are also unlikely outcomes of expired products, as they typically lose their potency and may cause adverse effects instead.