In the cosmetics industry, products are exposed to artificial light in display cases as well as sunlight through store windows. Colorants are susceptible to photodegradation in these conditions. In addition, fading of packaging usually renders a product unfit for sale regardless of the color stability of the consumable item.
Drug substances are often highly reactive to light energy, so it is critical for manufacturers to ensure their products retain their safety and efficacy after light exposure.
If you want to know more about how to test light stability https://www.q-lab.com/en-gb/applications/pharmaceuticals-cosmetics