The following is the translation of the given 'Bahasa' text to 'English' while preserving any HTML tags: "Serum containing vitamin C will easily deteriorate if not properly cared for. In some cases, damaged serum can even be harmful to the skin. The main sign of damaged vitamin C serum is a change in color. Dr. Housmand, a dermatologist from Dallas, mentions that if the serum changes color from its original color, then it is likely that the serum has already deteriorated."

If Sahabat Dream is still unsure, you can also confirm by smelling the aroma of the serum. In addition, pay attention to the texture of the serum. If the texture changes, then you need to replace it with a new serum. Although vitamin C serum deteriorates quickly, Sahabat Dream can take the following preventive steps.

One of the things that can accelerate the oxidation process of vitamin C is exposure to heat and sunlight. Dream friends are advised to store products properly and avoid direct exposure to sunlight.

On average, vitamin C serum lasts for three to 4 months. Usually, the serum packaging will state the shelf life after opening, as well as the expiration date. "The best option is to use a vitamin C-containing product within a 3-month period," said Dr. Houshmand.

Pay attention to the product packaging before purchasing. Good product packaging allows for extending the shelf life of the serum. It is recommended to buy products with dark-colored glass packaging and a pump dropper applicator to maintain product hygiene. Report: Salma Rihhadatul Aisy / Source: Skincare.com.