How To Spot If Your Vitamin C Serum Is Past Its Shelf Life, According To An Expert

By NEETI MEHRA

Photographed by Marissa Alves

A must-have on our skincare-laden shelves, a vitamin C serum is a powerful antioxidant that gives you a glow-up, while protecting it from ageing. Skin brightening, collagen-producing, and hyperpigmentation-reducing—vitamin C is touted to be a powerful skin ally, but you also need to show it some TLC. It has a tendency to oxidize faster than other products and ideally should be used within 3-6 months of opening.

Dr Renita Rajan MD DNB (DVL), Senior Consultant Dermatologist RENDER Skin and Hair, and Curator, CHOSEN by Dermatology, says a high-performance serum would ideally have three characteristics. "It should be stable, namely resistant to oxidation in the formulation and on the skin, potent in concentration and a compound that actually works and finally, presented in a formulation that actually penetrates well into the skin," she says.

"Stability is an issue with a vitamin C, so the best way to use a vitamin C serum is for short periods of time. You can cycle it with other products," says Dr Rajan. Vitamin C can be safely used topically by most people, without adverse reactions. But it might not be for everyone. Dr Chytra Anand, Chief Cosmetic Dermatologist, Kosmoderma Clinics cautions, "Since it's acidic, it can be highly irritating if the skin barrier is broken." She advises avoiding using it on acne-prone and rosacea-afflicted skin. "You should also look out for irritation, dryness, and stretchiness of skin—as vitamin C serums are not very hydrating and can dry the skin out," says Dr. Rajan, reactions which don't necessarily indicate the serum has gone past its shelf life.

Identifying an oxidized serum is fairly simple. Dr. Anand says you would know it by a little detective work, saying, "If crystals form in the vitamin C serum or it gets thicker. Or if the serum has a rancid odor, stings on application, irritates the skin, or triggers breakouts." Another tell-tale sign is a color change, where the serum turns to deep yellow, orange, or brown. "A mild amber color change and drying out of the serum where it is exposed to the air (near the bottle's mouth, for example) are not an issue," says Dr. Rajan.

Storing a vitamin C serum properly becomes necessary to keep it from oxidizing. Dr. Ankur Sarin and Dr. Jushya Sarin, Co-Founders of Sarin Skin Solutions, weigh in. They say, "A vitamin C serum in an amber bottle is preferable. Keep it away from direct sunlight and screw back the bottle cap tight after usage." If a temperature setting is suggested, follow that.

If by chance you’ve slathered on what seems to be a suspiciously oxidized serum, don't panic. "Just wash your face with cool water. While you will rarely get adverse events, you definitely won't get the benefits," says Dr Anand.

If your skin feels irritated after using an oxidized or expired serum, Dr. Ankur Sarin advises, "A hydrocortisone 1% cream can be used twice a day for 3-5 days on the development of irritation and itching." However, if your skin becomes dull and patchy after using it, dial the digits of your dermat immediately. It's definitely time to ditch the bottle and buy a new one.

This article was originally published on Vogue India.