I have a confession: I know far too much about vitamin C serum. My first husband (it always sounds rather glamorous to say that), a Texan, was friends with Alden Pinnell, who co-founded SkinCeuticals in Dallas in 1994 with his dermatologist father, Dr. Sheldon Pinnell. My ex-husband worked with them briefly and thanks to his involvement, I started using SkinCeuticals Vitamin C Serum 10 years before L’Oréal acquired the company. The studies behind it really made sense and, as a beauty editor for almost as long as I’ve been a journalist – I’d rather not put a timeline on it; thank you, vitamin C, for helping hide the evidence – I could sniff out real science from pseudo-science pretty quickly.

Dr. Pinnell, the brains behind the formulation, was a long-time professor at North Carolina’s Duke University, as well as the university’s J. Lamar Callaway Professor Emeritus of Dermatology and Chief of Dermatology at Duke University Medical Center. He and his research team discovered the mechanisms by which sun exposure causes photoaging and how the use of L-ascorbic acid (vitamin C) and topical antioxidants could help protect and repair skin from oxidative stress, including sun damage, while supporting collagen synthesis. Of course, SkinCeuticals is no longer the only brand harnessing vitamin C’s power; several newer formulas now use similar concentrations of L-ascorbic acid, vitamin E and ferulic acid found in their serum – more on that soon 

Here’s your vitamin C shopping checklist if you don’t go with SkinCeuticals: The formula should contain at least 10 to 15 per cent L-ascorbic acid, which is considered the ideal concentration for stimulating collagen production, reducing sun damage and fading dark spots while remaining reasonably well tolerated. You can go up to 20 per cent, but after that, absorption by the skin appears to plateau and irritation increases. It should be formulated at a low pH (2.3 to 3.5) so it can penetrate the skin, and packaged in opaque, airtight bottles, as vitamin C oxidises quickly when exposed to light and air. Ideally, it should also be combined with vitamin E (tocopherol) and ferulic acid. This trio has been shown to enhance antioxidant protection and improve the stability of vitamin C, helping it work more effectively.

Dermatologist Dr. Lisa Kellett, whose DLK on Avenue emporium in Toronto is a temple to science-backed treatments, agrees that it’s a powerful skincare ingredient, saying, “Vitamin C acts as an antioxidant, which helps protect cells from damage caused by free radicals.” Her own Clear Clinical Vitamin C Ferulic Serum contains a water-soluble, irritation-free vitamin C polypeptide, as well as plant-derived pseudo-collagen and jojoba to help hydrate and maintain elasticity, with 2% salicylic acid to slough off dead skin cells.I’ve spoken to some other people who are in the know about skincare and another recommendation is the drugstore brand, CeraVe’s Skin Renewing Vitamin C Serum. Its 10 per cent L-ascorbic acid formula is bolstered by ceramides and hyaluronic acid, so while it brightens and helps defend against environmental damage it also supports the skin barrier – a welcome bonus for mature or sensitive skin (and for your budget).

Here’s the other tip: use vitamin C daily, ideally as part of your morning routine. It builds up in the skin where it helps neutralize free radicals generated by UV exposure, reducing the oxidative damage that contributes to wrinkles, pigmentation and collagen breakdown. While it doesn’t replace sunscreen, its antioxidant protection adds a deeper layer of defence against the effects of UV damage. 

As a side note, I’ve also found it keeps my skin clear of blemishes. If I feel one coming I just pop an extra drop of serum on the offending bump – it tingles satisfyingly and seems to clear it right up. Take that wrinkles and acne!