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Skincare 101: How to choose a vitamin C serum

By Si Yau Tuong
18th July 2023

We want to help you make good skincare decisions, so here’s part five of our Skincare 101 series, with advice on choosing a vitamin C. Here is our handy guide. 

What does a vitamin C serum do?

Vitamin C is an essential ingredient renowned for its ability to strengthen the skin and defend it against the environment. In the right formulation, this useful antioxidant can brighten dull and discoloured skin, fade age spots by inhibiting pigment formation, bolster the skin’s defences against UV damage and boost its production of collagen and elastin. Vitamin C also tackles free radicals which are  unstable molecules that accelerate ageing.

What do you need to look for when choosing a vitamin C serum?

If you want your skin to reap all these great benefits, it is important that the product you use is well-formulated and that the vitamin C it contains is used at a high enough concentration to be effective (it that vitamin C is L-ascorbic acid, look for a product with a concentration between 10% and 20%). Keep in mind that higher concentrations may not necessarily deliver better results and could lead to skin irritation. Start with a lower concentration if you’re new to vitamin C or if you have sensitive skin. Vitamin C products also often have a low ph level of 3.5 which means they’re acidic and can sting once applied.

A tricky and highly unstable ingredient, vitamin C oxidises quickly on contact with UV light. So as well as careful formulation, opt for packaging that protects from light and air, preserving the vitamin C’s potency and ensuring it can work its magic.

An important to keep an eye out for is what else the serum includes, because how well a vitamin C product performs isn’t only about the ph and percentage of vitamin C it contains, it also depends on what that vitamin C has been combined with.

Some formulations incorporate synergistic ingredients like ferulic acid, which enhance the antioxidant performance of vitamin C.

Some of our favourite vitamin C serums:

Potent C Skin Care Serum 

A one-step multitasking product which produces particularly great results for both pigmentation and wrinkles. Created by two top dermatologists who want this to be the only product their patients will need. Absorbs well without any stickiness and you can use it once or twice a day, as you wish. £65.

Medik8 C-Tetra

This is a terrific ‘starter’ vitamin C serum if you haven’t tried a ‘serious’ one before. It is effective but also gentle as the type of vitamin C in here is well-tolerated even by sensitive skin. £39

Elequra Radiance Accelerator

This brilliant product makes the skin tone more even and genuinely brightens the complexion. Its innovative and effective formula makes product geeks salivate. It’s a water-based gel-serum made with concentrated, active ingredients including two different esters of vitamin C and 0.25% encapsulated retinol – so it’s strong stuff. There’s also hydrating hyaluronic acid, brightening, barrier-boosting niacinamide and plankton extract – and an exclusive brightening complex based on periwinkle extract. £98 (on sale now on the TTG shop for £68.60)

Starting your vitamin C journey

Choosing the perfect vitamin C is a transformative step towards better skin. By understanding the incredible benefits of this powerhouse ingredient and considering crucial factors such as formulation, concentration, and synergistic ingredients, you can confidently navigate the vast array of vitamin C products available. Remember, your skin’s needs and preferences are unique, so take the time to explore and find the vitamin C product that works for your skin.


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