Health? or Hype?
Make the right choice with recommendations you can trust, backed by expert testing.
Explore health recommendationsBy clicking a retailer link you consent to third-party cookies that track your onward journey. This enables W? to receive an affiliate commission if you make a purchase, which supports our mission to be the UK's consumer champion.
Best vitamin C serums for 2026 - reviewed by a cosmetics expert
Our independent tests and formula reviews reveal which vitamin C serums are worth the money and which are best left on the shelf
Senior researcher/writer, focusing on health and wellbeing, with over a decade of experience in product testing and investigative research.
Looking to brighten your skin tone and give it a boost? Our independent vitamin C serum reviews reveal the best brands to buy, based on an independent expert review of the ingredients, and our in-house tests.
We've reviewed 12 popular vitamin C serums available on the high street and online, including high-strength, fast-acting options and gentler alternatives.
Our research revealed that paying more doesn't always pay off - some budget products impressed in our tests - but our top scorer is a runaway winner that is worth the higher price.
How our tests find you the best
Formula analysis
We review the effectiveness of the formula, looking at the type of vitamin C, the concentration and the pH level. We also assess any claims made about the product.
Irritants
We check the fragrance and allergen load, and for other potentially irritating ingredients.
Stability and packaging
Vitamin C is prone to oxidisation, damaging its potency. We rate each product and pack design for oxidation and contamination risk
Why you can trust our reviews
We don't rely on one person's tryout; our independent cosmetic expert analyses the products, we then lab-test pH levels and vitamin C potency and our user panel rate the serums for scent, texture and skin residue.
The best vitamin C serums
Only logged-in Which? members can view our full vitamin C serum results, including the top-rated products.
Join Which? to get instant access to our test results and Best Buy recommendations below, as well as our Great Value picks.
| Vitamin C serum | Price (30ml) | Score | Efficacy | Tolerance & suitability | Formulation quality | User experience |
|---|---|---|---|---|---|---|
Sign up to reveal Get instant access to this and all our scores and recommendations Unlock tableGet Digital access at £9.99 a month, cancel at any time. Already a member? | 92% | ★★★★★ | ★★★★☆ | ★★★★☆ | ★★★☆☆ | |
| 74% | ★★★★☆ | ★★★☆☆ | ★★★★☆ | ★★★☆☆ | ||
| 72% | ★★★☆☆ | ★★★★★ | ★★★★☆ | ★★★☆☆ | ||
| 72% | ★★★☆☆ | ★★★★★ | ★★★★★ | ★★★★☆ | ||
| 71% | ★★★☆☆ | ★★★★★ | ★★★★☆ | ★★★★☆ | ||
| 71% | ★★★☆☆ | ★★★★★ | ★★★★★ | ★★★★☆ | ||
| 71% | ★★★★☆ | ★★★★★ | ★★★☆☆ | ★★☆☆☆ | ||
| 70% | ★★★★☆ | ★★★☆☆ | ★★★☆☆ | ★★☆☆☆ | ||
| 68% | ★★★☆☆ | ★★★☆☆ | ★★★★☆ | ★★★★☆ | ||
| 66% | ★★★☆☆ | ★★★★★ | ★★★★☆ | ★★★★☆ | ||
| 60% | ★★★☆☆ | ★★★☆☆ | ★★★★☆ | ★★★★☆ | ||
| 48% | ★★☆☆☆ | ★★★☆☆ | ★★☆☆☆ | ★★★★☆ |
Sign up to reveal
Get instant access to this and all our scores and recommendations
Unlock tableGet Digital access at £9.99 a month, cancel at any time.
Already a member?
Log in
Date published: October 2026. Overall score combines scores for each attribute tested, weighted according to overall importance. Star ratings are on a scale from one to five. The more stars, the better. Efficacy: Includes the humectant and barrier systems, theoretical effectiveness under ideal conditions based on formulation, claims vs product reality, and usefulness of supporting evidence. Tolerance & suitability: Includes fragrance and other potential allergens, irritants, preservatives, suitability claims, format and packaging. Formulation: Includes risks of oxidation and light degradation, signs of instability or degradation, texture, usability, and overall formulation design quality. User experience: 12 users from a panel of 30 assessed each serum's texture and scent.
Please note that, as pricing is dynamic, this is indicative only and may not be correct if prices change. Page last checked: October 2026. We are not able to show every retailer, and cheaper prices may be available.
The vitamin C serums we assessed
The vitamin C serums in our assessment are listed below in alphabetical order.
Only logged-in Which? members can view our full verdict on each. Join Which? to get instant access to our test results and recommendations.
Beauty Pie Superdose C C-Suite Rapid Action Power Brightener
Our score and verdict Log in or join Which? to instantly reveal
Available from Beauty Pie (£25 with membership)
Price: £25 (with membership) - £45
CeraVe Skin Renewing Vitamin C Serum
Our score and verdict Log in or join Which? to instantly reveal
Available from Amazon (£22.50), Boots (£22.50), Look Fantastic (£22.50)
Price: £22.50
Cien (Lidl) Vitamin C Glow Serum
Our score and verdict Log in or join Which? to instantly reveal
Available from £2.99 (not available online)
Price: £5
Drunk Elephant C-Firma Fresh Day Serum
Our score and verdict Log in or join Which? to instantly reveal
Available from Boots (£56.80), Cult Beauty (£73), Look Fantastic (£71)
Price: £71
e.l.f. Bright Icon Vitamin C + E + Ferulic Serum
Our score and verdict Log in or join Which? to instantly reveal
Available from Superdrug (£15.99)
Price: £17
Best anti-ageing creams - our lab tests reveal which products really work
Garnier Vitamin C* Brightening Serum
Our score and verdict Log in or join Which? to instantly reveal
Available from Amazon (£9.99), Boots (£13.99), Superdrug (£9.31)
Price: £13.99
L'Oréal Paris Revitalift Clinical 12% Pure Vitamin C Brightening Serum
Our score and verdict Log in or join Which? to instantly reveal
Available from
Price: £31.99
La Roche-Posay Pure Vitamin C12 Serum
Our score and verdict Log in or join Which? to instantly reveal
Available from Amazon (£33.75), Boots (£45), Look Fantastic (£33.75), Superdrug (£35.99)
Price: £45
Simple 10% Vitamins C + E + F Glow+ Serum
Our score and verdict Log in or join Which? to instantly reveal
Available from Amazon (£4.99), Boots (£9.99), Superdrug (£4.99)
Price: £6.65
SkinCeuticals C E Ferulic
Our score and verdict Log in or join Which? to instantly reveal
Available from Look Fantastic (£169)
Price: £169
The Inkey List 15% Vitamin C + EGF Serum
Our score and verdict Log in or join Which? to instantly reveal
Available from Amazon (£12), Boots (£16), John Lewis (£16), Look Fantastic (£12)
Price: £16
The Ordinary Vitamin C Suspension 23% + HA Spheres 2%
Our score and verdict Log in or join Which? to instantly reveal
Available from Amazon (£7.70), Boots (£7.70), Look Fantastic (£7.70)
Price: £7.70
How we review vitamin C serums
We buy all the products we test ourselves, and for vitamin C serums we worked with a senior cosmetic chemist to interrogate ingredient lists and claims, and analyse the formulas of different vitamin C serums to uncover the best.
Our expert evaluated the current science on various vitamin C derivatives and their use in skincare to develop an assessment framework to rate each serum's efficacy.
We also conducted independent lab tests to confirm each serum's stated concentration was accurate and appropriate, and to check the pH level.
Each serum was rated on:
Active efficacy: we assess whether the vitamin C derivative used, the concentration and the pH level work well together. The better the mechanistic match, the more likely the serum is to provide effective treatment that matches the brand's claims. We also evaluate the strength of evidence for any claims made - including any clinical evidence and user trials commissioned by the brands - to see whether they stand up to scrutiny.
Tolerance & suitability: We examine the fragrance and allergen load, strength of formula and other ingredients that can potentially cause irritation and assess whether the brand positions the product appropriately eg for all skin types / for sensitive skin. We also rate each product on its preservative system and whether the packaging posed any contamination risk.
Formulation quality: We evaluate each product for oxidation risk, including the packaging, test each serum's texture, and analyse how it layers under sunscreen and makeup.
User experience: We asked 12 panel testers to rate each serum based on its scent and texture.
Why you can trust us: at Which? we're free from manufacturer and retailer influence. Find out more about our impartiality and how your support helps us to stay editorially independent
What is vitamin C serum?
Vitamin C serum is a skincare product containing either vitamin C or a vitamin C derivative that is applied directly to the skin.
What does vitamin C serum do?
Strong clinical research, such as this 2017 review study, supports using vitamin C (specifically L-ascorbic acid) in skincare. However, effectiveness depends on the formula's stability and Vitamin C concentration.
When applied to the skin, Vitamin C can provide various benefits to skin health and overall appearance, including:
- Acts as an antioxidant that can neutralise free radicals caused by UV radiation and pollution, which can help to prevent premature ageing of the skin
- Stimulates collagen production, helping maintain skin firmness, hydration, and elasticity.
- Reduces hyperpigmentation by inhibiting enzymes that cause melanin production
How and when to use vitamin C serum
Ideally, apply vitamin C serum in the morning for daytime protection. However, you can use it at night if a morning application doesn’t fit your daily routine.
Vitamin C serum works best when applied directly to clean, dry skin. For best results, we recommend the following sequencing:
- Cleanse and dry your face
- Apply vitamin C serum
- Wait a few minutes for the serum to absorb into the skin
- Apply moisturiser (and sunscreen if required)
Vitamin C works best at an acidic pH, so if you use an alkaline cleanser, wait a few minutes after cleansing before applying your Vitamin C serum.
Vitamin C can irritate the skin, causing stinging and redness. This is particularly common for users with sensitive skin.
If you're prone to skin sensitivity, we recommend starting slowly: apply it every other or every third day; use a low-concentration product first (5%-10%), and, if possible, start with a derivative such as ascorbyl glucoside before using a product with L-ascorbic acid.
Do LED masks really work? – get our expert assessment of what the science says on LED masks and anti-ageing, and which masks have impressed in our tests so far
What to avoid using with vitamin C serum
It’s generally fine to use Vitamin C serum with other skincare products. You can use products containing ferulic acid, hyaluronic acid, niacinamide, and vitamin E alongside vitamin C serums.
Generally, it’s advisable to take care with Vitamin C and retinols, though; use vitamin C in the morning and retinols at night.
Vitamin C provides protection and works best during the day, while retinol primarily renews the skin, so it makes the most sense to use it at night and let it work overnight.
Vitamin C and retinol can both irritate the skin, so spacing them out throughout the day reduces the risk of adverse effects.
Products containing benzoyl peroxide should not be combined with vitamin C serums. Benzoyl peroxide oxidises vitamin C serum, making it ineffective.
Copper is also incompatible with vitamin C, so it is best used in the evening at a different time from any vitamin C products.
Read more of our independent vitamin supplement reviews, including the best multivitamins, best vitamin D supplements and best vitamin B12 supplements
How to store vitamin C serum
Vitamin C is famously unstable. Sunlight, oxygen and extreme temperatures can cause it to oxidise and lose effectiveness.
New, unopened vitamin C serum should be clear or clear with a hint of yellow; as it oxidises, the serum will gradually turn yellow, then orange, and finally brown. Once your serum turns a dark brown, it’s generally safe to assume that it has lost all effectiveness and should be discarded.
Some vitamin C types are more stable than others. L-ascorbic acid is sometimes called 'pure vitamin C' and is less stable than its derivatives.
You can't prevent vitamin C serum from oxidising once opened; in fact, even sealed vitamin C serums oxidise over time. However, you can slow down the process by keeping the bottle sealed when not in use and storing it in a cool, dark place.
Most vitamin C serums are formulated to remain relatively stable at room temperature; however, storing L-ascorbic acid products in the fridge can slow oxidisation.
What you need to know about vitamin C derivatives
Depending on the product, a serum will contain either L-ascorbic acid, sometimes referred to as 'pure vitamin C ', or a derivative.
L-ascorbic acid is often used in serums because it has the most evidence supporting its effectiveness. It's also potent, so users can see results fairly quickly. The trade-off is that it works at a more acidic pH than human skin, so those with sensitive skin or irritation may find it too harsh.
Fortunately, several vitamin C derivatives are available, including Ascorbyl Glucoside and Sodium Ascorbyl Phosphate. Derivatives are generally gentler than L-ascorbic acid and tend to work at a pH closer to that of your skin. This means that they can be gentler for those prone to skin irritation.
Derivatives aren't as potent as L-ascorbic acid, so they tend to work more slowly and may not tackle particularly dark hyperpigmentation.
Is a higher vitamin C concentration better?
Not necessarily; the ideal concentration depends on several factors. While higher concentrations can work faster, the overall formulation, pH, and the user's skin type all matter when choosing the ideal vitamin C serum.
Plus, while higher-concentration vitamin C serums work faster, they are also more likely to irritate sensitive skin. Those prone to rashes and irritation should use a gentler derivative or start with less than 10% L-ascorbic acid and incorporate it into your routine slowly.
Our vitamin C serum experts
Expert insider: our cosmetic chemist
We’ve worked with a senior cosmetic chemist to develop our assessment framework for vitamin C serums and to analyse and rate each one.
We are keeping the identity of our expert anonymous to help maintain the independence of our recommendations.
They are an independent consultant specialising in skincare formulation and regulatory support, with a master's degree in chemistry and years of experience developing products for mass-market and luxury brands.
James Aitchison, Which? senior researcher and writer
James has more than 10 years of experience as a product tester and editor. He has worked as a managing editor for health, lifestyle and home at Reviewed and USA Today.
At Which?, James is a senior researcher and writer in our health and wellbeing team, focusing particularly on skincare testing for our magazine and website. He worked closely with our external expert, independent labs and science team for many months to develop our Vitamin C serum test.
As well as vitamin C serums, he is currently testing out sleep aids, LED masks and collagen supplements