C E Ferulic vs Phloretin CF: Which SkinCeuticals Serum Is Right for You?

C E Ferulic and Phloretin CF are both SkinCeuticals AM antioxidant serums, formulated under the brand's Duke Antioxidant Patent with pure L-ascorbic acid (vitamin C) and ferulic acid at their core. The difference is the third ingredient and the skin each is built for: C E Ferulic adds vitamin E for ageing, dry or sun-damaged skin, while Phloretin CF adds phloretin for combination, oily or discolouration-prone skin.

At a glance

The formulation difference

Both serums share the same backbone: a high concentration of pure L-ascorbic acid stabilised with 0.5% ferulic acid, formulated to the low pH (2.0–3.5) that vitamin C needs to penetrate skin effectively. That's where the similarity in actives ends.

C E Ferulic pairs its 15% vitamin C with 1% vitamin E (alpha tocopherol), a fat-soluble antioxidant that works alongside vitamin C to help counter oxidative stress from UV exposure, pollution and other environmental aggressors. It's the combination most associated with SkinCeuticals' original antioxidant serum and the one most often recommended for skin that's already showing visible ageing.

Phloretin CF uses a slightly lower 10% concentration of vitamin C, but adds 2% phloretin, a plant-derived antioxidant with a different mode of action, alongside the same 0.5% ferulic acid. SkinCeuticals positions phloretin as the ingredient that helps address discolouration and uneven tone, which is why Phloretin CF is the sibling serum aimed at combination and oily skin rather than dry, mature skin.

Who each one suits

C E Ferulic: ageing, dry, mature or sun-damaged skin

C E Ferulic is formulated for normal, dry and sensitive skin types, and is the pick most often reached for by anyone whose main concern is visible signs of ageing, such as fine lines, loss of firmness or dullness linked to years of sun exposure. Its lightweight, watery texture layers easily under moisturiser and SPF without adding extra richness, so it works well even on drier skin that still needs a daily hydrating step afterwards.

Phloretin CF: combination, oily or discolouration-prone skin

Phloretin CF is formulated for normal, oily and combination skin, and is aimed at anyone whose main concern is uneven tone, discolouration or early signs of ageing rather than dryness. Because the texture is just as lightweight as C E Ferulic but the formula leans on phloretin rather than vitamin E, it's the more common recommendation for skin that runs oily or is prone to sun-related pigmentation and post-blemish marks. If active breakouts, rather than the marks they leave behind, are your main concern, it's worth asking our team whether a different SkinCeuticals antioxidant serum built specifically for blemish-prone skin would suit you better.

How they work

Both serums work the same way in principle: pure vitamin C at an acidic pH helps neutralise free radicals generated by UV rays, pollution and other environmental exposure throughout the day, and ferulic acid helps stabilise the vitamin C so it stays active in the formula. SkinCeuticals states that once absorbed, both serums remain effective for a minimum of 72 hours, which is why once-daily morning application, rather than reapplication through the day, is the standard way to use either one. Neither serum is a substitute for daily SPF — they're designed to be used alongside sunscreen, not instead of it, and both are described by SkinCeuticals as working best as a step underneath a broad-spectrum sunscreen rather than as a stand-alone replacement for one.

The reason the two formulas aren't interchangeable comes down to what the third antioxidant is doing. Vitamin E in C E Ferulic is fat-soluble, which is thought to help it interact well with the skin's own lipid barrier, making it a natural fit for drier or more mature skin that's also managing barrier concerns alongside ageing. Phloretin, by contrast, is the ingredient SkinCeuticals credits with the discolouration-focused benefits of Phloretin CF, which is why that formula is positioned for tone and texture concerns rather than dryness or barrier support.

Texture and application

Both serums have a similar lightweight, fast-absorbing fluid texture that sinks in within seconds and leaves no tacky residue, so either layers comfortably under moisturiser and SPF. Both also carry the characteristic scent of concentrated L-ascorbic acid, which fades shortly after application. Some people notice mild tingling on first use of either formula, particularly if it's their first time using a high-strength vitamin C serum; this is a normal response to the acidic pH and tends to settle with continued use, but stop and patch test again if irritation persists.

Application order is the same for both: cleanse, apply a few drops of whichever serum you've chosen to dry skin, allow it to absorb for a minute or so, then follow with your usual moisturiser and, in the morning, sunscreen. Neither is formulated for PM use, so if you also use a retinoid or exfoliating acid at night, that step stays separate from your vitamin C morning routine rather than being combined with it.

Storage and shelf life

Vitamin C serums are sensitive to light, heat and air, all of which can cause the L-ascorbic acid to oxidise and the formula to discolour and lose potency. SkinCeuticals states Phloretin CF remains stable for 36 months unopened and up to 6 months once opened when stored correctly, away from direct sunlight and heat, with the cap kept tightly closed between uses. A noticeably darker, orange-brown colour change in either serum is a sign the formula has oxidised and is past its best, even if it's within its stated shelf life.

Price and pack size

Both C E Ferulic and Phloretin CF come in the same 30ml size and sit in the same premium price band within SkinCeuticals' range — current pricing is shown on each product page rather than repeated here, since it can change.

Can you use C E Ferulic and Phloretin CF together?

They're designed as alternatives rather than a stacked routine — both are AM antioxidant serums serving the same step in a morning routine, so using both back-to-back isn't necessary and can mean applying more L-ascorbic acid than your skin needs in one go. If you're unsure which formula suits you, our team can help you pick one based on your skin type and main concern rather than layering both.

C E Ferulic vs Phloretin CF: the verdict

Choose C E Ferulic if your skin is normal, dry or sensitive and your main concern is visible ageing, sun damage or loss of firmness. Choose Phloretin CF if your skin is normal, oily or combination and your main concern is uneven tone or discolouration. Both deliver the same core promise, a daily antioxidant layer under SPF, formulated for a different starting point.

If you're new to vitamin C serums altogether, our full reviews of C E Ferulic and Phloretin CF go into more detail on each formula, and our SkinCeuticals brand guide covers where these two sit within the wider range. For a broader look at vitamin C serums beyond this one brand, see our guide to the best vitamin C serums in the UK.

If you're pregnant or breastfeeding, please contact our team for advice before use.