Are They Dupes?: Drunk Elephant C-Firma Day Serum VS Paula’s Choice C15 Super Booster

Last Updated on November 26, 2025 by Giorgia Guazzarotti

If you’re a regular here, you know Paula’s Choice C15 Booster is my fave vitamin C serum. I dig the lightweight texture, the bright glow it gives my complexion, and… it doesn’t break the bank (girl’s gotta eat, too). I’ve never thought I’d strayed. Why fix it if it ain’t broken, right?

So, when Drunk Elephant finally launched in the UK, I thought I’d try their C-Firma Day Serum for kicks and go back to my beloved C15 Booster once the tube ran out. Well, the tube’s almost run out and I’m not sure I want to go back. If there’s one serum that can give Paula’s Choice C15 Booster a run for its money, it’s Drunk Elephant C-Firma Day Serum. Question is, are they really dupes? Here’s how they compare:

What Ingredients Do Paula’s Choice C15 Super Booster and Drunk Elephant C-Firma Day Serum Have In Common?

VITAMIN C TO FIGHT WRINKLES AND BRIGHTEN SKIN

Both Drunk Elephant C-Firma Day Serum and Paula’s Choice C15 Booster have the same active ingredients: 15% ascorbic acid + 1% vitamin + 0.5% ferulic acid. Let’s focus on ascorbic acid for now. Ascorbic Acid is the pure form of vitamin C. It’s the most powerful. And the most unstable. I’ll explain what that means in a while. Let’s start with the positives. Ascorbic acid is an anti-aging superstar that:

• Fights the free radicals that give you wrinkles
• Boosts the production of collagen, the protein that keeps skin firm
• Reduces transepidermal water loss, helping to keep skin hydrated 
• Brightens skin and fades away hyperpigmentation

The catch? It’s unstable, meaning it goes bad quickly when exposed to light and air. Both brands packaged it in opaque bottles/tubes that keep it away from its natural enemies and extend its shelf life. Still, even with the right protective packaging, ascorbic acid doesn’t last you too long. These serums aren’t something you can buy today and use in 6 months’ time. You buy a bottle and finish it as soon as you can.

P.S. It’s easy to see when vitamin C goes bad. It changes colour until it slowly turns brown. Not this time. Drunk Elephant C-Firma Day Serum is a light orangey in colour. It’s the antioxidants in the formula that give it that colour. It’s not a sign that it’s gone bad before you bought it. Phew!

Related: My Vitamin C Serum Has Turned Brown! Can I Still Use It?

VITAMIN E AND FERULIC ACID TO FIGHT PREMATURE AGING

You can totally use vitamin C alone. But I don’t recommend it. Like all antioxidants, vitamin C works way better when it can play with its antioxidant friends. Its BFFs are vitamin E and ferulic acid.

A study conducted by Duke University has found that adding ferulic acid “into a topical solution of 15%l-ascorbic acid and 1%alpha-tocopherol improved chemical stability of the vitamins (C+E) and doubled photoprotection to solar-simulated irradiation of skin from 4-fold to approximately 8-fold as measured by both erythema and sunburn cell formation. This combination of pure natural low molecular weight antioxidants provides meaningful synergistic protection against oxidative stress in skin and should be useful for protection against photoaging and skin cancer.”

Translation: vitamin C + vitamin E + ferulic acid boost one another’s effectiveness and the protection your sunscreen gives you. Both Drunk Elephant C-Firma Day and Paula’s Choice C15 Booster have vitamin E AND ferulic acid, so you’re all covered here. But Drunk Elephant goes the extra mile. C-Firma Day Serum also has licorice, green tea and other antioxidants that can supercharge vitamin C.

Related: Why Your Vitamin C Serum Should Contain Ferulic Acid Too

What Else Is In Paula’s Choice C15 Booster And Drunk Elephant C-Firma Day?

DRUNK ELEPHANT C-FIRMA DAY

• Water/Aqua/Eau: It’s just water, plain old water, and it’s in here because you need something wet to mix all the powders and oils together or else you’d just have a big pile of dust.
• Dimethyl Isosorbide: This helps push the vitamin C deeper into your skin instead of it just sitting on top like when you spill juice on the table and it doesn’t soak into anything.
• Laureth-23: This makes water and oil actually mix together instead of staying separate like when you see oil floating on top of soup, because skincare has both watery ingredients and oily ingredients and they need to become friends.
• Glycerin: This grabs water out of the air and puts it in your skin so your face stays soft and bouncy instead of getting all dry and flaky like when you stay in the bath too long and your fingers get pruney.
• Lactobacillus/Pumpkin Ferment Extract: They took pumpkin and let it ferment with good bacteria (like how milk turns into yogurt) and now it calms down red angry skin and makes it less irritated.
• Sclerocarya Birrea Seed Oil: This is marula oil from an African tree and it’s really moisturizing, makes your skin super soft, and doesn’t clog your pores or make you break out.
• Dipotassium Glycyrrhizate: This comes from licorice root (the plant, not the candy) and it’s amazing at calming down redness and irritation, like when your skin is freaking out and you need it to chill.
• Glycyrrhiza Glabra (Licorice) Root Extract: More licorice root stuff that calms redness but also fades dark spots over time so your skin color looks more even everywhere.
• Vitis Vinifera (Grape) Juice Extract: They squeezed grapes and put the juice in here because grapes have tons of antioxidants that protect your skin from getting damaged and aging faster.
• Phyllanthus Emblica Fruit Extract: This is from a sour Indian fruit called amla that has a buttload of vitamin C in it, so it brightens your skin and protects it from pollution and UV rays.
• Camellia Sinensis Leaf Extract: This is literally just green tea, the drink, and it has antioxidants that calm down irritation and fight the things that make your skin age and look tired.
• Lactobacillus/Punica Granatum Fruit Ferment Extract: They fermented pomegranate with good bacteria and it brightens your skin while protecting it from damage and keeping everything balanced.
• Propanediol: This is a moisturizer that also makes the texture feel really smooth and nice when you rub it on instead of sticky or greasy.
• Gluconolactone: This gently dissolves dead skin cells sitting on top of your face without scrubbing or being harsh, so fresh new skin shows up and you look glowy.
• Sodium Hyaluronate Crosspolymer: This is a special version of hyaluronic acid that makes like a little net on your skin that traps water and won’t let it escape.
• Sodium Hyaluronate: This is hyaluronic acid and it holds a crazy amount of water (like 1000 times its own weight) so it plumps up your skin and makes it look juicy instead of deflated.
• Oryza Sativa (Rice) Bran Extract: This comes from rice and it brightens your skin while evening out your skin tone and keeping everything moisturized.
• Glutamylamidoethyl Imidazole: This protects your skin from pollution and UV damage, basically like putting an invisible shield on your face so bad stuff can’t hurt it as much.
• Tetrahydrobisdemethoxydiferuloylmethane, Tetrahydrodemethoxydiferuloylmethane, Tetrahydrodiferuloylmethane: These are all related to turmeric (that yellow spice) and they fight inflammation and aging but they won’t turn your face yellow like actual turmeric would.
• Pentylene Glycol: This moisturizes your skin and also helps keep bacteria from growing in the bottle so the product doesn’t go bad.
• Caprylhydroxamic Acid: This is a preservative made from coconut oil that stops bacteria and mold from growing in your product so it stays safe to use.
• Leuconostoc/Radish Root Ferment Filtrate: They fermented radishes to make a natural preservative that keeps the product fresh without being harsh or irritating.
• Sorbic Acid: This is a preservative that’s in lots of food like cheese and juice boxes, and it stops mold and yeast from growing in the product.
• Phenoxyethanol: This preservative kills bacteria so your product doesn’t turn into a science experiment with gross stuff growing in it.
• Sodium Benzoate: This is the same preservative in your juice box that keeps it from going bad, and it does the same thing here by stopping bacteria and mold.
• Caprylyl Glycol: This moisturizes your skin and helps the preservatives work better so the product lasts longer without going funky.
• Chondrus Crispus (Carrageenan) Extract: This comes from seaweed and it thickens the product so it’s not super runny, plus it moisturizes and soothes your skin.
• Ethylhexylglycerin: This makes your skin feel really soft and smooth and it helps the preservatives do their job better so everything stays fresh.

PAULA’S CHOICE C15 SUPER BOOSTER

• Aqua/Water/Eau: Literally just water, the exact same stuff that comes out of your tap, and it’s the base that makes everything else liquid enough to actually spread on your face instead of being a weird crusty powder sitting in a jar.
• Glycerin: This thing is like a moisture sponge that pulls water from the air and shoves it into your skin so your face stays soft and doesn’t turn into that dry flaky mess you get in winter when the heat’s blasting.
• Ethoxydiglycol: This is the delivery guy that actually gets the vitamin C to penetrate into your skin instead of just sitting on the surface like when you put lotion on but don’t rub it in and it just stays greasy on top.
• PPG-26-Buteth-26: This makes all the different types of ingredients actually mix together properly so you don’t end up with that gross separation where oil floats on top like when you leave Italian dressing sitting for too long.
• Mannitol: This babysits the vitamin C and keeps it stable so it doesn’t oxidize and turn orange and completely useless halfway through the bottle, which is what happens with cheap vitamin C products.
• Tridecapeptide-1: This is a peptide that basically sends messages to your skin cells telling them to make more collagen. The only proof it works comes from the manufacturer.
• Palmitoyl Tripeptide-5: Another peptide that tricks your skin into thinking it’s damaged so it starts pumping out collagen to “repair” itself, which reduces wrinkles and makes everything look firmer even though nothing’s actually wrong. At least, that’s what the manufacturer says.
• Ergothioneine: This is a hardcore antioxidant that protects your skin from all the crap floating around outside like pollution, cigarette smoke, and UV rays that are constantly trying to age you faster and give you wrinkles.
• Sodium Hyaluronate: This is hyaluronic acid in salt form and it can hold like a thousand times its weight in water, so it plumps up your skin from the inside and makes fine lines look less obvious because everything’s all juicy and hydrated.
• Pentylene Glycol: This adds a bit of hydration but its main job is helping preserve the product so bacteria doesn’t start throwing a rave in your bottle and turn your expensive serum into something gross.
• PEG-40 Hydrogenated Castor Oil: This forces ingredients that normally hate each other (like oil and water) to get along and mix nicely, plus it helps active ingredients like vitamin C actually penetrate deeper into your skin instead of bouncing off.
• Bisabolol: This comes from chamomile flowers and it’s super soothing, so when the vitamin C is being harsh and irritating your skin (which it can do), this calms everything down and stops your face from turning red and angry.
• Sodium Gluconate: This grabs onto any metal ions floating around in the water (like iron or copper) that could react with the vitamin C and make it break down faster, so it keeps everything stable and working longer.
• Decylene Glycol: This gives you a little bit of moisture and also backs up the main preservatives to make sure absolutely no bacteria or mold can grow in there and ruin everything.
• Oryza Sativa (Rice) Bran Extract: This comes from the outer part of rice grains and it’s loaded with antioxidants and vitamins that brighten your skin and even out your complexion so you don’t have random dark patches everywhere.
• Polyacrylate Crosspolymer-6: This is a fancy thickener that makes the serum feel smooth and luxurious on your skin instead of watery and runny like it’s gonna drip everywhere when you’re trying to apply it.
• 1,2-Hexanediol: This fights off bacteria to keep the product fresh and also improves the texture so it feels nicer when you’re smoothing it on instead of sticky or weird.
• Panthenol: This is provitamin B5 and it’s crazy moisturizing and soothing, plus it helps your skin barrier repair itself faster when it’s been damaged by harsh ingredients or environmental stress or you picking at your face.
• Sodium Phytate: This is another ingredient that catches metal particles that could mess with the vitamin C and make it oxidize, so it’s like extra insurance that your serum stays potent and doesn’t turn into useless brown liquid.
• Sodium Hydroxide: This adjusts the pH of the formula because vitamin C only works at a specific acidity level, so if the pH is off then you’re basically rubbing expensive water on your face that does nothing.
• Citric Acid: This comes from citrus fruits and it helps fine-tune the pH to that perfect vitamin C sweet spot, plus it’s a mild acid that gently exfoliates dead skin cells so your face looks fresher and brighter.
• Phenoxyethanol: This is a preservative that kills bacteria and prevents mold from growing in your serum, because without it your product would turn into a science experiment within like two weeks of opening it.

WHICH FORMULA IS BETTER?

Drunk Elephant C-Firma Day and Paula’s Choice C15 Booster share the same active ingredients. If it’s the benefits of vitamin C only you’re after, it doesn’t matter what you pick. BUT, there are 3 key differences between them that may swing the balance in favour of one of them – depending on your particular needs:

• Lighter texture: Drunk Elephant C-Firma Day Serum feels a little sticky on. Paula’s Choice C15 Booster has a lighter texture that absorbs more quickly.
• Hydration: Paula’s Choice C15 Booster is loaded with humectants (like glycerin and hyaluronic acid) that hydrate skin by drawing moisture in from the air. Drunk Elephant C-Firma Day Serum uses humectants AND marula oil (hence the sticky feeling) to attract moisture to the skin and lock it in.
• Simple formula: Drunk Elephant C-Firma Day Serum has more antioxidant and moisturising ingredients than Paula’s Choice. That’s both good and bad. More goodies equal more benefits. But the more ingredients you add to a formula, the higher the chance one of them will irritate your skin. If yours is sensitive, use products with the least number of ingredients possible.

Related: What The Heck Are Humectants And What Are They Doing In Your Skincare Products?

What’s The Texture Like?

Paula’s Choice C15 Booster is super lightweight and runny, like almost watery but not quite, and it just melts into your skin the second you put it on without leaving any residue or stickiness behind. You know how some serums just sit there on your face for like five minutes while you’re waiting for them to sink in? Yeah, this isn’t one of those, it’s gone immediately and you can move on with your routine without waiting around.

Drunk Elephant C-Firma Day is a completely different story though, it’s way thicker and has this slightly tacky feeling that hangs around for a bit after you apply it. Some people don’t mind that but if you’ve got oily skin and you’re already dealing with shine, this texture might drive you absolutely nuts because it’s not the most elegant finish. It’s not like disgustingly sticky or anything but there’s definitely a tackiness there that you notice, especially if you’re trying to layer other products on top or you’re rushing through your morning routine before work.

What’s The Packaging Like?

Paula’s Choice C15 Booster comes in this clean white bottle with orange accents (because apparently all vitamin C products are legally required to have orange on them somewhere) and it’s got a dropper applicator which is pretty standard for serums. The dropper makes it easy to control how much product you’re using so you’re not accidentally dumping half the bottle on your face, and you can just squeeze out exactly what you need. Some people love droppers, some people think they’re annoying and unhygienic because you’re sticking the dropper back into the bottle after it touched your face, but that’s a whole other debate.

Drunk Elephant C-Firma Day also comes in a white bottle but with an orange cap, keeping that vitamin C orange theme alive, and it’s got a pump applicator instead of a dropper. Pumps are nice because they’re more hygienic since nothing’s going back into the bottle and contaminating your product, plus you can pump with one hand which is clutch when you’re half asleep in the morning. The downside is sometimes pumps dispense too much or too little and you can’t really control it as precisely as you can with a dropper, but honestly it’s not a huge deal either way.

How To Use Them

Use these bad boys in the morning after you’ve washed your face but before you put on sunscreen, because vitamin C actually boosts your sunscreen’s protection and helps defend your skin against UV damage and all the free radicals flying around from sun exposure and pollution. Basically vitamin C and sunscreen are best friends and they work better together than they do separately, so slap on your vitamin C serum first, let it sink in for like 30 seconds to a minute (or however long it takes, you don’t need to set a timer or anything), and then put your sunscreen on top.

Which Of The Two Should You Go For?

• If you have dry or normal skin, you’ll love Drunk Elephant C-Firma Day Serum. Marula oil makes it more moisturising for your skin type.
• Oily skin? The sticky texture of the Drunk Elephant serum will drive you crazy. Paula’s Choice C15 Booster is way lighter and hydrates your skin without adding more oil.
• Sensitive skin? Again, Paula’s Choice C15 Booster is the better choice (no pun intended!). It has a simpler formula that reduces the risk of irritation. Having said that, 15% ascorbic acid itself could be too much for your skin – use it in moderation.

Related: Can You Use A Vitamin C Serum If You Have Sensitive Skin?

Price & Availability

Drunk Elephant C-Firma Day Serum ($79.00): available at Cult Beauty, Sephora, SpaceNK and Ulta

Paula’s Choice C15 Super Booster ($55.00): available at Cult Beauty, Paula’s Choice, Sephora and SpaceNK

Is Paula’s Choice C15 Super Booster A Dupe For Drunk Elephant Day Serum?

I wouldn’t call Paula’s Choice C15 Booster an exact dupe for Drunk Elephant Day Serum. They have the same active ingredients, so both will give you all the benefits of vitamin C. But Drunk Elephant’s moisturising texture makes it more suitable for dry skin. Lighter and more hydrating, Paula’s Choice is a better option for oily skin.