Review: COSRX Pure Fit Vitamin C Serum

Where to purchase: Available on the COSRX Website HERE

Price: £23

Volume: 20ml 

Made in: South Korea

What is it?: 23% pure vitamin C serum – works as an antioxidant + helps brighten one’s skin tone. Also helps to reduce the appearance of dark spots + fine lines.

Brand Description: A product formulated with ingredients to increase the stability and efficacy of vitamin C i.e. instead of water this contains 60% Propolis to ‘avoid’ any dryness caused by vitamin C. This also uses Aronia melanocarpa fruit extract + Buckthorn extract to help reduce irritation in the skin. This product aims to reduce redness while brightening the skin.

Supposedly Good for: There’s not a specific skin type group COSRX state this is aimed for.

What I think: Dry + Oily Skin types (especially oily/combo as this is lightweight) could use this. I do not recommend this for sensitive skins. I think sensitive skins, especially those with cracked skin or open wounds on the face (like raw active pimples/acne) would find that this product stings in that area for ages (i.e. the stinging doesn’t go away even after the product has absorbed etc) I would recommend a derivative Vitamin C as they could be gentler, or a lower % Vitamin C like the Stratia C+C Serum or Geek and Gorgeous Vitamin C (not my fav texture however) or any derivatives from the Ordinary (if your aim is to just brighten the skin)

Note – I did not refrigerate my Vitamin C hence why it oxidised so quickly (this was during the summer!) But it took nearly 2 months to get to this stage.

I would like to explain that this product oxidises within 2 months. I didn’t put it in the fridge which means it turned very quickly. Which is a shame and I worry that it’ll be a waste of money for some people, to have to use a product so quickly. I also just find it very finnicky to have to put a product in the fridge, and not everyone has a skincare fridge to easily pop things into. I also think it really doesn’t help that the packaging doesn’t accommodate for air exposure. I think if you’re going to have a high % vitamin C then you’ve got to put it in better packaging to slow down the oxidation process. I find it so hard to get through a serum in 2 months unless I use it every single day AND I apply a lot. And because this serum was quite irritating for me (Cosrx state if you are sensitive, use this every other day) then using this serum every other day would make me take longer to use the product up, and therefore – it reached full oxidiation before I was halfway through it.

Vegan?: No (due to the propolis)

Cruelty Free?: Yes

Packaging: Plastic droppper and plastic bottle

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Directions: ”After opening, replace the cap with the provided dropper + Apply two to three drops onto clean skin, avoiding the eyes” (from the COSRX website)

How I use it: I apply it straight after my Argireline Solution in my PM routine. If I did use this in my AM routine, I applied it right after cleansing, just before SPF.

Key Ingredients: 23% Ascorbic Acid (Not a derivative so this is potent stuff!) and Propolis extract (used to soothe, moisturise and replaces water). Aronia Melanocarpa Fruit Extract – an antioxidant. Sea buckthorn extract – skin conditioning. Sodium Hyaluronate – humectant. Allantoin – soothing.


Full Ingredients: Propolis Extract, Ascorbic Acid, Aronia Melanocarpa Fruit Extract, Hippophae Rhamnoides Extract, Butylene Glycol, 1,2-Hexanediol, Sodium Lactate, Water, Cassia Obtusifolia Seed Extract, Sodium Hyaluronate, Allantoin

NOTE: The Incidecoder have a full ingredient breakdown HERE

I like the ingredients, it’s just the packaging used to shelter these ingredients renders the product unable to stay fresh for so long and potent for so long.

Texture: It’s not sticky, it’s not thick or gloopy (it’s thinner than the geek and gorgeous vitamin C serum, thinner than the Skinceuticals CE Ferulic, thicker than the timeless C E Ferulic (HERE). It runs down the hand easily and also can be patted into the skin without feeling sticky. Layerable too. doesn’t feel heavy on the skin. I like that propolis feeling as it’s not sticky (Check my Propolis serum review from by Wishtrend)

You can see it already was oxidising, so the yellow is very obvious. But in terms of the texture, this is watery and lightweight, you can see it’s threatening to run down my hand.


Oily skins would very much like this texture because it’s not greasy, sticky, heavy or gloopy. It’s lightweight and has that propolis, serum-like, near watery texture. You can see this spreads on the hand easily and is lightweight / watery looking.


YOUTUBE VIDEO! – SWATCHING the Vitamin C Serum along with the Retinol and Vitamin E Serum by COSRX

Hope you enjoy watching!

Fragrance?: No added fragrance! and No essential oils – and I don’t get strong/harsh smells from this

Good Under Makeup?: Seems to be fine! (Not sticky or greasy)

How long have I been using this?: I had the bottle in the cupboard for a month before opening it and using it (I shouldn’t have done that and I should have kept this in the fridge – but I just can’t be bothered to refrigerate my skincare). So once I started using it, the product had already begun to turn yellow (you’ll see what it looks like in the Youtube video above, when it started to oxidise). And how yellow the product is in the pictures is what it looked like a month after opening and using in my routine.

The Effect?: I couldn’t use this for long enough (before this oxidised fully, which took 2 months or just over) to use the whole bottle and only got to just under halfway. I’m sure a high % like this would definitely improve the tone and brightness of the skin (I don’t doubt the effect) – my issue is that I couldn’t even get to the end of this product or use this for a long time to see the effect. I only got the immediate effect which, definitely this is a decently hydrating product, but my skin is sensitive – so I felt stinging when applying this. and the stinging didn’t seem to go away even after rubbing in / absorbing. So it was hard to feel encouraged to use this every day.

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2.00 £

What I like:

  • NOT a sticky texture (even I apply a lot, unlike the Geek and Gorgeous Vitamin C…)
  • Layerable
  • Relatively hydrating formula (doesn’t dry my skin out or evaporate)
  • I like the use of propolis instead of water (I personally just like the feel of propolis and how it goes on my skin)
  • I like that they tried to add ingredients to try and reduce irritation and also soothe the skin
  • Not Scented / Fragranced

What I don’t like:

  • If I have a nick in my face or any sensitive areas, this stings. And even non-sensitive but possibly dry areas (like the skin around the nostrils) – can feel irritated/sting, and continue to sting while the product is on.
  • Oxidised so fast (didn’t manage to reach the end of the bottle!)
  • Packaging doesn’t help slow down the oxidation process

Overall Rating and Conclusion: 2/5 – From what I’ve gathered, 15% L-AA is an absolute fine % in order to be a good antioxidant, and a higher % doesn’t necessarily mean better. Personally, I have very easily sensitised/irritated skin and this high % of vitamin C seems to be too much for me. It tingles, it stings and my skin never seemed to get used to it. And the irritation put me off using this, when I can use a 15% serum and still get good results.

Also, I’m really disappointed in how fast this product oxidised. Now I know that I definitely should have put the bottle in the fridge, but I have used pure LAA products that were in dropper bottles which I did not put in the fridge, and still lasted longer than this product.

The best one was the Timeless C E Ferulic which did also sting because the % was high, but at least they understood to formulate the product with a better preservation system to keep the product fresh for as long as possible (Review HERE). And also the Geek and Gorgeous Vitamin C Serum (15%) in a glass dropper, although faster at oxidising than the Timeless C E Ferulic, was less stingy (however definitely thicker and uncomfortable if too much is applied to the skin). I did really like the replacement of water with propolis – I thought that was a nice touch and was unique. I like propolis as an ingredient and the texture of it (good for oily, acne prone skins).

I think this product would be much better in better air-excluding packaging to make it last longer. And perhaps if COSRX reduced the % of vitamin C, to a good and effective 15% – more people would be able to use it (i.e. those with sensitive or easily irritated skins). But the texture was nice (definitely a nicer texture than the Skinceuticals C E Ferulic i.e. doesn’t ball / pill up and layers fine under skincare/makeup and also better in texture (thinner) then the Geek and Gorgeous vitamin C Serum, and I like the added ingredients to help improve the skin i.e they didn’t simply put vitamin C in a bottle, they tried to add some other skin-beneficial ingredients, which I appreciate.

Would I purchase?: No – the % was too high for my skin and it oxidised too fast for my liking

Dupe?: The Timeless 20% Vitamin C (Review HERE) or the Geek and Gorgeous Vitamin C Serum (Review HERE) Which is my fav out of the dupes? I did really like the texture of the timeless serum (because it’s not sticky like the other serums), but does contain alcohol.

My Skin Type: I am acne prone and have slightly dehydrated combo skin. My skin is usually tight where the cheeks and eye area is and the outer parts of my face. My T zone is oily. My skin isn’t a fan of thick/heavy formulas so I opt for lightweight formulas to prevent it from clogging up. My skin doesn’t like essential oils either and I try to avoid fragrance when I can.

Disclaimer: I am a skincare enthusiast and not a skin expert. I am not qualified to give out dermatological advice. This type of advice should only be given by a medical practitioner. Upon trying / using any of the reviewed products on the blog, please follow the manufacturer’s instructions and warnings and please seek medical advice if needed.


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