COSRX Pure Vitamin C 23% Serum with Vitamin E & Hyaluronic Acid, Brightening & Hydrating Facial Serum for Fine Lines, Uneven Skin Tone & Dull Skin, 0.7oz/20g, Korean Skin Care

I’ve seen a lot of improvement in my skins texture and tone over the past 3 months. My skin Is much softer and my freckles and dark spots have become less noticeable. The serum is oily and spreads easily. It does have somewhat of an odor (like bread). I think for the price it’s great product.

First time with this brand, but using Vit C serum for years.So far one of my favorites in the range of price. Smells uncomfortable fishy but that is the Vit C normal smell, after some seconds over the skin the smell is gone, and personally prefer this than any extra essence. The oil is pretty thin and absorbs immediately. Haven't had any reactions but I have quite of time with this VitC concentration. I like how my skin looks, give me a glossy renewed look every morning. Any result with dark spots or fine lines, but I realized that is normal aging and nothing to do with it lol, anyway my skin looks healthy and younger for my age. Totally happy with this brand in my second week of use.Update: one month of use and still love it!

(I reordered - so this will become a go-to product for me!)----I like the CosRx brand. It's one of my go-to brands along with Beauty of Joseon (such a gorgeous brand of skincare!, Belif (sometimes and some things), and Gangnam Glow, along with a few others. CosRX & BOJ are the two I have been reaching for more than any others, lately.This vitamin C isn't L-ascorbic acid but it is ascorbic acid--although sometimes there is confusion there if they are the same or not.The price like a lot of K-Beauty brands is very reasonable.I keep mine in the fridge. I have had vitamin C oxidize and when it does it's a waste of money since it's no longer effective when it turns orange. The color of your C should be light, like, well, like very hydrated pee - sorry, that's all I can think of to describe it! :) When it begins to turn orange, you should not use it. So refrigeration, or maybe if you use it within 3 months it may be okay.It does fizz when you open it. I've never had this happen with a serum. Kind of weird. As for the smell - well I have Parosmia from Covid a few years ago that I still have trouble with some scents and odors. I had a friend smell it and he said it smells like tuna, and that's what I thought - it smells like tuna smells to me with Parosmia. Not pleasant but it doesn't last. Also, keeping it in the fridge seems to make that smell not as bad, that or I'm used to it now.I use my C in a very specific way: I only use it in the mornings. I first cleanse my face (I use BOJ ginseng oil based cleanser), and then I will tone it with either Belif milky toner, BOJ ginseng essence if I'm using that as a toner that day, or CoxRx centella asiatica toner. Then I go do something - take my dog out, have some coffee - anything that takes about 20 minutes for the toner to absorb and my skin to be dry. Then I apply my vitamin C. I then let the C absorb by checking my emails or looking on Amazon or whatever - for 15-20 minutes. Then I go on with the rest of my skincare - serums, moisturizer, SPF if I am going to be leaving the house. I like to let each step absorb but I don't necessarily go the full 15-20 with the serums and moisturizers as I do the C.This does not irritate my skin. I did do a patch test as they advise. I put some on my inner arm, but I also put some along my right jawbone just on the bottom part of my cheek. I let that sit for hours until I knew it was okay.However, it is 23% and in hindsight I wouldn't go above 20%, especially with my rosacea prone skin. 20% is plenty high enough. 10% is on the lower end. So 10-20% is the 'sweetspot.' Just because I"m not reacting now, doesn't meant my skin won't be mad later. I try to use my lower concentrate from another brand sometimes instead of this.Vitamin C works well with and for my skin. I do like L-ascorbic acid products but really if you are using a retinoid (tretinoin) or some other stronger retinol, this products that aren't expensive work lovely.Would I order again? Probably will not. But I'd like to find a K-Beauty vitamin c that has ferulic acid along with the c, as this one does not.As with any skincare, you have to give it time. These things don't happen overnight. Consistency is key.

My skin feels amazing, used it just a couple of times and I can already see a difference. The only thing I did not like was the smells, smells awful but seems to be working great so far.

After showering on a Friday evening, I applied the serum to my face. The smell was absolutely disgusting, but I was prepared for that having read the reviews. I had no negative skin reactions. A couple of hours later I started to get a headache. I took some ibuprofen, put the heating pad on my head, and went to sleep. I woke up at 3am with a terrible headache and I felt nauseous. I want to note that I get frequent migraines and that this was not a migraine headache. It was a painful tightness all around the top of my head. Also, I realized that the heat from the heating pad was reactivating the smell of the serum on my face, which was really gross. When I finally tried to get up and move around at 7am it was awful. I felt like I had the stomach flu. Sweating, shaking, nauseous. And then I threw up. I really did think I was sick and didn’t even consider the serum until a few hours later. I talked to my sister and mentioned my thoughts about the serum. She suggested that I take a long hot shower to try and get it all off of me and to change my bedding. So I did, and by the end of Saturday I was feeling not 100% but so much better. I haven’t seen any other reviews that mention this type of reaction. I tried googling it too and found nothing, so obviously this could be some kind of weird coincidence that I got sick for a short time while trying to use this product. Either way, I’m too scared to try it again. The smell alone might make me sick anyway. Good luck!

Truth be told this is my 3rd purchased product from this skin line. I really enjoyed the other 2 product enough to purchase then for others as gifts or purchased a second round for myself! Sadly😞this product isn't that enjoyable. I have been wearing hyaluronic acid and vit C for years separately. So this seemed like I could simplify my routine on certain days. The product goes on fine... then stays sticky even after absorbed into your skin. My hair, random fuzz, and even my hand stick to my face after absorption. (Not ok with me!!) So with that it's not going to be purchases again. I will use it, but felt this sticky factor needed to be mentioned. I will say i really likes the fact they lid has a seal you have to break upon its initial opening. So I knew the content was un- tainted!

Friends, be grateful for this high quality Vit C serum. Of the countless Vit C’s I’ve tried, this smells, feels and produces results similar to the coveted Skin Ceuticals C serum, but without the price! Keep it in the fridge and use it daily. You’ll agree.

I don’t have any problems besides the smell. A very odd smell I had to come look at reviews to make sure it didn’t spoil…IDK ….. I just didn’t understand it. But the product itself is good and the smell is tolerable.