I just got my bottle but it causes no irritation. People who wrote bad reviews based on the fact that it makes a gas releasing sound are not reading the instructions which says that that is supposed to happen. Also it says that the bottle for that reason is not filled all the way and that is intentional. My bottle has plenty of product to last a while. I notice my skin looking a bit brighter and I have only used it twice!

I bought this product a few weeks ago and I was skeptical. Like many serums, how you apply makes a difference. When I first purchased, I would pour onto my face and rub in but saw little to no results in the first few weeks. After learning to pour into my hands, warm it up in with my fingers, and then apply by patting / pressing into my skin with the palms of my hands. Ive seen a radical difference in my skin once I changed to applying with this method. It’s super moisturizing and I’ve noticed my skin tone is getting clearer and softer. I don’t have a before photo but the attached photo is my skin after starting bottle number 2!

I can't say enough good things about this vitamin C serum! Not only does it effectively brighten my skin and reduce dark spots, but the addition of vitamin E and hyaluronic acid makes it incredibly moisturizing. My skin feels deeply hydrated and plump after each use, and the fine lines have noticeably diminished. The serum absorbs quickly and leaves my skin feeling smooth and refreshed, without any greasy residue. I've seen a significant improvement in my complexion—more even-toned and radiant. This serum has quickly become a staple in my skincare routine, and I highly recommend it to anyone looking for a multi-benefit serum that delivers visible results!

I've only used it once.That being said, it burns a tiny bit on a raw spot I have on my face and my face turned bright red! Otherwise it's OK. My redness faded quickly. It does smell like tuna. However the scent quickly dissipates. Very quickly. Especially if you put something over it, which you should. I dont like how it "dries" very sticky. Even after 5 mins my hand was still sticky. I applied snail mucin on top (as shown in my video) and it definitely lessened the sticky. Now it's soaked in a few hours, it feels nice.I notice a lot of reviews talk about the bottle only being half filled. It says in the little leaflet that is on purpose because of the ingredients used. When you open it there is a pressure release hiss. Like a soda bottle (as shown in my video) That is why there is lots of space in the bottle. If they filled it to the top that thing would burst from the pressure. And definitely spurt everywhere upon opening. I'm happy they didn't fill all the way up. I feel like this is going to be a good addition to my Cosrx family of product!