Review: OST C20 Pure Vitamin C21.5 Advanced Serum

You may know that one of my favourite products from Wishtrend is the OST Original Pure Vitamin C20 Serum. I reviewed it previously, but I didn’t have any before and after pictures. Nevertheless, I was really impressed how the serum changed my skin and made it so much better in various aspects. When I saw that there was a new version of this I was most excited to try this new OST C20 Pure Vitamin C21.5 Advanced Serum. And, as you might guess I had high expectations for this serum. Could it hold up to them?

The brand OST or C20 is best known for the popular OST Original Pure Vitamin C20 Serum in it’s signature orange packaging and the brown bottle. This serum is highly effective in terms of using the peeling ability of ascorbic acid in order to improve the skin condition. Despite being effective, it had some minor cons, for example it was very sticky, it was too aggresive for people with sensitive skin and it contained some artificial ingredients. The new OST C20 Pure Vitamin C21.5 Advanced Serum has a completelly different ingredient list and as the name says, the amount of vitamin C serum has been increased, too. The original serum contained 20 % of Vitamin C whereas in the new formula you will have 21.5 %. Vitamin C is an antioxidant and thus can prevent our skin from aging too early. The content of Vitamin C in both serums compared to other vitamin C containing products is rather high. It contains 20 % (21.5 %) Vitamin C. You have to know that a high concentration of Vitamin C doesn’t mean automatically that it is more effective concerning anti-aging. Normally, a high concentration of Vitamin C aims at a visible effect, because it tends to operate as a peeling by loosening dead and old cells. This is not a bad effect and stimulates the skin to regenerate itself, but keep in mind that it won’t affect the inner cell layers of your skin which have to be aimed if you really want an anti-aging effect.

As with the previous serum the cardboard box comes with a lot of description in Korean and in English. It is very detailled in how to use it and what precautions to take. The new serum has even more details in English, than the previous packaging. The ingredient list of the new formula is very short. You can look them up on COSDNA and you’ll discover that the ingredients are safe to use and that there is no artificial ingredient either. The ingredients of the old serum were safe to use, too, but the list of substances is much longer as you can look up >>here<<. Since both products contain Vitamin C they have to be stored in a cool place. They also do have to be protected from sunlight, in order to prevent the vitamin C from oxidizing. When I received the product the manufacturing date was really fresh, which is important for vitamin c products, too, because they have a short shelf life. Usually, I would recommend you to use it up as quickly as possible after opening.

You will find more information and detailled description about the serum on Wishtrend, too. The signature orange cardboard box contains a brown glass bottle and a separately packed dropper. You can simply exchange the lid of the bottle with the dropper after opening.

The dropper makes it very easy to take out the watery and runny product. The OST C20 Pure Vitamin C21.5 Advanced Serum has a clear color, which is also a sign that the vitamin C serum is fresh. If it turns yellow the vitamin in the bottle has started to oxidize. The scent of the product reminds me a bit of oranges, but with a different scent combined, which I cannot figure out. The scent is not strong and doesn’t linger on the skin, so it doesn’t matter anyways.

I’ve been using the OST C20 Pure Vitamin C21.5 Advanced Serum for 3 weeks now in the evening and on most days in the morning, too. When used during daytime keep in mind to use a sunblock, too! Below you can see how the serum effected my skin.

I had some redness, when I started to use the serum. After 3 weeks the pictures show that the redness has decreased and I could feel that my skin is smoothened. Apart from this I didn’t experience any changes in my skin structure. I used this serum in combination with the Klairs Moisture Rescue Kit I reviewed previously. I used it after the Klairs Supple Preparation Facial Toner and the Klairs Rich Moist Soothing Serum and before putting the Klairs Rich Moist Soothing Cream. Sometimes I mixed the cream with a few drops of the vitamin C serum instead. The Klairs products may have contributed in reducing redness, too. The OST C20 Pure Vitamin C21.5 Advanced Serum is definitively less sticky than the old formula, but it is still a bit sticky, which is why I still like it better mixed with some other product.

Did the new OST C20 Pure Vitamin C21.5 Advanced Serum fulfill my expectations? I’m not sure. Somehow I have the feeling that the old formula was more effective. I remember with the old formula, that I felt a stinging experience the first times I used it. I didn’t have any feeling like this for the new formula. Maybe, this new formula is better suited to sensitive skintypes than the old one. I could observe a decreased redness in my face, but I cannot assure that it is only due to the new vitamin C serum, but it will be a combination of my skincare routine as a whole. Maybe if I repurchased this serum I would go for the old version, just because I had the feeling it worked better for me (and to confirm my observation). I can recommend you to try this new formula of the C20 if you were unhappy with the previous ingredients. This formula is almost completely different and doesn’t contains any parabens or other artificial ingredients. It doesn’t contain alcohol either. The old formula does have some cons, like the extreme stickiness and the ingredients, but I would not claim that the new formula shows better results, even with a higher concentration of vitamin C. Both serum, the old and the new version can be purchased at Wishtrend. The old OST Original Pure Vitamin C20 comes with free shipping and retails for 14.99 US$ at the moment, which is really affordable for a vitamin C serum. The new OST C20 Pure Vitamin C21.5 Advanced Serum retails for 24.99 US$. Both bottles contain 30 ml. I made a post about the promotions from Wishtrend for March >>here<<. Also, keep in mind their friend-referral program: You can receive a 5 Us$ referral coupon if you use my invitation code 17939205 upon registration and you’ll receive this voucher immediately. There will be a specific field in your registration form called “friends invitation program” where you can put the code mentioned above. This way new customers can safe 5 US$ which is a great possibility to safe some money.

I shared this post with the Asian Beauty Blog Link Party! Feel free to check out the beautiful reviews presented in their threads:

Just as a short reminder: All products mentioned and reviewed on this blog are of my personal opinions. This product here was sent to me for reviewing purpose by www.wishtrend.com, which doesn’t influence me in providing my honest opinion on the products.