Serums are the new hot item in skincare and a must have in every morning and night routine. Many are now looking for serums that contain ingredients such as Ascorbic Acids like Vitamin C that will help even out the skin tone. Ascorbic acid serums are great for fading post acne scars, sun spots, pigmentation and even help to fight against acne.

Today, I will be comparing the new and improved OST C 21.5 Serum against another popular Vitamin C 20 serum. Let’s start comparing vitamin C ascorbic acid serums!




Ascorbic acid serums that contain high concentrates of vitamin C aren’t always the most pleasant to use. The number 1 issue being the texture of the serum being too sticky. Overly sticky serums block the absorption of additional layer skincare products and overall be uncomfortable and unpleasant to use.

You can tell how sticky a serum may be by seeing how thick the consistency of it is. As shown above, the “Other” serum is slightly more viscus then the OST C 21.5  Serum when shown traveling down a flat surface.





The second way to compare which product is more sticky is to apply any type of powder substance overtop of the applied serum.

In the above photo, sugar has be sprinkled over both serums after 3 drops of each have been applied to the skin. After shaking off the sugar powder, you can see the “Other” serum has more sugar stuck to it in comparison to the OST C 21.5 Serum.

So lets test out how these ascorbic acid vitamin c serums work on post acne scars and how they react on my skin.






I tested each serum out on opposite cheeks. I have post acne scars to see how my skin would react and how good the results would be after 10 days of day and night use.

On my first cheek with the most scars, I used the OST C 21.5 Serum. On the other cheek I used the “Other” vitamin c 20 ascorbic acid serum.


On this side of my cheek, the serum applied smoothly and absorbed quickly into the skin with s slight sticky texture that faded after 1 minute. When first applied, I felt a slight tingling and burning sensation. After a few seconds, the sensation went away. I then waiting 15 minutes before applying any additional product to make sure the serum was fully absorbing into my skin without being diluted.

Over the time span of 10 days, I did not experience any skin irritations. No hives, no itching, no burning and no redness. My skin actually improved very quickly in only 10 days of use. The redness in my cheeks improved, my pores appeared tighter and my acne scars started to heal very quickly!

I was very shocked at how quickly this serum worked for me in comparison to the old OST C 20 ascorbic acid formula.




Based on my personal results with the serums, I would choose the OST C 21.5 Serum as it did not cause me any irritations and provided my skin with the results I was hoping for out of an Ascorbic Acid Serum.

The “Other” serum has great potential for the skin if it did not contain any irritating ingredients such as Fragrance which could have been what caused my skin to have a bad reaction.

The new OST Vitamin C 21.5 Advanced Serum is something I highly recommend to try in anyones skincare routine who is looking for an Ascorbic Acid Serum that is less likely to cause irritation and will improve the appearance of post acne scars and other skin pigmentation concerns.





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