Dislike Serum

Review: C20 (OST) Original Pure Vitamin C20 Serum

10 November 2015


When my Obagi Vitamin C Serum bottle was nearly emptied out, I searched for a more pocket-friendly alternative and found this, C20 Original Pure Vitamin C20 Serum. Before I go on, can I just say that the name of the product is unnecessarily redundant and confusing. Previously, the brand was OST, but later (probably due to the widespread popularity of this serum), they changed the brand to C20. You know, putting it there twice just in case you forget that it’s C-2-0.

Anyway, yes. The serum. Compared to Obagi C10, this was twice the vitamin C concentration (20%), almost thrice the volume (30ml), but 1/3 the price?! Plus it’s extremely popular and well-received! Is this for real?

C20 Original Pure Vitamin C20 Serum

I use this serum the same way I used the previous serum – after toner, one drop on each area of the face (cheeks, forehead, nose+chin).

Of course, I also keep it refrigerated. Even many months after opening the bottle, the same light color is still pretty much preserved from the time I first opened it.


Light color = not oxidised = yay!
Crystals have formed though, probably because my fridge is too cold. However, the crystals do not affect the function of the dropper or serum.

I’ve been using this serum for several months now. I stuck with it every single day for the first month or so, but the interval slowly grew and eventually became just sporadic uses. The reason? I don’t enjoy using this.

The smell is fine (typical citrusy scent), and the texture is fluid and nice as well:


The problem is how it feels after application. The product description mentioned that users may experience “a slight tingling”.


Sure, most of the time, it’s “only” a prickly, uncomfortable feeling. But there were times (like when I have the occasional dry patch) when I felt like the acid was eating at my skin and searing the living lights out of it! You know the feeling of squeezing lemon juice over an open wound? Yeah, it’s the same feeling.

It also doesn’t help that this serum leaves the skin very sticky. Not cool at all. To be fair, the stickiness does disappear after layering other products over it, but ack. I don’t like the feeling, even for 15 minutes, which is the resting time required between vitamin C and other products.

My skin is generally softer and smoother when I use this, but otherwise, I didn’t really notice any lightening of skin tone or spots.


I really wanted to love this. Such an inexpensive serum with such high vitamin C concentrations and in such a big bottle!

However, the feeling of having my skin judged and then punished makes it a dread to use. I can almost hear the serum saying “WHY is your skin in such bad shape, huh?! THIS will show you! *acid sizzles* (what do you mean serums don’t talk?)

Having to endure pain and discomfort in the name of skincare? Sorry, tough love is not the way I roll.

This will probably work well for people with less sensitive skin (good for you guys!) but this is not for me. Alas, I will have to once again resume my search for a vitamin C serum! Please comment if you have suggestions! :)

Rating: 2/5



I bought it for $14.99 from Wishtrend (comes with free shipping too) Apparently, Wishtrend is also selling on Qoo10.sg and it’s on promotion for just S$11.50 right now!

Read the disclaimer regarding reviews here.

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  • Reply Kaeri 23 July 2016 at 11:40 am

    Hi Rin, for a long time I would have totally agreed with your review! Due to the internet hype I tried out the C20 and was not very impressed… It seemed like just any random enzyme peeling, leaving my skin softer for a day but that was about it. When I used it after a few months pause, it actually started the magic.
    The first use after a pause really stings for a minute, but the next day it so much worth it. My partner said I would look more rested than usual, so I looked in the mirror: My skin looked more radiant and healthy, even deep spots finally began to heal.
    However, I wouldn’t recommend to use it more often than 2 times per week as it can cause overly sensitive skin and redness when overdone.

    Also, you might want to try the newer C21.5. It’s almost non-sticky and the smell became better as well (the old one smelled metallic to me when oxidised… not nice); but maybe your skin simply doesn’t like vit C serums.

  • Reply Rin 26 July 2016 at 2:26 am

    Hi Kaeri, although I didn’t wait as long as a few months, I stopped and restarted using this product a few times, but it didn’t change much.

    And you might have seen me reference another vitamin C serum (obagi) in the first line of this post; my skin is fine when I use that vitamin C serum. Whatever the reason, it’s clear that rather than vitamin C serums, it’s just this product tha simply doesn’t work for me. Good that it works well for you though :)

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