[OST] Original Pure Vitamin C20 Serum : Review

8:17:00 PM Mei B 23 Comments

Hello Lovelies

I haven't updated for ages since I was busy with my final exams and other things (like Bigbang's comeback, which was the reason why I failed 2 exams and had to retake them T_T my life is a mess)... Anyways~

About 2 months ago (I guess?) I got my wishtrend order, and I was happy with it. (It takes 12~15 days for my orders to come from korea, but this one only took 9 days after being shipped out. Really fast innit?). I was originally on a no-buy period but.. I had to get my hands on the infamous OST Pure Vitamin C20 Serum that I'm gonna review today, and the Berrisom My Lip tint Pack in sexy red (You can check my review here)

Description and claims:

100% Pure vitamin for remarkable, healthy skin.
Original Pure Vitamin C20 Serum contains about 6,000mg of 100% Pure Vitamin C. It contains 20% concentration of L-Ascorbic acid, which maximize the benefits, and additional feature of peeling function. As natural antioxidants, it helps prevent premature signs of again, while it protects, softens, and moisturizes your skin. 

High portion of Vitamin C and still remarkably safe.
22.9% of Original Pure Vitamin C20 Serum is the real meaning of pure Vitamin C. One bottle of C20 serum contains vitamin c 40 times more than orange, 120 times more than strwberries and 200 times more than Mandarines. 

Proved Effectiveness.
Original Pure Vitamin C20 Serum not only offers whitening, exfoliation and pore care effect, but also helps smooth the rough area on your skin, caused by spots or acne breakouts, when used regularly or long term. After using the serum, research shows positive result on skin condition. Out of 2075 respondents, who used Original Pure Vitamin C20 Serum :
- 97.91% said, Skin looked brighter and more defined complexion.
- 96.00% said, The serum reduced unwanted skin pigmentation and blemishes.
- 92.20% said, Positive skin improvement after first usage.
- 86.52% said, The serum smoothen out uneven texture.
Source: Wishtrend

Volume: 30 ml


Water, Ascorbic Acid, Ethanol, Sodium Lactate, Butylene Glycol, Glucose, Camellia Sinensis Leaf Extract, Rosa Davurica Bud Extract, Carthamus Tinctorius (Safflower) Flower Extract, PEG-60 Hydrogenated Castor Oil Sodium Hyaluronate, Bis-PEG-18 Methyl Ether Dimethyl Silane, Diethoxyethyl Succinate, Ammonium Acryloyldimethyltaurate/VP Copolymer, Xanthan, PEG-180, Gluconolactone, Beta-Glucan, Citrus Aurantium Dulcis (Orange) Oil,Zinc PCA, Panthenol, Niacinamide, Glycerin, Tocopheryl Acetate, Lecithin, Caprylic/Capric Triglyceride, Ubiquinone, Diisopropyl Adipate, Phenoxyethanol, Methylparaben

How to use:

1) Apply after cleansing and toning. Use 2~3 drops and smooth in gently all over face (Especially smooth intensively the aged area such as pigmented or wrinkled lesions)
2) Initially, a slight tingling may be experienced. (a passing phenomenon)
3) Mixing with several drops of vitamin C20 and toner makes your skin refresh without being gooey.
4) After applying vitamin source C20, apply moisturizer is more effective. 


First of all, I wanna say that I'm in love with its orange box since I love orange and I love how it has that metallic effect (but unfortunately I couldn't catch it with my phone's camera)

The pics says everything lol, the only thing I would like to add is that you should make sure that the bottle stays in a vertical position, otherwise the product may leak out of it (like mine) and have an orange sticky mess inside of the box...

The serum: Swatches, scent...

The serum smells like burnt oranges, it has a light color (that oxidize later and turns into a yellow-orangish color)

As you can see, my serum's color changed a little bit since I opened it about a month ago, and because I was too careless to store it in the fridge and left it in my bedroom instead (note that the weather is effily hot in my city..) but it doesn't mean that the product isn't efficient anymore.

This serum is a bit thicker and stickier than the other serums, and takes a longer time to be absorbed. I usually use it directly after toning and leave it for about 30 min before the next step in my night routine (and since I started using it during spring, my night routine is often limited to cleansing+toning+serum only since my skin becomes a bit crazy during this time of the year, and I figured that the best solution is to leave it alone) this way I make sure it fully does its work since the ascorbic acid is easily influenced by the skin's pH, and it won't work if it's too high.
You may as well add it to your other skincare products if you want, but I personally prefer using it alone to prevent any unwanted chemical reactions.

And now let's move to the results... I believe that my skin loved it.

Remember when I said that my skin becomes crazy during spring? This is what I was talking about:

I didn't lie when I said that my skin loved it. The before Pic is the one I took right after using it for the first time (that's how awful my skin looks during spring...), and the other pic is how my skin looked after 20 days of using it regularly on daily basis. A big difference I know...
I can't judge if it reduced my blackheads since I have really tiny ones and use nose patches often (and my blackheads are still like they were the first day I started using this serum), and I don't think the it brightened my skin tone since I already have a fair skintone (I'm somewhere between NW10 and NW15).



- A really affordable price.
- Highly effective against acne and acne scars.
- Improves skin texture.
- Nice orange box (I love it what?) and packaged in a dark bottle to delay its oxidation.
- Contain a high amount of vitamin C (the higher amount I've ever seen in any serum)
- My skin tend to secrete a bit more sebum than usual, which is good for my dry skin.


- Leaked when the bottle is left horizontally.
- Sticky
- Tingles a little bit, but it's not really a con since it means that it's working right?

You can buy it:

OST Pure Vitamin C20 Serum retails for $14.99  at Wishtrend (use my invitation code: 125028803 to get $5 off your first purchase)

Would I repurchase it?

Sure. I've already ordered one for my brother, and I'm planning to purchase another one for me once I'm out of product (and maybe try this new formula since it seems really interesting.)


If you found this post helpful, don’t forget to share it on your favourite social media platform. Also don’t forget to follow me on social media to see what I’m doing and what I’m getting in the mail, and to follow up with my #Quick_Review s

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  1. You're lucky your skin didn't have a bad reaction like mine did.

    I'm happy for you :)

    Haha yes do influence your other family members to use korean beauty products!

    1. People spread the love and I spread how to give all your money willinglly to Sth Korea xD

  2. Hellooooo there?

    I just checked out this blog and yes this helped me! I just found out about this C20 serum things... and I was impressed by how magic it works for you!!! Oh my!!! I'm so envious with your clean skin... really...
    If you don't mind, I have question here. Do you think this serum will work for 18 years old girl?
    I mean I ever read once in a blog that usually young adults shouldn't wear serum? Because it might be too heavy?

    I really hope you'll answer me soon! Thank you so much to take your time reading this comment :)

    1. Aww thank you for the compliments and I'm glad my blog helped you ^^
      For the serum, I don't think it would have any negative effects on your skin as long as you use it correctly. Just start at first by using it one every 2 or 3 days, and then you can move into using it once a day (if you feel that it's better for you to use it once every 2 days, stick to it.)
      Personally I used it at 20yo, and then I passed it on to my brother who is 18yo as well, and he's doing just fine. His skin is brighter, his inflamed acne are healing fast and his old acne scars are fading as well.
      I hope it helped :)
      By the way I'm running a giveaway if interested ^^

    2. Hello again ^^

      First of all thank you so much for helped me! If you don't mind I have another question. Is it okay to apply my daily cream after I use the serum? I'm currently been using night cream given by dermatologist.

      I hope you'll answer me again soon!

      PS. I am joining your giveaway! I really hope to win because this is my very first time joining giveaway. SOOO excited ^^

    3. My pleasure dear ^^
      it's okay to use your daily cream as long as it doesn't contain niacinamide in it, just let the serum for about 30minutes until it's fully absorbed and the you can layer whatever products you are using.
      if it contains niacinamide, it's recommended to use them at different times.
      Good luck for the giveaway ;D

  3. this serum seems really interesting, but I have a question if you don't mind, do you think that it would work for me as well even though I have an extremely oily skin?
    thank you, and great blog again (:

    1. Yes it works for every skin type, but its stickiness might annoy you a little bit. If you don't like that sticky residue, try the upgraded version (21.5)
      And thank you for the compliments

  4. This is the first time I've read about a serum containing more than 15% of pure vitamin C, is it safe? And wow, I am genuinely amazed by the result you're getting from this serum and the best part is the price seems really reasonable too. Will check it out for sure.

    1. Well it improved my skin complexion a lot so I guess it's safe. Lemme know how your skin reacts to it yeah?

  5. Will this product be suitable for sensitive redness prone skin?

  6. As u can see in the poicture, I have sensitive redness prone skin myself and it suited me

  7. Will it help reduce pigmentTion as well ??

  8. Can this serum remove my dark patches on my forehead due to my hormonal imbalance after my pregnancy?do u encounter such case?

    1. I can't say if it does remove them or not since I don't know anyone who used it for such purpose

  9. Why we must apply sunblock after this serum if we use it during daytime?

    1. Vitamin C increases the skin's photosensibility, and thus you will burn much more easily (in addition to all these other sun harmful effects that would be more intense when your skin is weaker/photosensitive)
      A sunblock would block these harmful effects, and using a Vitamin C serum with sunblocks boosts its effect.
      By the way, you should use a sunblock whether you use vitamin C or not because the UV rays cause wrinkles, skin cancer, skin burns and all that jazz.

  10. I don't have refrigerator as I live in hostel will you please tell me how will I store it for long time?

  11. As I live in hostel I don't have any refrigerator please can you tell me how to store it for long run? Alternative?

    1. Hello Walia~
      Since it's winter now you don't have to keep it in a refrigerator, but during summer time if u don't have a mini bar or any other refrigerating thing, keep it in a drawer (in a somehow cold corner in your room) away from the sun rays and the heat (or even a box underneath you bed will do)

  12. After apply seruim night time can I apply my night whiting cream.

  13. After apply seruim night time can I apply my night whiting cream.