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My Signature C Source



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CLAIM TO FAME: A best-selling serum that contains 40 times more Vitamin C than orange, 120 times more than strawberries, and 200 times more than mandarins

FAST FACTS: Packed with potent amounts of vitamins for beautiful, healthy skin; contains 6,000mg of 100% pure Vitamin C; helps prevent premature skin-aging; protects, softens and moisturizes skin; has 20% L-Ascorbic acid concentrate for gentle peeling and exfoliation

PERFECT FOR: Clearing out imperfections and dark spots

Note: Given the nature of Vitamin C, the serum may crystallize around the opening of the bottle. This does not alter the quality of the product.

Feb 29, 2016
”19, M, Oily Skin. This product is incredible. I have a lot of post acne scarring, general redness, and uneven skin; introducing C20 into my routine changed my face in a matter of weeks. I cant even really tell what it did- what I know is that my skin’s redness is much more subtle and that many of my imperfections have been smoothed. I put this on after cleansing and toning, and while I don’t know any of the science behind it, I feel like I can say that it helps all the next products i use become more effective. Make sure you wait 20 minutes after using it for best results.”
– Raynor14 (from amazon.com)

A cost-effective way to change your skin
Nov 4, 2015
”I started using this serum about a month ago and I have already seen big changes in my skin. I am in my mid-30s and suffer from Melasma and fine lines. After a month of use my skin texture is so much smoother and the Melasma that is above my upper lip has faded a lot.”
– MT (from amazon.com)
Holy Grail
Sept 8, 2015
”I have combination/oily skin. After about using thus product for a month, I saw that my acne has improved, my pores were reduced a little in size, and my skin complexion became more even. I would buy this again and I definitely recommend this product!”
– Marla Baconawa (from amazon.com)

WHAT YOU GET: (1) bottle My Signature C Source
Water, Ascorbic Acid, Alcohol, Sodium Lactate, Butylene Glycol, Glucose, PEG-60 Hydrogenated Castor Oil, 1,2-Hexanediol, Phenoxyethanol, Sodium Hyaluronate, Bis-PEG-18 Methyl Ether Dimethyl Silane, Xanthan Gum, Diethoxyethyl Succinate, Ammonium Acryloyldimethyltaurate/VP Copolymer, Carthamus Tinctorius (Safflower) Flower Extract, Citrus Aurantium Dulcis (Orange) Peel Oil, Glycerin, Zinc PCA, Panthenol, Niacinamide, t-Butyl Alcohol, Camellia Sinensis Leaf Extract, Beta-Glucan, Tocopheryl Acetate, Lecithin, Caprylic/Capric Triglyceride, Ubiquinone, Diisopropyl Adipate

STEP 1: Apply after cleansing and toning. Use 2~3 drops and smooth in gently all over face (especially over the aged areas such as pigmented or wrinkled lesions).
STEP 2: Initially, a slight tingling sensation may be experienced (a passing phenomenon).
STEP 3: Mix with several drops of toner to make your skin refreshed without feeling gooey.
STEP 4: After applying vitamin source C20, apply moisturizer to increase efficacy.

If you desire more hydration, use this product with the C20 Vitamin Sleep 9 to 5 Crema Sleeping Cream. After applying the C20 Vitamin serum, apply the sleeping cream over this layer. This combination will amplify the effects of Vitamin C.

Caution: When you use this product, please avoid using any products that contain high levels of AHA, BHA (include Betain Salicylate), Retinal, Vitamin C (Ascorbic Acid). Because of the hot weather, some vitamin serum can be leaked. But this is a natural phenomenon that can only happen to pure vitamins. When this happens, wipe leaked liquid, and keep it in fridge. Then you may use it without any problems.


Formerly known as C20, Tiam has one simple mission: “Helping you to be more beautiful.” Tiam believes that as long as you wish to be beautiful, you will be beautiful! This South Korean brand explores, all over the world, to find the best beauty products and introduce them to inspiring beauty explorers.

View all from this brand
Sit tight, beautiful things
are worth the wait!

144 reviews

Share your experience with this product
4.2 out of 5
5 stars
4 stars
3 stars
2 stars
1 star
Certified Buyer
  • Skin Type Combination
  • Skin Tone Fair
  • Facial Features Mestiza
  • Age 28

Not for me

I bought this when it was on sale. I've have been wanting to try this since reading a lot of good reviews and watching video reviews on youtube. When I applied it at first, true to some people's claims, it stings a bit then it would go away after a few minutes. Then, it would feel like there's a thin film layer on your face. After days and weeks of using it, I didn't see any changes on my face. I didn't get any pimples though. I stopped using it after a few weeks of not seeing results. Maybe it's just not for me.

11 days ago
Certified Buyer
  • Skin Type Combination
  • Skin Tone Fair
  • Facial Features Mestiza
  • Age 25

Super effective!

Kinda hesitant at first to buy coz its quite pricey and my skin is so sensitive but gave it a try. It stings at first every time I apply it on my face but it's manageable. My hyperpigmentations did lighten, true to its claims. The only thing I don't like is its sticky, it feels like my face needs to wait several hours before it absorbs which is quite a hassle for some who doesn't have enough time or tinatamad at night. But overall 5 stars for its effectivity!

about 1 month ago
Certified Buyer


I recieve my serum Feb. 11, 2019 and freaaak dumating sakin ng oxidize na siya tapos may leak sa gilid as in pag open ko . Bakit naman ganung item ang ipinadala sakin . Sana naman mapalitan pa to hanu at wag na mangyari pa sa iba kasi nakakahinayang yung pera nanginastos ko . Sana maaksyunan to ASAP nakakawala ng tiwala BEAUTYMNL.

about 1 month ago
Top Reviewer
  • Skin Type Combination
  • Skin Tone Fair
  • Facial Features Morena
  • Age 20

There are better serums but this is okay naman

I bought this last October and have been using it until November. When the product got to me, it had already oxidized to a faint yellow (VITAMIN C IS ORIGINALLY TRANSPARENT IN COLOR). For a month of use, i did not notice any significant brightening because at that time I did not have acne/ acne scars. I had a breakout in late December so I started using this again to treat my hyperpigmentation. My serum already turned bright yellow so I guess the potency is reduced, so it took more than 2 weeks for it to take effect. I did not store my vit c serum well kasi. This product has a very sticky consistency and a weird odor, so it might need getting used to. For its effectivity, ithink it's okay. But there are better vit c serums out there.

about 2 months ago
Certified Buyer
  • Skin Type Oily
  • Skin Tone Medium
  • Facial Features Morena
  • Age 27

Gets the job done

This was the first serum I ever used and I must say I was pleased with the results. I usually apply this at night after cleansing and applying toner to my face. After using it for a few weeks, my acne marks were visibly reduced and I had less breakouts. After a month or two my skin became smoother and lighter (glowing!). I also loved its citrus scent! My only problem with this product was that it does oxidize and turned brownish in color even if I stored it inside the fridge completely away from sunlight. But still, this was very effective and a good buy for its price..

about 2 months ago
Certified Buyer
  • Skin Type Normal
  • Skin Tone Fair
  • Age 30

You Glow Girl!

This is the first and only Vitamin C Serum I have tried, but so far I am loving it! When I got into the Korean skincare craze, people were raving about Vitamin C serums, how it would make your skin glow and fade pimple marks on your face. I searched days for a serum that would do its magic and still be affordable (since I didn’t want to waste money on my first Vitamin C serum purchase). I came across the many good reviews of this product and that made me click the purchase button. And wow, did I not regret it! This has made my pimple marks fade over time (about 1 month use) that I cannot barely remember now where they used to be located on my face lol. And every time I use this overnight, my face just glows so beautifully the next day, I swear! The product stings upon application on the face (I make it stay on my face for not more than 15 minutes), but that just means it is working its magic! The (minimal) pain is so worth it! It is kinda sticky but smells so refreshing. I am on my 2nd bottle now, and definitely would repurchase soon! This product is indeed value-for-money, and really effective for me.

2 months ago

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