Korean Skincare, Serum, Vitamin C

How to use Vitamin C serum – Do and Don’t | Layering Vitamin C in your routine |

The vitamin C we are talking about is LAA – L Ascorbic Acid.

Check my previous post for a complete review on Vitamin C serum by TIA’M.

  1. AHA/BHA. Vitamin C has exfoliating properties and AHA/BHA are great exfoliants too, double exfoliation would make your skin very sensitive.
  2. Niacinamide – When mixed it changes the formula and causes vitamin C to oxidize. A lot of Vitamin C serum have Niacinamide but they are formulated such that they work together to enhance the effect. However topically applying Niacinamide isn’t safe.
  3. Benzoyl Peroxide, if you have inflammation and acne, the products prescribed by the dermatologist might contain Benzoyl Peroxide. This causes vitamin C to oxidize.
  4. Collagen – when it comes in contact with vitamin C it clots and hence it becomes useless to add further products into your skin.

THE DO’s |What enhances Vitamin C? :[2]

  1. Vitamin E – it enhances absorption rate, I used the Vitamin E toner by The Body Shop and the TIA’M A+ cream in my routine. They compliment each other’s antioxidant effect.
  2. Arbutin – Since arbutin inhibits melanin formation and vitamin C removes pigmentation, they work together to give an enhanced brightening effect.
  3. Peptide – Peptide signals the skin to produce collagen and when peptide meets Vitamin C it boosts the effect.

How to use vitamin C?

Vitamin C is an acid. Especially this particular form of vitamin C (LAA) is pH dependent i.e it penetrates your skin effectively and gives you maximum results when applied at a lower pH level.

pH is measured between 0-14, 0 being most acidic and 14 being most alkaline/basic. 7 is neutral. pH is really a measure of the relative amount of hydrogen and hydroxyl in a water solution. Water that has more free hydrogen ions is acidic, whereas water that has more hydroxyl ions is basic.

  • Our skin falls on the acidic side, the skin barrier also known as the acid mantle helps to retain moisture, keep away toxins and bacteria. Our skin pH is 5.5
  • When the skin becomes alkaline the acid mantle is no longer balanced and hence our skin becomes dry, dull and ages quicker. It also provides a good environment for bad bacteria which causes acne. Hence maintaining skin pH at 5.5-6 is very important. Always use a low pH cleanser.

How to lower skin pH before using LAA?
Method 1: Use a toner which has a pH of (3.5-4.5) to lower skin pH.
Method 2: After cleansing with a low pH cleanser wait for anywhere between 15 minutes to one hour before you apply the Vitamin C serum.

I follow method 2, I have a long gap between the time I wash my face(I do it immediately after returning home) and my routine again restarts two hours later before I am off to bed.

Oil Cleanse/Makeup remover – Low pH gel/foam cleanser – (a big time gap) – vitamin c serum- and so on……..

If you don’t like the wait time, you can buy a pH balancing toner instead.
Oil Cleanse/Makeup remover – Low pH gel/foam cleanser – pH balancing toner – vitamin c serum- and so on……..
How to layer multiple acids?

If you are already using AHA or BHA,

  • You can either use AHA/BHA in one routine and Vitamin C in another routine. But remember that AHA are more sensitive to light than LAA.
  • I rotate my acids and use them on alternate days. This is to be on the safer side and prevent over exfoliation.


Always patch test before you use. If you have sensitive skin, mix the Vitamin C with a toner and use it for a couple of days, later your skin will be able to handle the vitamin C.

Information sources : Internet


2 thoughts on “How to use Vitamin C serum – Do and Don’t | Layering Vitamin C in your routine |”

  1. Thanks for this useful post. Just recently buy the ordinary L-ascorbic acid to mix with peptide, but later on read on the site that I shouldn’t mix both. It’s confusing. also, it helps me to know that I shouldn’t add collagen to my vitamin C. So that’s another tip for me.


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