How to apply vitamin C serum on your face without irritation?

Vitamin C (ascorbic acid) is one of the best ingredients for the skin. It is one of the most studied anti-aging ingredients with proven benefits on the skin demonstrated in various clinical studies, but some formulations can be irritating. So what’s the best way to use vitamin C serum on the face, and what precautions one must take to avoid skin irritation? Also, Can you use vitamin C when out in the sun? These are some of the questions we face almost on a daily basis. So here is the guide explaining all about vitamin C and the best way to use Vitamin C on your face.

What are the benefits of Vitamin C serum?

Vitamin C benefits for skin

Ascorbic acid or pure vitamin C has exceptional benefits on the skin. Thus, it is an ingredient that should always be in your facial routine. Following are some of the benefits of Vitamin C:

  • Promotes the production of collagen and elastin in the skin reducing wrinkles and other signs of aging.
  • It is a powerful antioxidant that protects against solar radiation. Also, protects from the damaging effect generated by exposure to ultraviolet light, and pollution.
  • Prevents skin pigmentation by inhibiting melanin production. This results in luminous skin with a homogeneous tone.
  • Helps to counteract the damaging effects of the sun and hence lowers the risk of skin cancer by making it thicker.

Precautions and tips for using topical vitamin C

The good news is that vitamin C has no major side effects and can be used even if you are pregnant. But, many concentrated formulations of vitamin C are acidic and can cause skin irritation. Some here are some of the precautions to take if you use creams or serums with pure vitamin C (ascorbic acid):

  • Avoid contact with the eyes, eyelids, nasal mucosa, mouth, and open wounds.
  • Do not mix pure vitamin C (ascorbic acid) with retinoid or other acids as the combination could irritate.
  • Pure vitamin C is unstable in an aqueous solution. So, avoid leaving the serum exposed to air and light because it can oxidize (it turns yellowish) and would no longer be useful.
  • Products with pure vitamin C should come in opaque containers and sealed from light and air. Store them in a dark place and if possible in the fridge.

Note: with some derivatives of vitamin C, being more stable and less irritating, you do not have to take so many precautions. But, they may be less effective.

How to avoid irritation caused by vitamin C and adapt the skin to its use

Vitamin C is a hydrophilic molecule that dissolves well in water. But, it is repelled by the

Lipid (oily) barrier of the skin, and to be able to penetrate it requires an acidic ph. below 4. These extreme acids in the formulation make vitamin C irritating at times. Below are the several options you can do to avoid irritation:

  1. The effective concentration of ascorbic acid is between 8% and 20%. Start with the lowest concentration of 8% or 10% to get skin used to it, before moving to higher concentrations (concentrations greater than 12% to 15%).
  • Another option is to use vitamin C that comes in a formulation without water. These are solutions more akin to the skin because they have a lipidic nature; in such a way that vitamin C does not need an acidic pH to penetrate. Thus, being neutral, they can be less irritating. They also provide greater stability to vitamin C, which tends to oxidize in water. The only disadvantage of these formulations is that vitamin C does not dissolve well and is usually felt as grit. Though, sometimes even these can be irritating. A good option is the ordinary 8% serum.
  • Finally, you can substitute vitamin C for niacinamide which has similar benefits and can be less irritating on skin sensitive to vitamin C. 

Facial routine with vitamin C


  • Cleanse skin with lukewarm water or a makeup remover cream or toner, rinse and towel dry.
  • Dispense 4 drops of the serum with vitamin C on the fingers of the hands and tap the areas of the face where you want to spread the serum (avoid the eye area). Don’t stretch or rub the skin. Allow skin to absorb it for 5 minutes.
  • If your vitamin C product comes in a cream form, spread it over your face.
  • Vitamin C serums often contain hydrating ingredients, and you don’t need anything else. Although if you want to add more emollients and moisturizers you can apply a moisturizer on top of the serum with vitamin C.
  • If you are going to expose yourself to the sun, apply a moisturizing cream with sun protection on top of the vitamin C serum.
  • The anti-aging action of vitamin C can be supplemented at night with the use of retinoid, especially if you are over 25 years of age. They do have exceptional proven benefits.
    • Remove products and makeup with a makeup remover cream or toner.
    • On a clean and dry face, apply a retinoid cream or serum.
    • On top, you could apply a moisturizer with niacinamide.

Also Read How to Apply the Facial Serum to Achieve Better Results.

FAQs related to the vitamin C serum:

Q1:  If I am going to expose myself to the sun, can I apply vitamin C to my face?

Vitamin C can be used both during day or night skin care routine. During the day it reinforces the protection against the sun’s rays as it acts like an antioxidant wear. Antioxidants neutralize free radicals, formed before exposure to ultraviolet light. These free radicals are unstable molecules that can damage cells and tissues leading to aging and other skin diseases. Vitamin C prevents this damage and is an excellent ingredient to protect you from the sun. Apply first the serum with vitamin C and then the sun cream.

Q2:  Can I use vitamin C together with retinol?

If the vitamin C is pure (ascorbic acid), its use in combination with retinoid should be avoided. This is because the retinoids need a ph of 5 or 6 to act, while vitamin C requires a ph of 3.5 or less to be efficient. Another impediment is that retinoids are soluble in oil, and repel the aqueous solution of vitamin C. Thus, prevents it from penetrating the skin. Also, using two acids at the same time can cause skin irritation.

To solve this problem and be able to use both compounds, the options are:

  • Using retinoids at night and vitamin C during the day.
  • Use both at night alternating between the days.
  • Derivatives of vitamin C, if they can be combined with retinoids because the ph is similar. In such cases, the lighter solutions in water should be applied first, to penetrate the skin, and then apply the oily solutions.

Q3:  Can I mix vitamin C and hyaluronic acid?

Yes, they can be combined or mixed. Hyaluronic acid is a moisturizing molecule (which attracts water) but does not penetrate the skin or depends on a specific ph to do so. Thus, the ph of other serums does not affect its function. That is, hyaluronic acid can be combined with other ingredients. Apply the lightest solution first, or the most important active ingredient, which in this case, would be vitamin C.

Q4:  Can I use vitamin C together with niacinamide?

Niacinamide requires a ph of 5-7 to act, which interferes with the ph needed for vitamin C, which is acidic over 3.5. If the ph of niacinamide is lowered, it turns into niacin, which can cause redness or irritation to the skin. Thus, as a general rule, we recommend not to combine niacinamide with vitamin C, unless vitamin C is a derivative and comes in a neutral solution.

Q5:  Can a pregnant woman use a vitamin C mask?

vitamin C mask

Pregnant women can also use vitamin C creams for the face to lighten the blemishes caused by pregnancy. But it is important to know that because these blemishes are caused by hormonal factors, they can take longer to disappear.

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