Vitamin C in Skincare – The Ultimate Guide

Vitamin C or ascorbic acid is found in citrus foods and green leafy vegetables. It is also used in skincare because of its antioxidant properties.

• Antioxidant: Vitamin C can help to protect the skin from UV rays, pollution, and free radicals.

• Increase collagen production: It helps to improve skin texture, skin elasticity, and plumps up the skin.
• Helps with hyperpigmentation: Vitamin C can help with melasma, post-inflammatory pigmentation, sunspots. It can work better by mixing it with other actives.

• Other benefits: It can also help with stretch marks, dull skin, and acne scars.

• Unstable: when vitamin C is exposed to light, it gets oxidized to Dehydro Ascorbic acid (DHAA) which leaves a yellow color.

• It may irritate the skin due to their low pH formulation (2.6-3.5)

1. Vitamin C or L- Ascorbic acid: This is the most common type of vitamin C. Since it has a low pH formulation (2.6-3.5) it is acidic and can be very irritating, so it is not suitable for sensitive skin.
2. Sodium Ascorbyl Phosphate: This is another form of vitamin C and it is less irritating. It is water-soluble and has a pH of 6.
3. Magnesium Ascorbyl Phosphate: MAP is also a water-soluble derivative of Vitamin C. It is also less irritating than L- Ascorbic acid. It has a pH of 6-7. 60% of it is converted to L- Ascorbic Acid which helps to stimulate collagen production.
4. 3-0 Ethyl Ascorbate: This acid is highly stable and non-irritating. 3-0. Ethyl Ascorbate is the most effective form of vitamin C in boosting collagen and lightening the skin, with over 80% metabolized to pure L-ascorbic acid. It has a pH of 5-6.5.
5. Ascorbyl Glucoside: It is non-irritating and has a pH of 5-8.
6. Tetrahexyldecyl Ascorbate: Tetrahexyldecyl Ascorbate is a fat-soluble which helps it to penetrate deeper into the skin. It is non-irritating and safe for sensitive skin.
7. the powder form of vitamin C: it has a longer shelf life, but taking the wrong measure can lead to skin irritation.

• For Dry skin: Vitamin C can be irritating for dry skin, so you should make sure to repair the skin barrier. Combining vitamin C (non-irritating form like Sodium Ascorbyl Phosphate) with Niacinamide (which helps to repair the skin barrier) can be very good for dry skin.

• For Oily and Acne-prone Skin: Vitamin C is also good for oily and acne-prone skin as long as it’s not irritating.

• For Aging skin: Vitamin C is good for those people who have aging skin, hyperpigmentation, photodamaged skin.

• For Sensitive Skin and Skin of Color (darker skin): It’s better to choose those vitamin C’s that are less irritating than L- Ascorbic Acid. For example, Magnesium Ascorbyl Phosphate, 3-0 Ethyl Ascorbate, and Tetrahexyldecyl Ascorbate are some good vitamin C’s which are non-irritating.

• Vitamin C should not be used during Pregnancy and Breastfeeding.

You can combine Vitamin C with:

1. Niacinamide
2. Glycolic acid
3. Lactic acid
4. Hyaluronic acid
5. Vitamin E
6. Ferulic acid
7. Centella Asiatica
8. Arbutin
9. Tranexamic acid

Note: Some of these ingredients can be irritating so remember to do a test patch.

Mix with caution:

1. AHA/BHA’s
2. Retinol/retinoids.

How to start Vitamin C in my skincare routine?

• Make sure to conduct patch tests when using new products.

• Toner is not really necessary for a skincare routine

• A, B, C’s of skincare for normal skin is from Vitamin A, B, and C. For sensitive skin and skin of color, Vitamin B, A, and then C. Derivatives of Vitamin A and Vitamin C can be used for sensitive skin and skin of color.

• Chemical exfoliants should only be applied at night and should be used once or twice a week if you’re able to tolerate it.

• Sunscreen should be the last step in skincare

• You can apply your vitamin C in the morning for fighting free radicals and at night for collagen production and pigmentation.

• The optimal concentration of Vitamin C is 5%-20%. Start at a low concentration and increase from there when you’re able to tolerate it.

1. Use a gentle, non-foaming cleanser
2. Use a toner of choice.
3. You can apply your skincare actives such as niacinamide and then use Vitamin C.
4. Moisturize and then apply your sunscreen.

1. Use a gentle cleanser of choice
2. Toner is optional.
3. You use your AHA/BHA/PHAs
4. Wait for 30 mins and then apply your niacinamide, retinol, and then Vitamin C (this is to reduce irritation).
5. Moisturize.

Note: Using vitamin C with retinol and hydroxy acids can cause irritation, especially if you have sensitive skin and skin of color.

• Tip 1: you can try to use derivatives of Vitamin C and retinol to reduce irritation. Or just use niacinamide with vitamin C at night. This can reduce irritation.
• Tip 2: Since you’re using AHA/BHA/PHAs 1-2 times a week, you can modify your skincare actives such as Vitamin C or Retinol. For example:
  • Alternate nights: on 1st night you can use your AHA/BHA/PHAs with Vitamin C. On the 2nd night, you can use your AHA/BHA/PHA with retinol.

This routine is mainly an example of how basic skincare is and how you can combine all your actives with your hydroxy acids by avoiding irritation. There are many methods and ways on how you can layer these ingredients. There is no right or wrong. You just have to listen to your skin.

You should consult a dermatologist about your skincare routine and also ask about the products you’re planning to use.

It’s better to choose those Vitamin C’s which are less irritating than L- Ascorbic Acid. Sodium Ascorbyl Phosphate, Magnesium Ascorbyl Phosphate, 3-0 Ethyl Ascorbate, Ascorbyl Glucoside, and Tetrahexyldecyl Ascorbate are all Vitamin C’s which are non-irritating and safe for sensitive skin.

Look for Vitamin C that has air-tight packaging, and dark-tinted packaging, and combined with other antioxidants such as vitamin E, ferulic acid, and also humectants. So even if vitamin C degrades, you can still benefit from the other ingredients.

It’s very unlikely that it will do any harm to your skin. It will not be effective at fighting free radicals out in the sun and there are no studies that show skin damage caused by oxidized Vitamin C.

Vitamin C has a yellowish color and turns to a brown color when it oxides meaning that it has expired.

No, vitamin C cannot darken your skin, it’s mainly because it has oxidized either in the bottle or on the surface of your skin. This oxidization results in the serum turning brown, leaving a stain on the skin and giving it a tan look.

Vitamin C can be applied every morning to prevent sun damage and pollution as long as it doesn’t irritate the skin. You can also use it at night for collagen production and pigmentation.

Yes, copper peptides can make vitamin C ineffective and they shouldn’t be used together.

This study was done by Dr. Pinnel founder of SkinCeuticals but only pertains to 15% L ascorbic acid at a pH of 3.2. When vitamin C is applied to the skin 5 days in a row. It can saturate the skin and decrease over 4 days.

Yes, Vitamin C can cause purging if you use it at higher concentrations, so make sure to start at a low concentration or use a derivative of Vitamin C which is non-irritating. Purging is a temporary worsening of acne after you introduce a product that increases cellular turnover. This is more common in acne-prone skin.

Purging should last for a maximum of 4-6 weeks.