What is ascorbic acid and how does it work in skincare?

Often referred to by its other name—Vitamin C—ascorbic acid is known to be good for us, but why and how? Let's find out

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(Image credit: Getty Images)

Ascorbic acid (that's vitamin C to most of us) is a common ingredient that, when you look a little closer, often gets highlighted on product labels. 

While we're used to seeing it listed on the container when we grab our morning glass of OJ, lately you might have noticed it's also been making its way into our skincare routine.

Since we're pretty sure that most people aren't walking around worrying about getting scurvy these days, why the sudden uplift in the use of vitamin C in everything? Let's take a look at what exactly ascorbic acid is, why vitamin C is good for us, and when and how to use it.  

What is ascorbic acid (aka vitamin C)?

As it happens, vitamin C (often listed as ascorbic acid or L-ascorbic acid) is far more important than people think. We've all heard that it helps boost the immune system to keep us healthy and stave off the common cold, but it's so much more than that. According to the staff at the Mayo Clinic, vitamin C is an important nutrient for developing body tissues such as cartilage, muscle, and the collagen in our bones.

It also aids the body's healing process and acts as an antioxidant, meaning that it stabilizes oxygen molecules when they lose one of their electrons. More commonly known as free radicals, these occur naturally when the body produces energy. An excess of them can, however, cause damage to other cells.

Vitamin C—in less acidic forms—is also commonly found in makeup, skin care, and hair care products. If you're checking labels for ingredients, it might be listed as calcium ascorbate, magnesium ascorbate, magnesium ascorbyl phosphate, sodium ascorbate, or sodium ascorbyl phosphate.

Benefits of ascorbic acid

Many personal care products add low-acid forms of ascorbic acid as a preservative. However, more and more cosmetics brands are adding vitamin C as an active ingredient, because of the benefits of its antioxidants. These are said to have all kinds of anti-aging benefits and advantages for skin appearance, meaning vitamin C has the potential to even out skin tone, improve skin texture, and reduce or prevent signs of aging. Here are some of the specific benefits of vitamin C:

  • Prevents free radical damage: As an antioxidant, it prevents damage from free radicals that cause premature signs of aging. It can also lessen the appearance of wrinkles and fine lines.
  • Promotes collagen production: Vitamin C is an important factor in collagen production. According to Dr. Jennifer Herrmann, MD, a dermatologist, "collagen gives our skin support and structure, and as it degrades with age, we begin to notice wrinkles and lines."
  • Lessens discoloration: Dark spots and discoloration are caused by melanin production. Vitamin C stops the pigment from being produced.  

Side effects of ascorbic acid

Depending on your skin's sensitivity—and the concentration and acidity of the product—vitamin C (and its variations) may cause some irritation. If this happens, you can try using the product less frequently. If irritation starts after the first use, or is severe, you should stop using the product immediately. Talk to your dermatologist about how to get the benefits of vitamin C from a product that is less likely to irritate your skin.

When to use ascorbic acid...and when not to

Vitamin C is generally considered safe to consume and apply to the skin daily. 

It's worth noting, however, that people with consistently sensitive or oily skin may have problems using products that feature this ingredient; it is an acid so it can cause some redness, pain, or other irritation to some skin. This can be worsened if you use products containing ascorbic acid along with those containing other types of acids. 

It's suggested that you consult your dermatologist to see what product they recommend for your skin type. Also, try not to use a vitamin C product together with benzoyl peroxide products or anything containing retinol.

How to use and apply ascorbic acid

As long as your skin isn't too sensitive or oily to tolerate it, it's recommended that you use vitamin C daily or every other day. However, there’s some disagreement regarding the best time of day to apply it. Dr. Herrmann advises that either morning or evening is fine, as long as you apply it consistently at the same time of day. Also, if you're using a serum, make sure to apply it after washing your face.

While doctors say that serums are more effective than creams when it comes to reaping the benefits of vitamin C, Dr. Kristina Goldenberg clarifies this by saying that the form of the product is less important than the form of vitamin C that the product contains. She recommends using the purest form—meaning ascorbic acid or L-ascorbic acid. As a final thought, it's worth noting that ascorbic acid can also be more effective when combined with other antioxidants, such as vitamin E.  

Eunice Lucero-Lee
Eunice Lucero-Lee

Eunice Lucero-Lee is the Beauty Channel Editor for woman&home. A lifelong creative writer and beautyphile, she graduated from De La Salle University in 2002 and was hired a year later to front all beauty coverage for Pink Magazine, a teen lifestyle publication, after submitting a page-long thesis on why Stila was the best brand to come out of the Aughts. She was hired an hour later. 


Her writing—which has since then expanded to cover pop culture and astrology, both equal passions—led her to spearheading columns in Chalk Magazine, K-Mag, Metro Working Mom, and SugarSugar Magazine. Upon receiving her stripes at New York University’s Summer Publishing Institute in 2008 she was immediately headhunted to work as the Beauty Editor, thereafter Managing Editor of Stylebible.ph, the digital home of Preview, the Philippines’ best-selling fashion magazine, where she also did double-duty as Associate Editor of the print edition.


It was during this stint that the hallyu wave started taking hold and when she was tapped to co-found Sparkling, Asia’s first-ever English K-Pop print magazine. Originally planned as a one-off, the project became a runaway hit and saw her taking Korean classes on the weekends for three years, as she found herself frustrated by the lack of breadth translators provided for celebrity profile coverage. She was Editor-in-Chief until her move to New York in 2013. The now-iconic magazine has remained in publication since 2009 due to massive fan support.


A beauty, astrology, and pop culture obsessive and insider for over 18 years, Eunice is an internationally published editor (and now certified astrologer) whose work has been featured in publications such as Cosmopolitan, Esquire, and The Numinous, among many others. The former Editor-in-Chief of All Things Hair and a (very) proud cat mom, she spends her time in Manhattan figuring out the correct Pilates-to-sushi ratio, obsessing over celebrity natal charts, luxury skincare, and Scandi-noir crime procedurals, as well as finding the perfect K-Pop vid to save the day. She can still order drinks perfectly in Korean. Find her on Instagram @eunichiban.