An introduction to Vitamin C, its benefits, side effects, and best products
We’ve all heard of Vitamin C. It is in many foods that we eat with its quantity listed on the nutritional labels of various foods, or a popular cold and allergy preventative. We know that it is good for us and that it offers a great many benefits for our skin health. But did you know that there are 2 ways to deliver Vitamin C to your skin? You can eat it via food or you can use a topical Vitamin C serum that delivers it directly to your skin. Both methods have their own benefits and by understanding how Vitamin C works in your skin via scientific data, you can make a more informed choice about how to maximize these benefits for yourself.
What is Vitamin C?
Vitamin C is a water soluble vitamin that we all eat everyday via fruits and vegetables and is a popular skincare ingredient with several impressive benefits including repairing sun damage, reversing aging, speeding up wound repair and hydrating dry skin. L Ascorbic Acid is a a common type of Vitamin C and you may even see Vitamin C and Ascorbic Acid used interchangeably, but there are actually many more types of Vitamin C than just Ascorbic acid.
Vitamin C is an antioxidant and an essential nutrient involved in the repair and maintenance of your body’s connective tissues. It is key cofactor for enzymes involved in making collagen (keeps your skin plump), carnitine (helps body turn fat into energy), and catecholamine (neurotransmitters, or hormones that help deliver signals to your brain), and plays a vital role in several immune system functions.
Its antioxidant and collagen synthesis properties make Vitamin C an important molecule for skin health. Studies show that eating Vitamin C rich foods and applying Vitamin C on your skin surface both have beneficial effects for the skin, both internally and on the visible surface.
Our bodies cannot make Vitamin C and so must we must eat it everyday to get enough for our body processes. Fruits and vegetables are high in Vitamin C and so if you do not eat much of this food group, you could be suffering from some level of Vitamin C deficiency. Symptoms of Vitamin C deficiency can include dry skin and hair, easy bruising and gingivitis and bleeding gums.
Topical application of Vitamin C has shown improvement in pigmentation and texture to reversing age and sun damage like melasma and wrinkling. Vitamin C serums can help even out your skin tone, protect it from sun damage and pollution damage, help improve hydration in your skin. And paired with regularly sunscreen use, Vitamin C can slow down aging in skin both by reversing existing damage as well as preventing future damage.
Compared to AHAs which make your skin more susceptible to sun damage and BHAs that do not, Vitamin C also do not increase photosensitivity and go a step further. Vitamin C also treats existing UV damage while preventing future damage. It is not a sunscreen because it doesn’t absorb UV rays, but it limits the damage that UV can do to skin.
Vitamin C vs Ascorbic acid
Vitamin C and Ascorbic acid are used interchangebly, but actually Ascorbic acid is just 1 of the many types of Vitamin C. In skincare products, you may find a different kind of Vitamin C in the ingredients list like Sodium Ascorbyl Phosphate (SAP) or Magnesium Ascorbyl Phosphate (MAP). Later in this guide, we’ll go over a more complete list of Vitamin C types so that you can easily recognize them in skincare product ingredient lists.
Next up is the science behind the claims to Vitamin C. We’ll take a look at the studies behind each of the main benefits purportedly offered by using a topical Vitamin C on your skin. If you’d like to add a Vitamin C source to your skincare routine, see our product recommendations and reviews section at the end of this guide.
What are the benefits of Vitamin C?
Is there more to Vitamin C than marketing hype? Does it truly offer all of the skin benefits that we discussed above or you may have read in advertisements for skincare products?
There are several studies that show the very real results that Vitamin C have in reverse and preventing sun damage and aging like wrinkles, as well as in healing wounds (both deep wounds as well surface wounds like from picking at acne) and treating dry skin. We’ll look at 3 of the most commonly proclaimed benefits of Vitamin C.
Vitamin C for sun protection
Like sunscreen, Vitamin C is said to limit sun damage to your skin by protecting it from harmful ultraviolet light. It does not work like sunscreen, which absorbs UV light in the UVA and UVB spectrum. Instead, the antioxidant properties of Vitamin C neutralize free radicals that are created when ultraviolet light or other environmental stressors like pollution or radiation interacts with your skin.
What are free radicals?
If you don’t remember anything about atoms from high school chemistry, here’s a short primer. All stable atoms have equal and usually even numbers of protons and electrons. In chemical reactions, atoms lose or gain or share their electrons and become new chemical compounds. Most of the time, atoms are able to interact with other atoms to ensure an even number of electrons but sometimes, atoms end up with an odd number which leaves 1 extra unpaired electron. These are free radicals. Their unpaired electron makes them unstable atoms which then run around and cause havoc that can disrupt a healthy living cell.
When free radical damage accumulates, you start seeing aging symptoms like melasma, loss of collagen, and wrinkles. The antioxidants in Vitamin C (and vitamin E) counter these radicals and prevent this disruption and damage.
In one study, topical Vitamin C was applied to the skin of pigs to see if the presence of Vitamin C offered any extra sun protection. The study found that the skin had natural levels of Vitamin C that acted as an innate protective mechanism and which were eaten up after sun exposure, and that topical application of Vitamin C successfully increased its levels available in the skin. It also found that increasing Vitamin C directly correlated with increased protection from both UVB and UVA damage. [source:
Darr D1, Combs S, Dunston S, Manning T, Pinnell S. (1992) Br J Dermatol.]
So you have a certain amount of Vitamin C already existing in your skin that acts as a built in biological photo protection, and this amount depletes as it targets free radicals created by the UV spectrum and other environmental pollution. Applying a topical Vitamin C can help increase these available levels of antioxidant power in your skin.
Does eating Vitamin C rich foods also offer the same photo protection benefits?
There is limited research on this but some studies suggest that dietary Vitamin C does not offer the same photo protection benefits. However, eating both Vitamin C and Vitamin E seems to show similar results as topical Vitamin C application.
In 2 different studies, a group of men and women volunteers were administered a combination of dietary Vitamin C and Vitamin E. In one study, the volunteers were given a lower dosage of both vitamins for 3 months and in the second study, a higher dosage was prescribed for 8 days. In both studies, the volunteers were found to be less likely to sunburn from UVB light as a result of consuming Vitamin C and E. [source: Eberlein-König B1, Placzek M, Przybilla B. (1998) J Am Acad Dermatol. and Placzek M1, Gaube S, Kerkmann U, Gilbertz KP, Herzinger T, Haen E, Przybilla B. (2005) J Invest Dermatol.]
Topical formulations that contain both Vitamin C and Vitamin E are also more potent than Vitamin C alone.
Consuming Vitamin C has a lot of other benefits aside from photoprotection, but if your goal is to increase protection from the sun and its UV light, then applying vitamin C to the skin is a more efficient and direct way to deliver it to your skin.
Vitamin C for wrinkling
As we just learned, free radicals are created when ultraviolet light and environmental pollution interacts with your skin. When these free radicals accumulate, they cause damage like collagen breakdown and wrinkles. Vitamin C can help prevent this damage by countering the effects of the free radicals AND by encouraging the production of collagen.
Vitamin C stabilizes collagen to increase its production of collagen proteins which help repair the skin. Vitamin C also increases production of fibroblasts, which are the cell that produces collagen proteins and the extracellular matrix, all of which makes up your connective tissue. Fibroblasts tend to decrease as you age and produce less collagen proteins, but studies show that this process can be rejuvenated by Vitamin C.
One study found that Vitamin C sped up the proliferation and biosynthesis of collagen by older fibroblasts cells to a rate that was much faster than what was expected of the fibroblasts at their given age. Without Vitamin C, the older fibroblasts slowed down their collagen production causing normal aging skin results. This study tested fibroblasts from newborns between the age of 3 to 8 days old to fibroblasts from elderly people aged 78 to 93 years old. The results found that Vitamin C increased collagen production in both newborns and in the elderly:
“In the absence of ascorbic acid (control) proliferative capacities were inversely related to age; newborn cell lines proliferated faster and reached greater densities than elderly cell lines. However, in the presence of ascorbic acid both newborn and elderly cells proliferated at a faster rate and reached higher densities than controls. To determine whether there are age-related differences in extracellular matrix production and ascorbic acid responsiveness we examined and found that collagen biosynthesis (collagenase-digestible protein) was inversely related to age, but the stimulation by ascorbic acid appeared age independent.” [source: Phillips CL1, Combs SB, Pinnell SR. (1994) J Invest Dermatol.]
Does eating Vitamin C rich foods also prevent wrinkles?
Vitamin C has been shown to repair wrinkles caused by sun damage and aging, both if using topically as a serum and consumed in the form of food.
Using Vitamin C topically for 12 weeks or more has been shown to decrease wrinkles, decrease skin roughness, increase collagen production, and repair protein fiber damage. Several studies show conclusive evidence for these skin results. One of these studies tested 19 volunteers between the age of 32 and 76 with varying skin colors who were treated with a Vitamin C skin serum for 3 months. The results found improvements in wrinkles, texture, and general complexion:
“Clinical assessment demonstrated significant improvement with active treatment greater than control for fine wrinkling, tactile roughness, coarse rhytids, skin laxity/tone, sallowness/yellowing, and overall features.” [source: Traikovich SS. (1999) Arch Otolaryngol Head Neck Surg.]
Eating Vitamin C rich foods also show similar results, with a higher Vitamin C intake directly correlating with decreased skin wrinkles. In fact, one study even found that if you eat a lot of Vitamin C then you may not see as much benefit from a topical Vitamin C serum. This is likely because you are supplying your skin with plenty of Vitamin C to tackle radicals and facilitate collagen, even though eating Vitamin C is a slower way to get it to your skin than applying it topically. Most of us do not eat enough Vitamin C, so if you are, this is definitely deserving of self congratulations!
Vitamin C for skin healing from wounds
Because Vitamin C helps facilitate certain processes that contribute to the production of connection tissue, it is also plays an important role in wound repair, both deeper wounds that involve several layers of skin as well surface wounds like from picking at your acne.
During the age of exploration (1500-1800) when sea travel by European explorers on ships found routes to India and the Americas, sailors use to suffer from Vitamin C called scurvy. It wasn’t until much later that citrus fruit was found as a way to cure scurvy. In the meantime, long distance sailors fell ill to scurvy, which only took a month of little to no Vitamin C for a month. Symptoms included gum disease, mood changes, and most notably, a slowing or failure of wounds to heal.
Since Vitamin C is a building block in collagen production, scurvy patients did not have enough vitamin C levels to help produce collagen at the wound site as it would be used up in the process of wound repair without dietary replenishing source. Later, in the 1800s, the British navy began prescribing lemon juice to help ward off scurvy and sailors and migrants traveled with crate of oranges on their long trips by sea.
Today, scurvy is an infrequent illness and only found in areas of the world suffering from malnutrition. Lower levels of Vitamin C deficiency can be found in adults anywhere with bad diets and symptoms include sallow skin, gum disease, and other long term negative affects on your bone and heart health.
How to use a Vitamin C serum
Topical Vitamin C is an active, which means that it is an ingredient that has direct active action on the skin. Other actives include beta hydroxy acids (BHA), alpha hydroxy acids (AHA), and Vitamin A (retinoids and retinol).
There are some differing opinions on this in the skincare world, but we believe that to benefit maximally from an active, you should leave it on your bare skin for a time period ranging from 2 minutes up to 30 minutes (depending on the potency and your skin’s sensitivity) before applying more products on top. This allows the active to directly penetrate your skin and achieve maximum benefit. For a 10-20% Ascorbic acid Vitamin C serum, we recommend a period of 20 minutes of contact time before laying on more products.
Vitamin C works best at a pH level of around 3, and well formulated topical Vitamin C will have a pH level of near or at 3. When you layer on more products, you change the pH of your skin and hinder the Vitamin C from being able to affect your skin.
Some products may include a pH stabilizing ingredient that helps keep the Vitamin C at the optimal pH level even if you add more products on top. These products will note this and not recommend a wait time.
If you have sensitive skin and experience irritation when you use a high concentration of Vitamin C, you can also wash off the Vitamin C topical serum after 20 minutes before continuing the rest of your routine. That way you are able to benefit from the 20 minute contact time with your skin without leaving it on for hours to irritate your skin.
If you want to add a Vitamin C serum to your daily skincare routine, you only need to use the serum every 3 days. Vitamin C remains in your skin for up for a 3 days period before it begins to breakdown. You do not need to use it everyday.
Vitamin C serums also break down very quickly when they come into contact with sunlight and oxidize, turning an orange color. Well thought out serums should be in a blue or amber colored bottle to block sunlight, and you can keep them in the fridge to help slow down oxidation. Just remember that if your serum has turned a orange color, it has oxidized and it is time to replace it.
Step by step recommendations for using Vitamin C in your skincare routine
Step 1: Wash your face with a low pH and non irritating cleanser. Pat dry.
Step 2: Apply your Vitamin C serum. Follow the product recommendations for quantity but most only require 3-5 drops of solution for your entire face. You can also apply Vitamin C in your under eye area, but be sure to not get it in your eye.
Step 3: Wait 20 to 30 minutes to let your skin absorb the Vitamin C. Some Vitamin C products may include a pH adjuster, so you can choose to not wait.
Step 4: Continue with your skincare routine and feel free to layer on more products like moisturizer or sunscreen.
Types of Vitamin C
These are the 3 most common forms of Vitamin C available in skincare products:
1. L Ascorbic acid (LAA)
L Ascorbic acid (LAA) is the most common form of Vitamin C. L Ascorbic acid is a unstable compound and easily oxidizes after coming into repeated contact with air and sunlight and turns orange. Products that use the L Ascorbic acid form of Vitamin C usually have an expiration of 3 months or less.
2. Sodium Ascorbyl Phosphate (SAP)
Sodium Ascorbyl Phosphate (SAP) is a more stable and bioavailable form of Vitamin C than the more common L Ascorbic acid. Less irritating than Ascorbic acid.
3. Magnesium Ascorbyl Phosphate (MAP)
Magnesium Ascorbyl Phosphate (MAP) is another Vitamin C derivative that is water soluble, nonirritating, and more stable than L Ascorbic acid. Unlike L Ascorbic acid which can be found from 10-30% concentrations, MAP works best at lower concentrations between 1-5%.
Other names for Vitamin C include:
- Ascorbyl Palmitate (AA-PAL)
- Tetrahexyldecyl Ascorbate (THDA)
- Ascorbyl Tetra-Isopalmitate (VC-IP)
- Ascorbyl Glucoside (AA-2G)
- Ascorbyl Glucosamine
- Ascorbyl Methylsilanol Pectinate
- 3-O-Ethyl Ascorbate (EAC)
Vitamin C side effects
Vitamin C is usually less irritating than acids like beta hydroxy acids (salicylic) or alpha hydroxy acids (lactic, glycolic) or Vitamin A (retinoids), but can still have some side effects.
Some people can experience side effects such as redness, stinging, peeling, or even over exfoliation after using a Vitamin C serum. Vitamin C is a very acidic active so these side effects are not surprising.
To avoid these side effects, we recommend starting off with a lower concentration of Vitamin C and/or starting off a serum by only using it once a week and building up after 2-3 weeks.
Using a lower dosage will help with the redness and stinging and using any Vitamin C serum at a lower frequency like once a week to start with, will help your skin become accustomed and decrease the irritation.
If you’re doubling up Vitamin C with a BHA, AHA, or retinoid, you may notice signs of over exfoliation because all of these are active ingredients that cause some exfoliation. If you’re experiencing tightness, peeling or flaking that doesn’t seem to go away with moisturizer, you may need to dial back the acid use. We recommend slowly introducing Vitamin C if you’re already using a different active and carefully gauging your skin’s reaction to make sure that you do not end up over exfoliating your skin.
Vitamin C Products, Reviews, and Recommendations
Vitamin C products come in a large price range, from $10 to $200. We’ll give you a range of options in that price range, but it is our opinion that you do not need to be spending the higher end of that range on a Vitamin C serum.
Almost all L Ascorbic Acid Vitamin C products do not have a shelf life of more than 3 months, so if it oxidizes faster than you use it, then you’ll have to buy a replacement. We’ve also found that the more expensive Vitamin C options add additional extracts or other moisturizing ingredients that are extra and do not seem to do anything extra to help deliver Vitamin C to your skin other than making the serum more expensive. You always use a separate moisturizer in addition to that do not improve the absorption of Vitamin C by your skin and you can use other cheaper products for moisturizing your skin.
Here are our top picks for Vitamin C serums:
The Mad Hippie Vitamin C serum is our top pick because in addition to Vitamin C, it also has Ferulic acid (another antioxidant) as well as two skin hydrators – konjac root and hyaluronic acid.
It has 15% Vitamin C (in the form of Sodium Ascorbyl Phosphate which is a more stable and less irritating version of Vitamin C than the more common L ascorbic acid) and so does not oxidize as fast as other serums. The formulation also absorbs very quickly, does not feel sticky, make your skin look shiny, or feel as it sits atop your skin.
This is a Vitamin C serum that also has Vitamin E and Ferulic acid and if you run out before you use it, the price makes it far less painless to replace it. In our experience, Timeless Vitamin C shows many of great results of Vitamin C including brightness, improved skin texture, and reduced pigmentation within 4 weeks of regular use. This is a 20% concentration so be sure to start off slowly.
30% of the one of the highest Vitamin C concentrations available. You certainly shouldn’t start at this concentration if you have never used an active as you may experience irritation. However, if you’ve used lower concentrations and enjoyed the results and would like to take it up a notch, this is a great cost efficient option that shows good results. It also has Hyaluronic acid to help soothe and hydrate your skin while you use this very potent concentration.
Paula’s choice is known for well forumulated products and this is no exception. This Vitamin C serum has Triethanolamine as an ingredient, which is a pH adjuster. So if you do not want to deal with wait times, this is a great product to try.
This is a great option if you’re looking to build up your tolerance for Vitamin C from 10% to 15% to 20% within the same product line and no ingredient changes aside from a higher concentration of Vitamin C.