Simplifying Skincare
8 min readNov 1, 2021


Vitamin C Decoded

Protect, Repair, Enhance your skin!

Photo by Aiony Haust on Unsplash

Take an apple slice and leave it on your kitchen counter for 3–4 hours. You’ll notice a brown layer on the slice which means it oxidized (in simple terms deteriorated). Our skin reacts the same way — daily exposure to Ultraviolet (UV) rays and pollution (car exhaust, cigarette smoke, chemicals) create free radicals that oxidize our skin. Think of free radicals as bad actors, they get into the body and skin leading to inflammation and degradation of the healthy cells, essentially “rusting” them. On the skin it manifests as fine lines and wrinkles, texture changes, discoloration, dark spots, and decreased moisture levels.

Vitamin C mops up this oxidative damage on the skin making it the most potent antioxidant on the planet, and a must have ingredient in your skincare regimen. When it comes to healthy skin, research indicates that topical Vitamin C is significantly more effective than consuming it.

How does Vitamin C work and what are its benefits?

Vitamin C, also known as ascorbic acid, is a water soluble nutrient and is absorbed directly into the topmost layers of skin, thus getting to work immediately. Not only is Vitamin C a powerful antioxidant, it has other amazing benefits:

  1. Increases collagen (a protein needed to keep skin firm and youthful) — As we age we start to lose collagen. Research indicates that Vitamin C increases collagen in the skin by not only producing it but also cross linking it to form a collagen network. Vitamin C also blocks the action of the enzyme that breaks down collagen in the skin, thereby reducing fine lines and wrinkles — giving the skin a supple youthful look.
  2. Reduces pigmentation and brightens the skin — Acne marks, sun spots, and pigmentation are a result of excess melanin in the skin (a pigment that gives the skin color). Vitamin C inhibits the action of the enzyme tyrosinase that is responsible for producing melanin, therefore reducing spots and pigmentation in the skin — making the skin even and more luminous.
  3. Sun protection — Don’t confuse this with what sunscreen does to block out UV rays from the sun. Vitamin C does act like an antioxidant and takes care of the damage UV does inside the skin — cleaning up the free radicals.

What are the types of Vitamin C available and which one is right for you?

This is where it gets confusing — you’ll see tons of Vitamin C products on the market. It’s available in many different forms with the effectiveness varying between forms. This gets further complicated by stability issues of Vitamin C, making it even more important to understand the type of Vitamin C you’re buying and its formulation. This will ensure you get the maximum benefits from this amazing ingredient.

  1. Pure Vitamin C (Ascorbic acid or L-Ascorbic Acid or L-AA)

Ascorbic acid (henceforth referred to as L-AA) is the active form of Vitamin C that the body can readily use versus other forms of Vitamin C (called “derivatives”) that need to be converted to L-AA before they can have any effect on the skin. Most of the Vitamin C research has been done on L-AA and is proven to be the most effective at penetrating our skin barrier (outermost layer of skin). Then why doesn’t everyone stick to it? Here’s why…

  • Instability — L-AA is pretty unstable and can oxidize (break down) in the presence of water, at a high pH (anything above 4), or when exposed to light or oxygen. This essentially means that your Vitamin C formula gets less effective over time and how quickly this happens depends upon the formula. You can get a visual idea by examining the color of your Vitamin C product — if it’s yellow, orange or brown that means its oxidized rendering it ineffective.
  • Irritation — L-AA is formulated at a pH of 3.5 or less for two reasons: first, to help it absorb in the skin if the formulation is a water based serum; second, to keep it stable since it oxidizes at a high pH. Given that our skin’s natural pH is between 5–7, pH any lower than that can be very irritating on the skin, especially for people who have sensitive skin.


  • The best researched Vitamin C formula on the market is unarguably SkinCeuticals CE Ferulic with 15% L-Ascorbic Acid. The scientist Dr. Sheldon Pinnell did the most research on Vitamin C’s effects on skin and his patent (Duke patent) was the basis for the brand SkinCeuticals (now owned by L’Oreal). With so much research backing this product, no wonder dermatologists and scientists rave about this product. But the downside is its price, at $166 not everyone can afford it. And the formula also eventually breaks down. They have a newer product SkinCeuticals Serum 10 AOX+ at $70 and 10% L-AA which is perfect for beginners and or sensitive skin.

So what are the alternatives?

  • Copycat serums on the market have gotten around the patent, either by lowering the pH further or adding other ingredients. It’s still the L-AA formula that seems to work the best on skin, so go for these.
  • Skin types: dry, normal, aging or resistant skin
  • Products: Paula’s Choice C15 Super Booster and MaeLove Glow Maker
  • Just because SkinCeuticals formula was patented doesn’t mean other antioxidants don’t work — they actually do. Vitamin C by itself also works if stabilized. The fact is before buying a product you’ll need to rely on clinical studies done by the brand to determine how effective the product is.
  • Products: Ultraceuticals New Ultra C Firming Serum and Kiehls Powerful-Strength Vitamin C serum
  • There are also water-free products that use tiny L-AA particles in an oily base — no water so the formula stays stable. When applied L-AA starts to dissolve, creating tiny puddles of highly concentrated acid with very low pH on the skin — extremely irritating so not recommended.
  • Some companies use other stabilizing methods like colloidal gold particles. This is also fine at a higher pH (3.5–6.5) so perfect for sensitive skin people. It gets into the skin easily and is stable- meaning that a lower percentage of gold bonded L-AA can be as effective as a higher percentage of L-AA.
  • Skin types: Ideal for all skin types
  • Products: Naturium Vitamin C Complex Serum

2. Vitamin C Derivatives — The unfortunate downsides of L-AA have led to the development of Vitamin C derivatives. These are apparently stable, less irritating on the skin and have the ability to penetrate the skin barrier. Unlike L-AA that is immediately absorbed, derivatives first need to be converted to L-AA by the skin cells before they can work their magic — meaning they are less potent than their counterparts. They still work thus making them a good alternative to L-AA.

Note: There are certain derivatives that I don’t mention below (e.g., Ascorbyl Palmitate, 3-O-Ethylated Ascorbic Acid, Ascorbyl Glucosamine) because the research around them is very limited.

Derivative 1: Sodium Ascorbyl Phosphate (SAP)

Skin Types: All, especially acne-prone skin

Properties: stable & water soluble; pH 6 hence non-irritating

Benefits: offers all benefits of L-AA but less potent; additionally research indicates it is extremely effective in reducing acne

Products: Derma-E Vitamin C Concentrated Serum

Derivative 2: Magnesium Ascorbyl Phosphate (MAP)

Skin Types: All

Properties: stable & water soluble; pH 7 hence non-irritating

Benefits: offers all benefits of L-AA but less potent; additionally improves skin hydration within deeper layers of skin

Products: Glossier Super Glow

Derivative 3: Tetrahexyldecyl Ascorbate

Skin Types: All

Properties: oil-soluble means it can penetrate not only the outermost layer but the innermost layer of skin (dermis); pH between 4.5–5.5 hence non-irritating

Benefits: offers all benefits of L-AA but less potent

Products: Paula’s Choice Resist Super Antioxidant Serum

Derivative 4: Ascorbyl Glucoside

Skin Types: All

Properties: stable & water soluble; pH 5–8; non-irritating

Benefits: offers all benefits of L-AA but less potent

Products: The Ordinary Ascorbyl Glucoside Solution 12%

How to use Vitamin C in your skincare regimen?

  1. Begin early — ‘Prevention is better than cure’ so start in your early 20s. This is when collagen production starts to slow down aggravating skin problems.
  2. Use in the right order — L-AA is not great at absorbing into the skin so use it on bare skin, meaning use it right after cleansing your skin. This gives it enough time to penetrate the skin while being stable.
  3. Apply in the morning — Due to the sun protection benefits that Vitamin C offers, its best used in the morning before you head out under the UV rays.
  4. Use the right concentration — If you’re using L-AA products start with 10% and work your way up to 20%. There are products on the market with 30% concentrations but they don’t offer any additional benefits over lower concentrations. Again more potent means more irritating so stay between 10–20%.
  5. Avoid conflicting skincare ingredients — There are really two ingredients that you need to avoid with Vitamin C, first being benzoyl peroxide, and second is products containing copper (e.g., copper peptides). These ingredients deactivate ascorbic acid rendering it useless. Again even though they aren’t incompatible, avoid using exfoliating acids and retinol at the same time as Vitamin C — this can irritate your skin. Use them at different times in the day, vitamin C in the morning and retinol and exfoliating acids at night.
  6. Watch out for side effects — For people with sensitive or reactive skin, certain forms of Vitamin C can be very irritating leading to dryness, peeling and redness. These are typically L-AA serums that are formulated at a low pH making it difficult for the skin to adjust. Goes back to the point, stick to low percentages or use derivatives. Also like with any skin care product start slow, either with a patch test or 1–2 times a week. Another possible side effect of using Vitamin C is skin purging i.e. slight increase in acne activity if you’re prone to acne. This should subside in a few weeks.
  7. Store Vitamin C products correctly — Vitamin C is extremely sensitive to light and air since it oxidizes in their presence making it useless. Make sure these products are bought and stored in opaque containers and have an airless pump. Also don’t keep these serums for more than 3 months since they start degrading as soon as the first use. In short, don’t stock up.
  8. Check the color — If your Vitamin C has changed from a colorless serum to yellow, orange or brown that means it’s oxidized. You can continue to use it but it won’t be effective and will also stain your face, making it look yellow.

The bottom line…..

Vitamin C is one of the most well studied ingredients in skincare — in the grand hierarchy it’s right below the gold standard Retinoid. It does everything your skin needs — PROTECT from UV and environmental damage, REPAIR collagen to fight off fine lines and wrinkles, ENHANCE skin’s tone by reducing pigmentation. So start using it today!



Simplifying Skincare

Glow getter for Skin of Color | Expert tips for Radiant Skin | Lets shine together! Certified multitasker juggling a 9-5 in finance, 2 kids, and a passion!