Vitamin C in 3 words for you: an antioxidant, collagen booster, and skin brightener!

Read on to find out everything you need to know about vitamin C 🍊

What Is Vitamin C?

Vitamin C, a water-soluble vitamin, also known as ascorbic acid is an important vitamin needed by the body. It helps to protect your cells, maintain healthy skin and help with wound healing (to name a few things!). A lack of vitamin C in the body can lead to scurvy. Interesting… but I’m sure you’re not here to learn about scurvy so let’s move on to the benefits topical use can do for our skin!

What Are The Benefits Of Vitamin C?

Vitamin C offers powerful protection to your skin against the sun, environmental damage, and pollution.

Protection Against Free Radicals

Vitamin C is a powerful antioxidant that binds to free radicals.

FYI, free radicals are highly unstable molecules found in the air, our bodies and materials around us. They attach themselves to our healthy cells to become stable and this turns the cells into free radicals. When we have more free radicals than antioxidants in our bodies, our cells suffer oxidative stress, becoming damaged. So this could be the cells within collagen and elastin in our skin, for example. If collagen and elastin cells are damaged, they don’t function effectively to support the structure of our skin. This can then lead to visible signs of ageing.

In short, vitamin C basically binds to the free radicals so that your cells don’t. This protects them (and therefore, your skin) from the free radicals that would otherwise cause the damaging oxidative stress and as mentioned, the appearance of ageing. 

As Well As The Antioxidant Benefits, Vitamin C Also:

  • Makes sun damage and spots of pigmentation on the surface of your skin less visible by inhibiting your skin’s melanin production (which is what causes skin discoloration like dark spots and pigmentation).
  • Brightens dull skin.
  • Because it’s highly acidic it accelerates the production of elastin and collagen by triggering the skin to heal itself. This helps to reduce red blotches left after spots and delay the signs of ageing by supporting the skin’s structure.
  • It increases the effectiveness of sunscreen and gives the skin better protection from UV rays (mainly enhances UVA protection)

What Forms Of Vitamin C Exist?

I don’t know about you but trying to decipher the different (and many) forms of vitamin C out there just left me contemplating if I really needed that ever sought after glow. But once the headache from reading passed, I decided that ‘Yes!’ I did want that glow for me, for you, for everyone! 🤗

Ascorbic Acid

The gold standard form of Vitamin C for your face is pure vitamin C, known as ascorbic acid or L-ascorbic acid (L-AA). It’s the most researched form of the vitamin when it comes to benefits for the skin such as the ones mentioned above.

*Throughout I will use the terms ascorbic acid & L-ascorbic acid interchangeably but they are the SAME thing – pure vitamin C! If it’s a derivative I’m talking about, I’ll state it! 😘

You will see many ascorbic acid-containing products out there with high concentrations. This is because many studies that show efficacy used L-ascorbic acid with concentrations of 15% or higher. So, we know this is the minimum amount we want in our products in order to experience the benefits discussed above.

What About The Stability Of L-AA?

So, this great form of vitamin C is unstable. It can oxidise quickly when exposed to water, heat or air. This is because of L-ascorbic acid’s strong desire to bind to free radicals, like oxygen (this process is oxidation). Which is great on our skin but not if it’s happening inside the bottle it’s contained in!

Once vitamin C is oxidised, it changes colour from clear to slightly orange and then dark orange. This colour change shows that the activity of ascorbic acid is disabled. Basically it’s not performing much of those great benefits mentioned above!

This is why you will see brands either employ the use of an airless and dark coloured container (if a water-based formula) or they will base the L-AA in a water-less solution. This is all to help the ascorbic acid from being negatively affected by heat, light or air and ultimately, last longer.

Derivatives Of L-AA

So on to other forms of vitamin C, which are known as derivatives of ascorbic acid. These derivatives have been made to be stable (unlike ascorbic acid) and go by the names of:

  • Ethyl Ascorbic Acid: consists of L-AA and an ethyl group. This form is soluble in both water and oil. It acts directly like ascorbic acid and is closer in molecular weight to L-AA. This allows for faster visible results.
  • Tetrahexyldecyl Ascorbate (TDH): an analogue of L-ascorbic acid which is oil-soluble. This form of vitamin C can penetrate the epidermis (top layer of skin) and the dermis (second layer of skin) very well. As shown by many studies and unlike other forms of vitamin C.
  • Magnesium Ascorbyl Phosphate (MAP): a water-soluble, effective antioxidant for the skin but, less potent than L-AA. This form can increase skin’s hydration and is effective at skin brightening (more so than over derivatives). It’s usually found in a concentration of 10% or less due to how difficult it is to solubilise. 
  • Sodium Ascorbyl Phosphate: A water-soluble form of L-ascorbic acid. It’s L-ascorbic acid combined with palmitic acid, a fatty acid, and sodium. It’s potentially effective for brightening an uneven skin tone and has been shown in research to positively influence factors linked to breakouts (at concentrations between 1% & 5%). 
  • Ascorbyl Glucoside: a form of L-ascorbic acid combined with glucose. This makes it much more stable in water compared to L-AA but much less potent. It’s a well-researched derivative with great brightening abilities but its ability to improve uneven skin tone or spots is relatively weak.
  • Magnesium Ascorbyl Palmitate: oil soluble form of ascorbic acid.
  • Ascorbyl Palmitate: a non-acidic, oil-soluble form of L-ascorbic acid. Less stable than Sodium Ascorbyl Palmitate, Magnesium Ascorbyl Palmitate, or Ascorbyl Glucoside. Particularly good at minimising environmental damage to the skin but that’s about it!

Lots of different derivatives out there but hopefully this list helps you to feel a bit clearer on what’s in your different vitamin C products! Screen shot the list if you would like, so that it’s handy for you to refer back to!

They Have To Convert

Vitamin C derivatives are a great alternative to using L-ascorbic acid. However, they still need to be first absorbed by the skin and then converted to pure vitamin C (L-ascorbic acid). This conversion occurs when the derivatives have penetrated the skin.

A direct comparison on their potency compared to L-ascorbic acid cannot be made. This is because the efficacy of the conversion is often unkown. However, some derivatives have been shown to have better brightening effects than L-ascorbic acid (e.g. MAP). And so some research into the product reviews of a derivative form of vitamin C that you are looking at, is definitely worth it. This is especially true if you are primarily looking for brightening results. If you are looking for the other general benefits that vitamin C can offer, then that is where L-AA wins hands down!

*The Ordinary website has a pretty handy guide all about vitamin C derivatives, here*

Anhydrous Formulas

Many L-AA containing products and vitamin C derivatives are contained within formulas that are water free – or ‘anhydrous’. Basically the formula is completely free of water, giving the vitamin C more stability in the bottle it’s contained within and on your skin. 

One of these water-free formulas that can hold vitamin C is silicone (faced a hard time in the beauty industry lately but not as bad as it’s been made out to be!). There is, however, some evidence to suggest that silicone can interfere with the exposure of the vitamin C content to your skin. This is why you may see some brands, like The Ordinary or The Inkey List, increasing the percentage of vitamin C within their silicone based products to levels of 30%. This is to counteract this and increase the amount of vitamin C getting in to your skin.

There are other water-free formulations out there if you would prefer not to use silicone, however!

How Can I Include Vitamin C In My Skincare Routine?

Which Form?

So, like me, you’ve decided to give vitamin C a go, so which form of it and how do you start?!

Well, firstly, decide whether you want to go for pure vitamin C (L-ascorbic acid) or a derivative of vitamin C. This will depend on what you are looking to get out of the product. So, for example, I want the brightening benefits as well as the anti-ageing benefits and so I personally have gone with an L-AA product. 

You may also want to consider a derivative of vitamin C first before ascorbic acid, if you’re new to vitamin C or have particularly sensitive skin!

Another point to consider is whether you plan to keep your ascorbic acid product in your cupboard for a long time and not use it daily. This is because, as we’ve discussed, they can oxidise quickly so you want to use them up within a couple of months. If you want to have the product in your cupboard for a while and plan to use it as and when you want, I would go for a more stable derivative form!

Formulation & Skin Type?

Next I would consider the form in which the vitamin C or derivative is contained within. Some formulas that are water and oil-free can actually feel very oily when applied to the skin and so oilier skin types want to be wary! In this case, you may find a water-based vitamin C product is best. However, they can be sticky if they have a high percentage of vitamin C. Just something to be aware of!

You would also want to consider the concentration of the vitamin C product. In high concentrations, ascorbic acid can be highly irritating (because of its low pH). Sensitive skin types also need to be wary. Start low and slow – use a small amount (preferably of a lesser concentration like 10% L-AA), once or twice a week to build up some tolerance! Alternatively, use a less irritating derivative form of vitamin C, like Magnesium Ascorbyl Phosphate (mentioned above).

AM or PM Use?

A highly debated topic. Some say use in the morning as it protects the skin from environmental aggressors, pollution and sun which you would face more in the day than the night. It also can enhance the effectiveness of your suncream, which again, you would use in the day. However, others say that because vitamin C levels in the skin are depleted at night, it is best to use it then. You may also want to use it in the PM if you’re not a fan of the glazed look that it can give your skin!

Regardless of whether you use it AM or PM, consistency is key to experiencing the great benefits that vitamin C can offer. It is also best to use either daily or every other day.

BUT, only do this once you have built up a tolerance to vitamin C. I know it’s tempting but start slow, I can’t stress this enough! Start with once or twice a week for the first couple of weeks. Then increase to 3-4 times a week for another couple of weeks before moving to daily use. Your skin will thank you!

vitamin c

What Does Vitamin C Work Best With?


So we’ve discussed this before in a previous blog but it’s fine to use vitamin C and an acid in the same routine! Vitamin C and its derivatives should be made with a pH under 3.5. At this pH level, vitamin C can penetrate the skin. Since acids should be made with a pH range of 3-4, the acid won’t affect how the vitamin C is absorbed when layered on top of the acid. Really the acid is just creating the perfect base for the vitamin C to work with! 

If using a non-acidic form of vitamin C, like MAP or Ascorbyl Glucoside, then using an acid beforehand will actually help them to penetrate the skin and convert to vitamin C.

However, remember for some people’s skin, this might be too much! If your skin is sensitive or you are building up tolerance to either vitamin C or acids, then consider using them apart. As I always say, it’s down to what your own skin can handle – everybody is different!

Side-note; many people will say that using an acid and vitamin C can inactivate each other but I haven’t any evidence to show that. I’ve only found evidence to show what a great pairing they are together. Also, products, generally, have been designed by scientists in a lab to withstand being inactivated by other substances!

Vitamin E?

Vitamin C and E are both antioxidants which support each other and enhance the power of each other. Together they enhance the photo-protective effects of sunscreen. Vitamin C has been reported to enhance UVA protection, whereas vitamin E is more effective against UVB radiation. A great pairing really! ✅

Ferulic Acid?

Ferulic acid has been shown to provide antioxidant benefits to the skin. It can also enhance the stability of topical applications of vitamins C and E. Defence against environmental assault is another benefit which ferulic acid can provide!

You’ve gone from a great pairing above to an incredible trio if you have an ascorbic acid product containing both vitamin E and ferulic acid!


Vitamin C needs an acidic environment (pH around 3.5) and retinoids need a much less acidic environment to work (pH around 5.5). So, combining the two isn’t a good idea if you want both of them to be absorbed effectively and work best.

I would save your retinoids for evening use and vitamin C for the daytime, personally!


Like retinoids, niacinamide works at a different pH (around pH 5). This pH can basically affect how well the skin absorbs the vitamin C (as we’ve seen, absorbs most at a low pH around 3.5). So, they are better used separately!

*Just to point out, there are serums out there that contain vitamin C mixed with retinoids and niacinamide all together. That is fine, they have been specially formulated in a lab/by experts to work well together and for your skin!*

What Age Should I Start Using Vitamin C?

General consensus says to start using a vitamin C product from the age of 18. I wish I had started much earlier than I did (at 27!). So if you’re reading this now, you’re 18+ and don’t currently use any vitamin C in your skincare routine, get shopping and get glowing!

vitamin c
Vitamin C glow, I wish I had this at 18!

So, that’s vitamin C done – I hope this was all very helpful and not confusing!! I will be telling you more about the vitamin C product that I have tried and tested in my next blog post!

Look out for it and in the meantime leave me some comments below and I’ll get back to you!

Love & Knowledge,

S A M A N T H A 


P.S. You may also want to take a look at my own personal skincare journey & why I began Skin Acid Trip, here

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  1. Julie Turnbull 11/07/2020 at 21:31

    Could you please let me know if its ok to use hyaluronic acid in the evening before 0.5% retinol (all from the ordinary). I use HA before buffet & ascorbyl glucoside in the am.
    Many thanks
    Julie Turnbull

    1. Samantha 13/07/2020 at 08:43

      Hi Julie,
      I personally would say to use your HA after your retinol as ideally you want your retinol to be the first thing on your skin after cleansing. Don’t forget to make sure the skin is damp before applying your HA serum (I use either a rose water or mineral water mist).
      Hope that helps,
      Samantha x


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