Sodium Ascorbyl Phosphate Vs L-Ascorbic Acid: Which Is Better For Your Skin?

sodium ascorbyl phosphate vs l-ascorbic acid

Vitamin C is one of the best skincare ingredients you can incorporate into your skincare routine – mainly for its anti-aging, skin-lightening and UV-protective properties.

Up until recently, most vitamin C-containing skincare products were formulated with L-ascorbic acid (the pure form of vitamin C). Although L-ascorbic acid is a highly effective skincare ingredient, it’s caveat is that it can be irritating for people with sensitive skin and it is highly unstable and oxidizes easily in liquid form – leaving your product ineffective.

There is now another option if you would like to benefit from using vitamin C in your skincare routine (but aren’t a fan of L-ascorbic acid): sodium ascorbyl phosphate (or just SAP for short).

Read on if you’d like to know more about this mysterious skincare ingredient that may be just as beneficial (if not, better!) than L-ascorbic acid.

What Is Sodium Ascorbyl Phosphate?

Sodium ascorbyl phosphate (SAP) is an antioxidant that can be found in some skincare products such as serums and creams. It is a stable form of vitamin C (called a derivative in chemistry terms) that is made by combining ascorbic acid with a salt and a phosphate.

L-ascorbic acid is the bioactive form of vitamin C (the form our skin actually uses). However, when you apply SAP to your skin, enzymes must first convert it to L-ascorbic acid. Although this process makes SAP less active and less potent than L-ascorbic acid, it also means that SAP is much less likely to cause irritation, making it suitable for people with sensitive skin too.

Unlike L-ascorbic acid, which tends to be highly unstable and degrades easily when exposed to light or oxygen, sodium ascorbyl phosphate is one of the most stable forms of vitamin C. This means that products containing sodium ascorbyl phosphate are easier to formulate and don’t degrade quickly like vitamin C serums formulated with L-ascorbic acid.

vitamin c derivatives skincare sodium ascorbyl phosphate vs L-ascorbic acid
A list of vitamin C derivatives currently used in skincare formulations in place of L-ascorbic acid (which is extremely unstable and can be irritating for some people)

Is Sodium Ascorbyl Phosphate Good For Skin?

Just like L-ascorbic acid, sodium ascorbyl phosphate functions as a powerful antioxidant, helping to reduce the amount of damage that the sun (and pollutants) cause to your skin cells (this damage results in photo-aging which appears as pigmented spots, loss of skin tone, fine lines and wrinkles and even skin cancer).

In addition to acting as an antioxidant, sodium ascorbyl phosphate has also been shown to be an effective skincare ingredient for treating acne and fading hyperpigmentation.

Sodium Ascorbyl Phosphate Helps Prevent Photo-Aging

UV exposure accounts for up to 80% of visible signs of aging (also known as photo-aging). UV radiation causes photo-aging by inducing the generation of free radicals (molecules that are highly unstable because they are missing an electron).

Free radicals cause permanent damage to skin cells (and all other cells in the body) because they steal electrons from molecules within these cells in order to become stable again. This damage can appear as hyperpigmentation as well as fine lines, wrinkles and loose and saggy skin (if free radicals cause damage to the collagen and elastin fibers within skin cells).

Sodium ascorbyl phosphate (along with other forms of vitamin C) is effective at preventing photo-aging because it neutralizes or removes free radicals by donating electrons to them.

Now, we could avoid the sun altogether to prevent the generation of free radicals in our skin, however this isn’t practical! This is why it’s so important to always wear SPF and other sun protection. Adding a vitamin C serum to your skincare routine will give you added protection from free radical-induced skin damage.

Sodium Ascorbyl Phosphate Treats Acne

One big difference between sodium ascorbyl phosphate and L-ascorbic acid is that SAP has been shown to be effective at preventing and treating acne.

These researchers found that sodium ascorbyl phosphate works in two ways to prevent and treat acne. First, it has a strong anti-microbial effect (which lasts up to 8 hours after application), and secondly, it reduces the oxidation of sebum by up to 40%.

Sebum oxidation occurs when our skin is exposed to UVA radiation, pollutants and cigarette smoke. It is the oxidized by-products of sebum (and not sebum itself that causes acne and skin aging). For example, research has shown that when squalene in our skin is oxidized, by-products such as squalene peroxide lead to clog pores, contribute to inflammatory acne and may even contribute to wrinkling!

Sodium Ascorbyl Phosphate Promotes Collagen Production

L-ascorbic acid is known to stimulate collagen production, and the good news is that research suggests that sodium ascorbyl phosphate has the ability to do the same. So as well as preventing photo-aging by acting as an antioxidant, sodium ascorbyl phosphate keeps the skin firm by helping to boost collagen in our skin.

Incorporating a serum containing either L-ascorbic acid or sodium ascorbyl phosphate would therefore be beneficial for anyone who wants to have younger looking skin as after the age of 20, the collagen production in our skin begins to slow down. Your skin begins to lose collagen after the age of about 30 (although sun exposure, poor diet, pollution, cigarette smoke and other toxins speed up this process).

SAP Helps Fade Hyperpigmentation

One of the main reasons why people incorporate a vitamin C serum into their skincare routine is because of vitamin C’s ability to brighten the skin and fade hyperpigmentation.

Studies such as this one have found that just like L-ascorbic acid, sodium ascorbyl phosphate also has the ability to fade dark spots on the skin such as melasma and post-inflammatory hyperpigmentation by inhibiting the production of melanin.

Is Sodium Ascorbyl Phosphate Better Than L-Ascorbic Acid?

So you probably want to know whether you should use a vitamin C serum formulated with L-ascorbic acid or with sodium ascorbyl phosphate. Is sodium ascorbyl phosphate more effective than L-ascorbic acid?

Unfortunately, there are still unanswered questions as to how sodium ascorbyl phosphate works and whether it is more effective than L-ascorbic acid since the research on SAP is still so limited. However, here are two reasons why I have ditched my L-ascorbic acid serum and switched to using a vitamin C serum formulated with sodium ascorbyl phosphate:

1. Sodium Ascorbyl Phosphate Is The Most Stable Form Of Vitamin C

Out of all the different forms of vitamin C used in skincare products, sodium ascorbyl phosphate is the most stable.

Although L-ascorbic acid is the bioactive form of vitamin C that our skin utilizes, it is a highly unstable ingredient as it easily degrades when exposed to light or oxygen (which is going to happen every time you open your vitamin C dropper bottle). This makes L-ascorbic acid difficult to formulate and package and you’ll find that your vitamin C serum will go bad before you’ve finished the bottle.

So a vitamin C serum formulated with SAP will have a longer shelf life – even once it has been opened.

As well as being light and oxygen-stable, sodium ascorbyl phosphate is also water-stable, meaning that it’s easy to incorporate in different product formulations (not just vitamin C serums).

2. Sodium Ascorbyl Phosphate Is Less Irritating And Beneficial For Those With Sensitive And Acne-Prone Skin

For L-ascorbic acid to be effective, it needs to be formulated at quite high concentrations (usually 15-20%). This is because L-ascorbic acid is not easily absorbed through the skin’s lipid barrier. Unfortunately, this concentration can cause skin irritation and acne breakouts for some people (especially those with sensitive skin).

While there are vitamin C serums formulated with lower concentrations of L-ascorbic acid on the market, their effectiveness is questionable.

The good thing about sodium ascorbyl phosphate is that even those with sensitive skin can use products containing this form of vitamin C as it isn’t associated with the irritation that people often experience with L-ascorbic acid. This is because sodium ascorbyl phosphate has a salt molecule attached to it – which allows it to penetrate the skin’s lipid barrier easily.

Since SAP penetrates the skin so readily, a lower concentration is needed for the same effectiveness one would get with a vitamin C serum containing a high concentration of L-ascorbic acid.

Vitamin C Serums With Sodium Ascorbyl Phosphate

Not many skincare products are formulated with sodium ascorbyl phosphate since it is still a new skincare ingredient. But there are two vitamin C serums formulated with sodium ascorbyl phosphate that stand out as the best.

1. Neogen Real Vita C Serum

The Neogen Real Vita C Serum is a powerful Korean vitamin C serum enriched with 22% sodium ascorbyl phosphate. It also contains niacinamide for additional skin brightening effects as well as vitamin E (another powerful antioxidant that reduces UV damage) and panthenol (for skin hydration).

Full ingredients list: Water, Sodium Ascorbyl Phosphate(22%), 1,2-Hexanediol, Niacinamide, Dipropylene Glycol, Butylene Glycol, Citric Acid, PEG-60 Hydrogenated Castor Oil, Xanthan Gum, Citrus Aurantium Bergamia (Bergamot) Fruit Oil, Sodium Metabisulfite, Ethylhexylglycerin, Coptis Japonica Extract, Dextrin, Theobroma Cacao (Cocoa) Extract, Hippophae Rhamnoides Oil, Ascorbic Acid(0.1ppm), Tocopheryl Acetate(0.1ppm), Panthenol, Hydrolyzed Collagen, Citrus Paradisi (Grapefruit) Fruit Extract, Citrus Limon (Lemon) Fruit 

2. Mad Hippie Vitamin C Serum

Although not a Korean skincare brand, the Mad Hippie Vitamin C Serum is also a top notch vitamin C serum that is formulated with a combination of 10% sodium ascorbyl phosphate, vitamin E and ferulic acid to offer a compounding antioxidant effect.

In addition to these antioxidants, this serum also contains hyaluronic acid and glycerin (for skin hydration), konjac root (to help soften and soothe the skin) and chamomile extract (to also soothe the skin).

Full ingredients list: Water Deionized, Sodium Ascorbyl Phosphate (10%), Alkyl Benzoate, Vegetable Glycerin, Water, Glycerin, Sodium Levulinate, Sodium Anisate, Clary Sage (Salvia Sclarea), Grapefruit (Citrus Grandis), Hyaluronic acid, Amorphophallus Konjac Root Powder, Aloe Barbadensis Leaf, Vitamin E (Tocotrienol), Ferulic acid, Chamomile Flower Extract (Recutita Matricaria), Sodium Phytate, Xanthan Gum, Hydroxyethylcellulose

How To Get The Most Out Of Sodium Ascorbyl Phosphate

Even though sodium ascorbyl phosphate is much more stable and much less irritating than L-ascorbic acid, there are a few tips you should know to make sure you’re using SAP correctly so that you’re getting the most out of your product.

What Percentage Of Sodium Ascorbyl Phosphate Is Most Effective?

Since SAP is still such a new skincare ingredient, and most research focuses on L-ascorbic acid, it is still unknown what concentration of sodium ascorbyl phosphate is the most effective. However, the most effective concentration is likely less than what is required with L-ascorbic acid since SAP penetrates the skin barrier much easier and doesn’t require a low pH to work.

It’s best to look for serums containing sodium ascorbyl phosphate (instead of creams or lotions) as these generally contain a higher concentration of vitamin C. Some skincare companies actually do not disclose what the concentration of SAP is in their products, but they will usually give a lower limit (for example, they will state that their product contains no less than 10% SAP).

Also, if you would like to incorporate SAP into your skincare routine to help treat and prevent acne, then even 1% concentration of SAP has been found to have strong antimicrobial effects against acne-causing bacteria!

When Should I Apply Vitamin C Serum In My Skincare Routine?

You’ll also get the most benefit out of sodium ascorbyl phosphate (and any other form of vitamin C) if you apply it in the morning (due to it’s UV protective effects). And always wear SPF, since antioxidants on their own aren’t enough to protect your skin from the sun.

Just like L-ascrobic acid, sodium ascorbyl acid is pH dependent (meaning, it works best at a certain pH). However, unlike ascorbic acid (which is most effective in an acidic environment), SAP requires a more neutral pH (of about 6 to 7). So, it is recommended to apply any SAP-containing vitamin C serum after chemical exfoliants and any low pH toners or serums.

It’s also recommended to first wait 20-30 minutes after applying these products before you go ahead and apply your SAP vitamin C serum.

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