As a note, part of this post was originally shared on January 21, 2011, on the old blog. There are some great comments over there that I couldn’t bring over here, so I encourage you to check those out if you’re interested.
Vitamin C is a water soluble anti-oxidant has been proven in studies to be an anti-inflammatory that can stimulate collagen formation, lighten skin, treat hyperpigmentation, and heal wounds. It’s a water soluble ingredient that works best in creations with a pH of less than 3 (now that’s acidic!) and concentrations up to 5% are well tolerated by our skin. It’s present in every layer of our stratum corneum and it’s essential for stimulating collagen synthesis and the formation of the barrier lipids. Applying a lotion with a concentration of 5% over 6 months have been shown to improve the appearance of skin with photo-damage (and this isn’t the “improve the appearance” like the cosmetic companies use this phrase – this was an actual study!) and it’s been shown to reduce sunburn cell formation and reddening in humans. And it has been shown that it can influence the synthesis of specific ceramides, which can improve the water retaining properties – well, at least in vitro. (This hasn’t been confirmed in living human skin yet.)
Ideally we’ll partner Vitamin C with Vitamin E to create an anti-oxidizing powerhouse because the C will help the Vitamin E regenerate to keep the anti-oxidizing awesomeness going for quite some time, and we can throw in up to 0.05% beta-carotene to increase the anti-oxiding power. This combination has been shown to quench free radicals on our skin.
So why aren’t we using it in every single product we make? Because many forms are really unstable in water and it doesn’t easily penetrate our skin. Plus pH 3 is really acidic and that’s not a great pH for our lotions or serums to be. And it degrades easily when exposed to oxygen.
Let’s say you want to use Vitamin C in your creations. Is it possible? It is. The ideal product would be a non-ionic anhydrous product or emulsion in an air tight container (so a lotion or serum not including any cationic ingredients – like BTMS or cationic polymers – or anionic ingredients – like our bubbly surfactants – is right out). You can use it with silicones or oils as an anhydrous creation. And you need to ensure the pH is at the right level for the version you want to use.
There are quite a few versions of Vitamin C you can find, so check the INCI before you buy!
The white powder in the picture above is l-ascorbic acid, a water soluble powder that can oxidize quite easily in our hydrous products, converting into dehydroascorbic acid, the oxidized version, which you’ll notice has an orange or brown tinge. It has a suggested usage rate of 1% to 4% with a pH of 2.2 to 2.5, which is quite low, so you’ll have to keep an eye on the pH of your product and alter it accordingly. The ideal way to use this is in an anhydrous product, like this wonderful formula you can find at Lotioncrafter.And here’s another formula for C&E intensive serum from Lotioncrafter.
You can use an ester like ascorbyl palmitate in a serum or lotion as your source of Vitamin C, for instance. You can use the water soluble Vitamin C in an emulsion, but you will see some degradation of the ingredient, so don’t choose a pump bottle but something like a malibu/tottle or disc cap to keep it less exposed to the air.
I like using tetrahexyldecyl ascorbate, which I found at Lotioncrafter. It’s an oil soluble Vitamin C used to promote a more even skin tone. (I used it at 2% in this formula to see how my skin handles it, but you could use this ingredient as high as 10%.)You can use this in an anhydrous or emulsified formula in the oil phase. It’s nice when combined with l-ascorbic acid in a facial serum!
If you want to make products that contain water, like lotions or toners, magnesium ascorbyl palmitate (MAP) liposomes (INCI Water & Phospholipids & Magnesium Ascorbyl Phosphate, from Formulator Sample Shop), are really stable, and easy to use in products that contain water as they can handle pH levels of 4.5 to 6. These work really well in products that contain water.
You can find magnesium ascorbyl phosphate (powder), a stable, water soluble version of Vitamin C. (I found this at Lotioncrafter.) It works best at pH 6 to 7, and can discolour under pH 6. It can be used at 0.2% to 3% in the heated water phase as high as 70˚C. This may be a better choice for those with sensitive skin as this version is less exfoliating than L-ascorbic acid.
Emulsifiers: Aristoflex AVC – a facial serum with Vitamin C and ferulic acid – uses MAP liposomes
As well, I have an e-zine on the topic, AHA, salicylic acid, Vitamin C – oh my! which you can find in the store part of the blog.