The Stability of Vitamin C

We’re thrilled to see that vitamin C is enjoying a renaissance of sorts. A skin care work horse for many years, vitamin C has a long list of benefits such as protecting against UV damage caused by free radicals, restoring skin’s elasticity and brightening overall skin tone, to name just a few. However, this powerful antioxidant has one Achilles heel: stability. The stability of vitamin C has been the downfall of this potent ingredient, so it didn’t come as a surprise when a customer asked us how we stabilize our Apothekari Bespoke Vitamin C serums and what kind of shelf life she can expect from it.

There are many forms of vitamin C, including Sodium Ascorbyl Phosphate (SAP), Magnesium Ascorbyl Phosphate (MAP), 3-O-Ethyl Ascorbate, Ascobrbyl Glucoside, amongst others. We’ve chosen to formulate our Bespoke Vitamin C with the L-ascorbic acid form of vitamin C because it has the most clinical research to back up its usefulness in skin care.

Skin care products that lose their effectiveness aren’t good for anyone, so we’ve taken some steps to ensure that our serum retains its stability:

  • We add a couple of actives which deliver their own benefits – namely, ferulic acid and vitamin E – but which also help to stabilize the L-ascorbic acid.
  • We mix the serum to order so that the L-ascorbic acid is freshly added, helping to ensure that a bottle of the serum has a shelf life of 6 months as tested by our lab. This step is unique to other L-ascorbic acid serums on the market. It also allows us to avoid the use of certain ingredients, like propylene glycol, which may extend the shelf-life, but which some individuals are unable to tolerate.

We know that some newer ingredients may sound more exciting than the tried and true vitamin C, but we don’t think you’ll regret making Bespoke Vitamin C serum a part of your everyday routine. We like to think of it like our favorite pair of jeans: we may be tempted by new ones with trendy styles and colors but we always go back to our favorite because it makes us look and feel so good!