Home Cosmetic Science Talk Formulating ascorbic acid serum?

  • ascorbic acid serum?

    Posted by tinas on November 21, 2023 at 12:50 am

    I like to formulate a stabile ascorbic acid serum from ascorbic acid powder, I found this serum with 23% ascorbic acid from COSRX - why is this one stabile? Is there any ingredients here that prevent oxidation? The bottle is not airless. Here is the ingredients list: Water, Ascorbic Acid(23%), Propanediol, Dimethicone, Tromethamine, Panthenol, Ethyl Ascorbyl Ether, Squalane, Caffeine, Sodium Chloride, Sodium Hyaluronate, Sodium Sulfite, Disodium EDTA, Glutathione, Adenosine, Acetyl Glucosamine, Gardenia Florida Fruit Extract, Allantoin, Dextrin, Tocotrienols, Tocopherol, Elaeis Guineensis (Palm) Oil, Butylene Glycol, Arginine, Niacinamide, Pentylene Glycol, Alcohol Denat., Helianthus Annuus (Sunflower) Seed Oil, Glycyrrhiza Glabra (Licorice) Root Extract, Methyl Trimethicone, Carthamus Tinctorius (Safflower) Seed Oil, Camellia Japonica Seed Oil, Daucus Carota Sativa (Carrot) Root Extract, Beta-Carotene.

    Unknown Member replied 3 months ago 4 Members · 4 Replies
  • 4 Replies
  • fareloz

    November 21, 2023 at 3:35 am

    why is this one stabile?

    Is it? Have you ever had it? How long did it take for you to spoil? Based on the reviews I’ve seen on the Internet it is not stable.

    From the INCI I see they use Sodium Sulfite as an antioxidant that should keep AA stable, but I doubt it does it for long time (since there is 23% of AA). They might also have very acidic pH, below 3, that helps to have AA not protonated and therefore more stable in water.

    If you want to make an AA serum you can go several ways:

    1. Skinceuticals formula, where Ascorbic Acid is paired with Ferulic acid and mixed Tocopherols and most of the water replaced with Ethoxydiglycol. (you can read up on it here or on the internet).

    This formula is used in many other famous products too: Timeless, Geek & Gorgeous etc.

    2. Waterless formula. The main problem is water, if you remove it - the solution will be much more stable. There are several ways, one is to get dispersion of AA in silicones, like The Ordinary does with 30% AA cream and L’oreal with 10% small tube. But this is hard to achieve in DIY setup.

    3. Waterless formula with Propanediol (not propylene glycol). You can get 12% of AA + 88% pf Propanediol solution or if you add Urea you can get up to 20% of AA in Propanediol+Urea (the product is Matter of Facts serum)

    4. Do fresh batch frequently. There are some DIY suggestions to make a tiny batch once in few days and store it in the fridge in opaque bottle. If you have scales and all you need to to mix AA with water it is not as bothersome.

  • markbroussard

    November 21, 2023 at 7:11 am


    That Cosrx formula you reference is not going to be long-term stable. It’s probably good for 6 months at best.

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