To make a homemade topical ascorbic acid you should look for ascorbic acid tablets or capsules on your local health shop or drug store. The typical dose of ascorbic acid tablet is 500mg. Ordinary ascorbic acid tablet and capsule is of the L-Ascorbic form which is more effective than ascorbyl palmitate but it is very unstable. L-Ascorbic acid dissolved in water will only last for 2-3 days. An indicator of its effectiveness is the color of the solution. Fresh and highly effective L-ascorbic acid solution should be water clear in color and turns more yellow as it degrades and losses its potency. To be effective, topical ascorbic acid solutions should have a concentration of 5 to 20%. The higher the concentration the more effective is the product but the irritation also increases. Impurities in the water such as dissolved minerals will cause the L-ascorbic acid solution to degrade faster therefore you should always use distilled water.
For a 100mL 5% L-Ascorbic Acid solution – dissolve 10 pcs. of 500mg (5grams
vitamin-C) over 100grams (100mL) of distilled water.
For a 100mL 10% L-Ascorbic Acid solution – dissolve 20 pcs. of 500mg (10grams vitamin-C) over 100grams (100mL) of distilled water. Clean first the face using soap to remove oil and dirt. Apply the L-ascorbic
acid solution to the face using a cotton ball. If you have a leftover solution,
put it in an opaque container and then keep it in the refrigerator. It is best to prepare daily batches to keep the potency of the L-Ascorbic acid solution.
Ascorbic acid stability in aqueous solutions.Meucci E, Martorana GE, Ursitti A, Pischiutta MG, Miggiano GA, Castelli A.
Stable topical ascorbic acid compositions – US Patent 6146664
Topical ascorbic acid compositions – US Patent 5846996
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