As a matter of principle, we prefer to use vitamins of natural origin in our formulas when their concentration is compatible with the effectiveness of the product. In the case of vitamin C, for example, we use Acerola in the Iron formula.
For the spray, given the small volume, using the most concentrated acerola with 20% vitamin would only have provided 4 mg of vitamin C, a dose too low to be effective.
The many scientific studies on the subject have shown no difference in efficacy or bioavailability between the different origins (synthetic, natural) of ascorbic acid.