I have used vit C (ascorbic acid) for 4 years now, together with Iodine most times as I take the C 3-4 times a day.
It works fine, no problem. Gut health is good too; I believe most of the info on most sites about vit C and Iodine are wrong. Choose wisely!
Ascorbic acid is what animals make 5-15 grams a day of, adjusted to a human body weight. The one we take as supplement is not synthetic, but manufactured, from starch.
It is pretty much carbons strung together, like Sugar is.