Cheap bulk Vitamin C is sold as just the chemical ascorbic acid that really doesn't help your body the way a natural bioavailable supplement should. Your body needs Vitamin C in a natural form along with associated bioflavonoids. It's best to consume these through foods but if you are temporarily cutting back on fruit to restore insulin response or you decide to supplement your diet or already take Vitamin C is part of your regimen consider something better.
Here are two forms of Vitamin C along with a short video.
We keep this product on hand and I take it every other day and 1-3 times a day if I get sick, which is pretty rare.
Ester-C contains a buffered form of vitamin C - calcium ascorbate, a neutral acid that doesn't upset the stomach. It also contains citrus bioflavonoids like acerola, rutin, and hesperidin. They say to take 2 per day. One is fine. The price is up from pre-pandemic levels so if you know of a better alternative please let me know.
Solaray - Super Bio-Plex Vit C & Bioflavonoids
Non-buffered Vitamin C - 250 count
Solaray C - 100 count size if you want to try a smaller bottle
Solaray C with Quercetin (some used this when sick along with other supplements)
A short (1:20) video explaining the buffered C and the Bioflavonoid ratio
