Calcium chloride is a medical-grade calcium salt, not something you should reach for as a daily supplement. Most oral supplements use carbonate or citrate because they are gentler on the stomach. This form is highly concentrated and can burn or irritate the digestive tract when swallowed.
Doctors and hospitals use it intravenously for acute calcium deficiencies and certain emergency situations. In consumer products it shows up in tiny amounts as a food additive or inside water-filtration items. For bone health and general support, standard calcium forms work better and offer no meaningful absorption disadvantage.
Do not take calcium chloride by mouth yourself. Without medical supervision it can trigger stomach upset, harm the esophagus, or cause a dangerous calcium overload.