Trade sugar for function. Mix responsibly. IV Seltzer is a low-calorie, low-sugar functional seltzer built on milk thistle, real-root ginger, B-vitamins (B6, B12) and electrolytes — under 20 calories and just 4g of sugar per can, with no artificial sweeteners. Works as a premium mixer for vodka, gin, tequila or rum, or enjoy it straight over ice.