Agar comes from red algae. People use it as a plant-based substitute for gelatin in cooking.
As a supplement, agar provides soluble fiber. This fiber helps maintain bowel regularity and can create a sense of fullness. Many take it mixed with water or juice to ease occasional constipation.
Once in the stomach, agar expands with liquid. Always swallow it with a full glass of water to prevent a blockage in the throat or gut. It might also reduce how quickly your body absorbs medications or other supplements.