Calcium: What It Does, Best Sources, and Supplements That Actually Work

When you think of calcium, a mineral essential for bone strength, muscle function, and nerve signaling. Also known as Ca, it's not just for older people—it’s the foundation of your skeleton from childhood through old age. Your body doesn’t make calcium. You have to get it from food or supplements, and if you don’t get enough, your bones start to weaken over time. It’s not just about avoiding osteoporosis—low calcium can also cause muscle cramps, irregular heartbeat, and even numbness in your fingers and toes.

Not all calcium is the same. calcium carbonate, a common and cheap form found in antacids and budget supplements. Also known as CaCO3, it’s effective but needs stomach acid to absorb, so it’s best taken with food. Then there’s calcium citrate, a more easily absorbed form that works even on an empty stomach. Also known as CaC6H6O7, it’s pricier but better for people with low stomach acid, older adults, or those on acid-reducing meds. If you’re choosing a supplement, this difference matters. One study showed calcium citrate is absorbed 25% better than carbonate in people over 60. And don’t forget vitamin D—it’s the sidekick calcium needs to actually get into your bones. Without it, most of your calcium just passes through.

Food sources are often overlooked. Dairy is the obvious pick—milk, yogurt, cheese—but you don’t need to drink milk to get enough. Canned sardines with bones, kale, broccoli, fortified plant milks, and even tofu made with calcium sulfate can cover your daily need. Most adults need about 1,000 mg a day. Women over 50 and men over 70 need 1,200 mg. And no, drinking soda or eating too much salt doesn’t just hurt your waistline—it leaches calcium out of your bones. Too much caffeine? It can interfere too. The key is balance: enough calcium, enough vitamin D, and avoiding the habits that steal it.

What you’ll find below isn’t just another list of supplements. It’s a real comparison of what works, what doesn’t, and why some products are better for your body than others. You’ll see how calcium carbonate stacks up against citrate, what side effects to watch for, and which forms actually help people with digestion issues or chronic conditions. No marketing hype—just straight facts from real studies and user experiences. Whether you’re worried about bone density, taking meds that affect absorption, or just trying to figure out which bottle to pick off the shelf, the posts here will help you make a smarter choice.