Eggshells are more than just waste—they’re a natural source of calcium carbonate, which makes up about 95% of the shell. One average eggshell provides roughly 750–800 mg of elemental calcium, which is a significant portion of the daily recommended intake for adults (around 1,000–1,200 mg depending on age and needs). Calcium is essential for maintaining bone strength, and research suggests that consistent intake from bioavailable sources can support bone mineral density over time.
But the benefits don’t stop at the hard shell. The thin membrane lining the inside contains proteins like collagen, along with naturally occurring compounds such as glucosamine, chondroitin, and hyaluronic acid. These elements are often discussed in the context of joint health because they contribute to the structure of cartilage and connective tissues.
Multiple clinical studies have examined eggshell membrane (often abbreviated as NEM or similar preparations) as a dietary supplement. For example, randomized, double-blind, placebo-controlled trials have reported that participants taking eggshell membrane experienced reductions in reported joint pain and stiffness, with some noticing changes as early as 10 days. One meta-analysis of several trials found improvements in overall joint function scores and pain measures compared to placebo.
Research also highlights the calcium aspect. Studies on eggshell powder as a calcium source have shown it to be well-absorbed, sometimes comparable to or better than other forms like calcium carbonate supplements. In contexts like supporting bone health in postmenopausal women, eggshell-derived calcium has been linked to positive effects on bone density and reduced bone resorption markers.
But that’s not all—here’s where it gets interesting. The combination of calcium from the shell and bioactive compounds from the membrane offers a whole-food approach that some find appealing over isolated supplements.
