What are the nutritional benefits of eggshells?

January 11, 2026 •

4 min read

Eggshells, long discarded as waste, are primarily composed of calcium carbonate, the same mineral that builds bones and teeth. In fact, approximately one eggshell can provide a full day's calcium requirement for an adult. Beyond being an eco-friendly source of nutrients, research suggests they may offer unique health advantages over standard supplements.

Quick Summary

An inexpensive and bioavailable source of calcium, eggshells also contain other beneficial minerals and proteins, like collagen in the membrane. When properly sterilized and ground into a fine powder, they can support bone density and may help manage conditions like osteoporosis.

Key Points

Rich Source of Calcium: Eggshells are composed almost entirely of calcium carbonate, providing a highly concentrated and natural calcium source for supporting strong bones and teeth.
High Bioavailability: Research suggests that the calcium in eggshells is effectively absorbed by the body, potentially even more so than in some commercial supplements, possibly due to other organic compounds present.
Supports Bone Density: Supplementation with eggshell powder has been shown in studies to increase bone mineral density, offering a natural option for preventing and treating osteoporosis, especially in postmenopausal women.
Contains Joint-Supporting Nutrients: The eggshell membrane is rich in valuable compounds like collagen, chondroitin sulfate, and glucosamine, which are known to promote joint health.
Economical and Sustainable: Using eggshells as a dietary supplement is a low-cost, zero-waste way to get calcium, utilizing a resource that is otherwise discarded.
Requires Safe Preparation: To avoid bacterial contamination like Salmonella, eggshells must be properly cleaned, boiled, and thoroughly dried before being ground into a fine powder for consumption.
Beneficial for Various Conditions: Beyond bone health, studies have noted that eggshell powder may help with bone demineralisation, improve joint mobility, and reduce pain associated with conditions like osteoarthritis.

Eggshells as a Powerhouse of Calcium

The most significant nutritional benefit of eggshells is their high concentration of calcium. A single gram of processed eggshell powder contains between 381 and 401 mg of calcium, with the average whole eggshell offering over 1,500 mg. This makes it an incredibly potent and accessible dietary supplement for individuals who need to increase their calcium intake, particularly those with conditions like osteoporosis or dietary restrictions. The calcium in eggshells is in the form of calcium carbonate, which studies have shown to be highly bioavailable—meaning the body absorbs and utilizes it effectively. Some research even suggests that calcium from eggshell powder may be absorbed better than purified calcium carbonate supplements. This may be due to the natural organic compounds, such as proteins, present in the eggshell matrix.

Supporting Bone Health and Fighting Osteoporosis

Maintaining strong bones is crucial throughout life, and calcium is the primary mineral responsible. Inadequate calcium intake is a major risk factor for osteoporosis, a condition characterized by weak, brittle bones. Numerous studies have explored the effect of eggshell calcium on bone health:

One study in postmenopausal women with osteoporosis demonstrated that taking eggshell powder, alongside vitamin D3 and magnesium, significantly improved bone mineral density.
In another trial involving postmenopausal women, eggshell powder was more effective at increasing bone mineral density in the neck than a placebo, unlike purified calcium carbonate, which showed no significant effect.
Research in animal models has also shown that eggshell calcium can be effective in preventing bone loss.

These findings suggest that eggshell powder is a viable and potentially more effective alternative to traditional calcium supplements for improving bone strength and mitigating osteoporosis risk.

The Role of the Eggshell Membrane

Beyond the hard shell, the thin membrane lining the inside of the egg also offers nutritional benefits, mainly relating to joint health. This membrane is rich in beneficial compounds, including:

Collagen: A key structural protein that provides elasticity and strength to connective tissues.
Chondroitin sulfate: A compound known to support cartilage formation and repair.
Glucosamine: A natural compound often used in supplements to support joint health.

While the trace amounts in the membrane are small, studies on eggshell membrane supplements show they can benefit joint health. When making your own eggshell powder at home, there is no need to remove this membrane, allowing you to reap its benefits alongside the calcium.

Eggshell vs. Commercial Calcium Supplements

Choosing a calcium source can be complex, but eggshell powder offers a compelling, natural alternative to commercial supplements. Here is a comparison of eggshell powder and typical calcium carbonate supplements.


Feature	Eggshell Powder (DIY or commercial)	Purified Calcium Carbonate Supplement
Source	Natural, whole-food byproduct (chicken eggs)	Synthetically processed mineral from limestone or rock
Cost	Extremely inexpensive, utilizing kitchen waste	Varies depending on brand and formulation
Bioavailability	High, potentially better absorbed due to natural protein compounds	Effectively absorbed, but potentially less so than natural forms
Additional Nutrients	Contains naturally occurring minerals like magnesium, strontium, and fluoride	Usually contains only calcium carbonate, though sometimes fortified with Vitamin D
Joint Support	Contains beneficial membrane with collagen and glucosamine	Generally lacks joint-supporting proteins
Preparation	Requires sterilization and fine grinding at home	No preparation needed; comes in pill or tablet form

How to Safely Prepare and Use Eggshell Powder

Before consuming eggshells, proper preparation is essential to eliminate the risk of bacterial contamination, especially Salmonella.

Rinse the eggshells thoroughly with water to remove any residual egg white.
Boil the shells for at least 10 minutes to sterilize them completely.
Dry the shells completely by baking them in an oven at a low temperature (e.g., 200°F or 90°C) for 10–20 minutes. This also makes them brittle and easier to grind.
Grind the dried shells into a very fine powder using a coffee grinder or high-powered blender. The powder should have a fine, flour-like consistency to prevent any sharp fragments from irritating the throat or esophagus.
Store the finished powder in a sealed, airtight container in a cool, dry place.

Once prepared, you can add eggshell powder to various foods. A half-teaspoon is often enough to provide a substantial dose of calcium. Common methods include mixing it into smoothies, sprinkling it on cereal, or incorporating it into baked goods and soups. A balanced diet, however, remains the best way to meet nutritional needs, and supplementation should not replace it.

Conclusion

The nutritional benefits of eggshells are significant, offering a remarkably rich, inexpensive, and bioavailable source of calcium. This natural supplement can play a vital role in supporting bone density and may help manage conditions like osteoporosis, often proving more effective than commercially refined calcium carbonate. The eggshell membrane further enhances its value with compounds that support joint health. When prepared safely and correctly at home, eggshell powder is an accessible and sustainable way to boost your daily calcium intake and reduce kitchen waste. However, consulting a healthcare professional is always wise before beginning any new supplementation regimen.

This article is for informational purposes only and is not medical advice. Consult a healthcare provider before making dietary changes.

Frequently Asked Questions

Yes, properly prepared eggshells are safe to consume. The shells must be sterilized by boiling to kill bacteria like Salmonella and then ground into a very fine powder to avoid injury from sharp fragments.

A single chicken eggshell contains a substantial amount of calcium. One medium eggshell can provide up to 1,500 mg of calcium, which is more than enough to meet the average adult's daily needs.

To prepare eggshell powder, first rinse the shells well. Boil them for 10 minutes, then bake at a low temperature to dry. Finally, grind the shells into an extremely fine powder using a coffee grinder or high-speed blender.

Yes, several studies indicate that eggshell powder can be beneficial for individuals with osteoporosis. Its calcium content and other minerals have been shown to increase bone mineral density and reduce bone loss, particularly in postmenopausal women.

Some studies suggest that the calcium in eggshells may be more bioavailable and better absorbed than purified calcium carbonate supplements. The natural matrix of the shell, including its proteins, may contribute to this improved absorption.

Yes, the membrane of the eggshell contains collagen, glucosamine, and chondroitin sulfate, which can support joint and cartilage health. Some studies on eggshell membrane supplements suggest benefits for reducing joint pain and increasing mobility.

The fine powder can be mixed into smoothies, juices, soups, or even baked goods. A small amount, typically a half-teaspoon, can be added to your food to boost calcium intake without significantly altering the taste or texture.

If not ground finely enough, large eggshell fragments can injure the throat or esophagus. There is also a risk of bacterial contamination, like Salmonella, if the shells are not properly sterilized before consumption. High calcium intake from any source can cause issues like kidney stones, so moderation is key.