Eggshell Powder for Pets: Calcium Boost or Hidden Health Risk?

Calcium is an essential mineral for dogs and cats, critical for:

• Bone & teeth strength 🦴

• Muscle contraction & nerve function ⚡

• Blood clotting & heart rhythm ❤️

Commercial pet foods regulated by AAFCO (Association of American Feed Control Officials) are typically balanced in calcium and phosphorus. But in homemade diets, calcium is often deficient unless supplemented. Many pet parents turn to eggshell powder as a natural, inexpensive calcium source.

👉 The question: Is eggshell powder truly safe, or does it pose hidden health risks?

🧬 What is Eggshell Powder?

• Eggshells are 95% calcium carbonate (CaCO₃)

• Contain ~38% elemental calcium

• 1 tsp (about 5 g) of finely ground eggshell powder ≈ 1,800–2,000 mg of calcium 【Merck Vet Manual†source】【VCA Animal Hospitals†source】

That makes eggshell powder a powerful calcium booster—but also risky if not dosed correctly.

📊 Nutritional Comparison: Eggshell vs Other Calcium Sources

👉 Key point: Eggshell powder contains no phosphorus, so it’s suitable for balancing meat-only homemade diets (which are high in phosphorus).

🛠️ Step-by-Step: How to Make Eggshell Powder Safely

1. Wash eggshells thoroughly to remove residue.

2. Boil for 5–10 minutes to kill bacteria (e.g., Salmonella).

3. Dry completely (oven at 200°F for 10–15 minutes).

4. Grind into a fine powder using a coffee grinder.

5. Store in an airtight jar away from moisture.

⚠️ Safety Tip: Powder must be very fine—large fragments can irritate the gut or provide inconsistent calcium dosing.

📏 How Much Eggshell Powder to Give Pets?

• Dogs: ~1 tsp (5 g) per 10–12 lbs (4.5–5.5 kg) of meat in a homemade diet 【NRC Nutrient Requirements of Dogs and Cats†source】

• Cats: ~½ tsp per 8–10 oz of meat (as cats need higher calcium-phosphorus balance)

⚠️ Do NOT supplement if your pet is already on commercial kibble/wet food, as those are pre-balanced. Extra calcium can be harmful.

🚨 Risks of Eggshell Powder for Pets

1. Calcium Overload (Hypercalcemia)

   • Causes lethargy, constipation, irregular heartbeat.

   • Long-term: kidney stones, calcification of organs.

2. Imbalance with Phosphorus

   • Calcium must balance phosphorus (ideal Ca:P ratio = 1.1–1.4:1).

   • Excess calcium + low phosphorus = stunted growth in puppies/kittens.

3. Digestive Irritation

   • Poorly ground shells may scratch GI tract.

4. Breed/Health Sensitivities

   • Cats prone to urinary crystals (calcium oxalate) may worsen with excess calcium.

📌 Structured Routine: When to Use Eggshell Powder

• ✅ Use when feeding homemade raw or cooked meat diets lacking bones.

• ✅ Safe for adult healthy pets when balanced with phosphorus.

• ❌ Avoid in commercial pet food diets (already balanced).

• ❌ Avoid in pets with kidney disease, urinary crystals, or hypercalcemia (require vet-guided diets).

💬 Expert Insights

“Eggshell calcium is a viable alternative to bone meal in homemade pet diets, but precision is critical. Over-supplementation is far more common than deficiency.” – Dr. Rebecca Remillard, PhD, DACVN (Veterinary Nutritionist)

“Homemade diets should always be formulated by a veterinary nutritionist. Simply sprinkling eggshell powder without balancing phosphorus is not safe.” – WSAVA Global Nutrition Committee 【WSAVA Global Nutrition†source】

“Cats are especially sensitive to calcium imbalances, and inappropriate supplementation can trigger urinary stone formation.” – VCA Animal Hospitals 【VCA†source】

❓ FAQs: Eggshell Powder for Pets

1. How long does it take for eggshell calcium to work?
It supports long-term bone health; measurable effects take weeks to months.

2. Can I give eggshell powder with kibble?
No. Commercial foods already meet AAFCO calcium standards. Extra calcium = overdose risk.

3. Is eggshell calcium better than bone meal?
Eggshell is cleaner, but bone meal provides both calcium and phosphorus. Which is better depends on the diet.

4. Can puppies and kittens have eggshell powder?
Not without a nutritionist’s guidance. Calcium imbalances during growth can cause orthopedic issues.

5. Can eggshell powder help dogs with arthritis?
It supports bone strength but is not a treatment for arthritis. Use joint supplements instead.

6. Is it safe for cats prone to urinary crystals?
No. Too much calcium can worsen oxalate stone risk. Always consult a vet.

7. How do I know if my dog needs calcium supplements?
If feeding homemade meat diets without bones. Otherwise, ask your vet.

8. Can eggshell powder replace vet-prescribed calcium tablets?
Not unless your vet approves. Medical supplementation must be precise.

9. What’s the shelf life of homemade eggshell powder?
Stored dry in an airtight jar: up to 2 months. Longer if refrigerated.

10. Can I just crush eggshells and sprinkle them?
No. They must be sterilized and finely ground for safety and absorption.

🏁 Conclusion

Eggshell powder can be a safe, effective calcium supplement for pets on homemade diets, provided it’s prepared correctly and dosed with precision. However, the risks of over-supplementation, imbalanced nutrition, and health complications are real.

👉 The bottom line: Eggshell powder is not inherently dangerous, but it is not a casual supplement either. Always check with your veterinarian or a certified veterinary nutritionist before adding it to your pet’s diet.

⚠️ Disclaimer

This article is for educational purposes only. Nutritional supplementation in pets must be customized by a licensed veterinarian or veterinary nutritionist. Never add eggshell powder (or any supplement) without professional guidance.