Nutrition
Tortoise Calcium & Supplements Guide
Updated August 1, 2026
The #1 health threat: Metabolic bone disease (MBD) from incorrect calcium/UVB. Proper supplementation is life or death for captive tortoises.
🧪 Calcium with D3 vs without
Calcium WITHOUT D3
Use this if:
- • Tortoise has proper T5/T8 UVB
- • Tortoise is indoors
- • Gets 12+ hours of UVB weekly
Safest option — body makes D3 from UVB.
Calcium WITH D3
Use sparingly if:
- • No UVB (rescue situation)
- • Medical condition
- • Very rarely as supplement
Too much D3 is toxic.
📅 Supplement schedule
| Age | Calcium | Multivitamin |
|---|---|---|
| Hatchling | 4-5x/week | 1x/week |
| Juvenile | 3-4x/week | 1x/week |
| Adult | 2-3x/week | 1x/2 weeks |
Adjust based on diet quality. Tortoises eating high-calcium weeds need less supplementation.
💊 Multivitamins
Tortoises need vitamins A, B, E, and K in addition to calcium:
- Herptivite — popular, trusted
- Repashy SuperVite — comprehensive
- Zoo Med Reptivite — good option
Just a pinch on food — don't over-supplement.
🏺 Types of calcium
- Calcium carbonate: most common, affordable, highly bioavailable
- Calcium citrate: easier to absorb, good for older tortoises
- Oyster shell: natural, good alternative
Skip calcium with phosphorus — they already get enough from food.
🦴 Signs of MBD
- Soft or rubbery shell
- Shell deformities/pyramiding
- Weak legs, difficulty walking
- Tremors or shaking
- Loss of appetite
- Lethargy
MBD is irreversible but can be stopped if caught early. See a vet immediately.
Helpful supplies
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