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Reptile health

Metabolic Bone Disease in Reptiles

The most common husbandry-related illness in captive reptiles, and how correct lighting and diet prevent it.

By Aisha NkemdirimVeterinary review: Dr Elena Marsh8 min readPublished 2026-05-18Updated 2026-08-23

General information

Metabolic bone disease describes skeletal weakening caused by inadequate calcium, inadequate vitamin D3, incorrect calcium to phosphorus ratio, or insufficient UVB exposure. It is almost entirely preventable and almost entirely caused by husbandry.

Symptoms

Early signs are subtle; by the time deformity is visible, disease is advanced.

  • Lethargy and reduced appetite
  • Tremors or twitching in the limbs
  • Soft or rubbery jaw, swelling along the lower jaw
  • Bowed or bent limbs, or a kinked tail or spine
  • Difficulty lifting the body off the ground when walking
  • Pyramiding of the shell in tortoises

When veterinary attention is appropriate

Any of these signs needs a reptile-experienced veterinarian promptly. Advanced disease causes pathological fractures. Radiographs and blood calcium testing guide treatment, which may include injectable calcium and supportive feeding.

Prevention

Provide species-appropriate UVB from a linear tube with a reflector, positioned at the correct distance and replaced every six to twelve months. Dust insects with calcium at most feedings, use a D3 supplement on a species-appropriate schedule, gut-load feeder insects, and maintain correct basking temperatures so food can be digested and nutrients absorbed.