Ultraviolet Lighting for Reptiles

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Ultraviolet Lighting for Reptiles

Ultraviolet (UV) light is a type of radiation outside the visible light spectrum, found at higher energies than violet light. It comes in three forms: UVA, UVB, and UVC. UVA is used by reptiles to regulate their daily biological cycles and rhythms. UVC is damaging radiation that can lead to skin damage and cancer. UVB is the most important for reptiles — it is necessary for many species to properly absorb calcium from their diet, which is used to harden bones and support other metabolic processes throughout the body.

How UVB Works

UVB activates vitamin D precursors in the skin, allowing the formation of the active form known as vitamin D3. Vitamin D3 then enables calcium to be absorbed from the gut into the bloodstream. Studies indicate that D3 produced naturally in the body is safer and more effective than D3 provided through oral supplementation in diurnal species (those active during the daytime). Recent studies also show that some nocturnal species — such as leopard geckos and corn snakes — can benefit from UVB exposure as well.

Indoor vs. Outdoor Reptiles

Reptiles living outdoors get their UVB directly from the sun. UVB cannot pass through normal glass, so placing an indoor reptile near a window will not supply the UVB they need. Reptiles housed indoors must be provided artificial UVB light through bulbs specifically designed for reptiles.

Choosing the Right Bulb

We recommend Zoo Med brand UVB bulbs. For fluorescent bulbs:

  • 10.0: desert reptiles, tortoises, iguanas, and chameleons
  • 5.0: rainforest and nocturnal reptiles

The Zoo Med Powersun UVB is a mercury vapor bulb that produces both heat and UVB, but should only be used in larger enclosures.

Placement

  • Fluorescent UVB bulbs: ensure your reptile can get within 12–18″ of the bulb. Use branches or logs to allow climbing closer if needed.
  • Mercury vapor bulbs: place a minimum of 12″ away from the basking spot, as these bulbs produce a large amount of heat.
  • Dense screening: can block up to 50% of UVB. If your enclosure has a very dense screen, multiple bulbs may be recommended.

When to Replace Bulbs

UVB reptile bulbs should be replaced every 6–12 months depending on the model, even if they are still producing visible light. UVB bulbs have a special coating inside the glass that allows them to emit UVB — this coating wears off after about 6–12 months, after which the bulb will no longer provide the UVB your reptile needs.

Please feel free to ask us if you need further assistance choosing the correct lighting for your pet.