Do reptiles need UVB? · Leopard gecko

Do leopard geckos need UVB?

They can live without it if their insects are dusted with calcium and vitamin D3, but they use it: leopard geckos given low-level UVB make their own vitamin D3 and carry clearly higher levels of it. We recommend a low-output UVB tube aimed at a UV index of 0.5–1.5 at the basking spot, or 0.5–0.7 for albino and other pale morphs, with shade to retreat to.

UV zone: Zone 1 (shade, dusk)
UVI at basking spot: 0.5–1.5
Albino or pale morphs: UVI 0.5–0.7
Lamp: Low-output T5 tube

By the Pet Environment editorial team · Published November 4, 2026 · Care guidance, not veterinary advice

Why keepers disagree

Leopard geckos are active at dusk and at night and spend the day in burrows, so popular care books long said they don't need UVB, and ReptiFiles notes that many keepers still say so. Geckos kept that way get their vitamin D3 from a supplement dusted on their insects.

Both camps are partly right. A leopard gecko can get its vitamin D3 from food. It can also make its own from UVB, and three studies show that it does.

What the studies found

2013 · veterinary conference report
Leopard geckos under low-level UVB had blood levels of the vitamin D3 marker, 25-hydroxyvitamin D3, 3.2 times higher than geckos on dietary supplement alone (Wangen et al., as cited in the UV-Tool).
2018 · 12 adult males · 30 days
Two hours of UVB a day, one at dawn and one at dusk, raised the same marker from 42 to 80 nmol/L. Geckos without UVB went from 44 to 50 (Gould et al., figures as summarised by Oonincx et al.).
2020 · 18 hatchlings · 175 days
Every gecko got calcium and vitamin D3 on its insects; half also got two hours of UVB a day at a UV index of 1.0–1.6. The UVB group ended with higher vitamin D3 levels (61 vs 38 nmol/L), but both groups grew and gained weight the same, and none showed signs of bone disease (Oonincx et al.).

The 2020 authors' conclusion: unlike most day-active lizards, young leopard geckos without UVB still develop normally when they get enough calcium and vitamin D3 in their food. Whether the higher vitamin D3 from UVB brings other benefits, such as denser bones, immunity or healthier eggs in breeding females, hasn't been tested yet.

So should you add one?

We say yes, at a low level. The researchers behind the UV-Tool place leopard geckos in zone 1, the shade and dusk group, and see “no reason to withhold” UVB as long as the animal has a retreat to spend the day in. It also gives you a second source of vitamin D3 if the supplement routine slips.

Our leopard gecko setup guide builds it in: a 36 × 18 × 18 in (3 × 1.5 × 1.5 ft) minimum enclosure, a basking surface of 94–97°F under a halogen lamp, and over it a low-output 2.5-7% T5 linear tube (Ferguson Zone 1, UVI 0.5-1.5; 0.5-0.7 for albino morphs) covering 1/2 of the enclosure length.

How far away to mount the tube

From ReptiFiles' chart for the two low-output tubes it lists, the Arcadia ShadeDweller Max 2.5% and ShadeDweller 7%. It assumes the mesh blocks about 30%. Distances are from the lamp to the gecko at the basking spot; other lamps differ, and a UV index meter is the only way to be sure.

GeckoLamp mounted2.5% tube7% tube

NormalOver mesh2.5% 8–14 in7% 10–18 in
NormalInside the enclosure2.5% 10–18 in7% 12–20 in
Albino or paleOver mesh2.5% 12–14 in7% 16–18 in
Albino or paleInside the enclosure2.5% 14–18 in7% 18–20 in

Cover the warm half, next to the heat lamp, so heat and UVB meet at one basking spot and the cool end stays shaded.
Keep every hide. The gecko should be able to get fully out of the light whenever it wants.
No glass or plastic between the tube and the gecko: it blocks nearly all UVB.
Replace the tube every 12 months. UVB fades long before the light looks dim.
Pale morphs need more distance. Albino, patternless and other low-pigment geckos can be burned by UVB a normal gecko handles, so use the bottom two rows.
Skip coil bulbs and desert-strength tubes. Coils light only a small patch, and a strong tube mounted too close to the basking spot can damage eyes and skin.

Which tube types exist, what the percentages mean and what each animal's checklist calls for: reptile UVB lighting, explained.

If you go without UVB

Then the vitamin D3 has to come from food, every time. That means insects dusted with plain calcium, and a vitamin D3 or multivitamin powder on the schedule its maker gives. All the geckos in the 2020 study, with or without UVB, were on a supplement like that, so the study says nothing about a gecko that gets neither.

Watch for the signs of metabolic bone disease the Merck Veterinary Manual lists: not eating, lethargy, trouble walking, a soft, swollen or bent jaw or limbs, fractures and twitching muscles. Any of these means a visit to an exotics vet. Adding a UVB lamp is not a treatment.

Sources

Read November 4, 2026. The enclosure, temperature and lamp lines come from our leopard gecko guide and its sources. Care guidance, not veterinary advice: if your gecko is unwell, see an exotics vet. How we make these guides.