Do Crested Geckos Need UVB?

Crested geckos can survive on a complete CGD (Crested Gecko Diet) without UVB because the powder contains vitamin D3. However, research confirms they synthesize D3 from UVB exposure in the wild and benefit from low-level UVB in captivity. ReptiFiles strongly recommends providing UVB as part of a complete setup — it provides a more natural and reliable calcium metabolism pathway than supplementation alone.

The Arcadia ShadeDweller 7% T5 HO UVB kit is the gold standard for crested geckos. It provides low-level UVB appropriate for a crepuscular arboreal species without the risk of overexposure from higher-output bulbs.

• Arcadia ShadeDweller 7% T5 HO UVB kit — ReptiFiles recommended
• Mount on top of mesh lid — 10-15" above gecko's highest basking point
• Replace UVB bulb every 12 months — output degrades even if light is visible
• Run on a 12-14 hour timer to mimic natural day/night cycle
• Pair with full spectrum LED (Arcadia JungleDawn) for live plants and natural lighting

UVB and D3 supplementation must be coordinated carefully. Combining high-D3 supplements with UVB causes D3 toxicity — a serious condition that damages organs over time.

• With UVB: Calcium WITHOUT D3 for regular dusting on insects
• With UVB: Repashy Calcium Plus LoD as an all-in-one supplement option
• Without UVB: Calcium WITH D3 — CGD alone may not provide enough
• Never combine high-D3 supplements with UVB — causes organ damage

UVB placement matters as much as bulb choice. Glass blocks UVB entirely, and dense mesh reduces output. The bulb must be positioned so the gecko can choose its exposure level — always provide shaded retreat areas.

• Mount above mesh top — never through glass (glass blocks 100% of UVB)
• Dense screen mesh reduces UVB output — account for distance accordingly
• Provide full shade retreats so the gecko can self-regulate exposure
• Foliage and cork bark at multiple heights create natural UV gradients

With UVB: Better long-term calcium metabolism, more natural behavior, stronger overall health. Requires calcium WITHOUT D3 supplementation. Without UVB: Perfectly viable with complete CGD diet and calcium WITH D3 on insects. Many keepers use this path successfully. The builder supports both configurations and adjusts supplement recommendations accordingly.