Supplements & dusting
A gargoyle gecko's calcium, D3, and vitamins come mostly from a quality powdered meal-replacement diet (MRP), not from dusted insects. Metabolic Bone Disease (MBD) is still a real risk if the MRP is poorly formulated, over-diluted, or skipped in favour of unsupplemented insects.
The core supplements
This is where most of a gargoyle gecko's calcium, D3, and vitamin intake actually comes from — a good MRP is already formulated to a correct Ca:P ratio, so it does most of the supplementation work by itself. Mix fresh each time, discard what is not eaten within 24 hours, and do not thin it too far with water or the nutrient density drops.
Because the MRP diet already supplies D3, insects offered in rotation should generally be dusted with a D3-free calcium powder to avoid stacking too much D3 from two sources. Check the label of your specific MRP brand, since formulations vary.
A small dish of plain calcium lets the gecko self-regulate on top of the MRP diet. Replace it if it gets damp from misting, which happens more in a humid gargoyle setup than in a drier enclosure.
Not strictly required if the MRP diet is providing D3 reliably, but low-output UVB (roughly Ferguson zone 1, such as a 2.4–5% T5 tube) is increasingly recommended for general health, not just D3 synthesis. If you run UVB, this is not a reason to add more D3 dusting on top — the MRP diet's built-in D3 already covers it.