Best Insect Gut Load for Leopard Geckos (2026)

Leopard geckos are strict insectivores. Every calorie, every vitamin, every milligram of calcium your gecko absorbs comes from the insects you feed. The problem is that most feeder insects are nutritionally incomplete — they are low in calcium and high in phosphorus, with Ca:P ratios as poor as 0.13:1 in crickets.

Gut loading fixes this. By feeding nutritious, calcium-rich food to your feeder insects 24–48 hours before offering them to your gecko, you transform a mediocre food source into a genuinely nutritious meal. Without gut loading, even aggressive calcium dusting may not be enough to prevent metabolic bone disease over time.

We researched veterinary nutrition studies, keeper community feedback, and manufacturer data to rank the six best insect gut loads available. Here is what the evidence shows.

Quick Comparison: All 6 Gut Loads

Important: Gut loading does not replace calcium dusting. Even the best gut load product will not achieve a full 2:1 Ca:P ratio on its own. Always dust feeder insects with calcium powder before offering them to your leopard gecko.

Detailed Reviews

1. Repashy Bug Burger — Best Overall

Repashy Bug Burger is the gut load we see recommended most frequently across keeper communities, breeder forums, and veterinary-adjacent reptile care resources. ReptiFiles specifically recommends it as one of the top commercial gut loads for leopard gecko feeders.

The formula is a gel premix — add boiling water, stir, let it set, and offer to your insects. It feeds, hydrates, and calcium-loads your feeders simultaneously. No separate water crystals. No separate food dish. One product handles everything.

The reformulated version contains approximately 13% calcium, down from the original 20%. This change was intentional — Repashy's own research found that extremely high-calcium diets fed to insects long-term could contribute to visceral gout in reptiles. The current 13% level delivers strong calcium transfer without the risk of excessive calcium accumulation.

For most leopard gecko keepers, Repashy Bug Burger is the simplest path to consistent, high-quality gut loading. Offer it to your feeders 24–48 hours before feeding, and replace the gel every 48 hours to prevent spoilage.

2. Mazuri Better Bug Gut Loading Diet — Premium Pick

Mazuri Better Bug Gut Loading Diet is the professional standard. This is the gut load you will find in AZA-accredited zoos, university reptile research programs, and large-scale breeder operations. Mazuri's nutrition team formulated it with high calcium, beta-carotene, and omega-3 fatty acids — nutrients that transfer efficiently through the insect gut into your gecko.

The dry pellet format has a significant shelf-life advantage over gel products. An opened bag of Mazuri Better Bug Gut Loading Diet stored in a cool, dry location lasts months without spoiling. For keepers who buy in bulk or maintain multiple insect colonies, this longevity matters.

The trade-off is that dry pellets do not hydrate your insects. You will need a separate water source — fresh vegetables like butternut squash or collard greens work best, though water crystals are acceptable. This makes Mazuri Better Bug Gut Loading Diet a two-step process compared to Bug Burger's all-in-one approach.

If you are a breeder managing dozens of geckos or simply want the most research-validated option available, Mazuri is the gut load to choose.

3. Fluker's High Calcium Cricket Diet — Budget Pick (With Caveats)

Fluker's High Calcium Cricket Diet is the cheapest and most widely available gut load option. You can find it at PetSmart, Petco, and virtually every pet supply chain. At $4–$7, it costs less than half of what Repashy or Mazuri products run.

However, the effectiveness is genuinely disputed. Veterinary research on commercial calcium-fortified cricket diets has found that some dry powder products — including formulas similar to Fluker's — do not significantly raise cricket calcium levels compared to unfed controls. The calcium listed on the label may not actually transfer into the insect's gut at meaningful levels.

This does not mean Fluker's High Calcium Cricket Diet is useless. Many keepers report acceptable results when they combine it with fresh vegetables — the combination of commercial dry gut load plus collard greens, mustard greens, or butternut squash appears to outperform either approach alone.

Use Fluker's High Calcium Cricket Diet if budget is the primary constraint. But treat it as a supplement to fresh vegetable gut loading, not a replacement for it. And never skip calcium dusting — this product alone is not enough to correct the Ca:P deficit.

4. Repashy SuperLoad — Best Dedicated Gut Load

Repashy SuperLoad is purpose-built for the 24–48 hour pre-feeding gut-loading window. Unlike Bug Burger (which works as both a maintenance diet and gut load), SuperLoad is concentrated — higher calcium content, designed to maximize nutrient transfer in a short time frame.

This distinction matters for keepers who already maintain their insect colonies on a separate diet. If you feed your dubias or crickets a steady maintenance food (vegetables, chow, or Bug Burger) and want to supercharge them before offering to your gecko, Repashy SuperLoad is the right tool.

The gel format provides hydration alongside nutrition, same as Bug Burger. Prepare it identically — boiling water, stir, set. Offer to your feeders 24–48 hours before the scheduled feeding, then dust with calcium powder and serve.

For keepers who want the absolute maximum calcium transfer per feeding session, Repashy SuperLoad paired with a separate insect maintenance diet is the optimal two-product setup.

5. Zoo Med Natural Cricket Care — Best Cricket Maintenance

Zoo Med Natural Cricket Care fills a specific niche: keeping crickets alive while providing moderate gut-loading benefits. If you buy crickets in bulk — 500 or 1,000 at a time — cricket mortality is a real cost issue. Keeper reports consistently note that colonies maintained on Zoo Med Natural Cricket Care survive significantly longer than those fed only fresh vegetables.

The product contains calcium, vitamins, and spirulina. The nutritional profile is broader than basic cricket chow, though the calcium content is lower than dedicated gut loads like Repashy SuperLoad or Mazuri Better Bug.

The practical approach is to use Zoo Med Natural Cricket Care as your daily cricket maintenance diet, then switch to a high-calcium gut load (Bug Burger or SuperLoad) 24–48 hours before feeding. This two-product system keeps your cricket colony healthy while maximizing the nutritional value of each insect your leopard gecko eats.

If you keep only dubia roaches and do not maintain a cricket colony, this product is less relevant to your setup.

6. Fluker's Orange Cube Complete Cricket Diet — Best Hydration Combo

Fluker's Orange Cube Complete Cricket Diet is the convenience play. Each cube replaces both food and water crystals — no fresh produce to prepare, no water dishes to refill, no mold from forgotten lettuce. For keepers who want the simplest possible insect maintenance, Orange Cubes deliver.

The cubes provide moderate calcium and vitamins alongside hydration. Keeper data shows they keep crickets alive longer than water crystals alone, and the nutritional content adds measurable (though not exceptional) gut-loading value.

However, fresh vegetables like butternut squash, collard greens, and carrots provide superior hydration and nutrition compared to any commercial cube product. Oranges and squash deliver both water content and genuine nutrients — something gel cubes approximate but do not fully match.

Use Fluker's Orange Cube Complete Cricket Diet when convenience is the priority — travel, busy weeks, or as a backup when you run out of fresh produce. For your primary gut-loading routine, pair it with a dedicated high-calcium product.

How Gut Loading Works: The 24–48 Hour Window

Gut loading is simple in concept: you feed highly nutritious food to feeder insects before offering them to your gecko. The insects become a delivery vehicle for calcium, vitamins, and minerals that they would not naturally contain.

The timing matters. According to veterinary nutrition research, the gut-loading window is 24–48 hours. Within this period, nutrients from the gut-load diet fill the insect's digestive tract and are available to your gecko when consumed. Beyond 48 hours, the insect begins excreting excess nutrients, and the benefit diminishes.

Here is the practical workflow:

1. 24–48 hours before feeding: Move the insects you plan to feed into a separate container with your chosen gut load product
2. Day of feeding: Remove insects from the gut-load container
3. Dust with calcium powder: Lightly coat insects in calcium (with D3 if no UVB, without D3 if UVB is present)
4. Offer to your gecko: Feed immediately after dusting

This process applies equally to crickets, dubia roaches, mealworms, and superworms. The one exception is Black Soldier Fly Larvae (BSFL), which naturally have a Ca:P ratio of approximately 1.5:1 and do not require gut loading or calcium dusting.

Gut Loading Buying Guide

Commercial Gut Load vs. Fresh Vegetables

You do not necessarily need a commercial product. Fresh vegetables are excellent gut-load material — in some cases, better than commercial options.

The best vegetables for gut loading include:

• Collard greens — high calcium, excellent Ca:P ratio
• Mustard greens — similar profile to collards
• Butternut squash — high in beta-carotene, provides hydration
• Carrots — good source of beta-carotene
• Dandelion greens — high calcium, widely available in yards (pesticide-free only)

Vegetables to avoid:

• Spinach — contains oxalates that bind calcium, making it unavailable to the insect and your gecko
• Lettuce — mostly water with minimal nutritional value
• Broccoli — contains goitrogens that can interfere with thyroid function

The ideal approach, based on ReptiFiles' feeder insect nutrition data and keeper community consensus, is to combine a commercial gut load with fresh vegetables. Commercial products provide consistent calcium and vitamin levels, while fresh produce adds hydration, fiber, and micronutrients that dry formulas lack.

Which Insects Respond Best to Gut Loading

Not all feeder insects gut-load equally:

• Dubia roaches — respond very well to gut loading. Their larger gut capacity means more nutrient transfer per insect. Dubias are generally considered better feeders than crickets for leopard geckos
• Crickets — the most-studied insect for gut loading. Results are well-documented but vary significantly by gut-load product
• Mealworms — can be gut-loaded, though their smaller gut capacity limits total nutrient transfer
• BSFL — do not need gut loading. Their naturally high Ca:P ratio (approximately 1.5:1) makes them the exception
• Superworms — gut-load effectively, but should be offered sparingly due to high fat content

How to Choose the Right Product

Your decision depends on three factors:

1. Convenience: Want one product that does everything? Repashy Bug Burger. Want to combine commercial + fresh veggies? Mazuri Better Bug + collard greens.
2. Budget: Tight budget? Fluker's High Calcium Cricket Diet paired with fresh vegetables from your kitchen. The vegetables are doing most of the work anyway.
3. Colony size: Maintaining 500+ crickets? Zoo Med Natural Cricket Care for maintenance plus Repashy SuperLoad for the 24–48 hour pre-feed window.

For keepers with a single leopard gecko, Repashy Bug Burger covers everything. For breeders or multi-gecko households, the Mazuri Better Bug + fresh vegetable combination offers the best long-term value and the strongest research backing.