Can I use SDXL LORAs with Illustrious?
LoRA models depend on the architectural details of the base model they were trained with.
Stable Diffusion XL (SDXL) and IllustriousXL are related — IllustriousXL is itself an SDXL-based checkpoint — but subtle differences in training and parameter distributions mean many SDXL LoRAs might not behave well when used with IllustriousXL. Reddit
Think of it like this:
Compatible LoRAs:
Trained on SDXL 1.0 or SDXL-derived models
Often work best as long as the checkpoint is in that same SDXL family
Less compatible LoRAs:
Trained on very specific SDXL checkpoints (e.g., PonyXL or custom merges)
Can fail or produce poor results on IllustriousXL
Some might even crash or distort the output if internal layers’ expected tensor shapes differ
In other words: it is technically possible to use SDXL LoRA with an IllustriousXL checkpoint — if the LoRA is truly SDXL-compatible — but it’s not guaranteed and often requires testing and weight adjustment. TechTactician.com
🔧 Practical tips
1. Check the LoRA’s “Base Model” tag
Always look at the LoRA’s metadata on the download page (e.g., Civitai, Hugging Face).
If it lists “SDXL 1.0” or similar, it’s more likely to work with IllustriousXL than a LoRA explicitly trained for something else. Reddit
2. Test & adjust weight
Even if a LoRA loads, you’ll likely need to reduce its strength/weight (e.g., 0.4–0.8) to get cohesive results rather than overwhelming the Illustrious style.
3. Expect mixed results
Some users report:
SDXL LoRAs working fine on IllustriousXL
Others producing no visible effect or weird artifacts
Rare cases where they work “but look bad” unless carefully tuned Reddit
4. Prefer LoRAs trained on a closely related variant
If a LoRA explicitly mentions SDXL and Illustrious or Pony compatibility (some creators train them as such), you’ll see better results than with a generic SDXL LoRA.
📌 Example cases
✅ Works well:
LoRA trained on SDXL 1.0 and tested on SDXL derivatives
❓ Mixed results:
Generic SDXL LoRA applied to IllustriousXL
Some people find it fine; others see poor quality Reddit
❌ Likely won’t work:
LoRA trained on older Stable Diffusion (v1.x/2.x)
LoRA trained on extremely divergent SDXL variants unless they explicitly list compatibility
🧩 Summary
LoRA TypeWorks with IllustriousXL?SDXL-trained LoRA✔️ (often works, may need tuning)LoRA trained on IllustriousXL✔️ (best results)LoRA trained on PonyXL or other SDXL forks⚠️ (sometimes works)LoRA from SD1.5/2.x❌ (incompatible)
Conclusion: Yes — you can use SDXL LoRAs with IllustriousXL sometimes, but it’s not guaranteed. Best practice is to use LoRAs whose base aligns with SDXL and ideally ones that list compatibility with IllustriousXL.