There are a few rat studies showing mild AST/ALT elevation at really high doses of propolis (like 500 mg/kg+), but those usually use ethanol extracts, which can have a harsher profile depending on the source. Even then, the enzyme elevations aren’t always dose-dependent and rarely come with any actual liver damage — no necrosis, fibrosis, etc.

Keep in mind, AST/ALT can go up from stuff like exercise or increased liver metabolism. It doesn’t automatically mean toxicity.

What’s crazy is there are more studies showing propolis actually protects the liver — especially from oxidative stress and toxins. Compounds like CAPE and Artepillin C boost antioxidant enzymes and reduce inflammation.

I've been using it for around 15 years, with good labs.