Rat Study Sets 30 mg/kg/day NOAEL for a Proprietary Kratom Leaf Extract

Why it matters

The study supplies longer-term animal safety data for one standardized extract, while also showing dose-related effects that matter when clinicians and researchers assess product-specific risk. Its findings cannot be generalized to all kratom products.

The big picture

Human evidence on long-term kratom safety remains limited, and commercial products vary in alkaloid content and formulation. This 90-day rat study tested a named leaf extract standardized to mitragynine, so its dose findings are most directly relevant to that preparation and this animal model.

Key findings

• 160 Sprague Dawley rats received daily oral gavage with the proprietary SpecioTea extract for 90 days.
• The tested doses supplied 0, 15, 30, or 60 mg/kg/day of mitragynine.
• Food consumption and body weight were lower at doses of 15 mg/kg/day or more.
• Researchers reported adverse changes in ovaries, testes, and epididymides at 60 mg/kg/day.
• The authors designated 30 mg/kg/day as the no-observed-adverse-effect level; they could not establish a no-observed-effect level.

What they say

The authors wrote that the findings 'cannot be unilaterally extended to all kratom products in the marketplace,' because many differ substantially from traditional preparations.

Bottom line

**In this 90-day rat study of one standardized leaf extract, 30 mg/kg/day was the NOAEL, while lower-dose biological effects and high-dose reproductive-organ changes were observed.**