90-day CBD-rich hemp extract study in rats found no major toxicity but flagged kidney and liver signals

No adverse effects on organ weight, body weight, behavior, locomotion, food intake, or mortality were observed at any dose (0.5-35 mg/kg/day). However, blood analysis showed significant decreases in calcium, sodium, potassium, chloride, alkaline phosphatase, and creatinine. Males showed decreased alanine transaminase; females showed hyperalbuminemia. CBD accumulated in tissues in the order: brain < serum < liver < heart < kidney < muscle and skin.

Male and female rats received CBD-rich (77% CBD) full-spectrum hemp extract at 0.5, 5, 10, or 35 mg/kg/day orally for 90 days. Researchers assessed organ and body weight, behavior, locomotion, food intake, mortality, pathomorphology, blood cells, serum biochemistry, electrolytes, and CBD tissue distribution.

As CBD products proliferate, rigorous safety data remain limited. This 90-day study provides one of the more thorough safety profiles available, including tissue distribution mapping that shows CBD concentrates heavily in muscle, skin, and kidneys rather than the brain.

The tissue distribution data are particularly interesting: CBD concentrated most heavily in muscle and skin, with relatively low brain levels. This suggests oral CBD may have limited central nervous system bioavailability while potentially accumulating in peripheral tissues. The sex-dependent kidney and liver biomarker changes, while likely reversible, warrant monitoring in long-term human CBD users.

Rat metabolism differs significantly from human metabolism. The extract was full-spectrum (not pure CBD), so other cannabinoids and compounds may contribute to effects. No recovery period was included to confirm reversibility of biomarker changes. The highest dose (35 mg/kg) is relatively modest compared to some human CBD dosing.