Is cholecalciferol in Dr. Berg's Vitamin D3 & K2 toxic to humans?

Cholecalciferol, also known as vitamin D3, has been used as a rodenticide, particularly for controlling rat populations. In rats, the median lethal dose (LD50) is about 50 mg per kg of body weight, meaning it takes a relatively small amount to become fatal. In contrast, humans require drastically higher amounts for cholecalciferol to reach toxic or lethal levels—upwards of 2,450 mg, or roughly 98 million IU. For perspective, this is thousands of times more than typical daily supplementation, and even reaching 1–2 million IU would require extreme and prolonged intake.

This difference in sensitivity highlights the species-specific effects of cholecalciferol. Rats are far more vulnerable to it than humans, which is why it can be used effectively and lethally in pest control with doses that remain harmless in humans.

To better understand this, consider the analogy of cacao and chocolate. Cacao is the raw ingredient in chocolate, and moderate amounts provide health benefits to humans. However, even small quantities can be toxic to certain animals, like dogs or cats. Similarly, cholecalciferol is essential and beneficial for human health in the right amounts—but for rats, the same compound in even modest doses can be deadly.

The vitamin D3 used in our products is derived from lanolin, a natural substance found in sheep’s wool. Like human skin, lanolin can convert UV light into vitamin D3, making it a bioidentical and safe supplement source.

In summary, cholecalciferol is vital for human health and safe in appropriate doses, but it acts as a targeted poison for pests like rats due to their vastly higher sensitivity.