Rosemary may contain a compound that can fight Alzheimer's disease. Mice treated with it showed improved memory, more neuron synapses, and fewer toxic proteins

The compound is called carnosic acid, and scientists have now developed a stable version of it that showed encouraging results in mice.

Normally found in rosemary and sage, carnosic acid has antioxidant and anti-inflammatory effects, but it’s unstable in its raw form. Researchers created a synthetic, di-acetylated version called diAcCA, which is converted back into carnosic acid by the gut before entering the bloodstream. It absorbs 20% better than the original and reaches therapeutic levels in the brain within an hour.

 

Mice engineered with Alzheimer’s-like symptoms were given diAcCA or a placebo three times per week for three months.

The treated group showed improved memory, more neuron synapses, reduced inflammation, and fewer toxic proteins like amyloid beta and phosphorylated tau, which are key markers of the disease. The compound had no observed toxic effects.

Researchers noted that the mice didn’t just stop declining—they improved to near-normal levels. DiAcCA may also have applications in treating other inflammation-based diseases like Parkinson’s or type 2 diabetes. Since carnosic acid is already considered safe for consumption, the team believes drug development could move faster than usual.

There’s also a chance this compound could be combined with existing Alzheimer’s treatments to reduce side effects. Still, results are limited to animal tests so far, and human clinical trials are needed before anything moves forward.