Life Extension Magazine®

Rosemary in olive oil rich in polyphenols and terpenes


Rosemary is an herb rich in polyphenols, flavonoids, and terpenes. These compounds appear to be behind its benefits for eye and brain health, protection against stroke, and control of blood sugar levels.

Scientifically reviewed by: Holli Ryan, RD, LD/N, in August 2023. Written by: Laurie Mathena.

Rosemary, a fragrant Mediterranean herb, is known for enhancing dishes like chicken or lamb. But as prized as it is for its culinary contributions, rosemary’s medicinal benefits are even more impressive.

It has reached superfood status because of its abundance of plant compounds like polyphenols, flavonoids, and terpenes.

Ancient healers reportedly used rosemary for boosting the immune and circulatory system, improving memory, and promoting hair growth. Now, modern science has shown its benefits for brain health, eye health, diabetes protection, and more.

Brain Benefits

Rosemary contains rosmarinic acid and carnosic acid, shown to protect rat brain cell cultures from free radical damage.1 This is the kind of damage that can cause strokes and neurodegeneration.

Rosemary could also be beneficial for people who have experienced a stroke. In a rat model of a stroke, a rosemary extract reduced the extent of brain injury following the stroke, reduced swelling in the brain, reduced neurologic deficit scores, and reduced the permeability of the blood-brain barrier.2 This suggests that rosemary could help protect against brain damage and improve recovery following a stroke.

In another rat study, carnosic acid helped protect against beta amyloid-induced neurodegeneration in the hippocampus, the part of the brain responsible for learning and memory.3 Beta amyloid plaques are toxic protein “clumps” that accumulate in the brains of Alzheimer’s patients.

Eye Protection

That same beneficial compound, carnosic acid, has been found in a preclinical study to protect the retinal cells from degeneration and toxicity.4 This has led researchers to conclude that it could be beneficial against age-related macular degeneration, the leading cause of vision loss in people over 50.

Type II Diabetes

Rosemary shows promise in helping to manage blood glucose levels. In animal models of type II diabetes, rosemary extract and two specific molecules found in rosemary (carnosic acid and rosmarinic acid) were found to have insulin-like effects that can help regulate how the body processes glucose. They also helped protect against hyperlipidemia and hyperglycemia in animal models of type II diabetics.5

You can enjoy rosemary in soups and sauces, in a marinade, or as a rub on meat. Or for an extra health boost, try infusing it in extra virgin olive oil and drizzling over a salad or on roasted vegetables.


  1. Molecules. 2018 Nov 13;23(11):2956.
  2. Iran J Pharm Res. 2016 Fall;15(4):875-83.
  3. Cell J. 2011 Spring;13(1):39-44.
  4. Invest Ophthalmol Vis Sci . 2012 Nov 27; 53(12):7847-54.
  5. Nutrients. 2017 Sep 1;9(9):968.