The phrase "circulating levels" refers to the amount or concentration of a substance (like hormones, nutrients, or cells) that is moving or flowing within the bloodstream throughout the body. Full definition
The results demonstrated that men with low circulating levels of testosterone had an 88 % increased risk of mortality. (holtorfmed.com)
Based upon the causes of thyroid dysfunction, one can see why the accepted medical method of just giving more thyroid hormones to those with low circulating levels of T3 or T4 is inadequate. (myersdetox.com)
Other studies show that visceral obesity raises a person's risk of developing colon cancer, perhaps because it increases circulating levels of hormones that affect cell growth. (discovermagazine.com)