According to the BBC, blood and plasma transport hormones around the body. Many attach to hormone-specific plasma proteins, while others are free-roaming. They travel throughout the body via the extensive and complex system of blood vessels, the veins and capillaries.
Tulane University indicates that while numerous free-moving essential hormones are water soluble, two major groups, the steroid and thyroid hormones, are hydrophobic, so they are water insoluble. Therefore, to get around the body via the blood system, these lipophilic hormones bind with fatty transporter proteins. These proteins not only transport the hormones, they also prevent them from being chemically altered by other substances in the body before the hormones reach their target destinations, allowing them to perform their designated tasks.
The BBC explains that different glands produce different hormones, targeting specific areas or bodily processes. The adrenal gland, for example, produces adrenaline, preparing the body for increased activity by raising the heart rate, restricting blood flow to less important functions and increasing it to the muscles and the brain. Henry Ford Community College describes how hormones quickly travel throughout the body in the blood system, and how they pass through the capillary endothelium via diffusion, entering interstitial spaces to access their targets.