Hormones are chemicals your body produces and releases into the bloodstream in order to transmit important information and instructions to cells. Hormones are produced in and released by the endocrine glands (i.e. the thyroid, adrenal, and pituitary glands). Hormones are catalysts for a tremendous array of chemical actions on the cellular level that are vital for our proper and healthy development, growth, and energy. As such, they are responsible for an equally broad range of biological functions, from the physical to the mental and emotional.
Feeling happy, sad, and angry; being hungry and satiated; falling asleep and waking up; having sex: all of these are functions of hormones. So is our organ health, musculoskeletal health, cardiovascular and digestive health, and the health of our nervous and reproductive systems.
There are all different types of hormones, among the most prevalent and important of which are sex hormones (like testosterone and estrogen) and stress hormones (like cortisol and adrenaline).
Understanding how hormones work is relatively simple: think of it like a key fitting into a lock. Specific hormones travel to specific cells (called "target cells") which carry a "receptor" that can only be activated by that particular hormone. It is a hormone's attaching to and consequently activating its corresponding receptor that triggers the cell containing that receptor to perform a specific function. The hormone is the key, the receptor is the lock, the cell being triggered to perform its task is the door being opened.
The Difference Between Neurotransmitters and Hormones
If you've read our article on Neurotransmitters (or if you read it now), you'll see that they and hormones play quite similar roles--and in fact, some neurotransmitters are also hormones. Adrenaline, for example, is both a hormone and a neurotransmitter. The difference is only in its pathway (its starting point and destination), and as a consequence the resulting bio-function it triggers.
Hormones are released by the endocrine glands and travel great distances (relatively speaking) through the bloodstream to their receptor sites; neurotransmitters, on the other hand, are released by nerve "terminals" (or the ends of nerve cells) and transmitted over very short distances, just across the tiny synapse between one nerve cell and another.
In the case of adrenaline: it's a hormone when the adrenal gland releases it and it travels to the lungs or the heart; it's a neurotransmitter when it's released by one type of nerve cell and sent to another.
The key commonality between hormones and neurotransmitters - and what's most important to remember for the purposes of your health - is that they are the body's inner messengers. They tell our cells what to do and when to do it, and are therefore integral for so very many aspects of life.
A Word On Balance
You'll notice in the introduction to this article, we used words like 'balance' and 'proportion'. This concept is critical when it comes to the many roles hormones play in regulating our bio-system. Proper levels of each individual hormone isn't enough to do the job; those levels must also be in the proper proportions to one another.
Hormones do not exist or function independently of one another. The "life" of a hormone is one of interplay and relationships. A deficiency in one hormone could cause a deficiency in another hormone which might, in turn, cause an equally problematic excess in an altogether different hormone. And each of these deficiencies and excesses (individually and in combination) can cause its own set of symptoms and conditions.
That is why, when we talk of hormone health, we speak of 'balance': of correcting unhealthy 'hormonal imbalances' and restoring a healthy 'hormonal balance'. In biological terms, that state of balance is called 'homeostasis'.