What Exactly Do Hormones Do in the Body?
By Dr. Khanh Perrin
What exactly do hormones do in our bodies? Why are so many people talking about hormones and hormone replacement these days? What’s all the hype about? Why should I care about my hormones?

Let’s just talk about the big 5 for now: Testosterone, estrogen, thyroid, insulin, and cortisol.

The Big 5


Perhaps the best known hormone, or at least the one you’re likely familiar with. Testosterone is what’s considered a “master” hormone, meaning it is responsible for a TON of our bodily functions and well-being.

“Manufactured in male testicles and female ovaries, it’s most often associated with sex drive, but is also closely associated with muscle and bone mass and the distribution of fat cells. Low levels of testosterone cause erectile dysfunction, low sex drive, decreased semen production, loss of muscle, and low bone density.” – The Well


Estrogen, actually estradiol in our bodies, is another one of those “master” hormones, much like testosterone. However, while testosterone is vital in both men and women, estrogen is especially important in women. For reference, “normal” levels of estradiol in men range from between 10–40 picograms per milliliter (pg/mL) , whereas in women it’s more like 30-400 picograms per milliliter (pg/mL), but after menopause, it falls below 30 pg/mL.

“Also known as the female sex hormone, estrogen is released by a woman’s ovaries. It’s a crucial element of the development of breasts, pubic hair, and the widening of hips. In addition to regulating a female’s periods, estrogen is also involved in bone formation, blood clotting, and the health of your skin and nails. If you are depleted in estrogen, you may have low moods or depression. When estrogen levels Fluctuate, as they do during menopause, you may experience hot Washes, low libido, and weight gain.” – The Well


First of all, let’s get a common hang-up out of the way regarding this hormone. Thyroid is a hormone and your thyroid gland produces thyroid. So it’s the name for both the hormone and the gland which makes it. I know, sort of strange. Anyway, let’s move on!

“The thyroid gland is a vital hormone gland: It plays a major role in the metabolism, growth and development of the human body. It helps to regulate many body functions by constantly releasing a steady amount of thyroid hormones into the bloodstream. If the body needs more energy in certain situations – for instance, if it is growing or cold, or during pregnancy – the thyroid gland produces more hormones.” – NCBI

Thyroid is one of the most commonly misunderstood and overlooked hormones we deal with here at CraftCare. It’s hard to believe this could be the case when it’s SO IMPORTANT and effects so many aspects of our well-being, but alas, thyroid remains an unsung hero.


This may be the single most impactful hormone in the United States. We’re all aware that we’re decades deep in an obesity epidemic, and a shocking number of us are walking around with undiagnosed prediabetes.

The hormone responsible for regulating blood glucose (sugar) levels and many other metabolic functions is called insulin. Maybe you’ve heard of insulin in relation to diabetics needing to inject it regularly to stay in balance. Maybe you’ve heard of exorbitant price gouging by pharmaceutical companies. Regardless of what you’ve heard, insulin is crucial to our everyday lives and it’s what allows appropriate organs in our bodies to absorb glucose and convert it to fat for energy, rather than remaining in our blood and wreaking havoc.

“If your body doesn’t generate enough insulin or if it isn’t using it well, blood sugar accumulates and can set you up for diabetes.” –The Well


Cortisol is a hormone that’s sort of di_cult to paint in a good light, so let’s get through its primary functions then we’ll try to spin it and highlight the importance of its role in our bodies. Cortisol is the stress hormone. Actually, it’s what’s considered a “steroid” hormone, and it is actually derived from cholesterol. This connection should give a pretty clear picture of why we don’t like to see elevated levels of cortisol.

“It’s a natural alert system to let you know when you’re under duress. While it’s helpful when you need to be aware of imminent danger, consistently high cortisol levels can lead to anxiety, weight gain, migraines, heart problems, irritability, brain fog, and sleep disturbances.” – The Well

That said, cortisol is definitely helpful when we need it. In a high stress, potentially life threatening situation, cortisol and adrenaline work together to produce our height or Weight response, temporarily sharpen our memory, and boost our critical thinking ability. Ironically, chronic stress and an overabundance of cortisol could be behind a lot of the road rage we get to experience! (Only joking.)

So How Do I Get Started?

If you’re interested in HRT, be sure to find a provider who only prescribes bio-identical hormones. Also make sure to find a provider who specializes in the treatment, not just dabbles; HRT is a balancing act which should be carefully planned and monitored to ensure healthy, long-lasting benefits.

Located in Beverly Hills, California, CraftCare is led by Dr. Perrin Khanh, M.D., an integrative Functional Medicine Physician who specializes in bio-identical hormone replacement therapy for men and women.