Age Science: Hormones


From head to toe, hormones are involved in almost every biological process, including sexual reproduction, growth, metabolism and immune function. There are more than 50 hormones secreted into the body, responsible for thousands of body processes.

More than 20 different hormones — including insulin, testosterone and serotonin — influence your weight, shape, mood, appetite and eating habits, and an imbalance in any one of them could be cause for concern. Plus, a whole host of hormones influence our sex lives, explains Dr. Alvin Pettle and Lorna R. Vanderhaeghe, co-authors of Sexy Hormones (Fitzhenry & Whiteside, 2007).

“It’s like a symphony with many different instruments that all have to be balanced to play in harmony. Hormone deficiencies and excesses disrupt this natural rhythm, leading to discord in the body,” says Pettle.

“They work in unison, and when levels of each hormone are in the right proportions, you feel fit and strong, your skin is clear, you have energy and a sex drive,” adds Vanderhaeghe. “These complicated interactions mean that any one hormone deficiency or excess can cause a domino (cascade) effect that affects every hormone down the chain. For example, low progesterone causes an increase in estrogens. High estrogens promote weight gain because of low levels of thyroid hormones and elevated cortisol. Inadequate levels of some adrenal hormones may cause the thyroid to not function properly.”


The word hormone comes from the Greek hormo, meaning to set in motion, and that’s exactly what hormones do in the body, telling various tissues what to do and when. They are produced primarily by a network of endocrine glands, the main ones being the pineal, hypothalamus, pituitary, thyroid, thymus, adrenals, pancreas, ovaries and testes.

Once produced, they work in a sort of lock-and-key mechanism. The hormone (the key) attaches itself to specific receptor sites (the lock) on individual cells. If the key fits the lock, the door will open. If a hormone fits the receptor site, there will be an effect. “Sometimes, the hormone fits the lock exactly; other times, it alters the action of the lock,” says Vanderhaeghe. “Some of these locks can take more than one key, meaning several hormones can affect it.”



As we age, all our hormones and the corresponding endocrine glands weaken. They produce less hormones, and the receptor sites for these hormones are not as sensitive, explains Dr. Greg L. Pugen, a clinical instructor at the University of Toronto. As a result, we may not perform as we once did — energy, libido and metabolic functions can all be affected. “Even our mind may slow down, not be quite as quick processing information,” he adds. “And we may not handle the stress as well as we did in our 20s.” Pugen says that male hormone levels may drop more slowly than women’s but, after age 30, they go downhill from one to three per cent a year.

“By age 44, a male’s hormone profile might be anywhere from 14 per cent to 42 per cent less than when he was 30. However, by replacing deficiencies, we can improve and extend quality of life.” Pettle adds, “After 35, a woman’s hormones, by the very nature of their reproductive function, may begin to decline, especially progesterone. By 44, there may be as much as a 50 per cent reduction in a woman’s hormonal values of progesterone and testosterone.”


Hormone therapy aims to restore the body’s natural hormone levels and is best supervised by a physician.

To ascertain possible deficiencies, Pugen says he creates a hormone profile, which includes a good medical history and physical examination, followed by a full blood screen of all hormones necessary for continued good health, as well as nutrients and other inflammatory markers. Screening methods include blood and 24-hour urine and saliva tests, depending on the doctor’s level of investigation. Treatment options include prescription supplements and bioidentical hormones as well as over-the-counter supplements.

Hormone: Estrogens Source: Ovaries, Adrenals There is no single hormone called estrogen, explains Pettle. Rather, there are three types of body estrogens: estriol, the weakest; estrone; and estradiol, the strongest. Both men and women produce estrogens but in vastly different amounts. Too much estrogen can create a condition called estrogen dominance. Women with estrogen dominance are plagued with conditions ranging from endometriosis and fibroids to heavy periods and breast cancer. Estrogen dominance in men contributes to weight gain, breast development, lowered libido and prostate problems.

Hormone: Progesterone Source: Ovaries, Adrenals Progesterone is manufactured in the ovaries in women and in the adrenals in men. Its job is to balance the effects of all the other primary hormone groups in the body, including estrogen, testosterone and cortisol. Progesterone receptors can be found throughout the body, from the brain to the bladder. When progesterone is low or blocked from reaching the cell receptors, other hormones can get out of balance and start to create problems, ranging from oily skin and abdominal fat to anxiety and depression.

Hormone: Testosterone Source: Testicles, Adrenals Both men and women need and produce testosterone, although in differing amounts. Men produce testosterone in the testicles; women in the adrenals from DHEA and in the ovaries, where estradiol is converted to testosterone. Symptoms of excess testosterone range from acne and oily skin to weight gain; symptoms of low testosterone include low or no sex drive, memory decline, muscle wasting and weakness.

Hormone: DHEA Source: Adrenals

DHEA, another hormone produced in the adrenal glands, is a building block for testosterone and estrogens. DHEA and cortisol are linked — DHEA helps normalize cortisol levels, and high levels of cortisol cause a decline in DHEA. Symptoms of DHEA excesses and deficiencies are similar as those for low or high levels of other hormones.

Hormone: Cortisol Source: Adrenals

Cortisol is sometimes called the stress hormone because it is produced when the body is under stress. Research has linked elevated cortisol levels with fat accumulation, digestive problems, impaired immune function, chronic fatigue and memory loss. Chronically heightened cortisol levels eventually lead to adrenal exhaustion, causing the adrenal glands to no longer produce normal levels of cortisol. Estrogen levels also go up when cortisol levels increase. Cortisol reduction through stress management is important for hormone balance.

Hormone: Melatonin, Seratonin  Source: Pineal, The Brain Melatonin controls our sleep-wake cycles. It is secreted when it’s dark and suppressed by light. “People don’t realize that melatonin attaches onto the receptors of the breast and actually helps block the receptors from getting estrogen while you sleep, so it helps to prevent breast cancer as well,” adds Pettle. Melatonin is made from serotonin, a neurotransmitter chemical in the brain that transmits happy feelings and helps control moods by helping with sleep, calming anxiety and relieving depression. Low serotonin levels can lead to symptoms of anxiety, insomnia and fatigue.