The Hormone Theory of Aging

Could your hormones be aging you? There are many theories behind why we age, and one is the hormone theory of aging. Experts who back this idea believe hormones, which control the function of organs, could be behind aging – and maybe even the fountain of youth. Hormones might be the culprit behind the aging process.

Your body's endocrine system secretes and controls the hormones that regulate many body processes including metabolism, use of nutrients, excretion, and reproduction. As you age, these systems become less efficient, leading to changes in our bodies, such as menopause. The hormone theory of aging states that these changes eventually cause the effects of aging.

There is some evidence to support the hormone theory of aging. In one older study, researchers removed the pituitary gland of mice, which controls much of the endocrine system. The researchers then substituted the absence of the pituitary gland with supplementation of all of the hormones identified in mice. It turns out that those without a pituitary gland lived longer than a control group of normal mice who did have a gland. This led researchers to conclude that the pituitary gland must also excrete another, unknown, a hormone that negatively impacts aging.

Research on a variety of organisms has shown that mutations that reduce insulin-like growth factor 1 (IGF-1) result in longer lives. But reducing IGF-1 has inconsistent effects on age-related diseases in humans, reducing the risks for some but increasing them for others. Growth hormone stimulates the production of IGF-1, which is a strike against supplementing with human growth hormone to stop aging.

An intriguing review of studies, published in Frontiers in Endocrinology in 2019, noted that subjects on a caloric restricted diet had a similar endocrine profile to studied centenarians, with both having a favorable GH/IGF-1/insulin profile. This is only one area where lifestyle modification has been shown to improve hormonal function; another example of lifestyle changes improving hormone function is the observation that weight loss and exercise improve insulin sensitivity.

The concept that hormones or reduced production of hormones might cause aging has also led some to believe that they could be an anti-aging elixir. Growth hormone, which is produced by the pituitary gland, helps maintain tissues and organs throughout life. It's also responsible for childhood growth. Synthetic human growth hormone (HGH) has been touted as a potential fountain of youth, with proponents hoping it can stave off the decline in tissue growth from aging.

While some adults have growth hormone deficiencies and require supplementation, this is rare. Research is indecisive on any other potential benefits. In addition, the use of HGH has many potential side effects including swelling of the arms and legs, joint and muscle pain, carpal tunnel syndrome, diabetes, hypertension, and increased risk of colon cancer.

Another aspect to consider is that growth hormone stimulates IGF-1, and some theories are that a reduction in IGF-1 is beneficial for aging. In this case, adding growth hormone would produce the opposite of the desired effects.

Hormonal changes are an important part of aging. Whether they control the pace at which aging happens or are a consequence of other changes in the body is unknown. It is unlikely that hormone substitution in humans will increase lifespan and can even be dangerous. Some anti-aging doctors will prescribe HGH, but research does not support its use for anti-aging.

You might be surprised to learn that there are tons of other theories of aging. We can only hope to live long enough to see which are correct.