One Plot for Aging (Bones and Muscles)

One Plot for Aging (Bones and Muscles)

Created On
Dec 07 2020
Last Updated
Mar 24 2024

Muscle and bone health peak around the age of twenty-five. That's when the hormone responsible for maintaining them peaks.

This subsequent decline after the peak has been widely studied and is part of the natural aging process. The consensus of several studies is: there is decline in testosterone levels with age and it’s normal.

The natural decline in testosterone levels after youth happens both in men and women. Women just happen to have much lower levels compared to men (about one-tenth).

The Massachusetts Male Aging Study, from which this data is plotted, looked at the effect of aging on key hormones in human endocrine system. The full article can be accessed from The Journal of Clinical Endocrinology and Metabolism.

The plot above from this study shows a decline of approximately 1.2% per year in free testosterone levels.

This discussion is about bioavailable testosterone. Only about two-percent of all testosterone is in free form, that can be tested with a saliva sample.

Majority of testosterone is bound to SHBG (sex hormone binding globulin). With age, SHBG levels also reduce, which can increases the amount of bioavailable testosterone levels.

After menopause when most of the testosterone is produced by the adrenal glands, this may be sufficient enough to show an increase in testosterone levels in women.

Because it is responsible for maintaining muscle and bone health, the rate of decline correlates strongly to overall health in men and women.

Regular exercise, especially weight training, can help maintain testosterone levels and slow the body’s natural decline.

Other hormones in the endocrine system also decline with age, e.g., DHEA, which is precursor to many other hormones.

Experts consider testosterone as the most important male hormone to maintain well being and quality of life.

Healthy Testosterone Levels

The National Academy of Sciences says that apart from aging many other factors can affect testosterone levels.

These include high BMI (body weight), smoking, alcohol use, chronic diseases (e.g., diabetes, endocrine disorders), and use of certain medications (e.g., cortisol related medications).

In women, hormones produced by the ovaries drop significantly after menopause.

Menopause leads to significant hormones changes in women, e.g., estrogen, progesterone, testosterone and LH levels drop but FSH levels rise.

That's why a women's health test carefully selects ranges depending on menopausal status.

When to Consider Testing

The FDA believes more people are checking their testosterone levels than necessary. If you have doubts about your levels, first check the resources available on this site.

Health is very personal. Be informed. A good place to start is the detailed discussion on our page, All About Testosterone and then learn about Testosterone and Aging.

If you consider testing, a simple saliva test is the first step. Testing is easy, inexpensive, reliable, and confidential. An online testosterone test from a CLIA-certified lab can be ordered from the comfort of your home.

One key point to note: testosterone levels vary through out the day, starting high in the morning and gradually declining thoughout the day.

So always collect a sample around 30 minutes of waking up for most accurate results. And try to follow a regular routine as jet leg, night shifts, and changes in sleep patterns can affect your results.

Some medicines can also affect your levels. It's best to talk to your doctor before making any changes to your medication.

Order an At-Home free-Testosterone Test kit.

More from our research summaries: can help test your hormone levels from the comfort of home. For a full hormone analysis you can order a Male Health Test or a Female Health Test. We also provide individual hormone panels, e.g., a testosterone test kit. Our saliva based kits are reliable, convenient, and do not require any blood sample. Please see the FAQs for more information.