advertisement



Q & A Library


Print this page | Sign up for free e-bulletins
 | Bookmark This Page

Q
Testosterone Tumbling?
I recently read that testosterone levels among American men are on the decline, but I haven't seen an explanation of why this is so.  What's your view?
A
Answer (Published 4/11/2007)

The most recent look at testosterone levels among American men shows that they've been dropping over the past two decades. Levels tend to drop naturally as men age, but this appears to be a generational change – as one researcher put it, "In 1988, men who were 50 years old had higher serum testosterone concentrations than did comparable 50-year-old men in 1996."

Related Weil Products
Dr. Weil on Healthy Aging for Healthy Eating - Dr. Weil on Healthy Aging for Nutrition - Want to change your diet? The Dr. Weil on Healthy Aging online guide is your anti-inflammatory diet headquarters. Start your free trial and get access to an exclusive version of Dr. Weil's Anti-Inflammatory Food Pyramid, hundreds of recipes, eating guides, and more.

Testosterone, the primary male sex hormone, is also vital to bone and muscle strength. As a matter of fact, a study published in the October 23, 2006, issue of the Archives of Internal Medicine found that older men with lower testosterone levels had a greater risk of falling than men with higher levels. (Falls are associated with muscle weakness and muscle loss.)

Testosterone levels typically peak when men are in their late 20s and then, after age 30, decline gradually. The new study published on line on October 24, 2006, in the Journal of Clinical Endocrinology and Metabolism looked at testosterone levels from approximately 1,500 randomly selected men in the Boston area. In analyzing their findings, the researchers, from the New England Research Institutes in Watertown, MA, first adjusted for obesity, smoking and any drugs the men were taking. Still, they found that, each year, testosterone levels declined an average of 1.2 percent. And when they compared the new data to 1998 findings, they saw that testosterone levels are lower now than they were then. Fortunately, the lower levels remain in the normal range, 300-1000 nanograms/deciliter of blood (ng/dL).

What's to blame? One possibility could be exposure to a common insecticide, chlorpyrifos or its metabolite (TCPY). A study published in the journal Epidemiology in January, 2006, found that men exposed to this chemical had lower levels of circulating testosterone. Chlorpyrifos was commonly used on home lawns and gardens until 2000 when the U.S. Environmental Protection Agency limited its use to reduce the exposure of children after findings that it could over-stimulate the central nervous system causing nausea, dizziness, confusion, and at high exposures, respiratory paralysis, and death. When researchers from the University of Michigan, the Harvard School of Public Health in Boston and the Centers for Disease Control and Prevention measured levels of TCPY and 1-N (a breakdown product of the insecticide Sevin and the compound naphthalene found in cigarette smoke, diesel fuel and other byproducts of combustion) among 268 men recruited at an infertility clinic, they found that those who had higher levels of these chemicals in their urine also had lower testosterone levels. This is just one more reason to be cautious about the toxins and pollutants in our environment.

Who knows what other factors may play a role? Stress certainly can contribute to hormonal imbalances – high levels of the stress hormone cortisol correlate with lower levels of circulating testosterone, but for now, no one has the complete answer. The researchers who documented the testosterone declines suggested that further studies are needed to confirm their findings. More research into what's to blame would be helpful, as well.

Andrew Weil, M.D.

Creative Commons License Some Rights Reserved Creative Commons Copyright Notice
A portion of the original material created by Weil Lifestyle, LLC on DrWeil.com (specifically, all question and answer-type articles in the Dr. Weil Q&A Library) is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License.

The Weil Vitamin Advisor
Get your FREE personalized vitamin recommendation & supplement plan today!

Dr. Weil on Healthy Aging
Your Online Guide to the Anti-Inflammatory Diet. Start eating for your health - begin your free trial now.

Dr. Weil's Spontaneous Happiness
Achieve emotional well-being
in just eight weeks!
Start your 10-day free trial now!

Vitamin Library
Supplement your knowledge with Dr. Weil's essential vitamin facts. Learn why they are necessary and more.

Dr. Weil's Optimum Health Plan
Your 8-week plan to wellness.
Begin your journey today!
 

Dr. Weil's Head-to-Toe
Wellness Guide

Your guide to natural health.
Use the Wellness Guide today!

Dr. Weil's Anti-Inflammatory Diet Food Pyramid
Our interactive tool can help improve overall health through diet.

Condition Care Guide
Learn about health conditions from acne to vertigo, and Dr. Weil's view of the best treatment options for each.

Healthy Recipes
Discover a treasure trove of healthy, healing foods and creative, delicious ways to prepare them.

Q&A Library
Over 2,000 questions from you
and their corresponding answers
from Dr. Weil.

 
Copyright © 2014 Weil Lifestyle, LLC
Information on this web site is provided for informational purposes only and is not intended as a substitute for the advice provided by your physician or other healthcare professional. You should not use the information on this web site for diagnosing or treating a health problem or disease, or prescribing any medication or other treatment.

Ad Choice
Advertising Notice

This Site and third parties who place advertisements on this Site may collect and use information about your visits to this Site and other websites in order to provide advertisements about goods and services of interest to you. If you would like to obtain more information about these advertising practices and to make choices about online behavioral advertising, please click here