Science writer and experimenter. Conventionally published in science, technology, computers, personal development, health, & fitness.
Testosterone is a hormone present in both men and women’s bodies. In men, it is the main hormone responsible for our masculine characteristics, supporting spermatogenesis. In both men and women, testosterone positively affects sex drive, muscle mass, fat composition, lethargy, and mood. In women, testosterone therapy has been used successfully to combat symptoms of menopause.
The biological effects of testosterone on men have been known since antiquity. The reason we learned this so early is that the testes, where 95% of the man’s testosterone is secreted, are external to the male body and are easily removable. Say it with me boys, Ouch!
Aristotle (384–322 BC) accurately observed and reported the effects of castration. However, the castration of males has been documented as early as 1300 BC, as the country of China performed the practice to create eunuchs. Castration was also performed on slaves and defeated soldiers, in addition to being used as punishment for those who committed various crimes. As a side note, (no pun intended) for the Italian opera, young males were sometimes castrated before puberty to preserve their soprano singing voice (this practice was outlawed in 1870's). During the Chechen War, which took place in the Caucasus in 1996, war crimes that included the castration of enemies were reported from both sides.
There is currently more information and research available regarding testosterone and men. The data I am able to research on women isn’t as comprehensive or as definitive as reflected in this chapter. Fortunately, research is on-going.
What is Testosterone?
Testosterone is an anabolic steroid. The words anabolic steroid is like a Pavlovian dog whistle to most of the general population that suggests negative associations to some athletes and body builders. Some body builders abuse steroids in their quest to develop the best physique possible. However, we ought not label steroids as being “bad.” The human body uses many steroids every day to stay alive and function.
So yes, testosterone is the first anabolic steroid. Anabolic steroids do increase protein production, what we common layfolk think of as muscles and bone. However, athletes who are abusing anabolic steroids rarely do so with plain old testosterone. Designer steroids, based on testosterone, are available and are more potent than testosterone. And if they are abusing testosterone, it is at dosages that far exceed (2X-10X) a normal replacement (physiological) dose of testosterone commonly used in Testosterone Replacement Therapy (TRT). But this is not about using anabolic steroids for body building.
The focus of this book is for you to achieve the highest levels of mental and physical fitness possible, and in that quest, increasing testosterone to optimum levels will help you achieve your goals.
Men in their twenties will produce 5 to 10 milligrams of testosterone per day. Ninety-five percent (95%) of testosterone is produced by Leydig cells in the testicles. The remaining 5% is produced by adrenal glands.
Women in their twenties, in general, will produce between 1/10 and 1/20 of the amount of testosterone as compared to men, or 0.25 to 1 milligram.
While testosterone is thought of as a male hormone, women produce testosterone in both the ovaries and adrenal glands. Testosterone levels decrease with age in women, and by the time a woman reaches age 40, her testosterone levels have decreased by fifty percent. Interestingly, low testosterone in women mimic similar symptoms in men; lower sexual drive, lethargy, depression, weight gain, loss of bone density, and loss of muscle mass. Women under 50 years old with a testosterone level of 20 ng/dL is (in some ranges) considered low.
Non-pregnant women between the ages of 20 and 29 have an estrogen level that varies between 20 and 150 pg/ml. Estrogen levels vary depending upon where a woman is in her menstrual cycle. I’m sure testosterone levels in women vary also during the month. However, I haven’t found any supporting data on this, so I am using a static average testosterone value. I estimate a woman’s testosterone level at a midlevel value of about 40 ng/dL. If we convert her testosterone unit of measure from ng/dL to pg/ml, 40 ng/dl converts to 400 pg/ml of testosterone.
Women have 2–20X more Testosterone in their blood than estrogen.
Now it becomes interesting, and I believe it’s a fact few people know. A woman between 20 and 29 years of age has two to twenty times more testosterone in her system than estrogen. This ratio changes when a woman becomes pregnant, as pregnancy elevates a woman’s estrogen levels.
Interesting, but so what? This hormone imbalance becomes more pronounced at menopause when a woman’s hormone levels drop. A woman can experience the same symptoms of low testosterone as men. Typically, a doctor starting treatment using Hormone Replacement Therapy (HRT) will prescribe estrogen and progesterone but most likely will not include testosterone. If HRT treatment doesn’t alleviate the symptoms, could it be that testosterone needs to be included? No, say many doctors. But yes, say other doctors. Some female doctors who began treating their own symptoms have written books on the need to include testosterone in women’s HRT.
Kathy Maupin MD is a board-certified obstetrician and gynecologist who went through her own hormone hell in her early 40’s. Her symptoms, loss of sexual interest, exhaustion, increased body fat, lack of mental clarity, and others, were not alleviated until she began adding the hormone testosterone. This affected her so deeply, she became an anti-aging physician who has dedicated herself to treating midlife women with testosterone. In her book, The Secret Female Hormone, she describes the debilitating hormone imbalance she experienced before menopause and how she is helping other women.
An OBGYN discovered testosterone therapy for both himself and his wife, who is also a doctor; she was only 39 years old when she started testosterone therapy. He presented an interesting TED talk, you can view on Youtube here:
Testing Testosterone Levels
For an accurate measurement of testosterone in the body, you need to supply a blood sample to a lab. I know there are websites and doctors that believe “mail order” saliva tests are accurate. But according to the American Association of Clinical Endocrinologists (AACE), saliva testing for sex hormones, testosterone and estrogen, does not produce consistent results. The AACE claims saliva test results are highly variable.
Saliva tests may be useful, but only for establishing a baseline measurement of testosterone and estrogen. Because saliva is altered by replacement therapy (TRT or HRT), I don’t believe they should be used in either treatment. Also keep in mind, saliva tests for testosterone and estrogen are not FDA approved.
The other exception is a saliva test for cortisol, which is not accurate when compared to serum levels of cortisol.
To obtain accurate and consistent measurements of the testosterone hormones, I advise you to rely on blood testing, only.
When you have your blood test results, there are three numbers associated with your testosterone measurement; Total Testosterone, Bioavailable, and Free.
Total Testosterone is the accumulated number of all the different forms of testosterone in the body.
About 45% to 65% of testosterone is strongly bound to the Sex Hormone-Binding Globulin (SHBG) protein. The SHBG bound testosterone is biologically inactive.
Approximately 33% to 50% of testosterone is weakly bound to albumin. This percentage of testosterone is called bioavailable testosterone. This form of testosterone can be converted to free testosterone, when the body runs low on free testosterone.
Finally, we have 1% to 3% of free testosterone that is biologically active. This is the amount of testosterone that is available to the cells in your body to work its magic.
Now this isn’t to say that the total testosterone number isn’t important, in most cases, it indicates your general testosterone status. Meaning, if your total testosterone number is low, chances are your free testosterone and bioavailable testosterone values are low also.
Low T Men
Men with low testosterone in the United States is at epidemic levels. A study has shown that between the years 1987 and 2004, the population decline in American men’s testosterone decreased by over 17%. 1 This decline in testosterone was age independent, meaning age was factored out and has nothing to do with the decline in testosterone reported.
In 2007, The Journal of Clinical Endocrinology & Metabolism, published a study showing that approximately one-quarter of men over 30 have low testosterone.” 2
A few common indicators of low T include a diminishing sex drive, erectile dysfunction, excessive fatigue, depression, and apathy, along with a decrease in physical strength, endurance, bone density, and muscle mass.
If that isn’t enough bad news, low T has been linked to other unhealthy medical issues such as; increased insulin resistance, diabetes, metabolic syndrome, obesity, and high blood pressure. 3,4 These issues generate a question like what came first, the chicken or the egg? Did the low T cause obesity, diabetes, etc.? Or did the medical issue cause the low T? Take the case of obesity. Did carrying so much excess fat cause the low T, or did the man have low T, which caused him to pack on excess fat and become obese? It appears to work both ways.
When men with diabetes were randomly tested for testosterone, over half of the men had low testosterone. Similarly, men with low testosterone are more likely to develop diabetes.
Short-term studies show men who increase their T value show improvements with the above issues across the board. Results are not conclusive, say the researchers who caution that long term studies are required before they can consider that research complete. Until that time, the results are promising but not conclusive.
How Bad Can It Be?
Pretty bad. If we look at the declining sperm count of the American male, there is a 60% decrease in sperm count from the 1930’s to 2011. 5,6,7
I believe there is a similar decline in testosterone in the American male. As stated, in January 2007, the Journal of Clinical Endocrinology and Metabolism published a study of 1,532 men. Data was collected from men at three time periods between 1987 and 2004. The overall results show a population decline in testosterone of approximately 17% across the board. This decline is not due to age (age-independent) or lifestyle characteristics, as they had been factored out of the analysis.
Let’s look at one segment. The 60-year-old men in 1987 had a total testosterone level of approximately 505 ng/dl. In 2004, 60-year-old men had a testosterone level of approximately 435 ng/dl. That’s about a 15% decline for this segment. 8
If we take this 17-year period of time and extrapolated (extend the graph) the decline in testosterone backwards to the 1930’s, it appears plausible to me that testosterone may have declined by the same percentage as men’s sperm count. If we extend the graph of the decline forward, it would predict a continuous population decline in men’s testosterone. Do we see this happening? As will be discussed a little later on, LabCorp, a top American laboratory that performs blood tests, recently (July 2017) lowered their normal testosterone range for men. It dropped from 348–1197 ng/dl to 264–941 ng/dL. So rather than sounding an alarm of a population decline in men’s testosterone levels, they instead, normalized the decline and made the declined testosterone levels the new “normal.”
Low T Women
Women with symptoms of low testosterone are most likely underdiagnosed. Doctors will typically look for other causes first. As with men, low testosterone in women is also associated with lower sexual drive, lethargy, depression, mental fog, loss of muscle mass and bone density, as well as vaginal dryness. Women experience a significant drop in hormone levels during menopause. However, drops in hormone levels can occur before menopause that developed symptoms. For a woman to determine her hormone levels, she will need a blood test. Depending upon the lab, the range for testosterone levels in women may range from 8–70 nanograms per deciliter (ng/dL).
Benefits of High T (Men)
With men, we can pretty much reverse the symptoms of the low testosterone discussed, if it is low testosterone that caused these symptoms to begin with; increased libido, reduction of erectile dysfunction, greater energy, improved mood and confidence, greater strength, endurance, muscle mass, and bone density. In addition, there is supportive evidence that high testosterone levels improve insulin resistance and improve body composition. 9
Benefits of High T (Women)
As with men, if you are experiencing symptoms that are caused by low testosterone, increasing your testosterone into its normal midrange level (35–40 ng/dL) may alleviate these symptoms.
There is evidence to support that testosterone is essential for women’s physical and mental health. Despite the myths, testosterone in women is not masculinizing. It actually increases scalp hair growth, is cardiac protective, and helps prevent breast cancer among other values. 10
I wonder if in the early days of HRT before bio-identical hormones became available, if the hormones derived from pregnant equine (horse) urine could have been responsible for the negative reports.
Bio-identical hormones are synthesized from compounds extracted from plants. They are considered bio-identical because they are identical in molecular structure to human hormones.
Do You Have Low T?
Men, are you hypogonadal or experiencing andropause? Hypogonadal is just another way of saying low testosterone. Andropause, may be age related, the male equivalent to female menopause. The medical community is debating whether men go through a well-defined decrease in testosterone that could be defined as andropause (male menopause).
A woman’s hormone levels naturally drop as she ages, so pre-menopausal women may have low hormone levels.
Determining if your testosterone is clinically low requires a blood test. Each laboratory has its own “Normal Range” of testosterone. For Quest Diagnostics labs, which I use in NY, the range for men is 250–1100 ng/dl (ng/dl is nanograms per deciliter). For women, the range is 15–70 ng/dL. LabCorp has a different “normal” range, for men it’s 348–1197 ng/dl.
Men: In July 2017, LabCorp lowered their testosterone “normal” reference range for men to 264–941 ng/dL. Whoa! Why? Partial reason for this, as explained by LabCorp, is the higher BMI of the average male. BMI is a terrible indicator of health, but LabCorp is reflecting the growing obesity of the American male and its effect on testosterone levels. Obesity (fat) does lower testosterone.
The low normal(s) of 250 (Quest Diagnostics) and 264 ng/dL (LabCorp) allows doctors a reason not to prescribe testosterone and insurance companies a reason not to cover the cost of the medication.
The problem is compounded when you examine how these labs derive their normal reference ranges. While the two labs I contacted (Quest and LabCorp) didn’t respond to my request for information on how their testosterone reference ranges were determined, it is assumed to be from accumulating data from a wide variety of men (population). Population may vary from 18 to 80. A population whose body composition varies from fit to fat. Men who are couch potatoes and others who are athletes, men with diabetes and men with normal blood sugar, men with medical issues and men without medical issues. So, what the heck is normal, and why are you basing the “normal testosterone range” using this pool of men? Could we further assert that the greater majority (more than 50%) of men having blood tests are for medical reasons and not for annual checkups. If so, then is this the population that labs should be using to determine the normal range of testosterone?
Looking back at the value 265 ng/dl, which both Quest and LabCorp say is in normal range for a male. For whom is this considered a normal testosterone value? Certainly not a twenty-something year old man, trying to start a family with his wife or build muscle in a gym. Certainly not the 60 year-old-man from 1987 whose testosterone level was 505 ng/dl. And yet, by Quest and LabCorp standards, the man with a 265 ng/dl testosterone level is within the normal range. Most non-anti-aging physicians (and insurance companies) will use these lab results to tell that man he is okay and within normal testosterone range. In other words, ignore the symptoms of low testosterone, your blood results are normal. Reminds me of what physicians used to tell women about menstrual cramps, “It’s all in your head.” Don’t hear them saying that anymore do we? But I digress. I don’t think a twenty-year-old man and a ninety-year-old man should have their testosterone levels evaluated on the same “Normal Testosterone Range,” do you?
The population decline in testosterone is related to the population increase in chronic diseases.
Women: The situation is no better for women. According to the Mayo Clinic Laboratories, normal testosterone range for adult women is between 8 to 60 ng/dL. 11
LabCorp has premenopausal testosterone rangeat 10–55 ng/dL and postmenopausal from 7–40 ng/dL. Quest Labs shows a reference range for both pre and post menopause from 2–45 ng/dL.
At the lower end of this endocrinology range, testosterone is practically non-existent.
Hormone & Testosterone Replacement Therapy (HRT & TRT) or Boost Testosterone Naturally
If your testosterone values are medically low, you ought to have the option of hormone replacement therapy. You may want to try increasing your testosterone naturally, and if that fails, move on to replacement therapy. In attempting to boost your testosterone naturally, you ought to be improving your general health with diet, exercise, and supplements. Even if you fail, these first steps will form a solid foundation for HRT or TRT to work if required.
Hormone hell is where you have a low testosterone level that’s still considered in the “normal range.” However, it’s at the bottom of the normal range, which is not an optimal level. If you are clinically low, boosting your testosterone naturally may put you in hormone hell. Too low to be effective but too high for replacement therapy. If you are seeing an anti-aging specialist that’s worth their salt, I believe they won’t choose boosting your testosterone levels naturally to the lower range against you starting replacement therapy.
At the end of this chapter are resources for online anti-aging specialists who can order blood tests, check results, and prescribe HRT or TRT if needed.
Women and HRT (TRT)
Balancing female hormone levels is referred to as Hormone Replacement Therapy (HRT).
If men with low testosterone have an issue with the non-specialized MD prescribing TRT, the situation is compounded for women. In 2014, a task force commissioned by the Endocrine Society 12 recommended against doctors making a diagnosis of low testosterone in women due to lack of research in this area. Nonspecialized MDs are more concerned with high testosterone levels in women.
Things are improving, as a few estrogen replacement drugs also contain testosterone. Consider that unless you see a physician who specializes in anti-aging medicine, testosterone supplementation is pretty much off the table. At the end of this chapter are resources for online anti-aging hormone specialists who can order blood tests, check results, and prescribe testosterone, as well as other hormones if needed.
If you cannot balance your hormones and increase your testosterone naturally, as with men, you can consider HRT.
Women, Don’t be Afraid of Increasing Testosterone (Naturally or HRT)
Some women may be concerned that increasing their testosterone and exercising will make them bulky and man-like. Not likely. Barring any medical condition that may raise your testosterone to supra-female levels, a woman becoming bulky due to increased testosterone is not going to happen.
Look at top super models and women who are considered the most attractive women in the world. Most of these women have more muscle mass than the average woman. Being fit and healthy is sexy. Increasing your muscle mass will make you sexier, not masculine. The benefits of improving your testosterone levels to normal female levels will help you to lose fat, build muscle, improve libido, performance, and improve mental cognition.
If you’re still worried about working out, consider that normal testosterone levels in men are 10–20X greater than the level in women and men still must work hard to build muscle mass. This is why men are always looking for something extra they can do or take to spur results.
Woman’s Goal: 35 ng/dL
From my research on this topic, it is determined that a hormone specialist will bring your T levels to mid-high “normal female range,” or about 35 ng/dL. (This value is based on the last Quest lab diagnostic range for women being 15 to 70 ng/dL.)
Man’s Goal: Total Testosterone Level of 550 ng/dL or Greater
It’s hard to hit a target when you can’t see it. A man’s goal is to achieve a testosterone level of 550 ng/dl or greater. Why a minimum of 550 ng/dl? A five-year study (7) published by the Journal of the American College of Cardiology reported that men with a testosterone level of 550 ng/dl have a 30% lower risk of cardiovascular events. Any level of total testosterone below 550 ng/dL showed a significant increase in risk.
Other testosterone studies confirm that men who have high levels of testosterone have a decreased prevalence of many other diseases, such as high blood pressure, diabetes, prostate issues, and lower body fat percentages.
550 ng/dL is the bottom baseline, in this case, more is better. If you can push your testosterone higher into the 700–900 ng/dL range, you’ll feel better.
Conversion of measurement (ng/dL to nmol/l)
With testosterone, we want a minimum total level of 550 ng/dl for health. Depending upon your lab, the testosterone result may be given in ng/dL or nmol/l. It’s simple to convert one number to the other. To convert ng/dL to nmol/l multiply by 0.034. So a lab result of 550 ng/dL is converted to nmol/l by multiplying by .034. (550 ng/dL * .034 = 18.7 nmol/l). To convert nmol/l to ng/dL, you multiply by 29.4. So going back, 18.7 nmol/l * 29.4 = 550 /ng/dL (actual number is 549.78 but rounds up to 550)
Additional conversions (pg/ml to ng/dL)
Ten pg/ml equals one ng/dL. The measurements deciliter and milliliter measure volume. One deciliter (1/10 liter) equals one hundred milliliters (1/1000 liter).
Online Hormone and Anti-Aging Specialists
Full Disclosure: I am not in any way financially associated with, or financially benefiting in any way, with any referenced specialists below. Nor is their listing here an endorsement of their services. I know how frustrating working with non-specialized physicians can be, so they are provided as a potential source for both men and women who may not have local anti-aging specialists in their area. These specialists offer consultations, order blood tests, interpret the blood test results, and write prescriptions if needed and desired.
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1) Travison TG , et al. (n.d.). A population-level decline in serum testosterone levels in American men. — PubMed — NCBI. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/17062768
2) Prevalence of Symptomatic Androgen Deficiency in Men. (2007, November 1). Retrieved from https://academic.oup.com/jcem/article/92/11/4241/2598366
3) Low Testosterone and Your Health. (2008, July 3). Retrieved from https://www.webmd.com/men/what-low-testosterone-can-mean-your-health#1
4) Testosterone for the aging male; current evidence and recommended practice. (n.d.). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2544367/
5) Evidence for decreasing quality of semen during past 50 years. (12, September). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1883354/
6) Temporal trends in sperm count: a systematic review and meta-regression analysis. (2017, July 25). Retrieved from https://academic.oup.com/humupd/article/23/6/646/4035689
7) Auger J , et al. (n.d.). Decline in semen quality among fertile men in Paris during the past 20 years. — PubMed — NCBI. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/7816062
8) Population-Level Decline in Serum Testosterone Levels in American Men. (2007, January 1). Retrieved from https://academic.oup.com/jcem/article/92/1/196/2598434
9) Testosterone for the aging male; current evidence and recommended practice. (n.d.). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2544367/
10) Glaser R and Dimitrakakis C. (n.d.). Testosterone therapy in women: myths and misconceptions. — PubMed — NCBI. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/23380529
11) TTFB — Clinical: Testosterone, Total, Bioavailable, and Free, Serum. (n.d.). Retrieved from https://www.mayocliniclabs.com/test-catalog/Clinical+and+Interpretive/83686
12) Androgen Therapy in Women: A Reappraisal: An Endocrine Society Clinical Practice Guideline. (2014, October 1). Retrieved from https://academic.oup.com/jcem/article/99/10/3489/2836272
© 2020 John Iovine