We typically think of testosterone as the manly hormone, especially in regard to sexual function of men. Research shows that men with low testosterone, and even testosterone levels in the lower end of the normal range, have higher risks for diabetes, heart disease, cognitive dysfunction (poor brain function), bone density loss/osteoporosis, abnormal lipid lab tests. Women can also have low testosterone, but that is a subject for another blog!
It is quite interesting to look at how the reference (“normal”) lab ranges for testosterone have changed over the last 50 years. Several decades ago, normal levels were considered to be between about 450-1300 (depending on the lab), and now, most labs give reference ranges of 300 – 1000 ng/dL. There are several theories to explain the decrease in testosterone levels in men, but I think that toxins, heavy metals, and endocrine-disrupting chemicals like parabens and phthalates are contributing factors.
Hormones always impact each other. Stress, from any cause (emotional, dietary, toxins, lack of sleep, medical challenges) causes the adrenal glands to release of cortisol, a very important hormone that tells the body how to react to that stress. When stress goes away, the body functions are restored to normal. But, when stress becomes chronic, abnormal cortisol levels can interfere with normal testosterone production.
Many men, even young men, are unaware that testosterone deficiency in men is quite common. The following symptoms may be clues that you, or someone you love, is suffering from a low testosterone level.
- Low sex drive/low libido
- Erectile dysfunction, decreased frequency of erections, fewer spontaneous morning erections
- Muscle loss, or failure to build muscle with workouts
- Irritability, moodiness
- Anxiety, depression
- Joint pain
- Obesity, especially around the middle (the spare tire)
- Man boobs (gynecomastia)
- Hot flashes
- Poor endurance
What lab tests you should have to diagnose testosterone deficiency:
If I find low testosterone levels, then I start asking why. These tests help answer that question.
- Serum total testosterone and free testosterone
- LH (luteinizing hormone) & FSH (follicle stimulating hormone) to assess pituitary function: these pituitary hormones stimulate the testicles to work. LH stimulates testosterone production, and FSH stimulates spermatogenesis, or sperm production
- SHBG (sex hormone binding globulin), a protein that binds testosterone in the body and keeps it inactive and unavailable to work
- Estrogen blood levels: estradiol and estrone. Testosterone is broken down into dihydrotestosterone and estrogens. Balance between testosterone and estrogen is very important. Higher levels of estrogen in a man can cause man boobs (gynecomastia) and varicose veins.
- If there is a family history of hormone-related cancers (breast, prostate), then it is important to test sex hormone metabolites. Improper breakdown (metabolism) of estrogens can raise one’s risk of breast or prostate cancer or benign prostatic hypertrophy.
- 4 point cortisol panel, either in saliva or urine, to assess adrenal function. Sometimes just by addressing abnormal cortisol levels and the causes thereof, a man’s testosterone will go up as a result.
- I also check thyroid function, PSA (prostate-specific antigen), CBC (complete blood count), comprehensive metabolic panel. In some cases, I will order an MRI of the hypothalamic and pituitary areas of the brain. These areas are intimately involved in the control of testosterone production, and sometimes there can be damage or a brain tumor (benign or malignant) that can cause low testosterone.
- Testosterone therapy
There are various ways to prescribe testosterone:
Transdermal testosterone gel or cream. This is rubbed on the skin every day. Absorption is better in areas where there is no hair: top of the foot, above the collarbones, inner thigh or inner arm. Rubbing vigorously causes the blood vessels to dilate and improves testosterone absorption through the skin. However, there can be accidental transfer of testosterone to others, such as a spouse, or the kids, or pets. Some use a glove to apply, instead of a bare hand.
Intramuscular injections of testosterone cypionate or enanthate. These may be better for men over 60, because the skin does not absorb testosterone as well in older men. Injection frequency varies, usually every 1-2 weeks, but some men find that levels stay more stable with more frequent injections.
Testosterone undecanoate is a longer-acting testosterone; injections are usually every 6-8 weeks.
Testosterone pellets are implanted by a doctor every 3-4 months.
Sublingual (under the tongue) testosterone must be taken twice a day, and oral testosterone goes from the digestive tract to the liver. The liver breaks oral testosterone down, so less is available to get to the tissues. I don’t recommend taking testosterone orally.
Pharmaceutical brands of testosterone gel come in lower concentration (1%). Doses are lower and many men are unsatisfied with results.
If a man decides to use testosterone therapy, it is important to check testosterone levels periodically. I also follow estrogen levels to make sure testosterone is broken down appropriately. Too much estrogen can cause the prostate tissue to grow (prostatic hypertrophy). I also follow the CBC, because testosterone can increase the number of red blood cells, which could make the blood more likely to clot inappropriately if too high. I also periodically check the PSA. Some testosterone is diverted to dihydrotestosterone (DHT). As with everything, hormones are best in balance, and the proportion of testosterone to DHT is important.
Testosterone therapy in men can decrease testicular size and decrease sperm count. For younger men, usually less than 40 years old, or those who desire to maintain fertility, there are other options. Injectable human chorionic gonadotropin (hCG) will raise testosterone, as will clomid. Using either of these to raise testosterone in men is considered “off-label” and may not be covered by insurance.
Even young men can have low testosterone levels. If you think that you or someone you care about has symptoms suggestive of low T, then ask the doctor to check a level. It may make all the difference!
To your health,
Patty Powers MD