Osteoporosis is a condition that strikes both women and men. Fifty percent of women will experience a bone fracture due to osteoporosis at some point in life. So will twenty percent of men. Women are more likely to be diagnosed with osteoporosis than men, but men over 60 who are diagnosed with the disease are 78 percent more likely to become disabled or die. The endocrine problem that makes the greatest contribution to bone demineralization in women is estrogen deficiency, but the endocrine problem that makes the greatest contribution to osteoporosis in men is testosterone deficiency.
Why is testosterone important for healthy bones?
Both men and women produce both testosterone and estrogen. Men’s bodies produce more testosterone than estrogen. A man’s body transforms small amounts of testosterone into estrogen. Women’s bodies produce more estrogen than testosterone, made in the ovaries. In both men and women, testosterone is important to bone health in at least three important ways:
- Testosterone helps to build bone. Testosterone stimulates the transformation of “baby” osteoblasts, the bone cells that make new bone, into fully mature and functional osteoblasts. It also stimulates mature osteoblasts to add minerals to strengthen bone.
- Testosterone slows down the rate at which old bone is recycled. Testosterone regulates the multiplication of osteoclasts, the bone cells that break down old or fractured bone to make way for new structures. In this way the male hormone keeps bone from breaking down too fast.
- Testosterone stimulates the production of the “glue” that holds bones together. Testosterone in a man’s body can be transformed into estrogen. The estrogen a man’s body makes from his testosterone fuels osteocytes, tentacled cells that hold the mineral crystals that make up the matrix in place. Testosterone keeps osteocytes from premature apoptosis, the process through which they “turn themselves off” to make room for new osteocytes.
Testosterone also prevents the breakdown of bone that has been affected by metastatic cancer.
Hormone deficiency affects women’s bone development at an earlier stage of life than in men. Estrogen deficiency symptoms become relatively common in women after 50. Testosterone deficiency symptoms become relatively common in men only after 65. But testosterone is useful in preventing and treating osteoporosis in both sexes.
When is testosterone for male osteoporosis the first line of treatment?
Although testosterone is very important for strong bones in men, when men are determined to be at risk of osteoporosis but do not already have fractures, they are usually given bisphosphonates. Testosterone replacement therapy is usually offered only to men who have already suffered a fracture or who have low testosterone.
How low is low testosterone?
- “Normal” testosterone levels, determined by a blood test, are 300 to 1000 ng/dl.
- “Low” testosterone levels are between 250 and 300 ng/dl.
- “Hypogonadism,” or treatable low testosterone, is 250 ng/dl or lower.
About 24 percent of men over the age of 60 have testosterone under 300 ng/dl and may benefit from testosterone replacement therapy. However, the form of testosterone replacement makes a difference.
Gel, patch, shot, or pill?
Testosterone is given in four forms, gels, patches, injections, and pills. The form of testosterone makes a huge difference in its effects, and the most beneficial form of testosterone replacement therapy isn't what most people would expect.
Androgel. One way to take testosterone is with a gel applied to the skin every day. The gel delivers about 10 mg of the hormone every day, but it isn’t completely absorbed. Moisture on the skin, skin irritation, soap residues, and hair interfere with the amount of testosterone the body absorbs
Androderm. Another way to take testosterone replacement therapy is with a patch. A transdermal patch is placed on the arm. Absorption of the testosterone is incomplete but the man’s body may receive 5 mg up to 10 mg of testosterone daily.
Delatestryl, Depot-Testosterone. A much larger dose of testosterone is delivered by injection. Every two to four weeks a man takes an injection of 50 to 400 mg of testosterone delivered to muscle. Testosterone shots contain much more testosterone than either gels or patches. But do they offer greater testosterone benefits for preventing and treating osteoporosis?
The consensus of scientific research is that gels and patches elevate testosterone levels by an average of 546 percent, while testosterone injections raise testosterone levels by only 220 percent. Why should taking more testosterone result in lower testosterone levels?
Larger doses of testosterone are broken down quickly into estrogen. Smaller doses of testosterone build up in a man’s body. This is also the problem with the testosterone pill, Andriol.
What are the risks of testosterone replacement therapy for osteoporosis for men?
A study of 150,000 men found that testosterone replacement therapy was not associated with increased risk of prostate cancer. However, some other serious conditions may be aggravated by supplemental testosterone:
- Breast enlargement or tenderness (gynecomastia). Testosterone is converted to estrogen in the breast. In some men testosterone replacement may cause feminization of the breast.
- Sleep apnea. Sleep-disordered breathing usually normalizes after about 18 weeks of treatment.
- Cardiovascular risk. Risk to the circulatory system varies by type of testosterone replacement. Pills increase the risk of cardiovascular disease, but injections lower it.
Another consideration in testosterone replacement is that it modifies a man’s hypothalamus, pituitary, and adrenals so that there is even lower production of the body’s own testosterone. Once testosterone replacement is started, it may have to be a lifetime intervention.