What’s a Normal Testosterone?

April 8th, 2013 § 6 comments § permalink

Wiki (not sure if that’s his real name) wrote in a comment, “is low Testosterone unusual for young athletic men (under 25) , what will be your minimum level (red line) for Testosterone of men under 25, as i found the minimum level varies according to each lab … mostly skewed based on the middle aged men they usually test.”

Great question! A while ago, many used “age-indexed” testosterone, meaning that lower levels were considered normal in older men. Most in the field have abandoned that approach as it’s like saying, we know that diabetes is more common as people age, so we’ll just use higher blood sugars as normal when they get older. That would be an approach ignorant of the basis of the disease. To make matters worse, to create the age-indexed thresholds of normal testosterone, each lab essentially was required to do that themselves. So you had a lot of labs with different numbers, and that made interpreting those lab results really difficult.

Your question gets to another point, though, which is what is a normal testosterone for an individual man? Testosterone doesn’t work by itself; a whole machine inside the cell uses it. It’s like gas in a car: you can have the same gas, but a Ferrari will drive differently than a Volvo. (No offense to Volvo owners intended.) So one man’s testosterone of 350 ng/dL may be perfectly fine, but for another, that may be low.

That’s why guys need to do evaluation and treatment with their doctors. (If you are trying to figure out a good doctor who knows about hormones in men, check out that part of the FAQ.) A doctor can evaluate the whole man and see other signs of low testosterone, and tailor treatment with different medications (many of which are described elsewhere in this blog.)

Thanks, Wiki, for the great question!

Clomiphene Article in Fertility and Sterility

March 13th, 2013 § 2 comments § permalink

As I’ve written before in this blog, clomiphene is an effective if off-label treatment for men with low testosterone who want to preserve their fertility. If used directly, testosterone itself actually decreases the making of testosterone and sperm in a man’s testis. Clomiphene increases testosterone production in the testis by increasing the pituitary hormones that tell the testis to make testosterone.

In the March issue of Fertility and Sterility, a journal that I co-edit with Dr. Antonio Pellicer, Drs. Kim and co-authors review the published medical literature on treating low testosterone with clomiphene and other drugs besides testosterone. They conclude that clomiphene is a safe and effective treatment for men with low testosterone and note that less than one year of treatment with testosterone is usually reversible if a man wants his fertility to return. Unfortunately, we don’t know all that much about longer treatments with testosterone, and many men who have been on testosterone for several years do not have sperm return even with other forms of treatment.

Drs Kim and co-authors give us a nice review that supports the use of clomiphene for men with low testosterone who want to preserve their fertility.

Is Clomiphene Safe?

January 27th, 2013 § 20 comments § permalink

As I’ve written in earlier posts, clomiphene is a medication that a doctor can use to increase a man’s production of testosterone in his own body. (I’ve also written about how doctors can prescribe it. If you think that you’d benefit from this medication, you should see a doctor. I can’t answer personal questions about a man’s health on this blog. Medical care is always done best in person.) But clomiphene is “off-label” for use by men and didn’t go through the rigorous series of studies that the FDA mandates for a drug for a particular use.

One good question is whether clomiphene is safe for long term use by men. John Mulhall, a great doctor in New York, recently published a report in the British Journal of Urology studying the use of clomiphene for up to three years in 46 men diagnosed with low testosterone. Blood testosterone, bone scans, and symptom scores all improved, and men did not report problems with the medication.

There are limitations to this study. It wasn’t controlled, meaning that there wasn’t a group of men treated with a placebo, or sugar pill. 46 isn’t a lot of men, and three years isn’t really a very long time. But this kind of study is what needs to be done with more men and for a longer time to really determine the safety of clomiphene for long term use in men.

Clomid surely has its advantages compared to testosterone for use in men with low testosterone. It’s a pill, and other treatments are either shots or cumbersome skin applications. It also saves sperm, as testosterone itself reduces sperm production. But information about its use is less than that of testosterone, which puts men and their doctors in a kind of Catch-22. Mulhall and colleagues are to be commended for expanding what we know of the safety of this medication.

Declining Sperm in France?

December 22nd, 2012 § 0 comments § permalink

By Jim Hotaling, M.D.

Gawker recently reported on an article in the scientific journal Human Reproduction that found sperm numbers and shape to worsen in France during a 16 year period. Studies that claim sperm are declining worldwide have been published for at least the last 20 years.  If the trend is true, one guess for its cause was suggested by the Danish scientist Niels Skakkebaek, who argues that chemicals in materials such as plastics act as synthetic hormones that interrupt a man’s own internal natural hormones.

The Human Reproduction article is well designed, studying a very large group of 26,609 men from infertility clinics in France from 1989 to 2005.  Each man had two semen analyses, which adds to the strength of the paper as sperm counts change much even from day to day.  The scientists concluded that sperm count decreased 1.9% per year in France during the time period of the study.

Before jumping to the conclusion that the fertility of French men is dipping, there are some important limitations of the study. To their credit, the scientists state most of them clearly in their paper. The first is that the scientists studied men showing up in fertility clinics. These men as a group are probably different that the average guy in France. Second, the men got older during the study. While the age increase was small, 34.2 to 35.9 years, and may not mean much, the deCODE study suggests that changes in sperm may start early in a man’s life. Third, giving a sample in an fertility lab may not be the same as when it’s delivered naturally.

This study probably isn’t great cause for concern that sperm are on a steep decline in France. Even if the numbers are going down a bit, there’s still plenty of sperm in these men to do the job.

Taking Over the Pituitary

November 27th, 2011 § 18 comments § permalink

Bob recently asked about using hCG (human chorionic gonadotropin) rather than clomiphene to increase testosterone.  As I explained in How Clomid Works in Men, clomiphene stimulates the pituitary to make luteinizing hormone (LH), which then acts on the Leydig cells in the testis to make testosterone.  So why not use LH directly?

One way to take over the pituitary’s production of its reproductive hormones is to use human chorionic gonadotropin (hCG), which looks like LH to the body.  It effectively stimulates the Leydig cells to make testosterone.  But it’s expensive and must be injected.  So if the pituitary is working, clomiphene may be a better choice to start.  If the pituitary isn’t working, hCG can be tried.  But if the man’s LH is already very high, neither clomiphene or LH will help all that much, as the man’s body is already trying that strategy by itself.

The pituitary also makes follicle stimulating hormone (FSH), which acts on the Sertoli cells around the developing sperm cells.  To help stimulate the making of sperm in the testis, recombinant FSH (rFSH) or human menopausal gonadotropin (hMG) may be used.  Like hCG, these drugs are expensive and must be injected.

Thanks for the question, Bob!