Does Testosterone Replacement Cause Prostate Cancer?

By Michael A. Smith, MD

Even though testosterone is a key messenger in the body and blood levels decrease with age, many men are scared of replacement therapy. Why? They’re afraid of developing prostate cancer.

For many years now, doctors have been telling male patients that testosterone replacement therapy may be necessary in specific instances, but as a general anti-aging strategy, it can be dangerous. In particular, they’ve been misinforming their patients that the “unnecessary” use of testosterone increases their risk of prostate cancer.

But is this true? Does the evidence in the medical literature support the position that testosterone replacement causes prostate cancer? Let’s dig into it a bit.

Research Shows No Increased Risk with Testosterone

Harvard researchers have clearly shown that testosterone therapy does not increase the risk of prostate cancer. A team of researchers, led by Dr. Abraham Morgentaler, came to the conclusion that the medical establishment was wrong in suggesting that testosterone replacement therapy increases the risk of prostate cancer.

As a matter of fact, what the researchers actually found might surprise you. Dr. Morgentaler’s team meticulously showed that low testosterone actually increased the risk of prostate cancer. Go figure.

In one of their studies,1 they compared the results of testosterone therapy given for 12 months in two groups of men with low testosterone. The first group consisted of 20 men considered to be at high risk for prostate cancer based on biopsy results showing an allegedly precancerous condition called prostatic intraepithelial neoplasia (PIN).

The second group consisted of 55 men with normal biopsy results. At the end of one year of treatment, both groups had a similar, modest increase in PSA. One man in the study, who was in the high-risk group, developed cancer.

So, overall testosterone therapy resulted in a one-year cancer rate of 1.3% (one of 75 men). More importantly, the one-year cancer rate among the high-risk men with PIN was 5%. Keep in mind that the known cancer rate of men at high risk for developing cancer is 25% over three years. As you can see, testosterone therapy did not increase the risk of prostate cancer in anyone, including the men that were at high risk.

They concluded that the average physician’s fear of prostate cancer with testosterone therapy was unjustified. So, it’s pretty clear that raising testosterone isn’t fuel for a hungry tumor.

Increased Blood Testosterone Doesn’t Increase Cancer Risk

Another study,2 published in 2006, gave either testosterone injections or a placebo to men with low testosterone every two weeks for a total of six months. At the beginning and end of the study, measurements of testosterone and DHT (the more active form of testosterone within prostate tissue) were obtained from the blood and also from the prostate itself.

The results showed that although blood concentrations of testosterone and DHT rose substantially in the group receiving testosterone injections, the concentration of testosterone and DHT within the prostate itself did NOT change at all and was similar to the group that received placebo injections. In addition, biochemical markers of prostate cell growth also did not change with testosterone injections.

The Bottom Line on Testosterone Replacement and Cancer Risk

Simply put, testosterone replacement therapy has not been shown to increase the risk of prostate cancer. Overall, these are the main conclusions that we can draw:

  • Low blood levels of testosterone do not protect against prostate cancer.
  • Low blood levels of testosterone may increase the risk of prostate cancer.
  • High blood levels of testosterone do not increase the risk of prostate cancer.
  • Treatment with testosterone does not increase the risk of prostate cancer.
If you have low testosterone, we suggest speaking to your doctor about these findings. Low testosterone is a risk factor of heart disease and can certainly negatively impact your quality of life as you age.

Read more on this topic: Do I Need Testosterone Replacement?.

What do you think? Please share your take in the comments below.


  1. Curr Treatment Options Oncol. 2006;7:363-9.
  2. JAMA. 2006;296:2351-61


Anonymous said...

I am sorry but I have to disagree and developed prostate cancer after being prescribed testosterone cream for therapy the year before.

Robert Ray said...

Even though testosterone is a key messenger in the body and blood levels decrease with age.If you have low testosterone, we suggest speaking to your doctor about these findings. Low testosterone is a risk factor of heart disease and can certainly negatively impact your quality of life as you age. Then you should live a longer life.

Anonymous said...

I have prostate cancer. Will an increased level of testosterone feed or subdue my cancer?
Paul Blaak

LifeExtension said...

Anonymous - Testosterone therapy is not recommended for prostate cancer patients. It could actually fuel the growth of existing cancer cells.

Anonymous said...

I had a PSA of 4.45 two weeks ago and two years ago it was 2.59, these scores are almost exactly 2 years apart. I do seem to have BHP and the DRE was very good, no bumps etc . I turned 62 five months ago. My father had prostate cancer in 1990 and was 73 from which he recovered and it did not bother him after and he lived to be 84 dying of pneumonia. The doctors removed his testes and back then I guess that was common but it not clear that was necessary. It was very traumatic for him as you can imagine. Based on these factors my urologist says I should stop androderm which he had prescribed as I had low testosterone and he is pushing for a biopsy. I do not want one as I see some real potential downside and if he says thee is aggressive cancer cells he wants to do a robotic prostatectomy. I am concerned about his level of expertise as he has not recommended a PSA F test before a biop. The thought of surgery or radiation is NOT appealing given many factors especially the effects on libido, and ED, loss of ejaculate, sensation, and worse I have read as well as a potential unnecessary cost and trauma etc and I am very likely getting remarried soon. I can hardly afford the treatments as well. I would like to know if enhancing testosterone by androderm or herbal methods - bringing to normal, really would be ill advised, particularly as I have not been diagnosed with PC, there is just a concern if I may have it. I also would like to understand why & how that if - to quote your article "High blood levels of testosterone do not increase the risk of prostate cancer." you say testosterone therapy could fuel the growth of existing cancer cells. Thank you for your reply

LifeExtension said...

Anonymous - You pose some excellent questions which would best be addressed by one of our oncology health advisors. Here's the number to reach them: 1-800-226-2370.

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