Creatine Dietary Supplements May Increase Testicular Cancer Risks

New research suggests that a commonly used muscle-building creatine supplements may be linked to an increased risk of men developing testicular cancer.

Creatine dietary supplements are commonly used among males, especially younger men, to gain mass and rapidly build muscle. The product may also be taken to boost athletic performance and increase speed or stamina.

In a study published online late last month by the British Journal of Cancer, researchers from Yale University indicate that there may be a link between the muscle-building supplement and testicular germ cell cancer.

The research involved a population based case-controlled study, comparing 356 men with testicular cancer diagnosed between 2006 and 2010 to 513 men without cancer. All men were form either Connecticut or Massachusetts. Researchers found muscle-building supplements that contained creatine are a potentially modifiable risk factor that may be associated with testicular cancer.

The increased risk was especially seen among men who began using muscle-building supplements containing creatine before the age of 25. It was also seen among men who used different types of creatine containing supplements or used the supplements for a long period of time.

Researchers questioned participants about risk factors for testicular cancer, including smoking, drinking, exercise, family history of disease, undescended testicles, and past injuries to the testicles or groin. They were also asked about their lifetime supplement use, including the use of 30 different types of muscle building supplement powders or pills. The interviews revealed that 20% of participants with testicular cancer used muscle-building supplements.

The study focused on product labels, looking at major ingredients, including creatine, protein and androstenedione. However, researchers say despite studying product labels of muscle-building supplements in question, some products may have hidden ingredients not listed on the label, such as androgenic steroids, which have been linked to testicular cancer in rats.

Other products may have impurities or less-active ingredients than those listed on the product label, some may have natural ingredients that may act like artificial hormones and yet, it may still be unknown that other ingredients may damage the testicles in a way that is still unclear to researchers.

The FDA warned consumers on April 13 against using a muscle-building supplement called TriMethyl Xtreme, which may contain anabolic steroids that can cause liver damage.

Testicular cancer is a common cancer in men ages 15 to 39. Rates of testicular cancer have been on the rise in recent decades and researchers are unsure why. Testicular cancer has been linked to fertility problems and poor sperm quality.