A new study has found that illicit steroid use by males could do long-term damage to the functions of their testicles.
Published Tuesday in the Journal of Clinical Endocrinology & Metabolism, the study found that anabolic androgenic steroids (AAS) were linked to lowered capacity for testosterone production, also known as hypogonadism, even years after stopping the steroid use.
"Our results suggest that the capacity of testosterone production in Leydig cells of the testicles could be persistently impaired," lead author Jon Rasmussen, a researcher at the University Hospital of Copenhagen's Department of Endocrinology, told Inverse.
Rasmussen warns men who are even planning to use such steroids for body enhancement: "Don't even consider it. Use of anabolic steroids can cause persistent adverse effects on several organs in the body and could even be lethal."
Anabolic steroids are synthetic, lab-made variants of the male sex hormone testosterone. The use of these artificial steroids impairs the hypothalamus-pituitary-testicular hormonal axis, which then stops testosterone testicular production and impairs fertility, said Rasmussen.
The study observed 132 men between the ages of 18 and 50 with recreational strength training. Participants were divided into three groups: never users, current users, and former users of anabolic steroids who had quit three years earlier.
Since testosterone levels fluctuate during the day, the study used a new marker to assess the loss of testicular function called serum insulin-like factor 3 (INSL3), a hormone made from the same testosterone cells in the testes.
Compared to never users, men who used steroids once had much lower INSL3 concentrations. The longer the men used steroids, the lower the levels, the study found.
According to the study, anabolic steroid use is on the rise. A survey from 2014 showed that as many as 4 million American men have used anabolic steroids.
Some people take anabolic steroids like testosterone cypionate, nandrolone decanoate, or methenolone by pill or injection to improve strength or endurance in sports. Others use them to improve their lean muscle mass, whether it's for sports, physical work, or appearance.
The study also suggests that while the production of sperm in the testes (spermatogenesis) has not been studied, previous studies have shown that sperm count and activity may not be influenced by AAS.
Further research is required in the future to see if the actual "fertility potential" of semen would deteriorate.
