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Drugs & Male Fertility

Many drugs have a powerful impact on male fertility, and semen testing makes it relatively easy to measure this. Drugs have an abnormally significant effect on sperm because they’re by far the smallest cells we have, and their DNA is on single (rather than double) helix strands. The way they’re made in the testicles is also very unusual, which makes the whole process less stable in a potentially vulnerable environment.

Drugs are, by their very nature, chemicals that alter how the body works, and this can include sperm function and production. The effects of some drugs go beyond sperm health and fertility, they can also affect the health of the baby. It’s worth remembering that many medications are essential for health, and the consequences to stopping them can be severe, so if you’re concerned about the prescription drugs you take, we strongly recommend discussing your concerns with your MD/GP.

The effect of many commonly prescribed drugs are significant but temporary on a man’s fertility, and when men can stop taking them it results in: i

  • Improvements in semen quality by 93%
  • 85% of their partners became pregnant


It’s known that men with epilepsy are less fertile, which could be due to their medication more than their epilepsy. A study of men taking the anti-epileptic drugs carbamazepine, oxcarbazepine and valproate all had high levels of abnormal sperm. Men taking valproate also had smaller than normal testes, which reduced the number of sperm they produced. ii


Serotonin Re-uptake Inhibitors (SSRIs) such as Prozac and Seroxat are the most widely prescribed type of antidepressants. These are linked to problems with male sexual performance, and many men taking them experience:

  • A loss of sex drive
  • Inability to maintain an erection
  • Inability to ejaculate
  • A continuation of these issues after they’ve stopped taking the drugs

The sperm of men taking SSRIs look normal, but research iii shows that after four weeks of taking them, the average DNA fragmentation levels rise from 13.8% to 30.3%. DNA fragmentation rates increase the chances of implantation failure, miscarriage or abnormalities in children. iv


  • Only 6% of male smokers produce normal sperm samples (compared to 37% of non-smoking, non-alcoholic men)
  • Smoking cigarettes reduces both the number of normally shaped sperm a man produces and their ability to swim forward
  • The effect of smoking increases with the number of cigarettes smoked v
  • Additionally, when fathers smoke over 20 cigarettes a day, there’s a greater risk of their child having leukaemia vi
  • Smoking over 20 a day also shortens the reproductive life span of any daughters he has, compared to smoking less or not at all vii


Alcohol damages sperm, and only 12% of alcoholic men produce normal sperm samples (compared to 37% of non-drinking, non-smoking men). It’s well known that alcohol is a toxin, and it also alters sex hormone balance, with less testosterone and an increase in abdominal fat, which raises estrogen levels. Drinking alcohol significantly reduces the:

  • The volume of semen samples
  • Sperm concentrations
  • Sperm numbers in samples
  • Percentages of normally shaped sperm
  • Sperm motility viii-ix

The man drinking alcohol also significantly increases the chances of his partner having a miscarriage, which is rather sobering.

Recreational drugs

Non-prescription drugs such as marijuana, amphetamines and cocaine have been linked to significant reductions in libido for many years. They may also diminish testosterone and luteinizing hormone (LH) levels, which are essential for healthy sperm production. There’s more information on drugs and fertility in the Lifestyle section.

i’ The impact of commonly prescribed drugs on male fertility.’ Hayashi T, Miyata A, Yamada T. Hum Fertil (Camb). 2008 Sep;11(3):191-6. doi: 10.1080/14647270701739566.
ii’ Effect of epilepsy and anti-epileptic drugs on male reproductive health’ J. I.T. Isojärvi et al. Neurology January 27, 2004 vol. 62 no. 2 247-253 doi: 0.1212/01.WNL.0000098936.46730.64
iv ’Sperm chromatin structure assay (SCSA) parameters are related to fertilization, blastocyst development, and ongoing pregnancy in in vitro fertilization and intracytoplasmic sperm injection cycles’. Virro MR, Larson-Cook KL, Evenson DP (2004) Fertil Steril.81(5):1289-95
v ’Alcohol intake and cigarette smoking: impact of two major lifestyle factors on male fertility.Gaur DS, Talekar MS, Pathak VP. Indian J Pathol Microbiol. 2010 Jan-Mar;53(1):35-40. doi: 10.4103/0377-4929.59180.
vi Milne E, Greenop KR, et al. (2012). “Parental prenatal smoking and risk of childhood acute lymphoblastic leukemia.” American Journal of Epidemiology 175(1): 43-53
vii Fakuda M, Fakuda K, et al. (2011). ‘Paternal smoking habits affect the reproductive life span of daughters’ Fertility and Sterility 95: 2542-44.
viii ’Alcohol intake and cigarette smoking: impact of two major lifestyle factors on male fertility.’ Gaur DS, Talekar MS, Pathak VP. Indian J Pathol Microbiol. 2010 Jan-Mar;53(1):35-40. doi: 10.4103/0377-4929.59180.
ix’ Effect of chronic alcoholism on male fertility hormones and semen qualityK.R. Muthusami, Fertility and Sterility Volume 84, Issue 4, Pages 919-924, October 2005