Updated January 27, 2015.

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

 Trying to get pregnant?  Although there are a lot of bogus supplements out there, there are some that have stood up to randomized, placebo controlled trials that show improved sperm parameters.  There are a few high quality supplements on the market place such as Proxeed, Fertilaid, and many others.  Full disclaimer that I have no financial interest in either of these companies but they have been around the longest and have a pretty good track record.

 I will say you can probably save a lot of money by buying the following ingredients of these pills separately as I tell my patients to do.

Co-enzyme Q10:  This is a heart-healthy supplement that has had positive trials in fertility journals. I suggest 200 milligrams(mg) a day to boost sperm motility.  It's easy to take and is a good anti-oxidant.  One of the things that can inhibit sperm function is high levels of reactive oxygen species (ROS).  Sperm are pretty wimpy little guys and any oxidative stress can hurt their ability to penetrate an egg.

L-carnitine:  This amino acid improves sperm energy levels (motility) and shape (morphology) as well as count (concentration.)  Most studies have used between 1000 and 3000 mgs a day.  There have been a few recent studies that show a potential negative cardiac effect of this supplement in high doses over a prolonged time period so check with your doctor first and limit your ingestion to less than a year.

N-acetylcysteine (NAC): NAC is a powerful anti-oxidant that increases levels of glutathione in the liver and, at 600 mg a day, can boost male fertility.

 It may protect the liver from alcohol damage as well.  Limiting alcohol intake to no more than 2 drinks a day is key for male fertility too.  There was a study out of Brazil a few years back that showed that binge drinking (greater than 5 drinks a day) was worse than smoking, pot and cocaine for sperm quality!

Folic acid: Folic acid is a critical part of neurologic development in fetuses and therefore it is a key ingredient in female prenatal vitamins.  Its role in male fertility is less robust but 400 mg a day is probably safe and may work as a mild antioxidant.

Vitamin C: This vitamin is in every multivitamin and male fertility supplement and is also a good antioxidant.  500 mg a day is fine for a male fertility stand point.  Megadoses of vitamin C can lead to elevated oxalate loads which can increase kidney stone risk so be careful if you have a history of kidney stones.

Selenium: Selenium is a trace mineral that is in a lot of fertility supplements but doesn't have great data to support its use.  In high doses, greater than 100 milligrams, it may increase prostate cancer risk so just stick to a multi-vitamin.

Cool the pool.  One of the biggest barriers to sperm quality is excessive heat.  Avoid hot tubs, hot baths, prolonged hot yoga sessions.  There is even a male undergarment called, of all things, Snowballs underwear, which has anatomically correct ice packs to slide into underwear.  

If you've been trying for over 6 months without success, see a male fertility specialist.  You may have a correctable problem like a varicocele, which can increase sperm temperature and impair fertility.  Of course, like all things medical, frequent exercise, healthy diets loaded with fresh or frozen fruits and vegetables will also help your swimmers hit the pool kicking.  Good luck and happy swimming!