Do sperm supplements work? Results from the MOXI trial

Researchers in a 2020 study report on the results of the MOXI trial that tested the effectiveness of a sperm supplement cocktail (containing vitamin C, vitamin D, vitamin E, selenium, and more) and found no benefit.

Antioxidants are the big supplement that are recommended to men. “Free radicals” or “reactive oxygen species” (ROS) are nasty molecules created in the body as part of our regular metabolism of oxygen in “cellular respiration” (a cellular process that converts sugar from the food we eat to energy our cells can use) and by stressful environmental conditions, like from exposure to heat or UV. ROS are bad because they are very reactive molecules, and they can cause breaks in DNA’s structure.

Sperm DNA fragmentation can be induced by ROS and this can have an impact on male fertility. So eliminating ROS to prevent this sperm DNA damage is of great interest, and that’s where antioxidant supplements come in.

Antioxidants work by “scavenging” ROS, so ROS can’t cause damage to DNA. But do they actually work in lowering DNA fragmentation in sperm? And does this translate into improved IVF outcomes?

Previous studies have looked at antioxidant supplements (vitamin E, selenium, N-acetylcysteine, carnitine) and found benefits – but the quality of evidence is low. Small studies with lots of heterogeneity (variability). So a bigger study was of course needed!

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This study, the Males, Antioxidants, and Infertility (MOXI) trial (Steiner et al. (2020)) was set up to look at the impact of antioxidants on male infertility.

They looked at men who had abnormal semen parameters like low sperm concentrations, motility, morphology or high DNA fragmentation. They were given either a placebo (86 men) or a vitamin cocktail (85 men) containing:

500 mg vitamin C
400 mg vitamin E
0.20 mg selenium
1000 mg L-carnitine
20 mg zinc
1000 mcg (micrograms) folic acid
10 mg lycopene
2000 IU vitamin D

They took this pill every day for 3 months.

They found no difference in normal morphology, motility/total motile count, and DNA fragmentation. In terms of sperm concentrations/counts – men that took the antioxidant cocktail had lower values. Their sperm concentrations went from 21.0 million/ml to 17.0 million/ml, and their total counts went from 47.6 million to 37.0 million! It’s not clear why these supplements caused a decrease in sperm numbers.

They also looked at different types of semen abnormalities. Men who had low sperm concentrations (oligospermia), low total motility (asthenospermia), low morphology (teratospermia), or high DNA fragmentation did not show any improvements after 3 months with the antioxidant cocktail.

There were also no differences in pregnancy rates and live birth rates.

So sperm supplements did not work so well in this study! Were these negative results because they used a cocktail instead of single antioxidants? It’s possible but they did it this way because this is how most supplements are marketed and prescribed. However they can’t know for certain if there’s any negative interactions between the supplements. But again – this is how they are commonly prescribed so their cocktail shouldn’t be any different.

Reference

Steiner AZ, Hansen KR, Barnhart KT, Cedars MI, Legro RS, Diamond MP, Krawetz SA, Usadi R, Baker VL, Coward RM, Huang H, Wild R, Masson P, Smith JF, Santoro N, Eisenberg E, Zhang H; Reproductive Medicine Network. The effect of antioxidants on male factor infertility: the Males, Antioxidants, and Infertility (MOXI) randomized clinical trial. Fertil Steril. 2020 Mar;113(3):552-560.e3. doi: 10.1016/j.fertnstert.2019.11.008. Epub 2020 Feb 25. PMID: 32111479; PMCID: PMC7219515.

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About Embryoman

Embryoman (Sean Lauber) is a former embryologist and the founder of Remembryo, an IVF research and fertility education website. After working in an IVF lab in the US, he returned to Canada and now focuses on making fertility research more accessible. He holds a Master’s in Immunology and launched Remembryo in 2018 to help patients and professionals make sense of IVF research. Sean shares weekly study updates on Facebook, Instagram, and Reddit regularly. He also answers questions on Reddit or in his private Facebook group.

Reference

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