Amino acids Arginine, Carnitine and Glutathione Shown to Increase Male Fertility

Beautiful muscular man after bathContrary to common perception, it has now been established that infertility in up to 50% of all couples is caused by the male partner. Nearly 50% of this male infertility is idiopathic (of unkown cause). Male fertility is indeed a highly complex and sensitive process and its success depends on a large number of interdependent factors.

These include, but are not limited to the correct temperature range in the testicles, the male’s ability to achieve an erection sufficient for sexual intercourse, an ample supply of key nutrients to provide the building blocks for the spermatozoa during the process of spermatogenesis, the correct hormone balance such as plenty of testosterone and few stress hormones as well as little exposure to environmental toxins and potent antioxidants to combat oxidative stress.

A recent study has now conclusively shown that oral supplementation of key nutrients to males with suboptimal sperm can increase their fertility.

Key Nutrients

Arginine plays a crucial role in human health by regulating the diameter of blood vessels and therefore overall blood circulation throughout human body. In the context of fertility it also increases sperm vitality, a measure very similar to sperm motility, as well as count and morphology.1 This is thought to be due to the large amount of arginine found in the sperm head. The head’s function is to fuse with the female ovum to merging the two subsets of chromosomes and creating the new unique DNA for a new human being. If insufficient arginine is present, suboptimal numbers and morphology (shape) of spermatozoa are observed in spermiograms. Fertilisation is then less likely to occur as a result.

Carnitine, is synthesized from the two amino acids lysine and methionine. It is required for the transport of fatty acids into the cells power plants (mitochondria) to enable the breakdown of fats for the generation of metabolic energy.2 carnitine is therefore crucial for the body to convert fat into energy.

It has been shown to be significant improve semen quality especially in groups with lower baseline levels. Positively affected were sperm concentration and total count as well as forward sperm motility. The increase in forward motility was even more significant in patients with lower initial values.3

Glutathione is considered the human body’s most powerful antioxidant. Antioxidants protect the sperm’s precious DNA cargo, the male set of 23 chromosomes from oxidative attack by free radicals. A study investigating the effect of antioxidants on male subfertility found that 30% to 80% of cases in male subfertility are considered caused by the damaging effects of oxidative stress on sperm. Supplementation of antioxidants orally via food supplements may therefore improve sperm quality by reducing oxidative stress.4

Study Results

The key nutrients were arginine, carnitine and glutathione as well as other nutrients thought to increase fertility such as zinc, vitamin E, selenium, co-enzyme Q1o and folic acid. All key spermiogram parameters increased significantly following a three month long supplementation with the male fertility supplement PROFertil. The test group of 132 males reported 34 pregnancies after six months (26%) compared to 11 (15%) pregnancies in the placebo group of 73 slightly older males. No adverse effects were observed.


Treatment Group

Control (Placebo) Group

Ejaculatory Volume (ml)



Sperm Cell Density (mill/ml)



Total Motility (%)



Progressive Motility (%)


Normal Morphology (%)






 There is a large number of male fertility supplements on the market today. A comprehensive comparison of 10 such supplements was carried out by the website, which observed significant differences in price and nutrients provided.

  3. Lenzi A, Lombardo F, Sgro P, Salacone P, Caponecchia L, Dondero F, Gandini L (2003). Use of carnitine therapy in selected cases of male factor infertility: a double-blind crossover trial. Fertility and Sterility 79 (2): 292–300. PMID 12568837. ”