When a couple is unable to conceive, it is still too often the woman who consults first, and the man last. Yet a male factor is responsible for approximately half of couple infertilities, and the male evaluation is the simplest of all: a spermiogram. This guide begins there, then reports what studies show about what can, or cannot, improve it.
There is in this file a result that most pages on the subject omit: the largest trial ever conducted on male fertility supplements, 2,370 couples, concluded that two of their most common ingredients changed nothing. We report it first, because it frames everything else.
The evaluation first. Twelve months of trials without pregnancy, six if the woman is over 35 years old: spermiogram prescribed by a doctor, repeated at three months. The major trial. FAZST, JAMA 2020, 2,370 couples: 5 mg of folic acid and 30 mg of zinc per day in men for six months, 34% births versus 35% under placebo, no spermiogram parameter improved, DNA fragmentation slightly higher. At high dose, these two do nothing.
Antioxidants. Cochrane 2019, 61 trials, 6,264 men: a weak quality signal on births that disappears when biased trials are removed; inconclusive. By nutrient. Selenium, omega-3, CoQ10, carnitines and zinc improve parameters of the spermiogram in small trials; one parameter is not a pregnancy. Mediterranean diet is associated with better sperm, alcohol, caffeine and processed meat with worse sperm. All is read at three months.
The spermogram: when, how, why twice
A couple is considered infertile after twelve months of regular intercourse without contraception and without pregnancy, six months if the woman is over 35 years old. At this stage, the assessment is done for both partners, and the male component begins with a spermogram, prescribed by a general practitioner, gynecologist, or urologist, and performed in a laboratory after two to seven days of abstinence. It measures concentration, motility, morphology, and volume, and can be supplemented by a measurement of DNA fragmentation.
Sperm parameters vary greatly from one sample to another, with fever, stress, abstinence, and season. An abnormal spermogram is confirmed by a second one, three months later, before any conclusion; and it is the doctor who interprets both, because low values do not mean infertility and normal values do not guarantee it. The three months are not arbitrary: it is the duration of sperm cell production, and section 6 returns to this.
The major trial: folic acid and zinc, 2,370 couples
Supplements sold for male fertility commonly contain folic acid and zinc, based on limited prior evidence. No large-scale trial had examined their effectiveness. The FAZST trial included 2,370 couples planning infertility treatment at four American centers. Men were randomized to receive 5 mg of folic acid and 30 mg of elemental zinc, or placebo, daily for six months. The live birth rate was not different: 404, or 34 percent, with supplement, versus 416, 35 percent, with placebo. Most sperm parameters—concentration, motility, morphology, volume, and total number of motile sperm—were not different at six months. A statistically significant increase in DNA fragmentation was observed with supplement, 29.7 versus 27.2 percent. Digestive symptoms were more frequent with supplement. These results do not support the use of folic acid and zinc by male partners in the treatment of infertility.
Schisterman EF, Sjaarda LA, Clemons T, et al. JAMA 2020;323(1):35-48. DOI: 10.1001/jama.2019.18714
It is the reference trial in the field: funded by American health institutes, 2,370 couples, six months, live births as the primary endpoint. It says that giving much folic acid and zinc, 5 mg and 30 mg per day, which is more than ten times and three times the reference intakes, given to men consulting for infertility, changes nothing in births or sperm, and slightly increases DNA fragmentation. It closes the hypothesis that forcing the doses helps. It does not test nutritional doses, and it says nothing about deficient men, who were not targeted. But this is the first result to know before buying anything, and the reason why zinc and B9 in a formula should not be its argument.
Antioxidants: what Cochrane finds
Sixty-one randomized trials and 6,264 subfertile men, aged 18 to 65 years and followed in fertility clinics, were included, comparing 18 different oral antioxidants. Antioxidants could increase the rate of live births, odds ratio 1.79, 7 trials and 750 men, low-quality evidence: if the chance of birth is 12 percent under placebo, it would be 14 to 26 percent under antioxidants. This result is based on 124 births in seven relatively small trials. When studies at high risk of bias are removed, there is no longer evidence of increased births. Antioxidants could increase clinical pregnancies, 11 trials and 786 men, low-quality evidence. There is no difference in miscarriages, and antioxidants could increase mild digestive disorders. Subfertile couples should be informed that current evidence is inconclusive, due to serious risk of bias, insufficient reporting of births, and imprecision related to small sample sizes.
Smits RM, Mackenzie-Proctor R, Yazdani A, Stankiewicz MT, Jordan V, Showell MG. Cochrane Database Syst Rev 2019;3:CD007411. DOI: 10.1002/14651858.CD007411.pub4
Honest reading boils down to two sentences. There is a signal : seven small trials point toward more births under antioxidants, and eleven toward more pregnancies. And this signal is fragile : it disappears when only well-designed trials are kept, and it rests on 124 births total. Cochrane concludes "inconclusive," and calls for the large trials that are missing. This is exactly the level of evidence for an antioxidant formula for male fertility: reasonable hope, not a promise.
Nutrient by nutrient: spermogram parameters
Twenty-eight articles were included for qualitative analysis and fifteen for meta-analysis. Sperm concentration was increased by selenium, 3.91 million per milliliter, zinc, 1.48 million, omega-3s, 10.98 million, and coenzyme Q10, 5.93 million. Sperm count was increased by omega-3s and CoQ10. Total motility was increased by selenium, 3.30 percent, zinc, 7.03 percent, omega-3s, 7.55 percent, CoQ10, 5.30 percent, and carnitines, 7.84 percent; progressive motility only by carnitines. Morphology was improved by selenium, omega-3s, CoQ10, and carnitines. These results should be interpreted with caution due to limited sample sizes and considerable heterogeneity between studies.
Salas-Huetos A, Rosique-Esteban N, Becerra-Tomás N, Vizmanos B, Bulló M, Salas-Salvadó J. Adv Nutr 2018;9(6):833-848. DOI: 10.1093/advances/nmy057
| Nutrient | Concentration | Total motility | Morphology | Level of evidence |
|---|---|---|---|---|
| Selenium | + 3.9 M/ml | + 3.3 points | + 1.9 points | Small trials, consistent across three parameters |
| Omega-3 | + 11 M/ml | + 7.6 points | + 0.9 points | Greatest effect on concentration |
| Coenzyme Q10 | + 5.9 M/ml | + 5.3 points | + 1.1 points | Consistent on three parameters |
| Carnitines | Not significant | +7.8 points, only one to improve progressive mobility | +4.9 points | Greatest effect on mobility |
| Zinc | +1.5 M/ml | +7 points | Not significant | Small trials; FAZST negative at 30 mg on births |
| Folic acid | Not retained | Not retained | Not retained | FAZST negative at 5 mg |
This table improves laboratory values, and that's all it says. A few million sperm per milliliter and a few points of mobility are real improvements, but the trials measuring them are small and do not follow couples through to birth. The Cochrane review, which does, finds a weak signal. Between the two, the correct reading is this: selenium, omega-3, CoQ10 and carnitines probably improve the spermiogram of a man whose is impaired; that they lead to more births is not proven.
Diet
The systematic review published in Human Reproduction Update by the Reus team gathered 35 observational studies of sufficient quality on diet and male fertility. The direction is clear: diets rich in omega-3, in antioxidants, vitamin E, vitamin C, beta-carotene, selenium, zinc, lycopene, in vitamin D and folates, and low in saturated and trans fats, are associated with better sperm parameters. On the food side, fish, seafood, poultry, grains, vegetables, fruits and low-fat dairy go in the right direction; processed meat, potatoes, whole dairy and cheese, coffee, alcohol, sugary drinks and sweets in the wrong direction, in some studies. For the couple's chances of pregnancy,alcohol, caffeine and red and processed meat in men weigh negatively.
These are associations, and the authors say so: they must be confirmed by trials. But they outline a Mediterranean diet, consistent with the nutrient list from the previous section, and they point to what can be removed without losing anything: alcohol, sweets, processed meat, and excess coffee. This is the first lever, the one that costs nothing, and the one where the three months begin.
The three months, and the protocol
A sperm takes approximately 74 days to form in the testicle, then two to three weeks in transit. The sperm ejaculated today began its production three months ago. Everything that changes—diet, tobacco, a supplement—acts on sperm in production, not on those already mature, and only shows up on a spermogram after this delay. This is why trials last three to six months, and why redoing a spermogram at six weeks measures nothing.
Selenium 54 µg, vitamin E 60 mg, OPC from grape seed 300 mg, zinc 10 mg, vitamin B9 300 µg, with fenugreek and tribulus, in three capsules daily for one month, to be renewed over the duration of a spermatogenesis cycle. The zinc and B9 are at nutritional dose, ten times lower than FAZST levels; the formula's strength lies elsewhere, in the antioxidants that meta-analyses link to spermogram parameters.
See Male FertilityFor omega-3s, the nutrient with the greatest effect on concentration, our OmegaVie. And the spermogram first.
Frequently asked questions
When should a spermogram be done?
When a couple has not conceived after twelve months of regular intercourse without contraception, or six months if the woman is over 35 years old. The spermogram is prescribed by a physician and performed in a laboratory after two to seven days of abstinence. It measures concentration, motility, morphology, and volume, and can be supplemented by DNA fragmentation measurement. A single spermogram is not enough to conclude: values vary considerably from one sample to another, and a second test at three months is standard. A male factor is involved in about half of couple infertilities; the assessment is therefore done as a couple, and from the start.
Does folic acid and zinc improve the spermogram?
Not at the doses tested in the largest trial ever conducted. The FAZST trial, published in the JAMA in 2020, randomized 2,370 couples followed at a fertility clinic: the man received daily 5 mg of folic acid and 30 mg of zinc, or placebo, for six months. The live birth rate was 34% with supplement versus 35% with placebo. No sperm parameter was improved, DNA fragmentation was slightly higher with supplement, and digestive upset more frequent. The doses tested were pharmacological; the trial says nothing about nutritional doses, but it closes the hypothesis that giving more helps.
Do antioxidants improve male fertility?
Perhaps, and the evidence is fragile. The 2019 Cochrane review pooled 61 trials and 6,264 subfertile men, comparing 18 antioxidants to placebo. On live births, seven small trials suggest an increase of 12% to 14–26%, with weak-quality evidence; when trials at high risk of bias are removed, the effect disappears. Antioxidants slightly increase mild digestive upset and do not change miscarriage risk. The authors' conclusion: current evidence is inconclusive.
What nutrients improve semen analysis parameters?
A meta-analysis of randomized trials published in Advances in Nutrition reviewed 28 studies. Sperm concentration increased with selenium, zinc, omega-3s, and coenzyme Q10; total motility with selenium, zinc, omega-3s, CoQ10, and carnitines; morphology with selenium, omega-3s, CoQ10, and carnitines. The authors call for cautious interpretation, as sample sizes were small. And improving a parameter is not achieving pregnancy: this is the limitation that the Cochrane review underscores.
What diet for male fertility?
The systematic review of 35 observational studies published in Human Reproduction Update provides consistent guidance. Diets rich in omega-3s, antioxidants, vitamin D, and folates, and low in saturated and trans fats, are associated with better sperm parameters. Fish, shellfish, poultry, vegetables, and fruits move in the right direction; processed meat, alcohol, sugary drinks, and sweets in the wrong one. For pregnancy chances, alcohol, caffeine, and red and processed meat in men weigh negatively. These are associations, not proven causes, but they outline a Mediterranean diet.
How long to see a change?
Spermatogenesis lasts approximately 74 days, plus two to three weeks of transit: a sperm ejaculated today began forming three months ago. Any change therefore takes three months to show on a semen analysis, and this is why trials last three to six months. Redoing a semen analysis before three months does not measure the effect of what you changed.
What to remember about male fertility?
That assessment is done as a couple starting at twelve months, with a semen analysis prescribed and repeated. That the largest trial, 2,370 couples, shows that high-dose folic acid and zinc improve neither sperm nor live births. That antioxidants have a weak signal for live births, inconclusive per Cochrane. That selenium, omega-3s, CoQ10, and carnitines improve semen analysis parameters in small trials. That a Mediterranean diet is associated with better sperm. And that everything shows at three months, not before.
Sources
The studies cited below were identified via PubMed.
- Schisterman EF, Sjaarda LA, Clemons T, et al. Effect of folic acid and zinc supplementation in men on sperm quality and live births in couples undergoing infertility treatment: randomized clinical trial. JAMA, 2020;323(1):35-48. DOI
- Smits RM, Mackenzie-Proctor R, Yazdani A, Stankiewicz MT, Jordan V, Showell MG. Antioxidants for male subfertility. Cochrane Database of Systematic Reviews, 2019;3:CD007411. DOI
- Salas-Huetos A, Rosique-Esteban N, Becerra-Tomás N, Vizmanos B, Bulló M, Salas-Salvadó J. Effect of nutrients and dietary supplements on sperm quality parameters: systematic review and meta-analysis of randomized trials. Advances in Nutrition, 2018;9(6):833-848. DOI
- Salas-Huetos A, Bulló M, Salas-Salvadó J. Dietary habits, foods and nutrients in male fertility parameters and fecundability: systematic review of observational studies. Human Reproduction Update, 2017;23(4):371-389. DOI
