Here is the design of a clinical trial:

Official Title: The Impact of a Nutritional Supplement (Impryl®) on Male Fertility

Included conditions:
- Male Subfertility

Study Armgroups:
- {'label': 'Impryl', 'type': 'ACTIVE_COMPARATOR', 'description': 'One tablet daily for 6 months', 'interventionNames': ['Dietary Supplement: Impryl']}
- {'label': 'Placebo', 'type': 'PLACEBO_COMPARATOR', 'description': 'One tablet daily for 6 months', 'interventionNames': ['Other: Placebo']}

Interventions:
- {'type': 'DIETARY_SUPPLEMENT', 'name': 'Impryl', 'description': 'Food supplement with betaine, cystine, zinc, niacin, folic acid (5MTHF-glucosamine), Vitamin B12 (cobalamin), Vitamin B6, Vitamin B2 (riboflavin)', 'armGroupLabels': ['Impryl']}
- {'type': 'OTHER', 'name': 'Placebo', 'description': 'Inactive ingredients, placebo', 'armGroupLabels': ['Placebo']}

Primary Outcomes:
- {'measure': 'Ongoing pregnancy rate', 'description': 'Ongoing pregnancy ≥10-12 weeks of gestation', 'timeFrame': '15 months'}

Please estimate the sample size based on the assumption: 
The study is designed as a superiority trial with a two-sided alpha of 5% and a beta of 24% (76% power). The expected increase in ongoing pregnancy rate is adjusted to 6.5% due to the duration of spermatogenesis. The number of participants lost to follow-up is expected to be minimal.
Sample size calculation
        We aimed to recruit 1200 male participants as a part of an infertile couple, based on the following data and power calculation.
        Overall, the number of ongoing pregnancies in IVF and ICSI in the Netherlands was 19.8% and 21.5%, respectively, per started fresh cycle in 2015.32 The number of ongoing pregnancies in IUI is estimated to be around 5% to 13% per cycle, around 18% after three cycles and 20%to 30% after six cycles.33â35 Based on Radboudumc data, the ongoing pregnancy rate in EM is estimated around 20% after 6 months.
        A Cochrane review estimated the increase in clinical pregnancy rates after use of antioxidants with an OR of 3.43 (95% CI 1.92 to 6.11) based on seven RCTs with a total of 522 men.36 However, this concerns low-quality evidence, and the included population in this Cochrane review was couples with male factor subfertility, whereas in our study, we also include couples with unexplained infertility. Therefore, we assumed a more conservative OR of 1.5. Assuming a 20% ongoing pregnancy rate in the placebo group, this reflects in an expected pregnancy rate of 27.3% in the Impryl group.
        The study is designed as a superiority trial. Based on the above mentioned data, we expect a 7.3% increase in ongoing pregnancy number when men are treated with Impryl compared with placebo. However, after randomisation, patients can directly start with both intervention and achieving a pregnancy, either spontaneously or with fertility treatment. In these first months, the effect of the intervention is expected to be suboptimal due to the duration of the spermatogenesis (72 days before whole renewal). Therefore, we adjusted the expected increase of 7.3% to a more realistic effect of 6.5%. We assume an equal increase in all fertility groups (meaning EM, IUI and IVF/ICSI) from 20% to 26.5%.
        To test the effect of Impryl on the probability of ongoing pregnancy, a sample size of 600 men per treatment group (1200 in total) is needed, assuming differences in ongoing pregnancy rates of 6.5% and an expected ongoing pregnancy rate of 20% in the placebo group, a two-sided alpha of 5% and a beta of 24% (ie, 76% power). As we expect the number of participants lost to follow-up to be minimal, we will allocate 600 patients to both the intervention and the placebo arm. Figure 1 shows the distribution of the number of participants for the three different types of fertility treatment (EM, IVF/ICSI and IUI).
        
          Figure 1
          
            Flowchart study design. ICSI, intracytoplasmic sperm injection; IUI, intrauterine insemination; IVF, in vitro fertilisation.