An interventional study of Impryl and Placebo in Male Subfertility, sponsored by Radboud University Medical Center. Completed at 21 sites in Netherlands. Open to male participants aged 18 Years to 50 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-28.
Sponsored by Radboud University Medical Center · Not applicable, Interventional, and Treatment
Help build ClinicalTrials.gg — short surveys, remote interviews or testing, in your language. Take part →
Infertility is a worldwide problem and about 10%-15% of all couples will be affected by the inability to have children. In approximately 50% of infertile couples a male factor is involved. Male infertility is of multifactorial origin. In the past decade, the role of oxidative stress on sperm has been researched thoroughly and found to be the problem in 30% to 80% of male infertility cases.
Impryl® is a nutritional supplement mainly consisting of vitamin B, which works on the metabolic system by activating the one carbon cycle and recycling of homocysteine without the use of any direct strong antioxidants.
In this study the investigators want to determine the effectiveness of nutritional supplement Impryl® in men of infertile couples on ongoing pregnancy rate, with or without assisted reproduction technology (ART).
Rationale: Infertility is a worldwide problem and about 10%-15% of all couples will be affected by the inability to have children. In approximately 50% of infertile couples a male factor is involved. In the past decade, the role of oxidative stress on sperm has been researched thoroughly and found to be the problem in 30% to 80% of male infertility cases. Impryl® is a nutritional supplement which works on the metabolic system and regulation of oxidative stress by activating the 1-Carbon cycle and therefore recycling of homocysteine.
Objective: To determine the effectiveness of nutritional supplement Impryl® in men of infertile couples on ongoing pregnancy rate, with or without assisted reproduction technology (ART).
Study design: Multicentre, randomised double blind placebo controlled clinical trial/superiority study.
Study population: All participants in this study are male adults, age 18-50 years, part of a couple that is diagnosed with infertility, regardless the outcome of semen analysis. The couple will either start or is already started with fertility treatment, i.e. expectative management (EM, duration 6 months), intra-uterine insemination (IUI) with or without ovarian stimulation (mild ovarian hyperstimulation (MOH) or ovulation induction (OI)), either in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) treatment.
Intervention: Impryl® or placebo, with identical appearance one tablet each day for a total duration of maximal 6 months. Patients can start directly with study medication and fertility treatment (or to conceive spontaneously).
Main study parameters/endpoints: The primary outcome is the number of ongoing pregnancies confirmed by ultrasound at ≥ 10-12 weeks. Secondary outcomes are change in semen parameters between baseline and 3 months intervention in IUI/IVF/ICSI group, based on (pre-wash) total motile sperm count (TMSC), leading to a change in treatment category Furthermore the occurrence of pregnancy, time to pregnancy, embryo fertilization rate in IVF/ICSI, embryo-utilization rate in IVF/ICSI, number of miscarriages and live birth rate are documented within the study period. The occurrence of adverse events will be reported.
282 studies on the registry are indexed under Infertility, Male; 65 are open to participants now.
This study's enrollment of 1,200 is above the median of 80 across 187 interventional studies indexed under Infertility, Male.
Browse Infertility, Male studies →Radboud University Medical Center is the lead sponsor of 986 studies on the registry; 136 are open to participants now.
Of its 6 completed or terminated interventional studies of FDA-regulated products, 0 (0%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Couples with failure to conceive for at least 12 months and starting with EM or Couples starting with 1st/ 2nd/3rd cycle of IUI (with/without ovarian stimulation) or Couples starting with 1st/ 2nd/3rd cycle of IVF/ICSI
Furthermore:
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
One tablet daily for 6 months
Dietary Supplement: Impryl
One tablet daily for 6 months
Other: Placebo
Food supplement with betaine, cystine, zinc, niacin, folic acid (5MTHF-glucosamine), Vitamin B12 (cobalamin), Vitamin B6, Vitamin B2 (riboflavin)
Inactive ingredients, placebo
Ongoing pregnancy rate
Ongoing pregnancy ≥10-12 weeks of gestation
Time frame: 15 months
Overall pregnancy rate
All pregnancies confirmed with a positive pregnancy (HCG) test
Time frame: 15 months
Time to pregnancy 1 - start intervention
The time between start of intervention and reaching ongoing pregnancy
Time frame: 15 months
Time to pregnancy 1 - start fertility treatment
The time between start of fertility treatment and reaching ongoing pregnancy
Time frame: 15 months
Change in semen parameters leading to change in treatment category
Between baseline and 3 months intervention, based on pre-wash total motile sperm count (TMSC) from the subpopulation from Radboudumc and sites that deliver a pre-wash TMSC before IUI/IVF/ICSI
Time frame: 15 months
Number of miscarriages
Defined as a non-vital intra-uterine pregnancy before 16 weeks of gestation
Time frame: 15 months
Live birth rate
Live birth rate defined as beyond 24 weeks of gestation, the birth of a living child.
Time frame: 15 months
Adverse effects
Gastro-intestinal problems such as reflux, obstipation, diarrhea, nausea or vomiting, furthermore loss of appetite, headache, dizziness, pruritus or skin rash.
Time frame: 15 months
Embryo fertilization rate
Relative improvement. Fertilization rate is the percentage of oocytes with \>=2 PN after insemination (IVF) of injection (ICSI).
Time frame: 15 months
Embryo-utilization rate
Relative improvement of the embryo-utilization rate (EUR), defined as the number of high quality embryos obtained, embryo's used at transfer plus the number of embryos frozen, divided by the number of zygotes obtained in a cycle
Time frame: 15 months
Live birth rate
All live births
Time frame: 15 months
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No
Ran from Apr 2018 to primary completion in Dec 2024, 79 months.
Of 77 non-industry interventional studies with no phase under Infertility, Male, half reached primary completion within 28 months of starting (the median), counting those still running; a quarter within 17 and three quarters within 50. This study's 79 months is above that.
Counting every sponsor, half of 92 studies reached it within 34 months; a quarter within 17 and three quarters within 50.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in Jun 2025. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Radboud University Medical Center →