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Study evaluating the effect of isotretinoin on sperm production in men with low sperm count

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study focuses on oligozoospermia, a condition where there is a low count of sperm in the semen. The purpose of the research is to evaluate the effectiveness of isotretinoin on sperm production. Participants in the study will receive either the medication or a placebo.

During the study, individuals will take a weekly dose of isotretinoin, which is a form of retinoic acid, an active substance used in various treatments. The course of the study involves taking this medication for a period of 20 weeks to observe how it affects the production of sperm, as well as the sperm motility, which refers to how well the sperm can move, and sperm morphology, which relates to the shape and structure of the sperm cells.

The research process

The trial runs in 3 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initiation of treatment

    You will receive either a test medication or a placebo, which is a tablet with no active medicine, to address oligozoospermia (a condition where the number of sperm is lower than normal).

    If assigned the test medication, you will take isotretinoin in the form of a 40 mg soft capsule taken orally (by mouth) once every week.

  2. Step 2

    Treatment period

    This weekly administration of the medication will continue for a total duration of 20 weeks.

  3. Step 3

    Evaluation of results

    After the 20-week period, the sperm production levels will be measured.

    Additional measurements will be taken to assess sperm motility (the ability of sperm to move) and sperm morphology (the shape and structure of the sperm).

Who can join the trial?

7 criteria

  • You must be a male between the ages of 21 and 55 years old.
  • You must have a diagnosis of oligozoospermia, which means having a low sperm count (specifically, fewer than 15 million sperm per milliliter of fluid, or fewer than 39 million sperm in total during an ejaculation).
  • This low sperm count must have been confirmed by two separate semen analyses (tests that check the quality and amount of sperm) performed at least one month apart within the last 12 months.
  • You must have experienced infertility, which is the inability to conceive a child, lasting for more than 12 months.
  • You must be covered by a health insurance scheme.
  • You must be able to understand the goals and potential risks of the study and provide a signed informed consent, which is a formal document where you agree to participate after being fully told what the study involves.
  • You must be informed of the results of your preliminary medical examination, which is the initial health checkup performed before joining the study.

Who cannot join the trial?

24 criteria

  • Having a known genetic cause of infertility, which means an inherited problem with your DNA or chromosomal abnormalities (errors in the structure or number of chromosomes) that prevents making babies.
  • Taking any vitamin A supplements currently.
  • Having hepatic insufficiency, which is a condition where the liver is not working correctly, identified by high levels of specific liver enzymes called ASAT and ALAT in your blood.
  • Having severe renal insufficiency, which means your kidneys are not working properly, identified by albuminuria (protein in the urine) or abnormal creatinine levels (a waste product in the blood).
  • A history of severe allergic or anaphylactic reactions, which are dangerous and life-threatening allergic responses.
  • Having a known psychiatric disorder, such as depression, psychotic symptoms, or mood changes, measured by a specific mental health test score.
  • A known history of suicide attempts or a known risk of suicide.
  • Having had surgery of the genitourinary tract (the organs involved in urination and reproduction) within the last year.
  • Using isotretinoin (a type of medication often used for skin) within the 3 months before joining the study.
  • Using tobacco by smoking more than 5 cigarettes per day.
  • Chronic alcohol consumption, which means regular and long-term drinking of alcohol.
  • Having hypogonadotropic hypogonadism, a condition where the body does not produce enough hormones to regulate the reproductive system.
  • Using any systemic medication (medicine that travels through the whole body) within the 3 months before joining.
  • Being unable to agree to not donate blood during the treatment and for one month after.
  • Currently participating in another medical study.
  • Being under legal guardianship, curatorship, or judicial protection, which means a court has appointed someone to make decisions for you.
  • The inability to provide informed consent, meaning you cannot understand or sign the document that explains the study.
  • Having any other medical condition that interferes with spermatogenesis, which is the process of the body creating sperm.
  • A known hypersensitivity (extreme allergy) to isotretinoin or any of its excipients (the inactive ingredients used to make the medicine).
  • Having hyperlipidemia, which means having high levels of fats like triglycerides in your blood.
  • Having hypervitaminosis A, which is a condition caused by having too much vitamin A in your body.
  • A known allergy to peanut oil, soybean oil, or magnesium stearate.
  • Using other retinoids (medicines related to vitamin A) currently.
  • Using any medication that interferes with the body's ability to create sperm or process vitamin A, such as certain antibiotics or anti-seizure medications.
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Investigated drugs

Isotretinoin is a medication taken by mouth that is being studied to see how it affects the production of sperm in men who have low sperm counts.

What is already known about the treatment

  • Isotretinoin

    This medication is taken orally in the form of a soft capsule. While it is a well-known treatment used in medicine to manage severe acne, its effects on sperm production are currently being studied in clinical research. It works at a cellular level by influencing how cells grow and differentiate, specifically by interacting with certain receptors that control cell development. It is pharmacologically classified as a retinoid, which is a type of vitamin A derivative.

  • Placebo

    This is an inactive pill taken orally that contains no medicinal ingredients. It is used in clinical trials as a control to compare against the active medication to see if the treatment truly causes an effect. Because it has no active substance, it does not interact with the body at a molecular level or treat any medical conditions. It is classified as an inert substance used for research purposes.

Investigated diseases

Oligozoospermia - This condition is characterized by a lower than normal concentration of sperm in a man's semen. It occurs when the production of sperm cells in the testes is reduced. The condition may be present from birth or develop later in life due to various biological factors. As it progresses, the total number of sperm available for reproduction remains below the standard threshold. This reduction can affect the overall quality and quantity of the sperm cells produced.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-519644-33-00Protocol code7345Estimated enrolment100 patientsSponsorLes Hopitaux Universitaires De Strasbourg

sourced from the EU Clinical Trials Register and site verification

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