Comparative Evaluation of Letrozole, L-Carnitine, and Combination Therapy on Sperm Quality and ART Outcomes in Idiopathic Oligoasthenoteratozoospermia: A Three-Arm Randomized Trial

June 20, 2026 updated by: Tehran University of Medical Sciences

Comparative Evaluation of the Efficacy of Letrozole, L-Carnitine, and Their Combination on Sperm Quality, Oxidative Stress, and ART Outcomes in Men With Idiopathic Oligoasthenoteratozoospermia: A Three-Arm Randomized Clinical Trial.

This is a randomized clinical trial evaluating the efficacy of Letrozole, L-Carnitine, and their combination on sperm quality, oxidative stress, and ART outcomes in men with idiopathic oligoasthenoteratozoospermia.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

This three-arm randomized controlled trial included 90 men with idiopathic oligoasthenoteratozoospermia (iOAT) who were assigned to receive Letrozole (2.5 mg/day), L-Carnitine (1000 mg/day), or combination therapy for 3 months. Sperm parameters, hormonal profiles, oxidative stress biomarkers, mitochondrial function, and ICSI outcomes were assessed before and after treatment.

Study Type

Interventional

Enrollment (Actual)

90

Phase

  • Phase 2
  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Iran
      • Tehran, Iran, 1417613151
        • Shariati Hospital, Tehran University of Medical Sciences

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

Diagnosis of idiopathic oligoasthenoteratozoospermia (iOAT) per WHO 2021 criteria

Age 20 to 45 years

BMI between 18 and 30 kg/m²

No prior hormonal therapy or antioxidant supplements within the last 3 months -

Exclusion Criteria:

Varicocele, cryptorchidism, or genital tract infection

Hormonal disorders (hypogonadism, hyperprolactinemia, thyroid dysfunction)

Smoking, alcohol use, or drug abuse

Use of testosterone or anabolic steroids within the last 6 months

Female partner with severe infertility factors (age ≥40, tubal blockage, severe endometriosis)

-

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Letrozole
Letrozole 2.5 mg administered orally once daily for 3 months.
Drug: Letrozole 2.5mg
Letrozole 2.5 mg tablet administered orally once daily for 3 months.
Experimental: L-Carnitine Monotherapy
L-Carnitine 1000 mg administered orally once daily for 3 months.
Drug: L-carnitine
L-Carnitine 1000 mg capsule administered orally once daily for 3 months.
Experimental: Combination Therapy
Letrozole 2.5 mg plus L-Carnitine 1000 mg administered orally once daily for 3 months.
Drug: Letrozole 2.5mg
Letrozole 2.5 mg tablet administered orally once daily for 3 months.
Drug: L-carnitine
L-Carnitine 1000 mg capsule administered orally once daily for 3 months.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Sperm concentration (×10⁶/mL) after 3 months of treatment
Time Frame: 3 months
Change in sperm concentration from baseline to 3 months post-treatment
3 months
Progressive sperm motility (%) after 3 months of treatment
Time Frame: 3 months
Change in progressive motility from baseline to 3 months post-treatment
3 months
Normal sperm morphology (%) after 3 months of treatment
Time Frame: 3 months
Change in normal morphology from baseline to 3 months post-treatment
3 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Serum testosterone and estradiol levels after 3 months of treatment
Time Frame: 3 months
Change in hormonal profile from baseline to 3 months post-treatment
3 months
Sperm DNA fragmentation index (DFI) after 3 months of treatment
Time Frame: 3 months
Change in DFI from baseline to 3 months post-treatment
3 months
Total antioxidant capacity (TAC) and reactive oxygen species (ROS) levels after 3 months of treatment
Time Frame: 3 months
Total antioxidant capacity (TAC) and reactive oxygen species (ROS) levels after 3 months of treatment
3 months
Mitochondrial membrane potential (MMP) after 3 months of treatment
Time Frame: 3 months
Change in MMP from baseline to 3 months post-treatment
3 months
Fertilization rate and embryo quality after ICSI
Time Frame: 3 months
Assessment of fertilization rate and embryo quality following ICSI
3 months

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Percentage of patients with improved sperm parameters (concentration, motility, morphology) after treatment
Time Frame: 3 months
Proportion of patients showing clinical improvement in at least one sperm parameter
3 months
Incidence of treatment-related adverse events
Time Frame: 3 months
Monitoring and recording of any adverse events related to the study interventions
3 months
Pregnancy outcomes (biochemical and clinical) following ICSI
Time Frame: 3 months
Assessment of biochemical and clinical pregnancy rates after embryo transfer
3 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Tehran University of Medical Sciences

Investigators

  • Study Chair: Azim Hedayatpour, Professor, PhD, Tehran University of Medical Sciences

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

December 1, 2023

Primary Completion (Actual)

February 28, 2026

Study Completion (Actual)

March 31, 2026

Study Registration Dates

First Submitted

June 20, 2026

First Submitted That Met QC Criteria

June 20, 2026

First Posted (Actual)

June 25, 2026

Study Record Updates

Last Update Posted (Actual)

June 25, 2026

Last Update Submitted That Met QC Criteria

June 20, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • IR.TUMS.MEDICINE.REC.1403.465

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Due to the specific nature of the data and restrictions from the ethics committee, individual participant data (IPD) will not be shared.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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