NCT07258576 Menstrual Cycle vs. Oral Contraceptives: Effects on Muscle Protein Metabolism After Resistance Exercise
| NCT ID | NCT07258576 |
| Status | Recruiting |
| Phase | — |
| Sponsor | University of Toronto |
| Condition | Female Sex Hormones |
| Study Type | INTERVENTIONAL |
| Enrollment | 20 participants |
| Start Date | 2025-07-20 |
| Primary Completion | 2026-09-01 |
Eligibility & Interventions
Eligibility Fast-Check
Enter your details for a quick preliminary check. This does not replace medical advice.
What to Expect as a Participant
You will actively receive the study intervention — which may be a drug, biologic, device, or procedure.
This trial targets 20 participants in total. It began in 2025-07-20 with a primary completion date of 2026-09-01.
⚠ This information is for research awareness only. Always consult your physician before joining any clinical trial. Participation is voluntary and you may withdraw at any time.
Brief Summary
The muscles of the body are constantly breaking down old proteins and building new ones. These two processes, protein breakdown and protein synthesis, together are known as protein turnover. Protein turnover is essential for maintaining healthy muscle. Despite its importance, females have historically been underrepresented in protein metabolism research. A long-standing assumption has been that fluctuations in female sex hormones such as estrogen and progesterone, whether across the natural menstrual cycle or in individuals using oral contraceptives (OCs), make metabolism and training responses too variable to study. Because of this, many researchers have excluded female participants for logistical reasons. Resistance exercise, such as weightlifting, is the most effective way to increase muscle size and strength. Each resistance-training session triggers muscle protein synthesis (MPS), the process by which new muscle proteins are built. Consuming dietary protein or individual amino acids further increases the rate at which new proteins are formed. Over time, higher rates of protein synthesis support muscle growth and the maintenance of other lean tissues in the body. The purpose of this study is to examine how menstrual cycle phases and OC use influence the synthesis of proteins in both muscle tissue and the rest of the body. Improving scientific understanding in this area will support more effective, evidence-based training and nutrition recommendations for females.
Eligibility Criteria
Inclusion Criteria: * Age: 18-40 years * BMI between 18.5-29.9 kg/m2 (non-obese) * Recreationally active (resistance train minimum twice a week) * Using monophasic or triphasic oral contraceptives for \>1 year (for oral contraceptive users) * Have regular menstrual cycles (21-35 days) for the past 3 months and discontinued any hormonal contraceptive use for at least 6 months (non-oral contraceptive users) * Must meet a progesterone sufficiency test (non-oral contraceptive users) Exclusion Criteria: * Mid-luteal progesterone levels \<16umol * Chronic disease diagnosis (cardiovascular, thyroid, diabetes) * Current or recent remission of cancer * Regular use of non-steroidal anti-inflammatory drugs (NSAIDs; except low-dose aspirin), anticoagulants * Use of prescription drugs that would impact muscle protein synthesis, e.g. Statins, Lithium, ADHD medication. * Insertion of intrauterine device (IUD) - exception: copper * Use of emergency contraception in the last 3 months (e.g. Plan B) * Severe food allergies (e.g. soy, nuts) * Smoking, use of performance enhancing drugs (growth hormones, testosterone)
Contact & Investigator
Frequently Asked Questions
Who can join the NCT07258576 clinical trial?
This trial is open to female participants only, aged 18 Years or older, up to 40 Years, studying Female Sex Hormones. Full inclusion and exclusion criteria are listed in the Eligibility Criteria section. Always confirm your eligibility with the research team before applying.
Is NCT07258576 currently recruiting?
Yes, NCT07258576 is actively recruiting participants. Contact the research team at dr.moore@utoronto.ca for enrollment information.
Where is the NCT07258576 trial being conducted?
This trial is being conducted at Toronto, Canada.
Who is sponsoring the NCT07258576 clinical trial?
NCT07258576 is sponsored by University of Toronto. The trial plans to enroll 20 participants.