Healthy VolunteersPhase 1MP4 MPSNCT07173361
Progesterone and Muscle Protein Synthesis in Premenopausal Women (MP4-MPS)
A Phase 1 study testing Micronized progesterone (oral capsules) in people with Healthy Volunteers and Female, run by McMaster University at 1 site in Canada.
Trial summary
The goal of this clinical trial is to learn if micronized progesterone (PROMETRIUM®) influences the muscle-building response to resistance exercise in healthy premenopausal women aged 18-30 years. The main questions it aims to answer are: 1. Read more about this study
- Who is it for?
- Ages 18 to 30 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Healthy Volunteers, Female, Progesterone
- What is being tested?
- Micronized progesterone (oral capsules)
- Type of treatment
- Pill or oral medicine, Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 20 participants
- Where
- 1 siteCanada
- Study dates
- 1 Jan 2026to 30 May 2026
- Phase
- Phase 1
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 30 years
- Women only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Self-identifies as female and is assigned female at birth.
- Aged 18 to 30 years (inclusive).
- Body mass index (BMI) between 18 and 34.9 kg/m² (inclusive).
- In general, good health, as determined by a study-specific health screening questionnaire and medical history review.
- Reports regular menstrual cycles (21-35 days in length) for the past 3 consecutive months.
- Not currently using hormonal contraceptives and has completed a minimum 3-month washout period.
- Resting blood pressure <140/90 mmHg at screening and on the infusion day.
- Willing and able to provide written informed consent in English.
Who cannot join
- Current use of tobacco, vaping products, or nicotine-containing substances.
- Ineligible for physical activity as determined by the Get Active Questionnaire (GAQ).
- Any medical, orthopedic, or psychiatric condition that, in the opinion of the Investigator, could interfere with the participant's ability to comply with study procedures or pose additional risk.
- Current gastrointestinal or swallowing disorders that may interfere with supplement ingestion (e.g., chronic diarrhea, regurgitation, dysphagia).
- Currently pregnant, planning to become pregnant, or known/suspected to be pregnant.
- Use of hormonal contraceptives within the past 3 months.
Show all 26Show fewer
- Presence of any electronic medical devices or metallic implants that may interfere with DXA scanning or muscle biopsy procedures.
- History of neuromuscular disorders or muscle/bone wasting diseases.
- Current or recent use (within 3 months) of medications known to affect protein metabolism (e.g., glucocorticoids, systemic NSAIDs, isotretinoin, or anabolic agents).
- Personal or first-degree family history of thrombotic events (e.g., DVT, PE, stroke, myocardial infarction).
- Use of anticoagulant or antiplatelet medications.
- Excessive alcohol intake (>21 units per week; 1 unit = 10 mL of pure ethanol).
- History of bleeding disorders or known coagulation or platelet abnormalities.
- Known hypersensitivity or allergy to micronized progesterone, soya, peanuts, or any excipients in the study capsule.
- History or current diagnosis of liver dysfunction or hepatic disease, unless liver function tests have returned to normal ranges.
- History or presence of contraindications to progesterone therapy, including any of the following:
- Known or suspected estrogen- or progestin-dependent malignancies (e.g., breast or endometrial cancer).
- History of endometrial hyperplasia or unexplained abnormal uterine bleeding.
- Active or prior history of arterial thromboembolic disease (e.g., stroke, myocardial infarction, coronary artery disease).
- History of classical migraine with aura.
- Active or prior history of venous thromboembolism (e.g., deep vein thrombosis, pulmonary embolism) or thrombophlebitis.
- History of partial or complete vision loss due to ophthalmic vascular events.
- Clinically significant anemia or hematologic abnormalities (e.g., low hemoglobin or hematocrit) that may elevate the risk of biopsy complications.
- Participation in another interventional study involving investigational drugs or invasive procedures within the past 30 days.
- Documented history of severe vasovagal syncope or needle phobia that may interfere with study compliance or safety.
- Known allergy or intolerance to any ingredient in the BOOST® 2.24 nutritional drink (e.g., milk protein, soy, corn-derived ingredients, cocoa, or artificial flavorings).
Trial locations and contacts
1 site in 1 country.
Canada1 site
Exercise Metabolism Research Laboratory
Hamilton, Ontario, L8S 4K1
About this study
Official title: Investigating the Impact of Micronized Progesterone on Skeletal Muscle Metabolism
The goal of this clinical trial is to learn if micronized progesterone (PROMETRIUM®) influences the muscle-building response to resistance exercise in healthy premenopausal women aged 18-30 years.
The main questions it aims to answer are:
Read more
- Does progesterone change the rate of muscle protein synthesis after exercise?
- Does progesterone alter the difference in synthesis between an exercised leg and a rested leg?
Researchers will compare micronized progesterone to a placebo to see if progesterone changes the way skeletal muscle adapts to resistance exercise.
Participants will:
- Take two oral doses of progesterone (400 mg total, 34 and 10 hours before testing) or placebo
- Complete a unilateral leg extension exercise session in the lab
- Receive an infusion of a stable isotope tracer and provide blood samples
- Undergo muscle biopsies from the exercised and rested legs
Read the detailed description
This is a single-site, randomized, double-blind, placebo-controlled Phase 1 clinical trial designed to evaluate the effects of micronized progesterone on exercise-induced skeletal muscle protein synthesis (MPS) in premenopausal women.
Participants will be healthy, naturally menstruating women aged 18-30 years. Each will be randomized to receive either two oral doses of micronized progesterone (400 mg total, administered as 2 × 200 mg capsules, 34 and 10 hours prior to testing) or a matched placebo.
During the infusion trial, participants will consume a standardized nutritional drink (~530 kcal; 22 g protein, 52 g carbohydrate, 26 g fat) and perform unilateral resistance exercise consisting of single-leg extensions (1 warm-up set followed by 4 working sets to volitional failure, 2-minute rest between sets).
To assess myofibrillar MPS, participants will undergo a primed continuous infusion of L-[ring-¹³C₆]-phenylalanine, with incorporation into muscle proteins determined from serial biopsies collected from both the exercised and rested legs. Blood samples will be obtained throughout the infusion period to measure plasma amino acids and hormone concentrations.
The primary endpoint is the treatment (placebo vs. progesterone) × leg (exercised vs. rested) interaction in MPS over the 5-hour post-exercise period. Secondary outcomes include the exercise-induced change in fractional synthetic rate (ΔFSR), plasma hormone responses, and exploratory measures of body composition and strength.
This study will provide direct evidence on whether progesterone modifies the acute anabolic response to resistance exercise in reproductive-age women, addressing an important gap in female skeletal muscle physiology.
- Conditions
- Healthy Volunteers, Female, Progesterone, Premenopausal
- Being tested
- Micronized progesterone (oral capsules), placebo capsule
- Keywords
- Progesterone, Muscle protein synthesis, Stable isotope tracer, Female physiology, Premenopausal females, Exercise metabolism, Micronized progesterone, Resistance exercise, Skeletal muscle
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Micronized progesterone (oral capsules)Drug
Also called PROMETRIUM
Two doses of 400 mg total micronized progesterone, administered as 2 × 200 mg capsules ~34 hours and ~10 hours prior to infusion trial, taken with a standardized nutritional drink.
placebo capsuleDrug
Matched oral placebo capsules administered on the same schedule (~34 and ~10 hours prior to infusion trial) with a standardized nutritional drink.
| Study group | Role | What they receive |
|---|---|---|
| Experimental: Micronized Progesterone | Experimental | Drug - Micronized progesterone (oral capsules; 400 mg total as 2 × 200 mg at ~34 h and ~10 h pre-trial) Receives: Drug: Micronized progesterone (oral capsules) |
| Placebo Comparator: Placebo | Placebo comparator | Drug - Placebo (oral capsules; matched schedule and appearance) Receives: Drug: placebo capsule |
What is being measured
The primary outcome is the main question the study is designed to answer.
Myofibrillar muscle protein synthesis (MPS) rate
Incorporation of L-[ring-¹³C₆]-phenylalanine into myofibrillar proteins, measured via bilateral muscle biopsies (vastus lateralis, exercised vs. rested legs). The primary endpoint is the treatment (micronized progesterone vs. placebo) × leg (exercised vs. rested) interaction in MPS under fed conditions.
Measured: 5 hours after standardized feeding and unilateral resistance exercise (infusion period)
Secondary outcomes (6)
Myofibrillar MPS in rested leg (fed condition)
MPS in the rested (non-exercised) leg to assess whether progesterone alters postprandial muscle anabolism in the absence of exercise.
Measured: 5 hours after standardized feeding
Myofibrillar MPS in rested leg (fasted condition)
MPS calculated from baseline fasted blood/plasma enrichment and pre-meal biopsy to determine whether progesterone alters basal, fasted-state anabolism.
Measured: -240 to 0 minutes before feeding (fasted infusion period)
Circulating serum progesterone concentrations (pharmacokinetics)
Serial serum progesterone measured to characterize exposure; pharmacokinetic parameters include AUC, Cavg, Cmax, and Tmax.
Measured: -240 to 300 minutes (fasted and fed infusion periods)
Postprandial amino acid response
Serial serum amino acid concentrations (including essential and branched-chain amino acids) measured for PK parameters (AUC, Cavg, Cmax, Tmax) to contextualize MPS responses.
Measured: 0 to 300 minutes after standardized feeding
Plasma tracer enrichment verification
Plasma enrichment of L-[ring-¹³C₆]-phenylalanine at steady-state timepoints to confirm validity of MPS calculations (target ≥2.0%).
Measured: Throughout infusion (-240 to 300 minutes)
Baseline menstrual phase and hormonal status
Baseline serum estradiol, LH, and FSH concentrations to verify early follicular phase timing and ensure group comparability.
Measured: Pre-dose (-240 minutes)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Sep 2025
- Study start1 Jan 2026
- Primary completion30 May 2026
- Study completion30 May 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Healthy VolunteersStudies of the same condition, open and under way.
- More trials run by McMaster UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Parallel assignment with within-participant leg comparison. Participants are randomized 1:1 to micronized progesterone or matched placebo and complete the same unilateral resistance exercise and infusion protocol. Both groups receive identical procedures; only the study drug differs. The exercised leg serves as an internal comparator to the contralateral rested leg for physiologic endpoints (this is not a crossover). Randomization is computer-generated with concealed allocation; study staff, participants, and outcome assessors are blinded to assignment. Single-site conduct.
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 20 participants (actual)
Sponsor and investigators
- Lead sponsor
- McMaster University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Stuart Phillips, McMaster University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07173361
- Sponsor's protocol ID
- MP4-MPS
- Acronym
- MP4 MPS
- Status last verified
- Jun 2026
- First submitted
- 7 Sep 2025
- Last updated
- 17 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data (IPD) will not be shared due to the small sample size, the invasive nature of muscle biopsy procedures, and the risk of re-identification. Results will be disseminated in aggregate form through peer-reviewed publications and scientific presentations.
Study at a glance
From the registry record, last updated by the sponsor on 17 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Investigating the Impact of Micronized Progesterone on Skeletal Muscle Metabolism
- ClinicalTrials.gov ID
- NCT07173361
- Acronym / sponsor ID
- MP4 MPS / MP4-MPS
- Conditions
- Healthy Volunteers, Female, Progesterone, Premenopausal
- Keywords
- Progesterone, Muscle protein synthesis, Stable isotope tracer, Female physiology, Premenopausal females, Exercise metabolism, Micronized progesterone, Resistance exercise
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 20 participants (actual)
- Lead sponsor
- McMaster UniversityUniversity, hospital or other
- Study start
- 1 Jan 2026 (actual)
- Primary completion
- 30 May 2026 (actual)
- Study completion
- 30 May 2026 (actual)
- First posted
- 15 Sep 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this clinical trial is to learn if micronized progesterone (PROMETRIUM®) influences the muscle-building response to resistance exercise in healthy premenopausal women aged 18-30 years.
The main questions it aims to answer are:
- Does progesterone change the rate of muscle protein synthesis after exercise?
- Does progesterone alter the difference in synthesis between an exercised leg and a rested leg?
Researchers will compare micronized progesterone to a placebo to see if progesterone changes the way skeletal muscle adapts to resistance exercise.
Participants will:
- Take two oral doses of progesterone (400 mg total, 34 and 10 hours before testing) or placebo
- Complete a unilateral leg extension exercise session in the lab
- Receive an infusion of a stable isotope tracer and provide blood samples
- Undergo muscle biopsies from the exercised and rested legs
Detailed description
This is a single-site, randomized, double-blind, placebo-controlled Phase 1 clinical trial designed to evaluate the effects of micronized progesterone on exercise-induced skeletal muscle protein synthesis (MPS) in premenopausal women.
Participants will be healthy, naturally menstruating women aged 18-30 years. Each will be randomized to receive either two oral doses of micronized progesterone (400 mg total, administered as 2 × 200 mg capsules, 34 and 10 hours prior to testing) or a matched placebo.
During the infusion trial, participants will consume a standardized nutritional drink (~530 kcal; 22 g protein, 52 g carbohydrate, 26 g fat) and perform unilateral resistance exercise consisting of single-leg extensions (1 warm-up set followed by 4 working sets to volitional failure, 2-minute rest between sets).
To assess myofibrillar MPS, participants will undergo a primed continuous infusion of L-[ring-¹³C₆]-phenylalanine, with incorporation into muscle proteins determined from serial biopsies collected from both the exercised and rested legs. Blood samples will be obtained throughout the infusion period to measure plasma amino acids and hormone concentrations.
The primary endpoint is the treatment (placebo vs. progesterone) × leg (exercised vs. rested) interaction in MPS over the 5-hour post-exercise period. Secondary outcomes include the exercise-induced change in fractional synthetic rate (ΔFSR), plasma hormone responses, and exploratory measures of body composition and strength.
This study will provide direct evidence on whether progesterone modifies the acute anabolic response to resistance exercise in reproductive-age women, addressing an important gap in female skeletal muscle physiology.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Parallel assignment with within-participant leg comparison. Participants are randomized 1:1 to micronized progesterone or matched placebo and complete the same unilateral resistance exercise and infusion protocol. Both groups receive identical procedures; only the study drug differs. The exercised leg serves as an internal comparator to the contralateral rested leg for physiologic endpoints (this is not a crossover). Randomization is computer-generated with concealed allocation; study staff, participants, and outcome assessors are blinded to assignment. Single-site conduct.
| Arm | Type | Receives |
|---|---|---|
| Experimental: Micronized Progesterone | Experimental | Drug: Micronized progesterone (oral capsules)Drug - Micronized progesterone (oral capsules; 400 mg total as 2 × 200 mg at ~34 h and ~10 h pre-trial) |
| Placebo Comparator: Placebo | Placebo comparator | Drug: placebo capsuleDrug - Placebo (oral capsules; matched schedule and appearance) |
Who may qualify
- Ages
- 18 to 30 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (8 listed)
- Self-identifies as female and is assigned female at birth.
- Aged 18 to 30 years (inclusive).
- Body mass index (BMI) between 18 and 34.9 kg/m² (inclusive).
- In general, good health, as determined by a study-specific health screening questionnaire and medical history review.
- Reports regular menstrual cycles (21-35 days in length) for the past 3 consecutive months.
Key exclusion criteria (26 listed)
- Current use of tobacco, vaping products, or nicotine-containing substances.
- Ineligible for physical activity as determined by the Get Active Questionnaire (GAQ).
- Any medical, orthopedic, or psychiatric condition that, in the opinion of the Investigator, could interfere with the participant's ability to comply with study procedures or pose additional risk.
- Current gastrointestinal or swallowing disorders that may interfere with supplement ingestion (e.g., chronic diarrhea, regurgitation, dysphagia).
- Currently pregnant, planning to become pregnant, or known/suspected to be pregnant.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Micronized progesterone (oral capsules)Also: PROMETRIUMTwo doses of 400 mg total micronized progesterone, administered as 2 × 200 mg capsules ~34 hours and ~10 hours prior to infusion trial, taken with a standardized nutritional drink. | Drug | Experimental: Micronized Progesterone |
| placebo capsuleMatched oral placebo capsules administered on the same schedule (~34 and ~10 hours prior to infusion trial) with a standardized nutritional drink. | Drug | Placebo Comparator: Placebo |
Primary outcome
Myofibrillar muscle protein synthesis (MPS) rate
Time frame: 5 hours after standardized feeding and unilateral resistance exercise (infusion period)
Incorporation of L-[ring-¹³C₆]-phenylalanine into myofibrillar proteins, measured via bilateral muscle biopsies (vastus lateralis, exercised vs. rested legs). The primary endpoint is the treatment (micronized progesterone vs. placebo) × leg (exercised vs. rested) interaction in MPS under fed conditions.
6 secondary outcomes
Myofibrillar MPS in rested leg (fed condition)
Time frame: 5 hours after standardized feeding
Myofibrillar MPS in rested leg (fasted condition)
Time frame: -240 to 0 minutes before feeding (fasted infusion period)
Circulating serum progesterone concentrations (pharmacokinetics)
Time frame: -240 to 300 minutes (fasted and fed infusion periods)
Postprandial amino acid response
Time frame: 0 to 300 minutes after standardized feeding
Plasma tracer enrichment verification
Time frame: Throughout infusion (-240 to 300 minutes)
Baseline menstrual phase and hormonal status
Time frame: Pre-dose (-240 minutes)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Jun 2026.
- Individual participant dataSharing planned: No. Individual participant data (IPD) will not be shared due to the small sample size, the invasive nature of muscle biopsy procedures, and the risk of re-identification. Results will be disseminated in aggregate form through peer-reviewed publications and scientific presentations.
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Screening Protocol
Pain
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing Micronized progesterone (oral capsules) in people with Healthy Volunteers and Female, run by McMaster University at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 26 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 17 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Myofibrillar muscle protein synthesis (MPS) rate (time frame: 5 hours after standardized feeding and unilateral resistance exercise (infusion period)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Jun 2026.