Menstrual IrregularityFASTNCT06471582
Timing of Energy Availability on Menstrual Cycle Function
A study testing Artificially Sweetened Carbohydrate Beverage and Artificially Sweetened Beverage in people with Menstrual Irregularity, run by University of Colorado, Colorado Springs at 1 site in United States.
Trial summary
The primary aim of this clinical trial is to evaluate how fasted prolonged exercise may influence circulating reproductive hormones (i.e., estradiol, progesterone, luteinizing hormone) and menstrual cycle length when energy availability is maintained at or above 30 kcal/kg lean body mass/ day among women who regularly… Read more about this study
- Who is it for?
- Ages 18 to 40 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Menstrual Irregularity
- What is being tested?
- Artificially Sweetened Carbohydrate Beverage and Artificially Sweetened Beverage
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 64 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Aug 2024to 31 Aug 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
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 40 years
- Women only
- Healthy volunteers accepted
- Adult
Who may be able to join
- participates in structured running or cycling exercise for at least 30 minutes on 3 or more days per week
- accustomed to exercising for 90 minutes or more
- has regular periods every 21-35 days
- have not taken hormonal contraceptives for at least the past 6 months
- is not currently or trying to become pregnant or breastfeeding, and has not been pregnant or breastfeeding in the past 12 months
- does not currently have a diagnosis of a major menstrual cycle disorder (i.e., amenorrhea, polycystic ovary syndrome [PCOS], endometriosis, ovarian cancer, ovarian insufficiency, uterine or endometrial cancer)
- does not currently have a metabolic disease (i.e., hypothyroidism, hyperthyroidism, Cushing disease, Addison's disease, diabetes, congenital adrenal hyperplasia)
- does not currently have a major cardiovascular or respiratory disease
Who cannot join
- miss more than 7 consecutive days of aerobic activity (i.e., running, cycling, cross training)
- demonstrate clinical low energy availability as defined as energy availability <30 kcal/kg fat free mass
- report menstrual cycle lengths <21 or >35 days in the first 2 months of at-home monitoring
- do not demonstrate an anticipated rise in luteinizing hormone and progesterone in the first 2 months of at-home monitoring
- begin taking a hormonal contraceptive
- become pregnant
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- are diagnosed with a menstrual cycle disorder (i.e., amenorrhea, polycystic ovary syndrome [PCOS], endometriosis, ovarian cancer, ovarian insufficiency, uterine, or endometrial cancer)
- are diagnosed with a metabolic disease (i.e., hypothyroidism, hyperthyroidism, Cushing disease, Addison's disease, diabetes)
- are diagnosed with a major cardiovascular or respiratory disease
- are unable to follow instructions for any of the procedures
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
William J. Hybl Sports Medicine and Performance Center
Colorado Springs, Colorado, 80918
Marissa Baranauskas, PhD, 719-255-4475, mbaranau@uccs.edu
About this study
Official title: Implications for the Timing of Energy Availability on Menstrual Cycle Function
The primary aim of this clinical trial is to evaluate how fasted prolonged exercise may influence circulating reproductive hormones (i.e., estradiol, progesterone, luteinizing hormone) and menstrual cycle length when energy availability is maintained at or above 30 kcal/kg lean body mass/ day among women who regularly do running or cycling exercise. A secondary aim is to determine the effects of fasted prolonged exercise on serum leptin and cortisol.
Participants will be asked to do the following over a ~3 month enrollment period:
- attend a laboratory visit at the beginning of the study to have their resting metabolic rate, aerobic fitness, and body composition tested
- monitor their menstrual cycle length, urine hormones, perceived stress levels, and diet for ~3 months
- complete 3, 90-minute exercise sessions on a stationary bike or treadmill either fed (consuming a carbohydrate meal 1 h prior and 0.7 g carbohydrate/ kg body mass/ h during exercise) or fasted (consuming no meal prior and no carbohydrates during exercise) during month ~3
- saliva samples will be taken prior to and after 90-minute exercise sessions for quantification of leptin and cortisol
- Conditions
- Menstrual Irregularity
- Being tested
- Artificially Sweetened Carbohydrate Beverage, Artificially Sweetened Beverage
- Keywords
- functional hypothalamic amenorrhea, menstrual cycle, female athlete
- Medical subject headings
- Menstruation Disturbances
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Artificially Sweetened Carbohydrate BeverageDietary supplement
Beverage containing 0.7 g carbohydrate/ kg body mass/ h as a 2:1 mixture of glucose and fructose and artificial sweetener
Artificially Sweetened BeverageDietary supplement
Beverage containing no carbohydrates or kilocalories and an artificial sweetener
| Study group | Role | What they receive |
|---|---|---|
| Fed with Carbohydrates | Experimental | Participants will complete 3, 90-minute stationary cycle or treadmill exercise sessions 1 h after consuming a meal containing 1 g carbohydrate/ kg body weight. During exercise, they will consume an artificially sweetened beverage containing 0.7 g carbohydrate/ kg body mass/ h as a 2:1 mixture of glucose and fructose. Receives: Dietary Supplement: Artificially Sweetened Carbohydrate Beverage |
| Fasted without Carbohydrates | Placebo comparator | Participants will complete 3, 90-minute stationary cycle or treadmill exercise sessions following an overnight fast. During exercise, they will consume an artificially sweetened beverage containing no carbohydrates. Receives: Dietary Supplement: Artificially Sweetened Beverage |
What is being measured
The primary outcome is the main question the study is designed to answer.
Urinary estrone-3-glucuronide (E3G)
ng/mL
Measured: 3 months
Urinary pregnanediol glucuronide (PdG)
ug/mL
Measured: 3 months
Urinary luteinizing hormone (LH)
MIU/mL
Measured: 3 months
Menstrual cycle length
days
Measured: 3 months
Secondary outcomes (2)
Salivary cortisol
ng/mL
Measured: 3 days
Salivary leptin
ng/mL
Measured: 3 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Jun 2024
- Study start1 Aug 2024
- Primary completion31 Aug 2027 (estimated)
- Study completion31 Aug 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Menstrual IrregularityStudies of the same condition, open and under way.
- 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 N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 64 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Colorado, Colorado Springs
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Marissa Baranauskas, University of Colorado, Colorado Springs
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06471582
- Sponsor's protocol ID
- FAST
- Acronym
- FAST
- Status last verified
- Apr 2026
- First submitted
- 17 Jun 2024
- Last updated
- 1 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 1 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Implications for the Timing of Energy Availability on Menstrual Cycle Function
- ClinicalTrials.gov ID
- NCT06471582
- Acronym / sponsor ID
- FAST / FAST
- Conditions
- Menstrual Irregularity
- Keywords
- functional hypothalamic amenorrhea, menstrual cycle, female athlete
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 64 participants (estimated)
- Lead sponsor
- University of Colorado, Colorado SpringsUniversity, hospital or other
- Study start
- 1 Aug 2024 (actual)
- Primary completion
- 31 Aug 2027 (estimated)
- Study completion
- 31 Aug 2027 (estimated)
- First posted
- 24 Jun 2024 (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 primary aim of this clinical trial is to evaluate how fasted prolonged exercise may influence circulating reproductive hormones (i.e., estradiol, progesterone, luteinizing hormone) and menstrual cycle length when energy availability is maintained at or above 30 kcal/kg lean body mass/ day among women who regularly do running or cycling exercise. A secondary aim is to determine the effects of fasted prolonged exercise on serum leptin and cortisol.
Participants will be asked to do the following over a ~3 month enrollment period:
- attend a laboratory visit at the beginning of the study to have their resting metabolic rate, aerobic fitness, and body composition tested
- monitor their menstrual cycle length, urine hormones, perceived stress levels, and diet for ~3 months
- complete 3, 90-minute exercise sessions on a stationary bike or treadmill either fed (consuming a carbohydrate meal 1 h prior and 0.7 g carbohydrate/ kg body mass/ h during exercise) or fasted (consuming no meal prior and no carbohydrates during exercise) during month ~3
- saliva samples will be taken prior to and after 90-minute exercise sessions for quantification of leptin and cortisol
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Fed with Carbohydrates | Experimental | Dietary Supplement: Artificially Sweetened Carbohydrate BeverageParticipants will complete 3, 90-minute stationary cycle or treadmill exercise sessions 1 h after consuming a meal containing 1 g carbohydrate/ kg body weight. During exercise, they will consume an artificially sweetened beverage containing 0.7 g carbohydrate/ kg body mass/ h as a 2:1 mixture of glucose and fructose. |
| Fasted without Carbohydrates | Placebo comparator | Dietary Supplement: Artificially Sweetened BeverageParticipants will complete 3, 90-minute stationary cycle or treadmill exercise sessions following an overnight fast. During exercise, they will consume an artificially sweetened beverage containing no carbohydrates. |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (8 listed)
- participates in structured running or cycling exercise for at least 30 minutes on 3 or more days per week
- accustomed to exercising for 90 minutes or more
- has regular periods every 21-35 days
- have not taken hormonal contraceptives for at least the past 6 months
- is not currently or trying to become pregnant or breastfeeding, and has not been pregnant or breastfeeding in the past 12 months
Key exclusion criteria (10 listed)
- miss more than 7 consecutive days of aerobic activity (i.e., running, cycling, cross training)
- demonstrate clinical low energy availability as defined as energy availability <30 kcal/kg fat free mass
- report menstrual cycle lengths <21 or >35 days in the first 2 months of at-home monitoring
- do not demonstrate an anticipated rise in luteinizing hormone and progesterone in the first 2 months of at-home monitoring
- begin taking a hormonal contraceptive
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 |
|---|---|---|
| Artificially Sweetened Carbohydrate BeverageBeverage containing 0.7 g carbohydrate/ kg body mass/ h as a 2:1 mixture of glucose and fructose and artificial sweetener | Dietary supplement | Fed with Carbohydrates |
| Artificially Sweetened BeverageBeverage containing no carbohydrates or kilocalories and an artificial sweetener | Dietary supplement | Fasted without Carbohydrates |
Primary outcome
Urinary estrone-3-glucuronide (E3G)
Time frame: 3 months
ng/mL
Urinary pregnanediol glucuronide (PdG)
Time frame: 3 months
ug/mL
Urinary luteinizing hormone (LH)
Time frame: 3 months
MIU/mL
Menstrual cycle length
Time frame: 3 months
days
2 secondary outcomes
Salivary cortisol
Time frame: 3 days
Salivary leptin
Time frame: 3 days
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 1 May 2026.
- Individual participant dataSharing planned: No
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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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Artificially Sweetened Carbohydrate Beverage and Artificially Sweetened Beverage in people with Menstrual Irregularity, run by University of Colorado, Colorado Springs at 1 site in United States.
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 10 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: looking for participants now, as of the sponsor's last update on 1 May 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 United States. 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.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Marissa Baranauskas, PhD (719-255-4475, mbaranau@uccs.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Urinary estrone-3-glucuronide (E3G) (time frame: 3 months). The study lists 4 primary outcomes in all. 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 1 May 2026.