Skeletal Muscle PhysiologyNCT06188767
Testosterone-induced Muscle Memory and Underlying Mechanisms
A study testing Testosterone Undecanoate in people with Skeletal Muscle Physiology, run by Morten Hostrup, PhD at 1 site in Denmark.
Trial summary
The purpose of this project is to investigate underlying mechanisms of testosterone- and resistance training-induced muscle hypertrophy and muscle memory in humans. Read more about this study
- Who is it for?
- Ages 18 to 40 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Skeletal Muscle Physiology
- What is being tested?
- Testosterone Undecanoate
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 30 participants
- Where
- 1 siteDenmark
- Study dates
- 1 Apr 2025to 1 Dec 2028
- 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
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy men and women
- BMI of <26 and normal ECG and blood pressure
Who cannot join
- Smoking
- Chronic disease,
- Use of prescription medication
- Pain due to current or previous musculoskeletal injury
- Resistance training more than once per week in the 12 months leading up to the intervention
- Current or previous use of prohibited anabolic substances
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Denmark1 site, 1 recruiting
- Recruiting
The August Krogh Section for Human and Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen
Copenhagen, 2100
Lukas Moesgaard, MSc, +4561724440, lm@nexs.ku.dk
About this study
Official title: Long-term Effects of Anabolic Androgenic Steroids on Muscle Growth Potential: Testosterone-induced Muscle Memory and Underlying Mechanisms
The purpose of this project is to investigate underlying mechanisms of testosterone- and resistance training-induced muscle hypertrophy and muscle memory in humans.
- Conditions
- Skeletal Muscle Physiology
- Being tested
- Testosterone Undecanoate
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Testosterone UndecanoateDrug
Following testosterone/placebo injection, participants undergo supervised resistance training for 4 weeks. This period is followed by a washout period with no drug and either continued resistance training or detraining for 16 weeks. Thereafter, another 4-week period with supervised resistance training is commenced, with no drug.
| Study group | Role | What they receive |
|---|---|---|
| Testosterone | Experimental | Participants are randomized to a single injection of 1000 mg testosterone undecanoate Receives: Drug: Testosterone Undecanoate |
| Placebo | Placebo comparator | Participants are randomized to a single placebo injection Receives: Drug: Testosterone Undecanoate |
What is being measured
The primary outcome is the main question the study is designed to answer.
Fiber cross-sectional area
Immunohistochemistry to determine fiber cross-sectional area
Measured: The change in fiber cross-sectional is assessed at baseline, 4, 20 and 24 weeks
Myonuclei
Immunohistochemistry to determine number of myonuclei
Measured: The change in myonuclei is assessed at baseline, 4, 20 and 24 weeks
Skeletal muscle proteome
Pathway enrichment analysis of the muscle proteome using mass spectrometry-based proteomics
Measured: The change in the muscle proteome is assessed at baseline, 4, 20 and 24 weeks
Secondary outcomes (3)
Lean mass
Lean mass assessed by dual X-ray absorptiometry (DXA)
Measured: The change in lean mass is assessed at baseline, 4, 20 and 24 weeks
Satellite cells
Immunohistochemistry to determine number of satellite cells
Measured: The change in satellite cells is assessed at baseline, 4, 20 and 24 weeks
Muscle strength
1-repetition maximum
Measured: The change in 1-repetition maximum is assessed at baseline, 4, 20 and 24 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Jan 2024
- Study start1 Apr 2025
- Primary completion1 Dec 2027 (estimated)
- Study completion1 Dec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Skeletal Muscle PhysiologyStudies 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
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Morten Hostrup, PhD
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Morten Hostrup, PhD, University of Copenhagen
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06188767
- Sponsor's protocol ID
- TESTO
- Status last verified
- Apr 2025
- First submitted
- 18 Dec 2023
- Last updated
- 10 Apr 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 10 Apr 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Long-term Effects of Anabolic Androgenic Steroids on Muscle Growth Potential: Testosterone-induced Muscle Memory and Underlying Mechanisms
- ClinicalTrials.gov ID
- NCT06188767
- Acronym / sponsor ID
- TESTO
- Conditions
- Skeletal Muscle Physiology
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- Morten Hostrup, PhDUniversity, hospital or other
- Study start
- 1 Apr 2025 (actual)
- Primary completion
- 1 Dec 2027 (estimated)
- Study completion
- 1 Dec 2028 (estimated)
- First posted
- 3 Jan 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 purpose of this project is to investigate underlying mechanisms of testosterone- and resistance training-induced muscle hypertrophy and muscle memory in humans.
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
| Arm | Type | Receives |
|---|---|---|
| Testosterone | Experimental | Drug: Testosterone UndecanoateParticipants are randomized to a single injection of 1000 mg testosterone undecanoate |
| Placebo | Placebo comparator | Drug: Testosterone UndecanoateParticipants are randomized to a single placebo injection |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- Healthy men and women
- BMI of <26 and normal ECG and blood pressure
Key exclusion criteria (6 listed)
- Smoking
- Chronic disease,
- Use of prescription medication
- Pain due to current or previous musculoskeletal injury
- Resistance training more than once per week in the 12 months leading up to the intervention
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 |
|---|---|---|
| Testosterone UndecanoateFollowing testosterone/placebo injection, participants undergo supervised resistance training for 4 weeks. This period is followed by a washout period with no drug and either continued resistance training or detraining for 16 weeks. Thereafter, another 4-week period with supervised resistance training is commenced, with no drug. | Drug | Placebo, Testosterone |
Primary outcome
Fiber cross-sectional area
Time frame: The change in fiber cross-sectional is assessed at baseline, 4, 20 and 24 weeks
Immunohistochemistry to determine fiber cross-sectional area
Myonuclei
Time frame: The change in myonuclei is assessed at baseline, 4, 20 and 24 weeks
Immunohistochemistry to determine number of myonuclei
Skeletal muscle proteome
Time frame: The change in the muscle proteome is assessed at baseline, 4, 20 and 24 weeks
Pathway enrichment analysis of the muscle proteome using mass spectrometry-based proteomics
3 secondary outcomes
Lean mass
Time frame: The change in lean mass is assessed at baseline, 4, 20 and 24 weeks
Satellite cells
Time frame: The change in satellite cells is assessed at baseline, 4, 20 and 24 weeks
Muscle strength
Time frame: The change in 1-repetition maximum is assessed at baseline, 4, 20 and 24 weeks
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 10 Apr 2025.
- Individual participant dataSharing planned: Undecided
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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 Testosterone Undecanoate in people with Skeletal Muscle Physiology, run by Morten Hostrup, PhD at 1 site in Denmark.
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 2 inclusion and 6 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 10 Apr 2025. 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 Denmark. 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 Lukas Moesgaard (+4561724440, lm@nexs.ku.dk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Fiber cross-sectional area (time frame: The change in fiber cross-sectional is assessed at baseline, 4, 20 and 24 weeks). The study lists 3 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 10 Apr 2025.