HealthyNCT03860870
Response to Clenbuterol in Humans
A study testing Clenbuterol Oral Product in people with Healthy, run by University of Copenhagen at 1 site in Denmark.
Trial summary
Due to the long half-life (~36 hr) of clenbuterol, detection methods such as dried blood spots (DBS) are a potentially suitable method to easily and non-invasively detect doping misuse of this compound for several days after ingestion. 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
- Healthy
- What is being tested?
- Clenbuterol Oral Product
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 16 participants
- Where
- 1 siteDenmark
- Study dates
- 11 Mar 2019to 21 Dec 2022
- Phase
- Interventional
- 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 40 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy
- Male
- 18-40 years of age
- No known contraindications for anabolic drugs (e.g. cancer)
Who cannot join
- Abnormal ECG
- Steroid abuse
- Ongoing use of prescription medication
- heavy resistance training more than 2 times weekly
- Disease deemed by the MD to infer a risk to participate in the trial
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Detectability of Clenbuterol and Physiological Response in Human Skeletal Muscle
Due to the long half-life (~36 hr) of clenbuterol, detection methods such as dried blood spots (DBS) are a potentially suitable method to easily and non-invasively detect doping misuse of this compound for several days after ingestion. If, and how long, the compound can be detected by DBS has not yet been investigated but is of interest due to its potential in doping-control. The aim is to evaluate whether abuse of clenbuterol can be detected at relevant concentration levels in samples obtained using DBS and to assess the physiological response to clenbuterol in skeletal muscle..
- Conditions
- Healthy
- Being tested
- Clenbuterol Oral Product, Placebo
- Keywords
- dried blood spots, skeletal muscle biopsies, muscle strength, muscle signaling
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Clenbuterol Oral ProductDrug
Subjects ingest 4x20 microgram clenbuterol tablets
PlaceboDrug
Subjects ingest placebo tablets
| Study group | Role | What they receive |
|---|---|---|
| Clenbuterol | Experimental | Subjects ingest 80 micrograms of clenbuterol tablets Receives: Drug: Clenbuterol Oral Product |
| Placebo | Placebo comparator | Subjects ingest placebo tablets Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Blood clenbuterol concentration
Concentration of clenbuterol in dried blood spots
Measured: Before (baseline) as well as 3, 8, 24, 72, 168 and 240 hours after administration of clenbuterol
Secondary outcomes (10)
Blood clenbuterol concentration
Concentration of clenbuterol in venous blood
Measured: Before (baseline) as well as 3, 8, 24, 72, 168 and 240 hours after administration of study drug
Urine clenbuterol concentration
Concentration of clenbuterol in urine
Measured: Before (baseline) as well as 3, 8, 24, 72, 168 and 240 hours after administration of study drug
Muscle strength
Maximal voluntary isometric contraction in N/m2 of the quadriceps
Measured: Before (baseline) and 2.5 hours after administration of study drug
Muscle signalling
Protein kinase A phosphorylation in vastus lateralis biopsies
Measured: Before (baseline) and 2.5 hours after administration of study drug
Plasma K+
Venous plasma K+ concentration
Measured: Before (baseline) as well as 2.5 hours after administration of study drug
Muscle mTOR signalling
mTOR phosphorylation in vastus lateralis biopsies
Measured: Before (baseline) as well as 2.5 hours after administration of study drug
Metabolic rate
Respriatory exchange ratio of oxygen and CO2
Measured: Before (baseline) as well as 2.5 hours after administration of study drug
Maximal voluntary strength
Maximal voluntary isometric muscle strength of the quadriceps
Measured: Before (baseline) and after two-week treatment of study drug
Body composition
Lean and fat mass during a DXA-scan
Measured: Before (baseline) and after two-week treatment of study drug
Aerobic capacity
Maximal oxygen uptake during maximal exercise
Measured: Before (baseline) and after two-week treatment of study drug
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Mar 2019
- Study start11 Mar 2019
- Primary completion21 Dec 2022
- Study completion21 Dec 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for HealthyStudies of the same condition, open and under way.
- More trials run by University of CopenhagenThe 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 N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Two phases: First phase sequential Second phase crossover
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 16 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Copenhagen
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Morten Hostrup, PhD, University of Copenhagen
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03860870
- Sponsor's protocol ID
- CLEN
- Status last verified
- Aug 2024
- First submitted
- 26 Feb 2019
- Last updated
- 9 Aug 2024
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
Hostrup M, Moesgaard L, Fischer M, Wickham KA, Pleshardt M, Andersen AB, Bejder J, Thomassen M, Nielsen JJ, Dehnes Y, Bangsbo J, Nordsborg NB, Jessen S. Clenbuterol induces lean mass and muscle protein accretion, but attenuates cardiorespiratory fitness and desensitizes muscle beta2-adrenergic signalling. J Physiol. 2025 Oct;603(19):5529-5545. doi: 10.1113/JP289023. Epub 2025 Sep 14.
PubMed 40946331
Study at a glance
From the registry record, last updated by the sponsor on 9 Aug 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Detectability of Clenbuterol and Physiological Response in Human Skeletal Muscle
- ClinicalTrials.gov ID
- NCT03860870
- Acronym / sponsor ID
- CLEN
- Conditions
- Healthy
- Keywords
- dried blood spots, skeletal muscle biopsies, muscle strength, muscle signaling
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 16 participants (actual)
- Lead sponsor
- University of CopenhagenUniversity, hospital or other
- Study start
- 11 Mar 2019 (actual)
- Primary completion
- 21 Dec 2022 (actual)
- Study completion
- 21 Dec 2022 (actual)
- First posted
- 4 Mar 2019 (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.
Due to the long half-life (~36 hr) of clenbuterol, detection methods such as dried blood spots (DBS) are a potentially suitable method to easily and non-invasively detect doping misuse of this compound for several days after ingestion. If, and how long, the compound can be detected by DBS has not yet been investigated but is of interest due to its potential in doping-control. The aim is to evaluate whether abuse of clenbuterol can be detected at relevant concentration levels in samples obtained using DBS and to assess the physiological response to clenbuterol in skeletal muscle..
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Two phases: First phase sequential Second phase crossover
| Arm | Type | Receives |
|---|---|---|
| Clenbuterol | Experimental | Drug: Clenbuterol Oral ProductSubjects ingest 80 micrograms of clenbuterol tablets |
| Placebo | Placebo comparator | Drug: PlaceboSubjects ingest placebo tablets |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Healthy
- Male
- 18-40 years of age
- No known contraindications for anabolic drugs (e.g. cancer)
Key exclusion criteria (5 listed)
- Abnormal ECG
- Steroid abuse
- Ongoing use of prescription medication
- heavy resistance training more than 2 times weekly
- Disease deemed by the MD to infer a risk to participate in the trial
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 |
|---|---|---|
| Clenbuterol Oral ProductSubjects ingest 4x20 microgram clenbuterol tablets | Drug | Clenbuterol |
| PlaceboSubjects ingest placebo tablets | Drug | Placebo |
Primary outcome
Blood clenbuterol concentration
Time frame: Before (baseline) as well as 3, 8, 24, 72, 168 and 240 hours after administration of clenbuterol
Concentration of clenbuterol in dried blood spots
10 secondary outcomes
Blood clenbuterol concentration
Time frame: Before (baseline) as well as 3, 8, 24, 72, 168 and 240 hours after administration of study drug
Urine clenbuterol concentration
Time frame: Before (baseline) as well as 3, 8, 24, 72, 168 and 240 hours after administration of study drug
Muscle strength
Time frame: Before (baseline) and 2.5 hours after administration of study drug
Muscle signalling
Time frame: Before (baseline) and 2.5 hours after administration of study drug
Plasma K+
Time frame: Before (baseline) as well as 2.5 hours after administration of study drug
Muscle mTOR signalling
Time frame: Before (baseline) as well as 2.5 hours after administration of study drug
Metabolic rate
Time frame: Before (baseline) as well as 2.5 hours after administration of study drug
Maximal voluntary strength
Time frame: Before (baseline) and after two-week treatment of study drug
Body composition
Time frame: Before (baseline) and after two-week treatment of study drug
Aerobic capacity
Time frame: Before (baseline) and after two-week treatment of study drug
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 9 Aug 2024.
- Derived from this study: PubMed 40946331Hostrup M, Moesgaard L, Fischer M, Wickham KA, Pleshardt M, Andersen AB, Bejder J, Thomassen M, Nielsen JJ, Dehnes Y, Bangsbo J, Nordsborg NB, Jessen S. Clenbuterol induces lean mass and muscle protein accretion, but attenuates cardiorespiratory fitness and desensitizes muscle beta2-adrenergic signalling. J Physiol. 2025 Oct;603(19):5529-5545. doi: 10.1113/JP289023. Epub 2025 Sep 14.
- 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. 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 study testing Clenbuterol Oral Product in people with Healthy, run by University of Copenhagen 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 4 inclusion and 5 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 9 Aug 2024. 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?
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?
Blood clenbuterol concentration (time frame: Before (baseline) as well as 3, 8, 24, 72, 168 and 240 hours after administration of clenbuterol). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03860870, which also lists 1 linked publication.
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 9 Aug 2024.