Testosterone-induced Muscle Memory and Underlying Mechanisms

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.

Study Overview

• Status: Recruiting
• Conditions: Skeletal Muscle Physiology
• Intervention / Treatment: Drug: Testosterone Undecanoate

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Lukas Moesgaard; Phone Number: +4561724440; Email: lm@nexs.ku.dk

Study Locations

• Denmark
  • Copenhagen, Denmark, 2100
    • Recruiting
    • The August Krogh Section for Human and Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen
    • Contact: Lukas Moesgaard, MSc; Phone Number: +4561724440; Email: lm@nexs.ku.dk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Healthy men and women
• BMI of <26 and normal ECG and blood pressure

Exclusion Criteria:

• 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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Testosterone; Participants are randomized to a single injection of 1000 mg testosterone undecanoate	Drug: Testosterone Undecanoate; 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.
Placebo Comparator: Placebo; Participants are randomized to a single placebo injection	Drug: Testosterone Undecanoate; 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Fiber cross-sectional area	Immunohistochemistry to determine fiber cross-sectional area	The change in fiber cross-sectional is assessed at baseline, 4, 20 and 24 weeks
Myonuclei	Immunohistochemistry to determine number of myonuclei	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	The change in the muscle proteome is assessed at baseline, 4, 20 and 24 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Lean mass	Lean mass assessed by dual X-ray absorptiometry (DXA)	The change in lean mass is assessed at baseline, 4, 20 and 24 weeks
Satellite cells	Immunohistochemistry to determine number of satellite cells	The change in satellite cells is assessed at baseline, 4, 20 and 24 weeks
Muscle strength	1-repetition maximum	The change in 1-repetition maximum is assessed at baseline, 4, 20 and 24 weeks

Collaborators and Investigators

• Sponsor: Morten Hostrup, PhD

Study record dates

Study Major Dates

• Study Start (Actual): April 1, 2025
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): December 1, 2028

Study Registration Dates

• First Submitted: December 18, 2023
• First Submitted That Met QC Criteria: December 18, 2023
• First Posted (Actual): January 3, 2024

Study Record Updates

• Last Update Posted (Actual): April 10, 2025
• Last Update Submitted That Met QC Criteria: April 7, 2025
• Last Verified: April 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Antineoplastic Agents; Physiological Effects of Drugs; Hormones; Hormones, Hormone Substitutes, and Hormone Antagonists; Antineoplastic Agents, Hormonal; Anabolic Agents; Androgens; Methyltestosterone; Testosterone 17 beta-cypionate; Testosterone; Testosterone undecanoate; Testosterone enanthate
• Other Study ID Numbers: TESTO

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No