AuthorisedTherapeutic exploratory (Phase II)Interventional

SEMAGONA: A randomized four-arm parallel group double-blind double dummy 52-week clinical trial comparing the effects of s.c. Semaglutide 2.4 mg once-weekly, i.m. testosterone undecanoate 1,000 mg every 13th week, combination of s.c. Semaglutide 2.4 mg once-weekly and i.m. testosterone undecanoate 1,000 mg every 13th week, and placebo on body composition and hypogonadal symptoms in men with obesity-associated functional hypogonadism

Men living with obesity often develop low testosterone levels, a condition called functional hypogonadism. This can lead to low energy, loss of muscle, mood changes, and reduced sex drive. This 52-week clinical trial looks at two treatments: semaglutide (a weekly weight-loss injection) and testosterone (an injection given once every 13 weeks). Researchers want to find out whether combining these two treatments is more effective than taking just one of them, or taking a dummy medicine (placebo). The main goal is to measure changes in body composition, especially the amount of healthy muscle versus body fat, using specialised body scans. The trial also checks improvements in energy, mood, sexual health, heart health, and fertility markers. Taking part involves regular health checks and tests over one full year.

At a glance

Status

Authorised

Phase

Therapeutic exploratory (Phase II)

Sponsor

Region Hovedstaden

Enrolment target

248

Start

30 Sep 2026

Functional hypogonadism

What is this study about?

Living with excess body weight can change how a man's hormones work, leading to a temporary drop in testosterone. Doctors call this 'functional hypogonadism'. Unlike permanent hormonal conditions, it is directly linked to body weight and lifestyle. Men with this condition often experience persistent tiredness, low sex drive, erectile difficulties, muscle weakness, and feelings of low mood.

Losing weight can help the body produce healthy amounts of testosterone again. However, when people lose weight quickly, they often lose muscle along with fat. Testosterone replacement therapy can help rebuild muscle, but doctors are still learning how best to combine weight-loss treatments with hormone therapy to get the safest and most effective results.

This study compares semaglutide (the medicine found in Wegovy) alongside testosterone injections (Nebido). Over 52 weeks, the researchers want to find out if taking both treatments together protects muscle mass while reducing body fat. They also want to see if the combination leads to greater improvements in everyday well-being, heart health, and sexual function than either medicine taken on its own.

Key takeaways

Tests the combination of semaglutide (weight-loss drug) and testosterone over 52 weeks.
Aims to help men with obesity-related low testosterone build muscle and lose body fat.
Participants are placed into one of four groups, which may include a dummy drug (placebo).
Involves weekly self-injections, clinic visits every 13 weeks, and body composition scans.
Participation is entirely voluntary and includes close medical supervision throughout.

Who may be eligible?

This trial is designed specifically for adult men aged 18 and over who are living with obesity and have confirmed low testosterone levels related to their weight.

Because this study investigates low testosterone caused by excess weight, it is not suitable for men whose hormone levels are low due to permanent conditions of the testicles or pituitary gland. Men with certain pre-existing heart problems or other serious medical conditions may also be excluded for safety reasons.

A doctor from the study team will carry out a thorough health assessment, including blood tests and medical history reviews, to confirm whether taking part is safe and appropriate for you.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

You are a man aged 18 or older.
You are living with obesity or significant excess body weight.
You have symptoms of low testosterone, such as low energy, muscle loss, or reduced sex drive.
You are willing to receive both weekly and 13-weekly injections for one year.
You are able to attend regular hospital appointments for health checks, scans, and blood tests.

Answer every question to see your result.

What does participation involve?

If you take part, your involvement will last for 52 weeks (one year). You will be randomly assigned to one of four groups: semaglutide alone, testosterone alone, both medicines together, or dummy treatments (placebos). Neither you nor the study team will know which group you are in.

You will give yourself a small injection under the skin once a week (semaglutide or a dummy injection) and receive an injection into the muscle at the clinic every 13 weeks (testosterone or a dummy injection). Throughout the year, you will visit the hospital or research clinic for regular assessments. These will include blood tests to check hormone levels, DXA scans (low-dose X-ray scans that measure muscle and fat), heart checks such as ECGs and heart scans, semen samples to monitor fertility, and simple questionnaires about your mood and sexual well-being.

Potential risks and benefits

You may experience improvements in your weight, muscle strength, energy levels, and sexual health, although these benefits cannot be guaranteed, especially if you receive a placebo. Both medicines can cause side effects. Semaglutide commonly causes mild digestive issues like nausea, vomiting, or diarrhoea, while testosterone injections can cause skin changes, mood shifts, or temporary changes in sperm count. You will be closely monitored by a specialist team throughout the study. Joining is entirely your choice, and you can leave the trial at any point without it affecting your usual NHS medical care.

Locations (1)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

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Unverified
Denmark

Common questions

What is a placebo and why is it used?

A placebo is a dummy treatment that looks identical to the real medicine but contains no active drug. It helps researchers prove whether the real medicine genuinely causes the health changes seen during the trial.

Will I know which treatment I am receiving?

No. This is a 'double-blind' study, meaning neither you nor your study doctors will know which treatment group you are in until the trial ends. This ensures the results are completely fair.

Can testosterone treatment affect my fertility?

Yes, taking testosterone can temporarily reduce your body's natural sperm production. The study team will closely monitor your hormone levels and sperm count during the trial.

Do I have to pay for the medicines or tests?

No. All study medicines, scans, and clinic visits related to the trial are provided free of charge.

Can I leave the study early if I change my mind?

Yes. Taking part is completely voluntary. You are free to stop participating at any time, and doing so will not alter your regular medical treatment or relationship with your doctors.