By Dr. Asnat Raziel, bariatric surgeon specializing in obesity treatment, metabolic health and healthy longevity; Director of the Multidisciplinary Center for Obesity Treatment, Assia Medical, Assuta Ramat HaChayal, Tel Aviv
Enobosarm for muscle preservation: why it matters after 60
Enobosarm for muscle preservation is one of the topics at ObesityWeek this week, the American obesity congress in Washington. Veru will present a new analysis of the QUALITY trial. The trial studied older patients on Wegovy who also took an investigational pill. According to the company, the add-on protected muscle mass and the ability to climb stairs.
One thing up front: enobosarm is an investigational drug. No regulator in Israel or the United States has approved it.
The problem: weight loss that also costs muscle
Drugs like Wegovy lead to substantial weight loss. However, part of the weight lost is muscle, not fat. In younger people this is less of a concern. After 60, though, every kilogram of muscle matters for independence, balance and preventing falls.
That is why protein and strength training remain the foundation. They come before any drug.
Enobosarm for muscle preservation: what is the drug and how does it work?
Enobosarm is a daily pill from the SARM class, a selective androgen receptor modulator. In other words, it acts on the receptor for male sex hormones. But it does so in a more targeted way. The goal is to protect muscle and bone while increasing fat breakdown.
What did the QUALITY trial test?
QUALITY is a phase 2b randomized, double-blind trial with a placebo control group. It enrolled 168 patients aged 60 and older who were taking semaglutide for weight loss. Participants also received enobosarm 3 mg, 6 mg or placebo for 16 weeks.
After that, all participants stopped semaglutide. In the extension phase, for another 12 weeks, they continued on enobosarm alone or on placebo.
Enobosarm for muscle preservation: the key results
The company released the main results in January 2025. These are the figures, as reported in the company’s announcement of the trial results:
- Muscle mass: In the placebo group, lean body mass fell by 4.1%. In the combined enobosarm groups, it fell by only 1.2%. That is 71% less lean mass loss (p=0.002).
- Share of weight loss from muscle: On placebo, about 31.9% of the weight lost was lean mass. On enobosarm, only 9.4% (median).
- Fat: Fat mass fell by 10.9% on enobosarm, compared with 8.6% on placebo. The difference was not statistically significant (p=0.096).
- Total weight: Weight loss was similar, 4.4 kg on enobosarm and 4.7 kg on placebo.
Climbing stairs: the measure patients care about
Muscle mass on a scan is one thing. Being able to climb stairs is something else entirely. The trial measured stair climb power. Specifically, it counted who lost at least 10% of it.
On placebo, 42.6% of participants (20 of 47) lost at least 10% of their stair climb power. On enobosarm, only 19.4% (19 of 98) did. That is a 54.5% reduction in the share of participants whose function declined (p=0.0049).
What will Veru present at ObesityWeek?
According to the company’s November 9 announcement, Dr. Gary Barnette, Veru’s chief scientific officer, will give a talk at the congress on November 16. The talk focuses on a post hoc analysis of physical function in participants aged 65 and older.
The company also summarizes the extension phase, after participants stopped semaglutide. Enobosarm alone prevented weight regain, and fat loss continued. However, the announcement does not include figures from the new analysis. I will update once the company publishes the full data.
This congress brings a lot of news. For example, I wrote about experimental drugs to protect muscle at ObesityWeek and about what Novo Nordisk will present at the congress.
Safety and side effects
According to the safety data the company released, 20% of participants on placebo reported nausea, compared with 11% on enobosarm 3 mg. The company also noted that across 27 earlier studies patients generally tolerated the drug well. Still, no peer-reviewed journal has published the results yet.
What is next for enobosarm for muscle preservation?
Meanwhile, the company is running the phase 2b PLATEAU trial. It enrolled 239 patients aged 65 and older with a BMI of 35 or higher who are starting semaglutide. The main endpoint is the change in body weight after 68 weeks. The company expects an interim body composition analysis in the first quarter of 2027, and final results in the fourth quarter of 2027.
What does this mean for you?
First, the drug is still investigational, and there is no way to get it today. So the proven tools stay at the center: protein at every meal, regular resistance training and tracking body composition. My article on strength training and muscle mass has practical guidance.
Second, if you are over 60 and starting medication, it is worth planning ahead to protect your muscle. That way, weight loss improves your health without costing you your independence.
The bottom line
Enobosarm for muscle preservation is a promising direction for older adults on weight-loss medication. In the QUALITY trial it cut lean mass loss by 71% and better preserved stair climbing. In the end, these are company data from a mid-sized trial, and we need to wait for follow-up studies.
This article is general information and does not replace personal medical advice.
References
Enobosarm Protects Lean Mass in Topline Phase 2b Trial Results
Veru Announces Positive Topline Data from Phase 2b QUALITY Clinical Study
Veru Reports Positive Safety Results from Phase 2b QUALITY Clinical Study
Funding: Veru, the company developing enobosarm, pays for the studies.
