Side Effects

Ozempic Side Effects in Men: What Male Patients Should Know

GLP-1 Companion · 8 min read

Quick answer

Men on Ozempic face some unique considerations around testosterone levels, muscle mass preservation, sexual health, and cardiovascular outcomes. Here is what the research shows for male patients specifically.

Ozempic (semaglutide) and other GLP-1 receptor agonists produce similar weight-loss results in men and women, but the side-effect profile and metabolic implications are not identical across sexes. Men have distinct hormonal physiology, body composition characteristics, and cardiovascular risk profiles that influence how GLP-1 medications affect them. This article focuses on what male patients specifically need to know.

Common Side Effects: Similar Rates, Slightly Better Tolerability

The most common side effects of Ozempic — nausea, vomiting, diarrhea, constipation, and abdominal discomfort — occur in both men and women. Analyses of SUSTAIN and STEP trial data suggest that men may experience slightly lower rates of nausea and vomiting compared to women, potentially due to hormonal differences in gastric motility. That said, GI side effects are common for everyone during dose escalation and typically improve over the first 4–8 weeks.

Testosterone and Hormonal Effects

Obesity is strongly associated with low testosterone levels in men. Excess adipose tissue — particularly visceral fat — converts testosterone to estradiol via the aromatase enzyme, driving down free and total testosterone. Many men with obesity have clinically low testosterone (hypogonadism) even without any dysfunction of the testes or pituitary gland.

Weight loss from GLP-1 therapy consistently improves testosterone levels in men with obesity-related hypogonadism. A 2022 analysis of semaglutide trial data found that men lost a significant amount of visceral fat on GLP-1 therapy, which was associated with measurable increases in total testosterone. The improvements were most pronounced in men who started with the lowest baseline testosterone levels.

GLP-1 receptors have also been identified in Leydig cells (the testosterone-producing cells of the testes), suggesting the medication may have direct, weight-independent effects on testosterone. Research in this area is ongoing.

Sexual Health and Erectile Dysfunction

Erectile dysfunction (ED) is highly prevalent among men with obesity, type 2 diabetes, and metabolic syndrome. GLP-1 medications can affect male sexual health in two opposing directions.

Improved ED via weight loss: Numerous studies have shown that weight loss of 10% or more significantly improves erectile function, likely through improved vascular function, reduced inflammation, and normalized testosterone. GLP-1 medications often produce this magnitude of weight loss.
Reduced libido via caloric restriction: Some men report temporarily reduced libido during the aggressive weight-loss phase, which may reflect the body's caloric deficit response. This typically normalizes as weight stabilizes.
Direct GLP-1 receptor effects: GLP-1 receptors are present in penile tissue. Some preclinical data suggests potential direct vasodilatory effects, but human clinical evidence is still limited.

A 2023 study in Diabetes, Obesity and Metabolism found that men with type 2 diabetes on semaglutide reported significant improvements in erectile function scores over 52 weeks, independent of their degree of weight loss.

Muscle Mass Preservation: A Key Male Concern

Men typically have higher absolute and relative muscle mass than women, and many male patients are concerned about losing muscle while on GLP-1 therapy. This concern is legitimate. All weight loss — regardless of method — results in some loss of lean body mass (muscle). In GLP-1 trials, approximately 25–40% of total weight lost is from lean mass, with the remainder from fat.

The good news is that this lean mass loss is not inevitable or irreversible. Strategies to minimize muscle loss on GLP-1 medications include:

High protein intake: Target at least 1.6–2.0 g of protein per kg of body weight daily. This is achievable but requires deliberate effort, as GLP-1 medications substantially reduce appetite.
Resistance training: Strength training 3–4 times per week is the most potent intervention for muscle preservation during weight loss. This is non-negotiable for men prioritizing body composition.
Adequate calories: Very aggressive caloric deficits accelerate lean mass loss. Aim for a moderate deficit (500–750 kcal/day below maintenance) rather than extreme restriction.
Creatine supplementation: Has a well-established evidence base for supporting muscle mass during resistance training in the context of weight loss.

Body Composition Changes

Men on GLP-1 medications typically experience significant visceral fat reduction — the metabolically harmful fat surrounding the internal organs. This is particularly beneficial for men, who tend to carry more visceral fat than women at equivalent BMI levels. Reductions in visceral fat are associated with improvements in insulin sensitivity, blood pressure, lipids, and inflammatory markers.

Some men also report changes in body fat distribution as weight is lost — including visible changes in the face, neck, and buttocks (colloquially called "Ozempic face," "Ozempic neck," and "Ozempic butt"). These are the result of fat redistribution and skin laxity after rapid fat loss, not unique features of the medication itself.

Cardiovascular Benefits for Men

Men carry disproportionately high cardiovascular disease burden. The SELECT trial — the landmark cardiovascular outcomes study for semaglutide — enrolled a majority male population (about 75% men) and demonstrated a 20% reduction in major adverse cardiovascular events (MACE) including heart attack and stroke. This cardiovascular benefit is one of the most compelling reasons for men with obesity and established heart disease to consider GLP-1 therapy.

Hair Loss

While more commonly reported by women, hair shedding (telogen effluvium) from rapid weight loss can also affect men. Male pattern baldness should not be confused with this type of hair loss — telogen effluvium is diffuse, temporary, and resolves once weight stabilizes and nutritional status is optimized.

The Bottom Line

For most men, Ozempic and GLP-1 medications offer compelling benefits: weight loss, improved testosterone, better erectile function, significant cardiovascular risk reduction, and visceral fat elimination. The main male-specific concern to proactively manage is muscle mass preservation, which is achievable with adequate protein and resistance training. As with any prescription medication, these should be started and monitored under the care of a healthcare provider.