Long-Term Effects of Wegovy: A Honest Read of STEP 5, SELECT, and What We Don't Yet Know

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> Reviewed by FormBlends Medical Team · Last updated May 2026 · 12 sources cited · Topic: extended-duration semaglutide outcomes

Key Takeaways

• STEP 5 (Garvey et al. 2022) reported mean weight loss of about 15.2% over 2 years on semaglutide 2.4 mg
• SELECT (Lincoff et al. NEJM 2023) reported a 20% reduction in major adverse cardiovascular events over 3.3 years among adults with obesity and established cardiovascular disease
• Metabolic benefits (blood pressure, lipid, glucose) are maintained with continued therapy
• Known longer-term concerns include lean-mass loss, gallstones during rapid weight loss, ongoing GI tolerability, and rare ophthalmic and oncologic events under active surveillance
• Multi-decade safety is not yet fully characterized; semaglutide entered widespread U.S. use only in 2017-2018

Direct answer

The most clearly established long-term effects of Wegovy are sustained weight loss (about 15-17% over 2 years), reduced cardiovascular events (20% relative reduction in MACE over 3.3 years in eligible patients), and maintained improvements in blood pressure, lipid profile, and glycemic markers. Known longer-term side effects include lean-mass loss as part of weight reduction, gallstones during rapid weight loss, ongoing GI tolerability issues in a subset of patients, and rare ophthalmic and oncologic concerns under active surveillance. The very long horizon (10+ years) is still being characterized because the drug has been in widespread use for less than a decade.

Table of contents

1. What "long-term" actually means for Wegovy data
2. STEP 5: the 2-year weight outcomes
3. SELECT: the 3.3-year cardiovascular outcomes
4. Other long-term metabolic effects
5. Long-term side effects and tolerability
6. Body composition over time
7. What we do not yet know
8. Decision framework for long-term Wegovy use
9. The contrary view: limits of current long-term data
10. FAQ
11. Sources

What "long-term" actually means for Wegovy data

The phrase "long-term" is squishy. For Wegovy specifically, the best available data span 2-4 years in randomized trial follow-up. STEP 5 reaches 104 weeks. SELECT reaches a mean of about 39.8 months. STEP 4 covers maintenance over 68 weeks following 20 weeks of lead-in. Real-world cohorts with several more years of exposure are now being analyzed.

This is short by the standards of chronic disease epidemiology, where decade-long horizons are sometimes available. It is reasonable for a medication that received FDA obesity approval in June 2021. The horizon will grow as cohorts mature.

For purposes of clinical decision-making, the 2-4 year evidence is what is currently available. Cardiovascular outcome benefit, sustained weight loss, and metabolic improvements are well established within that window. Multi-decade questions (cancer risk profile, bone density, muscle aging, long-tail rare events) remain under study.

STEP 5: the 2-year weight outcomes

STEP 5 (Garvey et al., Nature Medicine 2022) was a randomized placebo-controlled trial of semaglutide 2.4 mg in adults with overweight or obesity. The trial followed 304 patients for 104 weeks. The primary outcome was percent change in body weight at week 104.

Results:

• Mean weight change in the semaglutide group: -15.2%
• Mean weight change in the placebo group: -2.6%
• Treatment difference: -12.6 percentage points
• Patients achieving 5% or greater weight loss: 77.1% on semaglutide vs 34.4% on placebo
• Patients achieving 10% or greater weight loss: 61.8% vs 13.3%
• Patients achieving 15% or greater weight loss: 52.0% vs 4.9%

STEP 5 is the principal evidence base for sustained weight loss on Wegovy. The trial showed that the weight loss achieved in the first year is largely maintained through year 2 with continued therapy. Weight typically plateaus around month 12-18 and stays at the new lower set point.

STEP 5 also captured metabolic markers. Mean systolic blood pressure decreased by 5.7 mmHg, HbA1c by 0.3 percentage points, and triglycerides by 22% at 104 weeks. These secondary outcomes track the weight loss in clinical importance.

SELECT: the 3.3-year cardiovascular outcomes

The SELECT trial (Lincoff et al., NEJM 2023) is the cardiovascular outcome trial that anchors Wegovy's long-term picture. It enrolled 17,604 adults aged 45 or older with BMI of 27 or higher and established cardiovascular disease, without diabetes. Patients were randomized to semaglutide 2.4 mg weekly or placebo.

Mean follow-up was 39.8 months (about 3.3 years).

Primary outcome (composite of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke):

• Semaglutide: 6.5% experienced the primary endpoint
• Placebo: 8.0%
• Hazard ratio: 0.80 (95% CI 0.72-0.90)
• Relative risk reduction: 20%
• Absolute risk reduction: 1.5 percentage points
• Number needed to treat for 3.3 years: about 67

Secondary outcomes also favored semaglutide, including reduced cardiovascular death and reduced heart failure events. Adverse events of interest included GI tolerability issues (more discontinuation in the semaglutide arm due to GI side effects) and gallbladder events (more cholelithiasis in the semaglutide arm).

SELECT shifted Wegovy's clinical positioning. The drug is no longer purely a weight-loss tool; it is also a cardiovascular risk-reduction therapy in eligible patients. The FDA approved a cardiovascular risk reduction indication for Wegovy in 2024 based on SELECT.

Other long-term metabolic effects

Wegovy's metabolic effects extend beyond weight and cardiovascular events. Sustained therapy is associated with:

• Reductions in systolic and diastolic blood pressure (typically 4-7 mmHg systolic)
• Reductions in triglycerides and improvements in HDL cholesterol
• Improvements in HbA1c, including in patients without diabetes
• Reductions in markers of inflammation including C-reactive protein
• Improvements in liver enzymes and reductions in hepatic steatosis (relevant to NAFLD/MASLD)
• Improvements in sleep apnea severity in some patients

These effects are largely consequences of weight loss combined with direct medication effects. They persist as long as the medication and the weight loss continue. They reverse if the medication is stopped and weight returns.

Long-term side effects and tolerability

The most common long-term side effects in trial and post-marketing data:

• Persistent or recurring nausea and constipation in a subset of patients, though typically milder after the first months
• Gallstones, especially during periods of rapid weight loss
• Occasional acute pancreatitis
• Possible association with NAION (still under investigation; see separate FormBlends article)
• Hair shedding during rapid weight loss, which typically resolves
• Lean-mass loss (about 25-40% of total weight loss is lean mass)
• Cosmetic facial volume loss (the "Ozempic face" phenomenon)

The boxed warning about thyroid C-cell tumors remains in effect; long-term human data have not shown a measurable increase in thyroid cancer at population scale but surveillance continues.

Body composition over time

Weight loss on Wegovy includes both fat and lean mass. The proportion has been studied with body composition imaging in several substudies. Roughly 25-40% of total weight loss is lean mass, depending on the specific study and population.

This is similar to or slightly worse than the lean-mass proportion observed with caloric restriction alone. Resistance training and adequate protein intake during weight loss reduce the lean-mass fraction in both medication-driven and diet-driven weight loss.

Clinical implications:

• Older adults are more vulnerable to functionally meaningful muscle loss
• Resistance training during therapy is recommended and is more important than aerobic exercise for preserving lean mass
• Adequate protein intake (typically 1.0-1.6 g/kg of target body weight) helps
• Patients with sarcopenia or pre-sarcopenia warrant closer monitoring

The clinical significance of lean-mass loss over multi-year horizons is being studied. Whether the lower muscle mass associated with sustained weight loss matters more than the cardiometabolic benefit depends on the patient and the duration of therapy.

What we do not yet know

Several long-horizon questions remain open:

• Cancer risk profile over 10-20 years of continuous exposure
• Bone density and fracture risk with multi-year therapy
• Muscle aging in older adults on long-term therapy
• Cognitive effects of sustained therapy (data so far suggest neutral to favorable, but the question is open)
• Long-term ophthalmic safety, especially regarding the emerging NAION signal
• Fertility and pregnancy outcomes for patients conceiving after long use (medication is contraindicated during pregnancy)
• What happens to weight, metabolism, and cardiovascular risk after eventual discontinuation in patients who have been on the drug for many years

These are being studied actively. Cohorts now reaching 5+ years of follow-up will provide answers over the next several years.

Decision framework for long-term Wegovy use

Patients most likely to benefit from sustained therapy:

• Obesity with established cardiovascular disease (SELECT population)
• Obesity with significant cardiometabolic risk factors
• Obesity with sleep apnea, fatty liver disease, or osteoarthritis
• Type 2 diabetes for those on Ozempic equivalent

Considerations during long-term therapy:

• Resistance training and adequate protein intake to preserve lean mass
• Routine eye care and adherence to the monitoring framework appropriate to your risk profile
• Awareness of thyroid symptoms; maintenance of MTC/MEN-2 contraindications
• Annual review of risk-benefit with your prescriber

Reasons to reassess or discontinue:

• Persistent severe side effects that do not respond to dose adjustment
• Development of contraindication (e.g., new thyroid cancer history)
• Pregnancy planning or pregnancy
• Patient preference based on values and priorities

The contrary view: limits of current long-term data

Two arguments for treating "long-term Wegovy effects" with more caution than current data alone suggest.

The horizon is still short. The longest randomized trial follow-up for semaglutide 2.4 mg is SELECT at 3.3 years. Real-world cohorts are now reaching 5-6 years. Decade-plus continuous exposure data do not yet exist for any meaningful population. Some safety questions (cancer latency, bone density over decades) require longer observation.

Patient population variability. Trial populations differ from real-world populations. SELECT enrolled patients with established cardiovascular disease; STEP 5 enrolled relatively healthy adults with obesity. Patients who fall outside the studied populations (e.g., very high BMI, advanced age, multiple comorbidities, ongoing alcohol use, eating disorders) may have different long-term experiences than the trial reports.

These limitations argue for ongoing post-marketing surveillance and individualized risk-benefit assessment, not for avoiding therapy. The current evidence supports use in eligible patients with the understanding that the picture will continue to refine over the coming decade.

FAQ

What are the long-term effects of Wegovy?

Sustained weight loss (~15% at 2 years), 20% MACE reduction over 3.3 years (SELECT), maintained metabolic improvements, and ongoing GI tolerability and rare adverse-event concerns under surveillance.

How much weight do patients lose long-term on Wegovy?

Mean about 15.2% at 2 years (STEP 5), maintained at similar levels through SELECT's 3.3-year follow-up.

Does Wegovy reduce heart attack and stroke?

Yes, in eligible patients. SELECT reported a 20% relative reduction in the composite of cardiovascular death, nonfatal MI, or nonfatal stroke.

What are the known long-term side effects of Wegovy?

GI tolerability issues, gallstones during rapid loss, lean-mass loss, hair shedding, cosmetic volume changes, and rare ophthalmic and oncologic concerns under study.

What is the SELECT trial?

A randomized trial of semaglutide 2.4 mg in 17,604 adults with obesity and cardiovascular disease, reporting MACE reduction over 3.3 years.

What is the STEP 5 trial?

A 2-year randomized placebo-controlled trial showing sustained ~15% weight loss on semaglutide 2.4 mg.

How long can you stay on Wegovy?

FDA labeling does not specify a maximum duration; chronic therapy is the standard approach.

Does Wegovy work after several years?

Yes, in studied populations. Effectiveness over horizons beyond 5 years is being studied as cohorts mature.

What are the unknowns about long-term Wegovy use?

Multi-decade cancer risk, very long-latency NAION risk, bone density changes, muscle aging, and what happens after eventual discontinuation in long-term users.

How does Wegovy compare to Ozempic for long-term effects?

Wegovy is semaglutide 2.4 mg; Ozempic is semaglutide at lower doses for diabetes. Long-term molecule-level effects are the same; population-level outcomes differ because the indications are different.

Is there a tipping point where Wegovy stops working?

Weight typically plateaus around month 12-18 and stays at the new lower set point. Effectiveness does not generally diminish further with continued therapy, but real-world experience varies.

Related guides

• Long-Term Effects of Ozempic: SUSTAIN-6, Real-World Diabetes Outcomes, and the Open Questions
• Is Ozempic Safe Long-Term? The Honest Answer From the Current Evidence Base
• How Long Does Wegovy Last in the Fridge? Pre-Use Shelf Life by Dose Step
• How Long Does It Take for Wegovy to Work? Mapping the STEP 1 Curve to Your Calendar
• What to Eat on Ozempic: The Long-Term Dietary Framework
• How Long Can Wegovy Be Out of the Fridge? The 28-Day Window

Sources

1. Wilding JPH et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). New England Journal of Medicine. 2021.
2. Garvey WT et al. Two-Year Effects of Semaglutide in Adults with Overweight or Obesity: The STEP 5 Trial. Nature Medicine. 2022.
3. Rubino D et al. Effect of Continued Weekly Subcutaneous Semaglutide on Weight Loss Maintenance (STEP 4). JAMA. 2021.
4. Lincoff AM et al. Semaglutide and Cardiovascular Outcomes in Obesity Without Diabetes (SELECT). New England Journal of Medicine. 2023.
5. Marso SP et al. Semaglutide and Cardiovascular Outcomes in Patients with Type 2 Diabetes (SUSTAIN-6). New England Journal of Medicine. 2016.
6. Davies M et al. Semaglutide 2.4 mg Once a Week in Adults with Overweight or Obesity and Type 2 Diabetes (STEP 2). The Lancet. 2021.
7. Wadden TA et al. STEP 3: Effect of Semaglutide 2.4 mg with Intensive Behavioral Therapy. JAMA. 2021.
8. Newsome PN et al. Semaglutide in Nonalcoholic Steatohepatitis. New England Journal of Medicine. 2021.
9. FDA. Wegovy Prescribing Information. 2024 update.
10. Wang Y et al. Glucagon-Like Peptide-1 Receptor Agonist Use and Risk of Thyroid Cancer. JAMA. 2024.
11. Hathaway JT et al. Risk of Nonarteritic Anterior Ischemic Optic Neuropathy in Patients Prescribed Semaglutide. JAMA Ophthalmology. 2024.
12. American Diabetes Association. Standards of Care in Diabetes 2025.

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Platform Disclaimer. FormBlends is a telehealth platform connecting patients with independent licensed clinicians and U.S. pharmacies. We do not provide direct medical care. Long-term therapy decisions belong to you and your provider.

Compounded Medication Notice. Compounded semaglutide is not FDA-approved. It is prepared by state-licensed 503A pharmacies in response to individual prescriptions. Compounded preparations are not interchangeable with branded Wegovy or Ozempic.

Results Disclaimer. Trial outcomes reported here reflect averages in defined populations. Individual response varies. Long-term outcomes in real-world cohorts may differ from trial averages.

Trademark Notice. Wegovy and Ozempic are registered trademarks of Novo Nordisk A/S. Mounjaro and Zepbound are registered trademarks of Eli Lilly and Company. FormBlends is not affiliated with, endorsed by, or sponsored by Novo Nordisk, Eli Lilly, the FDA, or any other entity referenced in this article.