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Clinical Data

Real Results. Real Data.

Evidence-based weight loss outcomes from clinical trials and real-world studies. Every number on this page comes from published, peer-reviewed research.

Last reviewed: April 2026

14.9%

Semaglutide 68 weeks

STEP 1

22.5%

Tirzepatide 72 weeks

SURMOUNT-1

24.2%

Retatrutide 48 weeks

Phase 2

Weight Loss Trajectories

How GLP-1 Medications Compare Over Time

Mean body weight change from baseline across three landmark clinical trials. Toggle each compound to compare trajectories.

Week 12: Early response visibleWeek 24: Half-way milestoneWeek 48: Near maximum effectWeek 68: STEP 1 endpoint

Sources: STEP 1 (Wilding et al., NEJM 2021, n=1,961, DOI: 10.1056/NEJMoa2032183); SURMOUNT-1 (Jastreboff et al., NEJM 2022, n=2,539, DOI: 10.1056/NEJMoa2206038); Retatrutide Phase 2 (Jastreboff et al., NEJM 2023, n=338, DOI: 10.1056/NEJMoa2301972). Data points are approximate representations of published mean trajectories.

Dose Response

Semaglutide Outcomes by Dose Tier

Weight loss increases with each dose escalation. The standard titration protocol gradually increases from 0.25mg to the target maintenance dose.

Source: STEP trial program (semaglutide 2.4mg). Dose-response data derived from STEP 1 titration schedule and published sub-analyses. Approximate values shown for illustration.

Semaglutide deep dive|Tirzepatide deep dive|Weight loss timeline calculator
Side Effect Reality Check

What Actually Happens (and When It Gets Better)

GI side effects are real but transient. Most patients see significant improvement within the first 4-8 weeks as the body adapts.

Semaglutide vs. Tirzepatide

Side Effects Decrease Over Time

Sources: STEP 1 (Wilding et al., NEJM 2021) and SURMOUNT-1 (Jastreboff et al., NEJM 2022) adverse event reporting. Time-course data is approximate based on published safety analyses. Fewer than 5% of participants discontinued due to GI side effects in either trial.

FormBlends approach: Our gradual titration protocol and physician monitoring are specifically designed to minimize side effects. Most patients experience mild, transient GI symptoms that resolve within weeks. Read the full side effects guide

The Retention Problem

Why Long-Term Planning Matters

GLP-1 medications work. But adherence is the real challenge. Understanding this is the first step to beating the odds.

1 in 12

patients remain on GLP-1 treatment at 3 years

64.8%

of patients without diabetes discontinue within 1 year

46.5%

of patients with diabetes discontinue within 1 year

~0.8 kg/mo

average weight regain after stopping medication

Estimated Weight Regain After Stopping

Sources: Gal et al., Obesity 2024 (persistence study); STEP 1 extension trial (Wilding et al., Diabetes Obes Metab 2022). Regain rate is approximate mean from published extension data.

The FormBlends Weight Regain Prevention Program

A structured 4-phase program designed to help you maintain results whether you continue, reduce, or stop GLP-1 therapy.

Learn About the Program
What Affects Results

Factors That Influence Your Outcomes

Clinical trials show averages. Individual results depend on several modifiable and non-modifiable factors.

Starting BMI

Higher starting BMI is associated with greater absolute weight loss. The percentage lost remains relatively consistent across BMI ranges.

High impact

Dose Adherence

Consistent dosing is strongly correlated with outcomes. Missing doses or inconsistent timing reduces efficacy significantly.

High impact

Diet & Exercise

Patients who combine medication with structured nutrition and resistance training lose more weight and preserve more muscle mass.

High impact

Treatment Duration

Most weight loss occurs in the first 40-52 weeks. Continued treatment is needed to maintain results long-term.

Medium impact

Metabolic Health

Patients with insulin resistance, PCOS, or metabolic syndrome may respond differently. Co-existing conditions affect trajectory.

Medium impact

Previous Attempts

History of yo-yo dieting and metabolic adaptation can affect response rate, though GLP-1 medications work via different pathways than caloric restriction alone.

Low-medium impact
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Community Outcomes Dashboard

FormBlends is building a mobile app with integrated dose tracking, weight logging, and health monitoring. When we collect enough anonymized data from real patients, aggregated community outcomes will appear right here.

What the App Will Track

Daily weight logging
Dose timing & adherence
Side effect tracking
Progress photos (private)
Meal logging with AI analysis
Exercise & activity data
Lab result integration
Mood & energy scoring
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Questions & Answers

Frequently Asked Questions

How much weight can I expect to lose on semaglutide?
In the STEP 1 clinical trial (n=1,961), participants on semaglutide 2.4mg lost an average of 14.9% of their body weight over 68 weeks, compared to 2.4% in the placebo group. Individual results vary based on starting BMI, dose adherence, diet, exercise, and other factors. Your physician will help set realistic expectations based on your specific situation.
How does tirzepatide compare to semaglutide for weight loss?
In the SURMOUNT-1 trial (n=2,539), tirzepatide at the highest dose (15mg) produced 22.5% mean body weight reduction over 72 weeks, compared to 14.9% for semaglutide 2.4mg over 68 weeks in STEP 1. Tirzepatide is a dual GIP/GLP-1 receptor agonist, which may explain the enhanced efficacy. However, direct head-to-head comparisons should be interpreted cautiously as trial populations and designs differ.
What happens if I stop taking GLP-1 medication?
Research shows that weight regain is common after discontinuing GLP-1 therapy. Studies indicate an average regain of approximately 0.8 kg per month after stopping, and only about 1 in 12 patients remain on treatment at 3 years. This underscores that obesity is a chronic condition. FormBlends offers a Weight Regain Prevention Program to help patients who transition off medication maintain their results.
Are these results from real patients or clinical trials?
All data currently displayed on this page comes from published, peer-reviewed clinical trials including STEP 1 (NEJM, 2021), SURMOUNT-1 (NEJM, 2022), and the retatrutide Phase 2 trial (NEJM, 2023). We are building a mobile app to collect anonymized, real-world outcomes from FormBlends patients, which will be displayed here once sufficient data is available.
What are the most common side effects of GLP-1 medications?
The most common side effects are gastrointestinal: nausea (40-45%), diarrhea (25-30%), vomiting (20-25%), and constipation (20-25%). These are typically mild to moderate, occur most frequently during dose escalation, and tend to decrease significantly after the first 4-8 weeks of treatment. Fewer than 5% of clinical trial participants discontinued due to side effects.
Does starting BMI affect how much weight I will lose?
Yes. Clinical trial data consistently shows that patients with higher starting BMIs tend to lose a greater absolute amount of weight, though the percentage of body weight lost is relatively consistent across BMI categories. Patients with BMI 35+ tend to see the most dramatic absolute results. Your physician will discuss expected outcomes based on your individual health profile.

Related resources

Weight regain prevention guide

Evidence-based strategies to maintain your results long-term.

Progress tracker

Log your weight, measurements, and milestones over time.

Drug pipeline tracker

Next-gen GLP-1 compounds in clinical development.

Semaglutide deep dive

Mechanism, dosing, side effects, and clinical trial data.

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Medical Disclaimer: All data on this page is sourced from published, peer-reviewed clinical trials and is presented for educational purposes only. Individual results will vary based on starting weight, medical history, dose adherence, lifestyle factors, and other variables. The outcomes shown represent mean results from controlled trial populations and should not be interpreted as guaranteed results for any individual. GLP-1 medications require a prescription and physician supervision. FormBlends does not make claims about specific individual outcomes. Always consult your physician before starting or modifying any medication regimen. This page does not constitute medical advice.

Data Sources: STEP 1 (Wilding et al., NEJM 2021); SURMOUNT-1 (Jastreboff et al., NEJM 2022); Retatrutide Phase 2 (Jastreboff et al., NEJM 2023); STEP 1 extension (Wilding et al., Diabetes Obes Metab 2022); GLP-1 persistence studies (Gal et al., Obesity 2024). All DOIs available upon request.

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