Peptide Comparison
LiraglutidevsSemaglutide
FDA-approved once-daily GLP-1 receptor agonist (Victoza/Saxenda) that reduces HbA1c by 0.9–1.6%, promotes 5–10% body weight loss, and demonstrated a 13% reduction in major adverse cardiovascular events in the landmark LEADER trial of 9,340 patients
The revolutionary once-weekly GLP-1 medication that helps your body feel full faster and longer, leading to significant weight loss while also protecting your heart—FDA approved and backed by some of the largest clinical trials in obesity medicine history.
At a Glance
Quick
comparison
Dose Range
Liraglutide
0.6–3.0 mg
Semaglutide
0.25–2.4 mg
Frequency
Liraglutide
Once daily
Semaglutide
Once weekly
Administration
Liraglutide
Subcutaneous injection
Semaglutide
Subcutaneous injection
Cycle Length
Liraglutide
Ongoing/indefinite
Semaglutide
Ongoing/indefinite
Onset Speed
Liraglutide
Gradual (3-4 weeks)
Semaglutide
Moderate (1-2 weeks)
Evidence Level
Liraglutide
Strong human trials (Phase 3 or FDA approved)
Semaglutide
Strong human trials (Phase 3 or FDA approved)
Efficacy
Benefit
ratings
Weight Management
Metabolic
Healing & Recovery
Weight Loss
Appetite Control
Heart Protection
Technical Data
Compound
specifications
Liraglutide
Molecular Formula
C172H265N43O51
Molecular Weight
3,751 Da
Half-Life
~13 hours (enabling once-daily dosing); Tmax 8–12 hours; steady state in 3–5 days
Bioavailability
~55% after subcutaneous injection; >98% plasma protein binding to albumin via C16 fatty acid moiety
CAS Number
204656-20-2
Semaglutide
Molecular Formula
C187H291N45O59
Molecular Weight
4113.58 g/mol
Half-Life
Approximately 7 days (168 hours)
Bioavailability
89% (subcutaneous); 0.4-1% (oral, with absorption enhancer)
CAS Number
910463-68-2
Protocols
Dosing
tiers
Liraglutide
Semaglutide
Applications
Best
suited for
Liraglutide
Type 2 diabetes patients with HbA1c >7% requiring both glycemic control and weight management
Liraglutide is particularly well-suited for individuals focused on type 2 diabetes patients with hba1c >7% requiring both glycemic control and weight management. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Obese individuals (BMI ≥30) or overweight (BMI ≥27) with weight-related comorbidities seeking FDA-approved pharmacotherapy
Liraglutide is particularly well-suited for individuals focused on obese individuals (bmi ≥30) or overweight (bmi ≥27) with weight-related comorbidities seeking fda-approved pharmacotherapy. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Patients with established cardiovascular disease or high cardiovascular risk seeking cardioprotective diabetes therapy
Liraglutide is particularly well-suited for individuals focused on patients with established cardiovascular disease or high cardiovascular risk seeking cardioprotective diabetes therapy. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Patients on metformin requiring add-on therapy with favorable weight and cardiovascular profile
Liraglutide is particularly well-suited for individuals focused on patients on metformin requiring add-on therapy with favorable weight and cardiovascular profile. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Semaglutide
People with Obesity Seeking Significant Weight Loss
If your BMI is 30 or higher (or 27+ with weight-related health conditions), semaglutide is currently one of the most effective non-surgical weight loss options available. Clinical trials show average weight loss of 15% of body weight—that's 30+ pounds for someone starting at 200 pounds.
Those Who've Struggled with Diet and Exercise Alone
Semaglutide works by changing the biological signals that drive hunger and cravings. If you've tried to lose weight through willpower alone and found yourself constantly battling hunger, this medication addresses that underlying biology rather than just telling you to eat less.
People with Type 2 Diabetes Needing Better Control
Originally developed for diabetes, semaglutide excellently controls blood sugar while also promoting weight loss—addressing two major health concerns simultaneously. It can often allow people to reduce or eliminate other diabetes medications.
Individuals at High Cardiovascular Risk
The SELECT trial proved that semaglutide reduces heart attacks, strokes, and cardiovascular death by 20% in people with obesity and existing heart disease—even without diabetes. It's one of the few weight loss medications proven to improve hard cardiovascular outcomes.
Safety Profile
Side
effects
Liraglutide
Common
- Nausea
- Diarrhea
- Vomiting
- Decreased appetite and headache
Uncommon
- Injection site reactions
Serious
- Acute pancreatitis
- Gallbladder disease
Semaglutide
Common
- Nausea
- Constipation or Diarrhea
- Decreased Appetite
- Vomiting
Uncommon
- Gallbladder Problems
- Hair Loss (Telogen Effluvium)
Serious
- Pancreatitis
- Thyroid Tumors (Theoretical Risk)
Research Status
Safety
& evidence
Liraglutide
Evidence Level
Strong human trials (Phase 3 or FDA approved)
FDA Status
FDA approved for this use
Safety Overview
Liraglutide (Victoza, Saxenda) is FDA-approved with extensive safety data from 15+ years of clinical use in diabetes (GLP-1 agonist) and obesity indications. Gastrointestinal side effects (nausea, vomiting, diarrhea) occur in 30-40% of patients during dose escalation but diminish significantly after 2-3 weeks of stable dosing. Black box warnings include risk of medullary thyroid carcinoma and pancreatitis, though absolute incidence remains rare. Injection site reactions are minimal. The compound shows no hepatotoxicity, nephrotoxicity, or major drug interactions at approved doses.
Contraindications
- xPersonal or family history of medullary thyroid carcinoma (MTC) — black box warning based on rodent thyroid C-cell tumor findings
- xMultiple Endocrine Neoplasia syndrome type 2 (MEN 2)
- xKnown hypersensitivity to liraglutide or any excipients
- xPregnancy (Saxenda indication) — contraindicated; effective contraception required
Semaglutide
Evidence Level
Strong human trials (Phase 3 or FDA approved)
FDA Status
FDA approved for this use
Safety Overview
Semaglutide has been studied in over 20,000 participants across multiple large clinical trials, making it one of the most thoroughly researched weight loss medications available. The FDA approved it after rigorous review of safety data. While GI side effects are common (especially early on), serious side effects are rare. The SELECT trial showed it actually reduces cardiovascular events, adding a safety benefit beyond just weight loss.
Contraindications
- xPersonal or family history of medullary thyroid carcinoma (MTC)
- xMultiple Endocrine Neoplasia syndrome type 2 (MEN2)
- xHistory of serious allergic reaction to semaglutide
- xCurrent or recent pancreatitis
- xPregnancy or planning to become pregnant
Decision Guide
Which is
right for you?
Choose Liraglutide if...
- Type 2 diabetes patients with HbA1c >7% requiring both glycemic control and weight management
- Obese individuals (BMI ≥30) or overweight (BMI ≥27) with weight-related comorbidities seeking FDA-approved pharmacotherapy
- Patients with established cardiovascular disease or high cardiovascular risk seeking cardioprotective diabetes therapy
- Patients on metformin requiring add-on therapy with favorable weight and cardiovascular profile
Choose Semaglutide if...
- Significant weight loss
- Long-term weight management
- Cardiovascular risk reduction
- Blood sugar control