Zepbound vs Saxenda (tirzepatide vs liraglutide)

Which is better, tirzepatide or liraglutide?

Tirzepatide wins on efficacy by a margin that cross-trial uncertainty cannot erase: roughly 21% versus 8% weight loss in placebo-controlled trials, and superiority to semaglutide 1 mg on HbA1c in SURPASS-2, a drug that itself beat liraglutide directly. Liraglutide is the better pick when cost dominates (generic pens are on the market, tirzepatide has no generic) or when a prescriber wants a daily drug with a decades-long safety record and diabetes cardiovascular outcomes data. [1] [2] [3] [5] [10]

How do tirzepatide and liraglutide compare?

Tirzepatide and Liraglutide compared by dimension
Dimension	TirzepatideFavored	Liraglutide
Mechanism [7] [8]	Dual GIP and GLP-1 receptor agonist, half life about 5 days.	Selective GLP-1 receptor agonist, half life about 13 hours.
Placebo-controlled weight loss [1] [2] [3] [6]	15.0%, 19.5%, and 20.9% at 5, 10, and 15 mg vs 3.1% placebo at 72 weeks in SURMOUNT-1 (2,539 adults); 91% of the 15 mg group lost at least 5%.	8.4 kg vs 2.8 kg placebo at 56 weeks in SCALE Obesity and Prediabetes (3,731 adults); 63% vs 27% lost at least 5%.
Note: No direct trial. Liraglutide lost to semaglutide 2.4 mg in STEP 8, and semaglutide 1 mg lost to tirzepatide in SURPASS-2.
Type 2 diabetes [2] [4] [9]	SURPASS-2: HbA1c down 2.01 to 2.30 points vs 1.86 with semaglutide 1 mg at 40 weeks; approved as Mounjaro.	Victoza approved since 2010; SCALE Diabetes showed 6.0% weight loss at 3.0 mg vs 2.0% placebo in type 2 diabetes.
Cardiovascular outcomes [5] [7] [9]	No published placebo-controlled cardiovascular outcomes trial in obesity at the verification date; the Zepbound label carries no cardiovascular risk reduction indication.	LEADER: hazard ratio 0.87 for major adverse cardiovascular events and 0.78 for cardiovascular death in 9,340 adults with type 2 diabetes; Victoza carries a cardiovascular indication.
FDA labeled indications [7] [8] [9]	Zepbound: chronic weight management and moderate to severe obstructive sleep apnea in adults with obesity. Mounjaro: type 2 diabetes.	Saxenda: chronic weight management (adults and adolescents 12 and older). Victoza: type 2 diabetes (adults and children 10 and older) and cardiovascular risk reduction.
Route and dosing frequency [7] [8]	Subcutaneous injection once weekly; 2.5 mg start, 2.5 mg steps every 4 weeks to 5, 10, or 15 mg.	Subcutaneous injection once daily; 0.6 mg start, increased weekly by 0.6 mg to 3.0 mg (Saxenda).
Common side effects [1] [3] [7] [8]	Nausea up to 31%, diarrhea up to 23%, vomiting up to 12%, constipation up to 12% at 15 mg in SURMOUNT-1; label advises a barrier contraceptive for 4 weeks after starting and after each dose increase.	Nausea, diarrhea, constipation, vomiting; heart rate up 2 to 3 beats per minute; serious adverse events 6.2% vs 5.0% placebo in SCALE.
Note: Both carry the thyroid C-cell boxed warning and the same medullary thyroid carcinoma and MEN 2 contraindications.
Regulatory and compounding status [8] [10] [11] [12] [13] [14]	FDA approved (Mounjaro 2022, Zepbound 2023). Shortage-based compounding ended in early 2025; no generic.	FDA approved (Victoza 2010, Saxenda 2014). Generic liraglutide approved from December 2024. FDA listed liraglutide injection as in shortage in its October 2024 and February 2025 GLP-1 updates, and FDA's Drug Shortages database still lists it as of September 2026, with Victoza and Saxenda at limited availability. Brand and generic liraglutide are marketed, and on April 30, 2026 FDA proposed not to include liraglutide on the 503B bulks list; that proposal was not final as of September 2026. Ask any pharmacy offering compounded liraglutide which FDA rule it relies on.
Typical cost [7] [8] [10]	Zepbound list price about 1,059 USD per month; manufacturer single-dose vials roughly 349 to 499 USD; about 25 USD with commercial coverage and a savings card.	Saxenda list price about 1,349 USD per month, but generic liraglutide at the diabetes strength runs roughly 200 to 500 USD cash; often 25 to 100 USD with commercial coverage.

Evidence grade and regulatory status

Pulled from each peptide’s own record, so it stays in step with the peptide pages.

Tirzepatide and Liraglutide: grade, status, and cost
Attribute	Tirzepatide	Liraglutide
Class	Dual GIP and GLP-1 receptor agonist (39 amino acid peptide, acylated for once weekly dosing)	GLP-1 receptor agonist (acylated analog of human GLP-1, 97% sequence homology, once daily dosing)
What it is	FDA approved weekly GIP and GLP-1 drug with 20.9% average weight loss at 15 mg in a 72 week randomized trial; beat semaglutide head to head.	First daily GLP-1 drug: FDA approved since 2010, about 8% weight loss at 3 mg over 56 weeks, proven heart benefit, now available as a generic.
Evidence	Evidence: Human RCT evidence	Evidence: Human RCT evidence
FDA status	Regulatory: FDA approved	Regulatory: FDA approved
Compounding	FDA approved products (Mounjaro May 2022, Zepbound November 2023). FDA declared the tirzepatide shortage resolved on December 19, 2024; compounding by 503A pharmacies had to stop by February 18, 2025 and by 503B outsourcing facilities by March 19, 2025, except for a documented patient specific clinical need. FDA has warned about unapproved compounded and counterfeit tirzepatide products. On April 30, 2026 FDA proposed not to include tirzepatide on the 503B bulks list; that proposal was not final as of September 2026. Adding a vitamin such as B12 or niacinamide does not by itself make a compounded GLP-1 different from the approved drug. Under FDA's April 1, 2026 policy update, such a combination may be treated as essentially a copy when the strengths are within 10% of approved products and the route is the same, unless a prescriber documents a real difference for the individual patient. A September 2026 FDA warning letter applied this to semaglutide and tirzepatide vitamin combinations, said high production volume suggested the claimed differences were a pretext, and questioned significant-difference statements picked from preset menus on prescribing platforms.	FDA approved products (Victoza January 2010, Saxenda December 2014). FDA approved the first generic liraglutide referencing Victoza in December 2024, and generic products referencing Saxenda followed in 2025, so branded, generic, and authorized generic pens are all on the market. FDA listed liraglutide injection as in shortage in its October 2024 and February 2025 GLP-1 updates, and FDA's Drug Shortages database still lists it as of September 27, 2026 (first posted July 18, 2023; updated September 22, 2026), with Victoza and Saxenda presentations at limited availability and unbranded presentations available. FDA states that a compounded drug may not be identical or nearly identical to an FDA-approved drug unless the approved drug is on FDA's drug shortage list. On April 30, 2026 FDA proposed not to include liraglutide on the 503B bulks list; that proposal was not final as of September 2026. Ask any pharmacy offering compounded liraglutide which FDA rule it relies on.
WADA	WADA: Not WADA prohibited	WADA: Not WADA prohibited
Routes	Subcutaneous injection once weekly (pen or single dose vial)	Subcutaneous injection once daily (prefilled pen)
Typical cost	Manufacturer list price is up to 1,086.37 USD per fill for Zepbound and 1,112.16 USD for Mounjaro (checked 2026-09-22). Manufacturer self-pay Zepbound vials and KwikPen cost 299 USD per month at 2.5 mg, 399 at 5 mg, 499 at 7.5 mg, and 699 at 10 mg and above, with a 449 USD on-time refill offer for the 7.5 mg and higher KwikPen through 2026. With commercial insurance a savings card can bring a covered prescription to 25 USD, and eligible Medicare Part D enrollees pay 50 USD per month for the Zepbound KwikPen under the Medicare GLP-1 Bridge (July 2026 to December 2027). A study published in 2025 found compounded tirzepatide advertised at a median 330 USD for the first month during the shortage; compounding is now limited to patient specific needs.	Manufacturer list price is 1,349.02 USD per month for Saxenda and 543.51 to 815.27 USD per month for Victoza depending on the daily dose (checked 2026-09-22). Generic liraglutide pens cost from about 112 USD per month for the diabetes strength and about 372 USD for the 3 mg weight management generic with a discount card, against average retail prices of about 616 to 924 USD. With commercial insurance the Saxenda savings card can bring a covered prescription to 25 USD. Medicare Part D covers liraglutide for type 2 diabetes but generally not for weight loss alone, and the Medicare GLP-1 Bridge does not include it.
Last verified	Sep 27, 2026	Sep 27, 2026

Has tirzepatide been tested directly against liraglutide?

No published trial has compared tirzepatide and liraglutide directly. The dimensions above come from separate studies and labels, and cross-trial comparisons are less reliable than a direct trial.

What do tirzepatide and liraglutide cost?

Typical cost of Tirzepatide and Liraglutide
Dimension	Tirzepatide	Liraglutide
Typical cost	$275 to $1,112 per month	$112 to $1,349 per month
Price detail	Tirzepatide price by channel	Liraglutide price by channel

Where a price index exists, the range is the cash price per month across branded, compounded, and telehealth channels, without insurance. The cost pages give each channel separately with its sources. Otherwise the typical cost from the peptide record is shown. Legal access depends on your state: see peptide legality by state.

Frequently asked questions

How much more weight loss does tirzepatide give than liraglutide?

Roughly two and a half times as much in their own trials: 20.9% at 15 mg over 72 weeks in SURMOUNT-1 versus about 8% at 3.0 mg over 56 weeks in SCALE. No trial has compared them directly, but the indirect chain (liraglutide lost to semaglutide in STEP 8, semaglutide 1 mg lost to tirzepatide in SURPASS-2) points the same way. [1] [2] [3] [6]

Why would anyone choose liraglutide over tirzepatide?

Price and track record. Generic liraglutide pens have been approved since December 2024 and can cost a few hundred dollars a month cash, while tirzepatide has no generic. Liraglutide also has 15 years of post-marketing experience and a completed cardiovascular outcomes trial in diabetes, and its daily dosing lets a prescriber stop it quickly if side effects appear. [5] [8] [10]

Are the side effects the same?

The same kind: gastrointestinal effects that peak during dose escalation, gallbladder and pancreatitis warnings, and the thyroid C-cell boxed warning. Tirzepatide's label adds a specific warning that oral contraceptives may be less effective for 4 weeks after starting or increasing the dose. [1] [3] [7] [8]

Which is better for the heart?

Liraglutide has the completed evidence: LEADER showed a 13% relative reduction in major adverse cardiovascular events in type 2 diabetes. Tirzepatide's Zepbound label carries no cardiovascular risk reduction indication at the verification date. [5] [7]

Can either be compounded?

Tirzepatide, not routinely: FDA ended the shortage-based allowance for compounded tirzepatide in early 2025. Liraglutide is different: FDA listed liraglutide injection as in shortage in its October 2024 and February 2025 GLP-1 updates, and FDA's Drug Shortages database still lists it as of September 2026, with Victoza and Saxenda at limited availability. FDA states that a compounded drug may not be identical or nearly identical to an FDA-approved drug unless the approved drug is on FDA's drug shortage list. Brand and generic liraglutide are also marketed, and on April 30, 2026 FDA proposed not to include liraglutide on the 503B bulks list. Ask any pharmacy offering compounded liraglutide which FDA rule it relies on. [10] [11] [12] [13] [14]

Conditions studied

From the blog

Peptides for weight loss, ranked by human evidence
Tirzepatide, semaglutide, and liraglutide lead on human trials. Retatrutide is trial-only, and AOD-9604 and 5-amino-1MQ are animal-only. Ranking, legal status, and dated prices.

Sources

Numbered citations above point to these primary sources. PubMed entries link to the indexed abstract.

Cite this page

Free to cite and quote with a link. Data is licensed CC BY 4.0 with attribution to PeptideAgent.

APA style: PeptideAgent. (2026, September 27). Tirzepatide vs liraglutide: evidence, cost, and legality. https://peptideagent.ai/compare/tirzepatide-vs-liraglutide
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