Looking for an expert comparison of tirzepatide vs. liraglutide for weight loss?
Look no further, as this informative guide offers a comprehensive examination of the two innovative peptides and their features.
Tirzepatide and liraglutide are both medications used to treat type 2 diabetes and chronic weight management issues.
While the two share many similarities, they also exhibit unique characteristics and regulatory statutes. Tirzepatide is a novel dual-incretin mimetic recently approved as a diabetes medication, but it is still under investigation as a weight loss peptide.
Liraglutide is one of the first incretin mimetics approved for blood sugar management in type 2 diabetics, yet it is also approved for reducing cardiovascular risk in diabetics and managing weight issues in adolescents and adults.
This guide provides an overview of the similarities and differences between tirzepatide and liraglutide, aiding researchers in determining which peptide merits further investigation for their specific needs. We will also share our top place to buy both research-grade liraglutide and tirzepatide online at fair prices.
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What is Tirzepatide?
It acts on the receptors of two important hormones involved in postprandial blood sugar regulation: glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1).
By mimicking these hormones, tirzepatide stimulates insulin release, suppresses glucagon production, and improves glycemic control in type 2 diabetes (T2D).
Tirzepatide has a unique structure composed of 39 amino acids, incorporating modified sequences from GIP and the GLP-1 agonist exenatide. The result is a peptide with an affinity for both the GIP and GLP-1 receptors, with a preference for GIP .
The peptide is also conjugated to a C20 fatty di-acid moiety, extending its half-life to about five days. This allows tirzepatide to be dosed just once per week instead of daily (like liraglutide) [4, 5].
The United States Food and Drug Administration (FDA) has approved tirzepatide for treating T2D as a once-weekly subcutaneous injection. It is available by prescription under the brand name Mounjaro [1, 6].
Further, the peptide has shown promise in clinical trials for weight loss in overweight and obese individuals, both diabetics and nondiabetics. It is also an active target for its potential to reduce cardiovascular risk in diabetics.
What is Liraglutide?
As a GLP-1 RA, liraglutide mimics the action of the naturally occurring hormone GLP-1. Liraglutide shares a high similarity (97%) to the active form of GLP-1 and binds to GLP-1 receptors in various organs, including the pancreas, brain, stomach, and fat tissue. It is modified for extended half-life allowing for once-daily dosing.
By mimicking the action of GLP-1, liraglutide activates the corresponding receptors in various organs, leading to increased insulin secretion, decreased glucagon secretion, slowed gastric emptying, and reduced appetite [10, 11].
Liraglutide is available under brand names like Victoza and Saxenda. Victoza is prescribed as a T2D treatment and has also been shown to reduce cardiovascular risk in T2D.
Saxenda is a higher dose (3mg/daily) formulation of liraglutide specifically approved for chronic weight management in overweight and obese individuals, including adults and adolescents .
Beyond its approved indications, liraglutide is being investigated for its potential use in other conditions, including non-alcoholic fatty liver disease, polycystic ovary syndrome, and neurodegenerative diseases like Alzheimer's [12, 13, 14, 15].
Tirzepatide vs. Liraglutide | Comparing Benefits
Tirzepatide and liraglutide have similar effects and uses, such as improving glycemic control, inducing weight loss, and reducing cardiovascular mortality in diabetics.
However, tirzepatide is a novel peptide that, as of writing, is approved only for T2D, while liraglutide has gained FDA approval for a broader range of indications.
Despite this, early evidence suggests that tirzepatide may have the upper hand in effectiveness when compared to liraglutide. Continue reading to delve deeper into our expert comparison and explore these peptides’ specific advantages and characteristics.
Weight Loss | Which is More Effective?
Liraglutide is already FDA-approved as a weight loss medication, while tirzepatide is still in clinical trials. Nevertheless, studies reveal that the two peptides may have similar weight loss mechanisms and comparable effectiveness.
Both peptides work to reduce appetite and increase satiety by interacting with GLP-1 receptors expressed in the brain, specifically in regions that play a crucial role in regulating appetite, such as the hypothalamus .
In addition, tirzepatide activates the GIP receptors, which are also distributed in the hypothalamus. Preliminary studies suggest that increased activation of these receptors also significantly decreases hunger and increases satiety .
Thus far, there has not been a trial that has directly compared tirzepatide against liraglutide for weight loss. However, we can look at the weight loss reported in the clinical research on each peptide.
One recent meta-analysis examining the effects of liraglutide in overweight and obesity demonstrated significant weight loss in both T2D and non-diabetic patients .
It pooled data from a total of 14 trials that lasted from 20 to 56 weeks and involved the maximum daily dose of 3mg. Nondiabetics achieved an average weight loss of about 11lb, a waist circumference reduction of about 1.43in, and a decrease in BMI of -1.95kg/m². Diabetic patients showed slightly lower weight loss, with an average reduction of about 9lb, a waist circumference decrease of -1.22in, and a BMI reduction of -1.86kg/m² .
On the other hand, a 2022 meta-analysis on the weight loss potential of tirzepatide in T2D pooled data from 7293 patients and reported that the highest dose of 15mg/weekly resulted in a mean weight reduction of about 18lb. The analysis included nine studies with durations that varied from eight to 52 weeks. At the 10mg/weekly dose, tirzepatide also led to a weight loss of 16.16lb and 11.66lb at 5mg/weekly .
Tirzepatide is currently under study as a potential treatment of obesity in the SURMOUNT development program launched by Elly Lily.
The published results from SURMOUNT-1, which included over 2500 subjects (BMI>27kgm²) without T2D, demonstrated that over a span of 72 weeks, both the 10mg and 15mg tirzepatide groups achieved a weight loss of about 20% (19.5% and 20.9% respectively) .
Notably, the 10mg dose of tirzepatide showed impressive results in non-diabetic patients, as the weight loss was nearly identical to that of the higher dose. It is also worth mentioning that since the average weight of the participants in the study was around 230lb, this translates to an average weight loss of over 40lb .
Although both peptides can cause significant weight reduction, the dual agonism of tirzepatide may potentially explain its superior weight loss effectiveness compared to liraglutide.
Diabetes Management | Which Works Better?
Both tirzepatide and liraglutide are developed and approved as medications for improving glycemic control in type 2 diabetics.
Doses of up to 15mg/weekly tirzepatide were granted FDA approval following a comprehensive clinical development program called SURPASS and consisting of several phase-3 trials.
These trials compared tirzepatide to placebo, 1mg semaglutide, and long-acting insulin. The dual-incretin mimetic consistently demonstrated its superiority in lowering glycated hemoglobin (HbA1c) levels across all the studies.
Further, Karagiannis et al. (2022) performed a systematic review and meta-analysis of seven trials involving over 6,600 participants.
The authors reported that tirzepatide at doses of 5mg, 10mg, and 15mg exhibited dose-dependent reductions in HbA1c levels compared to placebo, with mean differences ranging from 1.62% to 2.06% .
On the other hand, liraglutide is approved for glycemic control at doses significantly below its maximum recommended daily dose of 3mg. It is injected at 1.2-1.8mg/daily for T2D management.
Nevertheless, liraglutide has demonstrated significant reductions in glycated hemoglobin (HbA1c) levels ranging from 0.9% to 2.2% within six months of treatment initiation, as evidenced by a systematic review encompassing 43 randomized trials.
The review also emphasized the well-tolerated nature of liraglutide therapy and its low risk of hypoglycemia, with the positive effects of treatment sustained for at least 12 months .
Overall, both tirzepatide and liraglutide effectively reduce HbA1c levels and are well-tolerated. Yet, tirzepatide appears to be superior for glycemic control in T2D patients.
It is important to note that liraglutide is also approved for reducing the risk of cardiovascular disease in T2D patients.
This approval was based on the LEADER trial, which demonstrated that liraglutide decreased the incidence of cardiovascular events in T2D patients, such as heart attack and stroke, by 13% compared to placebo. It also reduced the risk of all-cause mortality by 15% and showed a significant 40% reduction in fatal myocardial infarction .
On the other hand, tirzepatide is currently undergoing a phase-3 trial called SURPASS-CVOT to assess its potential cardiovascular benefits in T2D patients. The study aims to compare the cardioprotective effects of tirzepatide with another FDA-approved GLP-1 agonist called dulaglutide and is expected to be concluded by late 2024 .
Other Potential Benefits | Tirzepatide and Liraglutide
Preliminary studies suggest that tirzepatide may help to reduce liver fat and improve markers of non-alcoholic fatty liver disease (NAFLD) in T2D patients.
The researchers examined various liver function and inflammation biomarkers, including ALT, AST, K-18, Pro-C3, and adiponectin. After 26 weeks, the 15mg tirzepatide group demonstrated significant reductions in all biomarkers compared to baseline.
Compared to placebo, 10mg and 15mg of tirzepatide led to significant decreases in specific biomarkers for liver function such as K-18 and Pro-C3, as well as a decrease in adiponectin. Additionally, when compared to dulaglutide, tirzepatide at 10mg and 15mg doses also resulted in significantly reduced ALT .
In comparison, liraglutide's effects on NAFLD markers, such as liver fat and aminotransferase (ALT) levels, appear non-significant according to a meta-analysis of five studies by Kalogirou et al. (2021). However, the authors did find a significant decrease in serum triglyceride levels, primarily in patients with T2D, but that liraglutide therapy did not significantly impact other lipid parameters .
Instead, liraglutide may have potential neuroprotective effects. One 12-month study revealed that the peptide might significantly improve cognitive function and brain cortex volume in Alzheimer's patients . The potential effects of tirzepatide on neurodegenerative diseases are yet to be investigated.
Tirzepatide and Liraglutide | Dosage Comparison
Tirzepatide and liraglutide are dosed differently given their distinctive pharmacokinetic parameters, such as half-life.
The dual-agonist tirzepatide is dosed once weekly thanks to its long half-life of five days. On the other hand, liraglutide has a much shorter half-life of 13 hours and must be injected daily .
Researchers should note that both peptides should be initiated at a low dose before gradually increasing the dose over several weeks or months to reduce the likelihood of adverse effects.
Liraglutide Dose for Weight Loss
The recommended starting dose of liraglutide is 0.6mg/daily in weight reduction settings. It should then be increased by 0.6mg increments each week.
- Liraglutide Dose: Start with 0.6mg/daily in week one, followed by an increase to 1.2mg/daily in week two, 1.8mg/daily in week three, 2.4mg/daily in week four, and 3.0mg/daily in weeks five and beyond.
- Frequency: Once daily at regular times.
- Study Duration: 20-64 weeks.
- Notes: The optimal liraglutide dose will vary depending on the research aim. Dosages may need to be adjusted on a case-by-case basis but should never exceed 3mg/daily.
Tirzepatide Dose for Weight Loss
Tirzepatide is typically initiated at doses as low as 2.5mg/weekly for T2D. That dose is then increased by 2.5mg increments every four weeks until achieving the desired dosage, not to exceed 15mg/weekly [20, 24].
Similar doses are also used in chronic weight management research, although the peptide is not yet approved for this indication.
Here is a sample dosing protocol based on the latest scientific data on tirzepatide for weight loss:
- Tirzepatide Dose: Initiate at 2.5mg/weekly for the first 4 weeks of the experiment, followed by an increase to 5mg/weekly in weeks 5 to 8, 7.5mg/weekly in weeks 9 to 12, and 10mg/weekly in weeks 13 to 16. Depending on the subject’s response, consider increasing further to 12.5mg/weekly in weeks 17 to 20 and 15mg in weeks 21 and beyond.
- Frequency: Once weekly, subcutaneously.
- Study Duration: In published research, weight loss studies have lasted 24-72 weeks.
- Notes: Researchers are advised against exceeding a weekly dose of 15mg tirzepatide.
Tirzepatide and Liraglutide | Side Effects
Studies into both liraglutide and tirzepatide therapy have provided extensive information on the potential side effects of each.
Overall, the two peptides appear to have favorable safety profiles, similar side effects, and identical contraindications. The incidence of adverse reactions increases with the dose for both compounds.
Gastrointestinal side effects are the most common complaints in both tirzepatide and liraglutide trials.
For example, a meta-analysis on tirzepatide side effects has pooled data from ten trials and 6,836 participants. According to the data, 15mg tirzepatide was associated with:
- Nausea (24.08% of subjects)
- Diarrhea (20.79%)
- Constipation (7.57%)
- Vomiting (13.98%)
- Dyspepsia (6.79%)
- Upper abdominal pain (7.61)
In clinical trials, the discontinuation rate of tirzepatide was highest at the 15mg dose, with 10% of participants discontinuing the drug due to adverse events.
Serious side effects were found to be rare, occurring in less than 1% of participants, and included conditions such as cholelithiasis, cholecystitis, and pancreatitis.
Hypersensitivity reactions were also observed in a small percentage of subjects, affecting approximately 2-4% of participants in most studies .
Studies on liraglutide report similar side effects. For example, a trial conducted by Pi-Sunyer et al. (2015) examined the effects of 3mg liraglutide once-daily administration on patients with chronic weight issues.
The study involved 2487 patients receiving liraglutide and 1244 receiving placebo, and reported the following side effects:
- Nausea (40.2% of subjects)
- Diarrhea (20.9%)
- Constipation (20.0%)
- Vomiting (16.3%)
- Dyspepsia (9.5%)
- Upper abdominal pain (5.7)
Other common liraglutide side effects included headache, dizziness, joint pain, and fatigue, but these also occurred with similar frequency in the placebo group (5-15%). Hematoma at the injection site affected 5.7% of liraglutide patients and 7.5% of the placebo group.
Rare but serious side effects related to liraglutide therapy included pancreatitis and gallbladder disease, which were reported in less than 1% of subjects, with cholelithiasis occurring in 20 patients from the treatment group compared to 12 patients in the placebo group. Acute pancreatitis was observed in four liraglutide group patients and none in the control group .
Both peptides are contraindicated for use during pregnancy and lactation. Further, animal studies on tirzepatide and liraglutide have shown either may increase the risk of thyroid cancer.
Currently, no data suggests that the same risk exists in humans. Nevertheless, subjects with a history of thyroid cancer or multiple endocrine neoplasia syndrome types 2 (MEN-2) should not undergo tirzepatide or liraglutide therapy [6, 39]
Where to Buy Weight Loss Peptides Online? | 2024 Edition
Tirzepatide and liraglutide are both available to qualified researchers and may be purchased online from a limited number of vendors.
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Tirzepatide vs. Liraglutide | Verdict
Tirzepatide and liraglutide are both known to improve glycemic control, facilitate weight loss, and exert cardioprotective effects.
However, the unique mechanisms of tirzepatide result in its superior effectiveness compared to liraglutide. At the same time, the two peptides appear to have a comparable risk and side effect profile in weight loss settings.
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