Unraveling the Impact of GLP-1 and GIP on Weight Loss in the 21st Century

Mar 17, 2024
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Unraveling the Impact of GLP-1 and GIP on Weight Loss in the 21st Century


GLP-1 and GIP are pivotal gut-derived hormones, integral in glucose metabolism regulation and appetite suppression, paving the way for innovative GLP-1 agonist weight loss solutions [1]. With the advent of GLP-1 mimetics like liraglutide and semaglutide, obese individuals now have access to approved alternatives for weight management beyond traditional methods, marking a significant shift in obesity treatment without the prerequisite of diabetes [1]. Additionally, tirzepatide, a novel GLP-1/GIP co-agonist, has received approval for managing type 2 diabetes mellitus and is showing promising tirzepatide weight loss results, signifying a potential paradigm shift in weight loss strategies [1].

The exploration of GLP-1/GIP co-agonism heralds fewer side effects, suggesting a breakthrough in long-term obesity management [1]. This advancement introduces a compelling narrative in the 21st-century weight loss chronicle, directly contrasting with conventional weight loss methodologies. Incorporating key terms such as "GLP-1 agonist weight loss," "tirzepatide weight loss," and "semaglutide weight loss" into the dialogue is not only relevant but essential in underscoring the pivotal role of these agonists in redefining weight management approaches [1].

Understanding Obesity and Its Impact

Global Prevalence and Impact

  • Obesity has emerged as a significant global health concern, linked to various comorbidities including type 2 diabetes, hypertension, and cardiovascular diseases, affecting millions worldwide [3].
  • The condition is notably fueled by factors such as economic growth, industrialization, urbanization, sedentary lifestyles, and a shift towards high-calorie diets, leading to a dramatic increase in obesity rates globally [4].
  • It is not just adults; childhood obesity is also on the rise, posing long-term health risks and placing a substantial burden on healthcare systems [4].

Understanding the Complexity of Obesity

    • Obesity is a multifaceted disease influenced by genetic, behavioral, socioeconomic, and environmental factors, making it a complex challenge in chronic disease prevention [4].
    • The Body Mass Index (BMI) is commonly used to classify obesity levels, ranging from underweight to morbid obesity, with waist circumference serving as a critical measure of abdominal adiposity and related health risks [4].

The Socio-Economic and Health Implications

    • Obesity's prevalence has dire implications, contributing to at least 2.8 million deaths annually due to related health conditions [5].
    • The condition also exacerbates vulnerabilities in populations already facing challenges such as food insecurity, mental illnesses, and impacts certain racial and ethnic groups more severely [6].
    • Beyond health, obesity imposes significant economic burdens through medical costs, lost productivity, and disability claims, highlighting the urgency for effective management and treatment strategies [6].

The Role of GLP-1 and GIP in Weight Management

GLP-1 and GIP play crucial roles in weight management, primarily through their impact on insulin secretion and appetite regulation. Understanding these mechanisms is essential for appreciating the therapeutic potential of GLP-1 and GIP agonists in obesity management:

  • GLP-1 Functions:
    • Amplifies insulin secretion post-nutrient intake [7].
    • Inhibits appetite and food intake, contributing to weight loss [7].
    • Used therapeutically to lower glucose levels [8].
    • GLP-1 agonists, such as liraglutide and semaglutide, are effective in treating or preventing obesity [11].
  • GIP Functions:
    • Unlike GLP-1, it may promote obesity [7].
    • Antagonists of the GIP receptor can reduce weight in experimental models [7].
    • Supraphysiological dosing of GIP agonists alters energy balance with an antiobesity effect [2].
  • Dual Agonists (Twincretins):
    • Activate both GLP-1 and GIP receptors, offering a more effective treatment for diabetes and obesity with fewer side effects [1] [8].
    • Tirzepatide, a co-agonist, improves glycemic control and reduces body weight [1].
    • GLP-1R/GIPR co-agonists like tirzepatide have received Fast Track designation for obesity management [9].

These insights into GLP-1 and GIP's roles in weight management underscore the significance of dual agonists in offering a novel approach to combat obesity and diabetes, with tirzepatide exemplifying the therapeutic promise of this strategy [1] [2] [7] [8] [9] [11].

Clinical Evidence on GLP-1 and GIP Agonists

Clinical evidence highlights the significant impact of GLP-1 and GIP agonists on weight loss, particularly in individuals with type 2 diabetes mellitus (T2DM). Key findings include:

  • Efficacy of GLP-1 and GIP Agonists:
    • Chimeric peptides activating both GLP-1 and GIP receptors have shown remarkable weight loss and glucose-lowering efficacy in obese individuals with T2DM [7].
    • Semaglutide, a GLP-1 agonist, approved for type 2 diabetes and chronic weight management, has demonstrated reductions in weight and improvements in cardiovascular and kidney functions [12].
    • Tirzepatide, a dual-activity GLP-1 and GIP agonist, contributes to improved cardiac and kidney function, and glycemic control via weight reduction [12].
  • Clinical Trials and Approvals:
    • The SURMOUNT-4 trial revealed that continued tirzepatide treatment maintained and augmented initial weight reduction, whereas withdrawal led to substantial regain of lost weight [15].
    • VK2735, a dual GLP-1/GIP receptor agonist, showed up to 13.1% placebo-adjusted mean weight loss in a Phase II trial for obesity treatment [14].
  • Concerns and Considerations:
    • Despite the promising results, concerns about safety, particularly gastrointestinal adverse events induced by high-dose administration of GLP-1 receptor agonists, remain [17].
    • Off-label prescribing of GLP-1 agonists is common, but limited research on their safe and effective use in children and the potential for medication interactions and worsening of other health conditions have been noted [12].

These findings underscore the potential of GLP-1 and GIP agonists in advancing obesity treatment, while also highlighting the need for careful consideration of their use in clinical practice.

Comparing GLP-1 and GIP Agonists with Traditional Weight Loss Methods

Comparing GLP-1 and GIP Agonists with Traditional Weight Loss Methods:

  1. Foundational Approaches:
    • Diet and Exercise: Recognized as the cornerstone of weight loss strategies, essential for initial weight management efforts [18].
    • Over-the-Counter Medications: Alli (orlistat) is an adjunct to a reduced-calorie diet, offering a non-prescription aid to weight loss [18].
  2. Prescription Support:
    • GLP-1 and GIP Agonists: Prescribed to manage blood sugar levels and reduce hunger, aiding in weight loss beyond traditional methods [18].
    • Telehealth Programs: Combine one-on-one coaching with prescription drugs, including GLP-1 and GIP agonists, for comprehensive long-term weight loss strategies [18].
  3. Considerations and Outcomes:
    • Efficacy: GLP-1 and GIP agonists have demonstrated superior weight loss results compared to traditional methods alone. However, they are associated with a higher likelihood of side effects such as diarrhea, nausea, and vomiting [19].
    • Accessibility and Cost: The availability and cost-effectiveness of GLP-1 and GIP agonists are influenced by insurance coverage, potentially limiting their use among certain populations [19].

Practical Considerations and Patient Eligibility

In considering the practical aspects and determining patient eligibility for GLP-1 and GIP agonist treatment, several key factors must be taken into account:

  • Eligibility Criteria:
    • Primarily used for managing type 2 diabetes mellitus and obesity [20].
    • Being used for weight loss, but insurance will not cover this indication.
    • Recommended after considering first-line therapies such as metformin, based on American Diabetes Association guidelines [20].
    • Not suitable for patients with a history of hypersensitivity reactions, pregnancy, severe gastrointestinal diseases, or pancreatitis [20] [10].
  • Monitoring and Adjustments:
    • Regular monitoring includes hemoglobin A1c levels, glycemic patterns, and signs of pancreatitis [20].
    • For patients with renal impairment, dosage adjustments are necessary due to the renal elimination of these agonists [20].
    • Administration methods vary, with semaglutide offering both injectable and daily oral options [10].
  • Insurance and Authorization:
    • From January 1, 2024, prior authorization is required to cover GLP-1 and GIP agonists, except for patients with documented type 2 diabetes with UnitedHealthcare [22].
    • Patients without a type 2 diabetes diagnosis on file will need prior authorization for coverage or continued coverage [22].
    • Semaglutide prescribed for weight loss can be dispensed if the patient pays for the medication directly.

Understanding these considerations is crucial for healthcare providers and patients alike to ensure the safe and effective use of GLP-1 and GIP agonists in treating obesity and type 2 diabetes mellitus.


Through the comprehensive exploration of GLP-1 and GIP agonists, we've unveiled their pivotal role in revolutionizing weight management strategies, distinguishing them from traditional methods. The advent of dual agonists such as tirzepatide underscores a new era in obesity treatment, demonstrating superior efficacy with potentially fewer side effects. By juxtaposing these next-generation therapies against conventional approaches, their significance not only lies in their innovative mechanism of action but also in their ability to provide hope for millions struggling with obesity and its associated comorbidities.

Considering the complex landscape of obesity management, integrating GLP-1 and GIP agonists offers a promising pathway toward achieving sustainable weight loss and improving overall health outcomes. As we continue to navigate the intricacies of these treatments, it's imperative for individuals seeking effective weight loss solutions to take informed steps toward their health goals. Take charge of your health – book a weight loss consultation with Dr. Lukner today. The journey of understanding and utilizing these advanced pharmacological interventions marks a significant advance in our ability to combat obesity, paving the way for a healthier future for those affected.


What do GLP-1 and GIP do in the body?

GLP-1 and GIP are hormones that play significant roles in the body's regulation of pancreatic function and fat storage. They contribute to the growth and preservation of β cells in the pancreas, which are responsible for insulin production. While GIP can increase the glucagon response after eating and promote fat storage in adipose tissues, GLP-1 has the opposite effect on glucagon and does not encourage fat deposition.

In what way does GIP contribute to weight reduction?

Studies have found that the activation of GIP, when combined with GLP-1 receptor activation, leads to more substantial weight loss in mice compared to the use of either agent on its own. This effect is due to a combination of reduced calorie intake and an increase in energy expenditure.

How might GIP improve the weight and glucose-lowering effects of GLP-1-based treatments?

GIP is thought to boost the effectiveness of GLP-1 receptor agonists by increasing appetite suppression and promoting healthier white adipose tissue (WAT) and storage capacity. This improvement helps to decrease the unwanted accumulation of fat in areas of the body where it is not typically stored, known as ectopic fat accumulation.

What proportion of individuals experience weight loss with GLP-1 agonists?

In clinical trials involving 17,183 patients, 50.2% of participants treated with GLP-1 receptor agonists lost at least 5% of their body weight, and 17.5% achieved a weight loss of 10% or more, both figures being significant compared to a placebo group. Notably, individuals without type 2 diabetes mellitus (T2DM) saw greater average weight loss than those with T2DM.


[1] - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9992880/
[2] - https://diabetesjournals.org/diabetes/article/70/9/1929/137729/The-Role-of-GIP-Receptor-in-the-CNS-for-the
[3] - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10341852/
[4] - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4859313/
[5] - https://www.who.int/news-room/facts-in-pictures/detail/6-facts-on-obesity
[6] - https://stop.publichealth.gwu.edu/understanding-obesity
[7] - https://academic.oup.com/jcem/article/105/8/e2710/5847843
[8] - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8994606/
[9] - https://www.tandfonline.com/doi/full/10.1080/14656566.2023.2192865
[10] - https://www.ncbi.nlm.nih.gov/books/NBK551568/
[11] - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9945324/
[12] - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10533252/
[13] - https://www.nejm.org/doi/full/10.1056/NEJMoa2301972
[14] - https://www.pharmexec.com/view/viking-therapeutics-glp-1-gip-receptor-agonist-shows-positive-results-in-obesity-clinical-trial
[15] - https://jamanetwork.com/journals/jama/fullarticle/2812936
[16] - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9063254/
[17] - https://www.bmj.com/content/384/bmj-2023-076410
[18] - https://www.healthline.com/health/weight-loss/glp1-for-weight-loss
[19] - https://www.scientificamerican.com/article/mounjaro-and-ozempic-arent-the-same-heres-how-weight-loss-drugs-compare/
[20] - https://www.uptodate.com/contents/glucagon-like-peptide-1-based-therapies-for-the-treatment-of-type-2-diabetes-mellitus
[21] - https://www.asahq.org/about-asa/newsroom/news-releases/2023/06/american-society-of-anesthesiologists-consensus-based-guidance-on-preoperative
[22] - https://www.uhcprovider.com/en/resource-library/news/2023/prior-auth-glucagon-like-peptide-1-medications.html