Retatrutide

Overall Health Benefits of Retatrutide

1. Promotes weight loss [1-6]
2. Improves blood sugar levels [1-6]
3. Improves blood pressure [4, 6]

What is Retatrutide?

Retatrutide, a new medication created by the pharmaceutical company Eli Lilly, has a major potential for the treatment of obesity and diabetes. Also known as GGG Tri-agonist, GLP-1/GIP/glucagon tri-agonist, or LY3437943, this injectable medication is set for FDA approval. It is similar to existing weight loss medications like tirzepatide and semaglutide but has increased efficacy. When combined with proper diet, regular exercise, and lifestyle modifications, retatrutide can help improve weight loss outcomes and treat comorbidities related to obesity such as diabetes or hypertension (high blood pressure).

How Retatrutide Works?

Retatrutide is more effective than other weight loss medications. It exerts its therapeutic effects through three important mechanisms:

• Gastric inhibitory polypeptide receptor (GIPR) agonist: As a GIP receptor agonist, retatrutide enhances appetite suppression and prevents fat accumulation, resulting in decreased energy intake and increased energy expenditure.
• Glucagon-like peptide 1 receptor (GLP-1R) agonist: Retatrutide reduces body weight by improving blood sugar levels via enhanced insulin release from the pancreas and reduced release of glucagon (a hormone that increases blood sugar).
• Glucagon receptor (GR) agonist: Retatrutide decreases glucagon release to improve blood sugar levels, decrease food intake, and increase energy expenditure which ultimately results in weight loss.

Chemical Structure of Retatrutide

Research on Retatrutide

A. Promotes Weight Loss

Retatrutide is more effective than other weight loss medications because of its combined mechanism of action. As a GIPR agonist, it enhances appetite suppression and prevents fat accumulation. As a GLP-1 agonist, it enhances insulin release from the pancreas while reducing glucagon release, resulting in improved blood sugar levels. As a GR agonist, it also decreases glucagon release and boosts insulin secretion. These mechanisms decrease energy intake and increase energy expenditure which ultimately results in weight loss.

A number of studies support retatrutide’s ability to induce weight loss:

1. In adults (aged 20-70 years) with type 2 diabetes for at least 3 months, the administration of retatrutide at 3/6/9/12 mg resulted in robust reductions in body weight with an acceptable safety profile. [1]
2. In high-fat-fed mice, twice daily administration of retatrutide for 21 days decreased body weight and nonfasting blood sugar levels and increased circulating insulin concentrations in the blood. [2]
3. In obese mice, the administration of retatrutide (LY3437943) decreased body weight, improved blood sugar control, and increased energy expenditure. [3]
4. In forty-five healthy human subjects, the three highest doses of subcutaneous (under the skin) administration of retatrutide produced a statistically significant weight loss that was maintained up to day 43. [4]
5. In diet-induced obese mice, retatrutide reduced food intake and body weight by 45% via reduced fat mass, making it superior to other GIPR and GLP-1R agonists. [5]
6. In patients with type 2 diabetes (T2D), subcutaneous administration of retatrutide for 12 weeks resulted in reductions in body weight of up to 8.96 kg with a safety and tolerability profile similar to other incretins (peptides that stimulate insulin secretion). [6]

B. Improves Blood Sugar Levels

Retatrutide improves blood sugar levels through its effects on the hormones insulin and glucagon. Insulin lowers blood sugar levels while glucagon increases blood sugar levels to achieve homeostasis or balance. As a GLP-1 agonist and GR agonist, It enhances insulin release from the pancreas while reducing glucagon release. This in turn helps achieve healthy blood sugar levels.

Evidence suggests that retatrutide can produce beneficial effects on the blood sugar levels of people with diabetes and uncontrolled blood sugar:

1. In adults (aged 20-70 years) with type 2 diabetes for at least 3 months, the administration of retatrutide at 3/6/9/12 mg resulted in robust reductions in blood sugar levels with an acceptable safety profile compared with placebo treatment. [1]
2. In high-fat-fed mice, twice daily administration of retatrutide for 21 days decreased nonfasting blood sugar levels by increasing circulating insulin concentrations in the blood. [2]
3. In obese mice, the administration of retatrutide improved blood sugar control and increased energy expenditure which persisted up to day 43. [3]
4. In forty-five healthy human subjects, the three highest doses of subcutaneous administration of retatrutide resulted in increased mean fasting insulin and C-peptide, with maximum levels observed at 24 and 48 hours, which in turn lowered blood sugar levels. [4]
5. In diet-induced obese mice, retatrutide lowered blood sugar and insulin levels, indicating improved insulin sensitivity (the body’s response to the effects of insulin). [5]
6. In patients with type 2 diabetes, subcutaneous administration of retatrutide for 12 weeks decreased (glycated hemoglobin, also known as HbA1c and is a measure of blood sugar) with a higher safety and tolerability profile. [6]

C. Improves Blood Pressure

Retatrutide can help improve blood pressure by addressing obesity. By decreasing energy intake and increasing energy expenditure, It can promote weight loss. Evidence suggests that weight loss is associated with blood pressure reduction. [7-9] This indicates that retatrutide may be beneficial in people with hypertension.

Studies support the blood pressure-lowering effects of retatrutide:

1. A Phase 1 clinical trial, which is the first human study assessing the safety and tolerability of single-ascending doses of retatrutide (LY3437943), included forty-five healthy subjects who were randomized to receive subcutaneous LY3437943 (6 rising dose levels) or placebo. [4] During the treatment period, important data such as vital signs, electrocardiogram (ECG), laboratory data, and adverse events were monitored. Fasting insulin, C-peptide, weight, and appetite were also measured. Results showed that the subjects who received retatrutide had significant weight loss, increased insulin levels, and decreased systolic blood pressure (returned to near baseline by Day 29).
2. A Phase 1 proof-of-concept study assessed the safety and tolerability of several ascending doses of retatrutide in patients with type 2 diabetes (T2D). [6] In this study, seventy-two diabetic patients were randomized to receive retatrutide or placebo. During the treatment, the researchers assessed vital signs, laboratory data, and adverse events. After 12 weeks, the group that received retatrutide had decreases in systolic and diastolic blood pressure with a higher safety and tolerability profile compared to the placebo group.

Associated Side Effects of Retatrutide

Retatrutide side effects are very uncommon. There have been some side effects associated with the use of this drug wherein the patient had one of the issues listed below at some point while being on retatrutide. However, these side effects weren’t confirmed to be associated with the treatment and could have been a coincidence and not related to the use of retatrutide. Despite this, it was listed as a side effect associated with it even though these associated side effects are very uncommon.

Side effects associated with retatrutide may include the following:

• Chest pain
• Depression
• Difficulty breathing
• Dizziness
• Dry mouth
• Fatigue
• Headache
• Irregular heartbeat
• Swelling in the hands and feet

References

1. Urva, S., Coskun, T., Loh, M. T., Du, Y., Thomas, M. K., Gurbuz, S., Haupt, A., Benson, C. T., Hernandez-Illas, M., D’Alessio, D. A., & Milicevic, Z. (2022). LY3437943, a novel triple GIP, GLP-1, and glucagon receptor agonist in people with type 2 diabetes: a phase 1b, multicentre, double-blind, placebo-controlled, randomised, multiple-ascending dose trial. Lancet (London, England), 400(10366), 1869–1881. https://doi.org/10.1016/S0140-6736(22)02033-5.
   View Summary +

   LY3437943, a novel triple GIP, GLP-1, and glucagon receptor agonist in people with type 2 diabetes: a phase 1b, multicentre, double-blind, placebo-controlled, randomised, multiple-ascending dose trial

   Multi-receptor agonists that target the glucagon, glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide 1 (GLP-1) receptors may improve outcomes in type 2 diabetes because this condition is linked to hyperglycemia and obesity. The single peptide LY3437943, also known as retatrutide, is currently in development for the treatment of type 2 diabetes and obesity since this medication acts on these receptors.

   The safety, pharmacokinetics, and pharmacodynamics of several weekly doses of LY3437943 in persons with type 2 diabetes were examined in a phase 1b experiment. Four centers in the USA enrolled adults with type 2 diabetes, a glycated hemoglobin A1c (HbA1c) score of 7.0-10.5%, and a body mass index (BMI) of 23-50 kg/m2. Over a 12-week period, the participants were randomized to receive dulaglutide 1.5 mg, placebo, or once-weekly subcutaneous injections of LY3437943. Nine participants received LY3437943, three received a placebo, and one received dulaglutide. The primary outcome was to evaluate the safety and tolerability of LY3437943 and the secondary outcomes were the pharmacokinetics and pharmacodynamics of the medication. The study found that LY3437943 showed an acceptable safety profile and its pharmacokinetics suggested suitability for once-weekly dosing. LY3437943 significantly decreased plasma glucose (blood sugar), HbA1c, and body weight in a dose-dependent manner.

   The findings provide support for phase 2 development of LY3437943 for the treatment of type 2 diabetes and obesity since the medication can produce robust reductions in body weight and blood sugar levels.

2. Gault, V. A., Bhat, V. K., Irwin, N., & Flatt, P. R. (2013). A novel glucagon-like peptide-1 (GLP-1)/glucagon hybrid peptide with triple-acting agonist activity at glucose-dependent insulinotropic polypeptide, GLP-1, and glucagon receptors and therapeutic potential in high fat-fed mice. The Journal of biological chemistry, 288(49), 35581–35591. https://doi.org/10.1074/jbc.M113.512046.
   View Summary +

   A novel glucagon-like peptide-1 (GLP-1)/glucagon hybrid peptide with triple-acting agonist activity at glucose-dependent insulinotropic polypeptide, GLP-1, and glucagon receptors and therapeutic potential in high fat-fed mice

   The study examines the effectiveness of novel peptides that are a combination of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and glucagon. These three compounds are known to bind to the same receptor superfamily and play a crucial role in glucose homeostasis (blood sugar balance), insulin secretion, and energy regulation. Nine new peptides were created and their biological effects and potential therapeutic use were evaluated. These peptides demonstrated total DPP-IV resistance and enhanced in vitro insulin secretion. The most promising peptide was discovered to be [dA(2)]GLP-1/GcG. In cells transfected with the GIP, GLP-1, and glucagon receptors, it increased cAMP synthesis. When combined with glucose (blood sugar), [dA(2)]GLP-1/GcG dramatically boosted the blood levels of insulin and decreased blood sugar levels in normal and obese diabetic mice. Moreover, it produced a sustained insulinotropic and glucose-lowering effect in animals receiving high-fat diets.

   In high-fat-fed rats, [dA(2)]GLP-1/GcG reduced body weight, nonfasting plasma glucose, and boosted circulating plasma insulin concentrations when given twice daily for 21 days. By day 21, it also greatly increased insulin sensitivity and glucose tolerance. Interestingly, the [dA(2)]GLP-1/GcG mice showed increased locomotor activity without any significant changes in metabolic rate. Studies in knock-out mice confirmed the biological action of [dA(2)]GLP-1/GcG which is related to its ability to target GIP, GLP-1, and glucagon receptors.

   Overall, the data suggest that the novel triple-acting hybrid peptides have significant potential as therapeutic options for obesity and diabetes.

3. Coskun, T., Urva, S., Roell, W. C., Qu, H., Loghin, C., Moyers, J. S., O’Farrell, L. S., Briere, D. A., Sloop, K. W., Thomas, M. K., Pirro, V., Wainscott, D. B., Willard, F. S., Abernathy, M., Morford, L., Du, Y., Benson, C., Gimeno, R. E., Haupt, A., & Milicevic, Z. (2022). LY3437943, a novel triple glucagon, GIP, and GLP-1 receptor agonist for glycemic control and weight loss: From discovery to clinical proof of concept. Cell metabolism, 34(9), 1234–1247.e9. https://doi.org/10.1016/j.cmet.2022.07.013.
   View Summary +

   LY3437943, a novel triple glucagon, GIP, and GLP-1 receptor agonist for glycemic control and weight loss: From discovery to clinical proof of concept

   As the prevalence of obesity rises, there is a requirement for new treatments to improve the management of body weight and metabolic health. Developing multi-receptor agonists may present opportunities to meet this medical demand. LY3437943 is a new triple agonist peptide that affects the glucagon receptor (GCGR), the glucose-dependent insulinotropic polypeptide receptor (GIPR), and the glucagon-like peptide-1 receptor (GLP-1R). In vitro, LY3437943 demonstrates a well-balanced activity between GCGR and GLP-1R, but more activity towards GIPR.

   When given to obese mice, LY3437943 decreased body weight and enhanced glycemic/blood sugar control. A greater amount of body weight was lost as a result of the GIPR and GLP-1R-driven reduction in caloric intake and the GCGR-mediated increase in energy expenditure. LY3437943 demonstrated a safety and tolerability profile equivalent to other incretins in a phase 1 single ascending dosage study. The body weight loss was maintained after a single dose up to day 43 and its pharmacokinetic characteristics suggested it may be used once a week.

   These findings imply that additional clinical testing of LY3437943 is necessary.

4. Available from https://diabetesjournals.org/diabetes/article/70/Supplement_1/104-OR/139575/104-OR-Novel-GIP-GLP-1-Glucagon-Receptor-Agonist.
   View Summary +

   104-OR: Novel GIP/GLP-1/Glucagon Receptor Agonist LY3437943: A First-in-Human Dose Study in Healthy Subjects

   Many metabolic diseases are being treated using multifunctional incretins, which are substances that boost insulin secretion and enhance blood sugar control. One such substance, LY3437943, has been discovered to exhibit strong agonist activity on three distinct receptors, including the glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptors.

   To evaluate the safety and tolerability of LY3437943, a randomized, double-blind, placebo-controlled Phase 1 clinical trial was conducted on 45 healthy subjects. The subjects were given six different rising doses of LY3437943 or placebo subcutaneously, and their vital signs, ECGs, laboratory data, and adverse events related to the administered medication were monitored. Results revealed that gastrointestinal symptoms such as nausea, vomiting, and abdominal discomfort, which were dose-dependent and mainly mild in severity, were the side effects of LY3437943. After one week of treatment, these side effects begin to disappear. Moreover, dose-dependent increases in heart rate and drops in systolic blood pressure were seen, but by Day 29, they had almost completely recovered to baseline levels. LY3437943 had a mean terminal half-life ranging from 134 to 165 hours across the six doses, supporting once-weekly dosing. Dose-dependent increases in fasting insulin and C-peptide were observed, with maximum levels seen at 24 and 48 hours, returning to near baseline levels by Day 15. Dose-dependent weight loss was also observed, with statistically significant weight loss seen with the three highest doses compared to the placebo. This beneficial effect was maintained up to Day 43 following the single administration of the two highest doses.

   Overall, the results of this Phase 1 clinical trial indicate that LY3437943 has a safety and tolerability profile similar to other incretins, with pharmacokinetic and pharmacodynamic outcomes that support further clinical evaluation.

5. Available from https://diabetesjournals.org/diabetes/article/70/Supplement_1/679-P/140585.
   View Summary +

   679-P: The Novel GIP, GLP-1, and Glucagon Triple Receptor Agonist LY3437943 Exhibits Robust Efficacy in Preclinical Models of Obesity and Diabetes

   The increase in the prevalence of obesity-related illnesses, including type 2 diabetes, nonalcoholic steatohepatitis, and nonalcoholic fatty liver disease (NASH/NAFLD), has prompted researchers to look for novel therapies that can enhance metabolic health. Multi-receptor agonists have come to light as a possible remedy for this issue.

   The effectiveness of LY3437943, a new tri-agonist at the GIP, GLP-1, and glucagon (Gcg) receptors, in enhancing metabolic health was examined in a study. The outcomes of this study showed that LY3437943 controlled adipocyte lipolysis (breakdown of fat cells) and hepatocyte glucose output (blood sugar production by the liver) in endogenous cells and had a potency balance that favors GIPR agonism. Acute treatment with LY3437943 inhibited stomach emptying and increased glucose-dependent insulin production, according to in vivo investigations. Prolonged investigations in diet-induced obese mice led to decreased food intake and decreased body weight, mostly due to decreased fat mass. Moreover, LY3437943 enhanced liver health indicators by lowering liver triglycerides (blood fat) and plasma alanine aminotransferase (a liver enzyme).

   In conclusion, LY3437943 is a novel tri-agonist that can produce superior weight loss and blood sugar control compared to other incretin receptor-targeting molecules, making it a potential treatment option for patients with obesity and metabolic diseases. Moreover, the rodent and cynomolgus monkey PK modeling suggested the potential for weekly dosing in humans. Further evaluation of the clinical benefits of LY3437943 in patients with metabolic diseases is warranted.

6. Available from https://diabetesjournals.org/diabetes/article/71/Supplement_1/340-OR/146500/340-OR-LY3437943-LY-a-Novel-Triple-GIP-GLP-1.
   View Summary +

   340-OR: LY3437943 (LY), a Novel Triple GIP/GLP-1/Glucagon Receptor Agonist, Provides Glucose Lowering and Weight Loss in Patients with T2DM after 12 Weeks of Treatment

   Multi-receptor incretin agonists are being developed with the goal of treating various metabolic diseases. LY is a triple agonist that is currently being studied for its strong activity on the glucagon receptor, glucagon-like polypeptide-1 (GLP-1), and glucose-dependent insulinotropic polypeptide (GIP) receptors. Due to its pharmacokinetic characteristics, previous studies have demonstrated that LY can be safely taken once per week.

   A Phase 1 proof-of-concept trial evaluated the safety and tolerability of several ascending doses of LY in type 2 diabetic patients (T2D). In this study, 72 patients were enrolled and were randomly assigned to one of five ascending dose cohorts of subcutaneous LY, a placebo, or dulaglutide 1.5mg. The safety and tolerability of LY were monitored through vital signs, laboratory data, and adverse events (AEs). Efficacy was measured by monitoring changes in glycated hemoglobin (HbA1c) and body weight at week 12. The most common treatment-emergent AEs were gastrointestinal in nature and mostly mild in severity. These include nausea and diarrhea. By week 12, the mean systolic and diastolic blood pressure decreased from baseline in the LY group compared to the placebo group. Meanwhile, the pulse and heart rate increased from baseline within most LY cohorts and dulaglutide, but not with placebo. All groups showed a decrease in mean HbA1c by week 12, with higher doses of LY demonstrating statistically significant placebo-adjusted decreases of up to 1.56%. A dose-dependent decrease in mean placebo-adjusted body weight of up to 8.96 kg was observed with LY, except in the initial cohort.

   In conclusion, the safety and tolerability profile of LY is similar to other incretins. The ability of this medication to induce weight loss and lower blood sugar levels suggests that it can provide additional benefits versus current therapies in the treatment of T2D and obesity.

7. Neter, J. E., Stam, B. E., Kok, F. J., Grobbee, D. E., & Geleijnse, J. M. (2003). Influence of weight reduction on blood pressure: a meta-analysis of randomized controlled trials. Hypertension (Dallas, Tex.: 1979), 42(5), 878–884. https://doi.org/10.1161/01.HYP.0000094221.86888.AE.
   View Summary +

   Influence of weight reduction on blood pressure: a meta-analysis of randomized controlled trials

   Hypertension is strongly associated with increased body weight. To determine the impact of weight reduction on blood pressure, a meta-analysis of randomized controlled trials was conducted. The analysis included 25 trials published between 1966 and 2002, with a total of 4874 participants. The trials involved weight reduction through energy restriction, increased physical activity, or a combination of both. A random-effects model was used to account for heterogeneity among the trials. According to the findings, losing 5.1 kg of weight was associated with a -4.44 mm Hg systolic and -3.57 mm Hg diastolic blood pressure drop. The decreases in systolic and diastolic blood pressure were 1.05 mm Hg and -0.92 mm Hg, respectively, as expressed per kilogram of weight lost. Those who lost an average of over 5 kg in weight had considerably lower blood pressure decreases than people who lost less weight. The data also showed that populations using antihypertensive medication had considerably lower diastolic blood pressure than populations not receiving treatment. The study emphasized the importance of weight loss in the management of hypertension, particularly in populations taking antihypertensive drugs.

   The findings of the meta-analysis show that losing weight is crucial for both preventing and treating hypertension. Overall, this suggests that weight reduction through energy restriction and increased physical activity is an effective strategy for reducing blood pressure in populations with hypertension and that population with greater weight loss experience greater reductions in blood pressure.

8. Bacon, S. L., Sherwood, A., Hinderliter, A., & Blumenthal, J. A. (2004). Effects of exercise, diet and weight loss on high blood pressure. Sports medicine (Auckland, N.Z.), 34(5), 307–316. https://doi.org/10.2165/00007256-200434050-00003.
   View Summary +

   Effects of exercise, diet and weight loss on high blood pressure

   Almost 50 million people in the US suffer from high blood pressure (BP) hypertension, which is a serious health problem. Although being one of the most frequent causes of outpatient visits, high blood pressure is usually uncontrollable. Pharmacological techniques can lower blood pressure in hypertensive people, but not everyone reacts to anti-hypertensive drugs successfully. In addition, they can be expensive and have side effects that reduce the overall quality of life and compliance of patients. Moreover, abnormalities associated with hypertension, such as insulin resistance and hyperlipidemia (high lipid levels), can be worsened by some anti-hypertensive medications.

   Behavioral therapies are becoming more popular as a technique to treat high blood pressure. Exercise and the DASH (Dietary Approaches to Stop Hypertension) diet are the two main behavioral therapies that are recommended to control blood pressure. Losing weight is also advised for those who are overweight. Systolic (SBP) and diastolic blood pressure (DBP) can both be decreased by exercise alone by about 3.5 and 2.0mm Hg, respectively. In comparison to individuals on a typical American diet, patients who follow the DASH diet, which contains high fiber and low-fat dairy products, fruits, and vegetables, can have SBP and DBP levels that are reduced by 5.5 and 3.0 mm Hg, respectively. For overweight hypertensive patients, an 8-kg weight loss can result in 8.5 mm Hg SBP and 6.5 mm Hg DBP decreases. A combination of exercise and a weight-loss regimen can reduce SBP and DBP by 12.5 and 7.9 mm Hg in overweight hypertension patients. These BP reductions are associated with improvements in left ventricular structure and function, as well as peripheral vascular health. Both exercise training and weight loss have been shown to decrease left ventricular mass and wall thickness, reduce arterial stiffness, and improve endothelial function.

   These findings support the use of behavioral interventions in the management of high BP. Although pharmacological treatments have been effective, behavioral interventions offer a more natural and affordable option for managing high BP, particularly in individuals who are unable to tolerate or benefit from medications.

9. Fantin, F., Giani, A., Zoico, E., Rossi, A. P., Mazzali, G., & Zamboni, M. (2019). Weight Loss and Hypertension in Obese Subjects. Nutrients, 11(7), 1667. https://doi.org/10.3390/nu11071667. 
   View Summary +

   Weight Loss and Hypertension in Obese Subjects

   Obesity and being overweight are strongly correlated with arterial hypertension, also referred to as high blood pressure. Via a number of processes, including insulin and leptin resistance, perivascular adipose tissue dysfunction, reduced kidney function, activation of the renin-angiotensin-aldosterone system, and increased sympathetic nervous system activity, obesity can cause hypertension.

   It has been noted that reductions in weight can also lower blood pressure. A study described the relationship between obesity and hypertension and evaluated the effects of weight loss on blood pressure using a variety of methods, including medication, bariatric surgery, dietary and lifestyle changes, and exercise. A total of 13 studies from the past ten years were examined, and while they all showed that losing weight had a good impact on blood pressure, the degree and persistence of this effect differed from study to study.

   To completely understand the impact of weight loss on hypertension, more long-term data are needed. Despite the lack of conclusive long-term data, weight management should be a priority in obese patients with hypertension, given the promising results from recent studies. This emphasizes the importance of educating individuals about the potential benefits of maintaining a healthy weight and encouraging healthcare providers to include weight management in the treatment plan for hypertension.