From GLP-1 to Master Signaling Molecules—The Next ‘Aha’ in Longevity Science

The Hormone Everyone’s Talking About—And What It Means for Pets

In human health, GLP-1 has become shorthand for a new class of weight-loss drugs. But in the data, GLP-1 is not a pharmaceutical invention. It’s a naturally occurring hormone that’s been in every mammal all along. It quietly coordinates three of the body’s most critical systems, including:

• Gut health—GLP-1 slows gastric emptying and supports nutrient absorption

• Metabolic health—GLP-1 enhances insulin secretion and glucose regulation

• Cellular function—GLP-1 influences mitochondrial activity and inflammatory tone.

That scope puts GLP-1 at the center of what researchers are recognizing as master signaling molecules — bioactive compounds that serve as control centers for the body’s internal communication network. Insulin, adiponectin, IGF-1 and other messengers work together to keep the body’s systems in sync. When that communication falters, the effects ripple across every major function. Understanding and supporting this network represents the next frontier in longevity science: targeting upstream mechanisms that extend healthspan.

From Symptom Support to Master Signaling Molecules

For decades, pet wellness has been discussed in silos: joint support, digestive care, and skin and coat health. But emerging research suggests these are not isolated issues; they are downstream effects of more profound changes in the body’s signaling systems.

Master signaling molecules focus on identifying and supporting the bioactive compounds that serve as control centers for the body’s internal communication network. These molecular messengers, hormones, peptides and other bioactive compounds act as master regulators that keep core systems in sync. When these signaling molecules falter with age or stress, multiple systems are affected at once, often years before overt disease appears.

In human health, this perspective is driving the longevity and metabolic-health movements. Now, it’s gaining ground in veterinary science as well.

The Science Behind the Shift

A recent cross-sectional study by McKenzie et al. (2025) examined metabolic aging in 451 companion dogs, using both blood biomarkers and validated quality-of-life tools.¹ The findings demonstrated:

• Older dogs had elevated fasting insulin, alkaline phosphatase (ALP), alanine aminotransferase (ALT), cholesterol and circulating fatty acids

• Adiponectin, a hormone linked to metabolic flexibility and longevity in humans, was significantly reduced

• These changes correlated with higher Canine Frailty Index (CFI) scores and lower Health-Related Quality of Life (HRQL) scores, even when values stayed within standard veterinary reference ranges.

In other words, subtle changes in metabolic signaling molecules like insulin and adiponectin were tied to measurable declines in vitality and resilience. This mirrors patterns in human aging research, reinforcing the translational value of companion-animal studies.

Why GLP-1 Is the Master Signaling Molecule

GLP-1’s broad, system-wide influence makes it an ideal entry point for understanding master signaling molecules. It shows how a single bioactive compound can:

• Modulate appetite and satiety through the gut–brain axis

• Improve insulin sensitivity and glycemic control

• Influence inflammatory pathways that impact cellular repair.

In humans, GLP-1 is being studied not just for weight management but for cardiovascular health, neuroprotection and even longevity.² In dogs, research is only beginning, but the biological logic is strong, and the opportunity to support endogenous GLP-1 activity through nutrition is compelling.

Clinical Breakthrough: First Nutritional GLP-1 Support in Humans

The convergence of human and pet health research has reached a tipping point, with breakthrough ingredients moving seamlessly between species. This is exemplified by recent clinical advances with eriocitrin, a citrus bioflavonoid that has emerged from human GLP-1 research.

A landmark 2025 study published in Frontiers in Nutrition represents the first successful nutritional approach to supporting GLP-1 activity in combination with metformin.³ In this randomized, controlled trial with 71 prediabetic patients, a standardized citrus flavonoid supplement (250 mg daily containing 70 percent eriocitrin) delivered remarkable results:

• Preserved active GLP-1 levels while the placebo groups showed 15 percent declines

• 5 percent reduction in postprandial glucose at 120 minutes post-meal

• 17 percent increase in adiponectin levels—the same hormone that declines in aging dogs

• 12 percent reduction in TNF-α, a key inflammatory marker

• 7.5 percent improvement in antioxidant capacity (FRAP)

• Significant improvements in body composition and blood pressure.

Most significantly, the study demonstrated that citrus flavonoids work synergistically with existing therapies, enhancing metabolic outcomes beyond what pharmaceutical intervention achieved alone.

Earlier foundational studies with ERIOMIN (standardized eriocitrin extract) showed that 200 mg daily delivered a 15 percent increase in GLP-1 levels, 5 percent reduction in blood glucose, and 7 percent improvement in insulin resistance in prediabetic patients.⁴ A follow-up crossover study confirmed these findings, showing a 17 percent increase in GLP-1 levels alongside significant reductions in glucose (5 percent), insulin resistance (11 percent), and inflammatory markers.⁵ The mechanism was revealed in a third study: ERIOMIN modulates gut microbiota composition, increasing beneficial bacteria that support glucose metabolism and GLP-1 production.⁶

This human breakthrough has immediate implications for companion animal nutrition, as the biological pathways governing GLP-1 signaling are highly conserved across mammalian species.² The success with eriocitrin in human trials serves as proof of concept for the broader master signaling molecules category, demonstrating that these bioactive compounds can indeed be supported through targeted nutraceutical interventions.

The Science Driving Human-Pet Convergence

Beyond eriocitrin, several other ingredient classes are drawing attention for master signaling molecule support:

• Omega-3 fatty acids—Known modulators of inflammatory signaling, with evidence for cardiovascular, cognitive and joint benefits in both species

• Prebiotics and probiotics—By shifting gut microbial populations, they can influence gut-derived hormones and immune signaling

• Polyphenols and plant adaptogens—Investigated for effects on oxidative balance, mitochondrial function and stress-response pathways.

By framing these as master signaling molecule-supportive rather than symptom-specific, formulators can target upstream mechanisms that affect multiple systems at once.

Measuring What Matters

Tools like the Canine Frailty Index (CFI) and VetMetrica HRQL scores bring human geroscience metrics into veterinary research. They offer a way to link biochemical changes in signaling molecules like insulin, adiponectin and GLP-1 with functional outcomes that matter to pet owners: energy, comfort and quality of life.

As more studies incorporate these measures, master signaling molecules can move from concept to quantifiable standard—allowing earlier interventions and clearer ROI for preventive nutrition.

Looking Ahead

The development of master signaling molecules in the pet space is rapidly accelerating as pet owners continue to apply their wellness logic to their animals. Furthermore, the availability of shared supply chains and research portfolios makes it easier to translate human health bioactives into formulations for pets. This approach offers a fresh perspective on pet wellness, recognizing the interconnectedness of biological systems and the bioactive compounds that act as control centers.

While GLP-1 is currently the most recognized master signaling molecule, it represents just the beginning of a broader movement aimed at optimizing hormonal and metabolic communication.

As this field advances, we can expect to see:

• Routine metabolic signaling molecule panels in veterinary care

• Increased crossover trials between human and companion-animal research

• Growing consumer awareness that “whole-body wellness” begins with healthy internal signaling. The same science that’s reshaping human longevity has the potential to give pets not just more years, but more good years—and master signaling molecules may be the bridge. Just as oral care and parasite control became standard pillars of preventive health, supporting master signaling molecules is poised to become the next foundation of proactive care for pets. NIE

References:

1 McKenzie, B., Peloquin, M., Graves, J.L., et al. (2025). Changes in insulin, adiponectin and lipid concentrations with age are associated with frailty and reduced quality of life in dogs. Scientific Reports, 15, 5380. https://doi.org/10.1038/s41598-025-89923-z.

2 Nauck, M. A., & Meier, J. J. (2018). Incretin hormones: Their role in health and disease. Diabetes, Obesity and Metabolism, 20(S1), 5–21. https://doi.org/10.1111/dom.13129.

3 Cesar, T., Oliveira, M.R., Sandrim, V., Mendes, A., Bruder, R., Oliveira, R., Sivieri, K., & Milenkovic, D. (2025). Citrus flavonoid supplement enhances glycemic and metabolic control in prediabetic patients on metformin: a randomized controlled trial. Frontiers in Nutrition, 12:1639901. https://doi.org/10.3389/fnut.2025.1639901.

4 Ribeiro, C. B., Ramos, F. M., Manthey, J. A., & Cesar, T. B. (2019). Effectiveness of Eriomin® in managing hyperglycemia and reversal of prediabetes condition: A double-blind, randomized, controlled study. Phytotherapy Research, 33(7), 1921-1933. https://doi.org/10.1002/ptr.6386.

5 Cesar, T. B., Ramos, F. M. M., & Ribeiro, C. B. (2022). Nutraceutical eriocitrin (Eriomin®) reduces hyperglycemia by increasing glucagon-like peptide 1 and downregulates systemic inflammation: A crossover-randomized clinical trial. Journal of Medicinal Food, 25(11), 1050-1058. https://doi.org/10.1089/jmf.2022.K.0103.

6 Ramos, F. M., Ribeiro, C. B., Cesar, T. B., et al. (2023). Lemon flavonoids nutraceutical (Eriomin®) attenuates prediabetes intestinal dysbiosis: A double-blind randomized controlled trial. Food Science & Nutrition, 11, 1-13. https://doi.org/10.1002/fsn3.3654.

7 Creevy, K. E., et al. (2022). An open science study of ageing in companion dogs. Nature, 602, 51–57. https://doi.org/10.1038/s41586-021-04282-9.

*Side-bar start:

What Are Master Signaling Molecules?

Master signaling molecules represent an emerging framework in human and veterinary science that focuses on identifying and supporting the master signaling molecules that serve as control centers for the body’s internal communication network.

Master signaling molecules like GLP-1, insulin, adiponectin and IGF-1 influence multiple systems at once, from gut health to cellular repair. When these molecular signals are strong and balanced, the body functions as an integrated whole; when they falter, declines appear across systems, often years before overt disease.

Supporting master signaling molecules means targeting upstream mechanisms—through nutrition, lifestyle and preventive care—to preserve vitality and extend healthspan.

In short, think strong signaling molecules, strong systems stronger healthspan.

*Side-bar end

Rob Brewster is the president of California-based Ingredients by Nature. As a third-generation ingredient manufacturer for the natural products industry, Brewster is proud to be part of the health and wellness world. He followed in his grandfather’s and father’s footsteps, helping their company Brewster Foods grow since he joined in the 1990s and then partnering with Syntech to form Ingredients by Nature, a world leader in citrus bioflavonoids and extracts. As president, Brewster invests heavily in citrus flavonoid science for condition-specific applications and holistic wellness. For more information, visit IngredientsbyNature.com.