Scientists propose oxytocin as a keystone linking social connection to wellbeing

Oxytocin has spent more than a century being labeled the hormone of birth, lactation and, later, love. A new perspective article in Frontiers in Neuroscience argues that these familiar labels have never captured what the molecule actually does. Written by C. Sue Carter of the Kinsey Institute at Indiana University and the University of Virginia, and Hans P. Nazarloo of the University of Florida Health Sciences, the article proposes that oxytocin is best understood not as a single hormone with a single job, but as the center of an extended regulatory system that reaches into nearly every corner of mammalian physiology.

The perspective, published on 28 October 2026 in the journal’s Neuroendocrine Science section, does not report new experimental data. Instead, it synthesizes decades of research and offers a conceptual framework. The authors suggest that the oxytocin system, viewed as a whole, may act as a kind of keystone in mammalian biology: a component whose significance comes from its position and relationships rather than from acting alone, connecting regulatory physiology to the benefits of social connection.

Early research implicated oxytocin in birth and lactation, and by the 1970s it had acquired the popular nickname of a love hormone. The authors argue that these designations probably slowed the field, because they seemed to point to a sex-specific role for the hormone. Later work implicated oxytocin in both sexes in social monogamy, parental behavior and other behaviors, but even that expanded nomenclature, they write, did not capture the molecule’s functional complexity.

Oxytocin is now understood as a critical component of an adaptive regulatory system that extends well beyond reproduction and sociality. Among the many functions attributed to it are autonomic and cardiovascular regulation, metabolism, immunity, inflammatory processes and regulation of the microbiome. The system also includes vasopressin, the autonomic nervous system and the immune system, and the authors describe it as affecting essentially every bodily function, helping to coordinate physiology with social context and each individual’s history.

A central idea in the article is that oxytocin’s effects are most apparent in the face of a challenge. The hormone has sometimes been called an anti-stress hormone, and the authors highlight its role in managing inflammation and oxidative stress. They connect these properties to what they have previously described as a social solution to the stress of life, and to the repeatedly described benefits of social factors for wellness and, eventually, longevity.

The authors build their keystone argument around a regulatory process they term sociostasis. Because oxytocin and its receptors can coordinate multiple processes across brain and body, they argue, its influence extends beyond the individual to support the general benefits of sociality. In this framing, challenge and adversity can lead either to dysregulation and disease or to adaptation and resilience, and the oxytocin system, through its reciprocal relationships with social connection and physiological regulation, may help shape that balance. The article also links the framework to stress-response hormesis, the phenomenon in which manageable stress produces beneficial adaptations.

The authors are careful to note that a keystone is not the entire structure and does not act independently of the structure around it. Oxytocin sits at the center of an ancient system, they write, capable of supporting mammalian physiology and longevity through effects on both physiology and behavior. In their view, sociostasis can provide a regulatory context in which manageable challenge becomes hormetic, supporting wellbeing, resilience and ultimately what is sometimes called the healing power of love. The classical form of oxytocin, they note, emerged coincident with the evolution of mammals and nurture directed toward offspring.

Not all of the article is conceptual. The authors also address a long-standing practical problem: measuring oxytocin accurately has been a repeated source of controversy, and both the measurement and interpretation of the molecule’s biochemical and functional properties remain works in progress. Rather than seeking one definitive measure of oxytocin, they argue, researchers may need multiple valid measures to reveal how the system is organized, regulated and functionally engaged, because different methods may be capturing different facets of a dynamic regulatory system.

The authors frame this measurement difficulty as an opportunity rather than a defect. The apparent complexity of oxytocin measurement, they suggest, may not simply be methodological noise; properly studied, it may help reveal previously undiscovered properties of one of mammalian biology’s most ancient and broadly integrated regulatory systems. They add that their discussion is not intended to diminish the value of attempts to measure specific features of the molecule, noting that an extensive literature based largely on peptide concentrations has established much of what is known about oxytocin biology.

Despite the admitted limitations of current measurements, the authors point out that double-blind studies in both human and nonhuman models have repeatedly discovered statistically and biologically significant relationships between endogenous and exogenous oxytocin and diverse functions. Awareness of oxytocin’s functions, they write, has also offered insights into human evolution. The perspective closes with the argument that understanding the broader oxytocin system as a central element in mammalian biology reframes the deep biology of processes that can contribute to human health and wellbeing, while acknowledging that the field’s analytical and conceptual challenges remain very much works in progress.

Subject of Research: A perspective on the oxytocin system as a proposed keystone of mammalian sociality, stress resilience and wellbeing.

Article Title: Is the oxytocin system a keystone in human wellbeing?

Article References: Carter, C. S., & Nazarloo, H. P. (2026). Is the oxytocin system a keystone in human wellbeing?. Frontiers in Neuroscience, 20, Article 1989082. https://doi.org/10.3389/fnins.2026.1989082

Image Credits: AI Generated

DOI: 10.3389/fnins.2026.1989082

Keywords: oxytocin, vasopressin, sociostasis, hormesis, stress resilience, social bonding, neuroendocrinology, wellbeing, autonomic nervous system, inflammation, measurement controversy, Frontiers in Neuroscience