The Biology of BDSM: What Cortisol, Endorphins, and Endocannabinoids Actually Do

Psychology and Neuroscience of Kink

Estimated reading time: 20 minutes

Reader promise: This article explains, accurately and without overstatement, what the scientific research shows about the biological and neurological processes involved in Bondage, Discipline, Dominance, Submission, Sadism, and Masochism (BDSM). It covers what happens in the bodies of Dominants and submissives during scenes, what altered states of consciousness the research has documented, and what the evidence means and does not mean for how we understand kink.

The Question Science Finally Started Asking

For most of the history of Western medicine, the question asked about BDSM practitioners was: what went wrong? What trauma, what developmental failure, what psychological defect produced this? The research that spent decades trying to answer that question found very little, largely because the premise was wrong. More recent science has started asking a more productive question: what actually happens, biologically, when people practise consensual BDSM? What does the body do during a scene? What does the brain do? And what do those findings tell us about why people pursue these practices, what they get from them, and how they work as experiences?

The answers that have emerged from a small but growing body of research are genuinely interesting. They do not confirm the old pathological picture. They reveal a biologically coherent set of responses involving the stress system, the reward system, and specific neurological states that help explain why BDSM is experienced as pleasurable, bonding, and in some cases psychologically transformative. This article presents that research carefully, notes its limitations honestly, and offers a framework for understanding what the science currently says and where the significant gaps remain.

The Key Study: Wuyts and Colleagues, 2020

The most directly relevant biological study of BDSM to date was conducted by Wuyts, De Neef, Coppens, Fransen, Schellens, Van Der Pol, and Morrens, published in the Journal of Sexual Medicine in 2020. The researchers recruited 35 BDSM couples, each consisting of a Dominant and a submissive partner, and compared their biological markers before and after an active BDSM interaction against a control group of 27 non-BDSM individuals tested during a normal social interaction. Biological measurements included cortisol, beta-endorphins, and endocannabinoids (specifically anandamide and 2-AG), giving the study a multi-hormone picture of what the body does during BDSM practice.

The findings were specific and role-differentiated. Submissives showed increases in both cortisol and endocannabinoid levels as a result of the BDSM interaction. Dominants showed increased endocannabinoid levels only when their interaction involved power play, not necessarily impact play or other physical elements. Beta-endorphin levels did not show the statistically significant changes the researchers had predicted, which they noted as a limitation and a finding requiring further investigation. Oxytocin levels, the bonding hormone that had been theorised to play a role in BDSM intimacy, showed no significant changes across the group as a whole, though the researchers noted this result required cautious interpretation given the study’s limitations.

The study was explicitly described by its authors as a pilot study, limited by sample size, geographic specificity (a Flemish Belgian BDSM community), and the complexities of measuring hormone levels in naturalistic conditions. These limitations are important and the findings should not be overstated. What the study provides is not a complete biological account of BDSM but a promising first empirical look at real-time biological changes during consensual BDSM practice. The findings are suggestive and deserve replication with larger and more diverse samples.

What These Hormones Actually Do

Cortisol and the Stress Response

Cortisol is the body’s primary stress hormone, produced by the adrenal glands in response to real or perceived threat. It mobilises energy, heightens alertness, and prepares the body for demanding physical or psychological challenges. The finding that cortisol increased in submissives during BDSM interactions is counterintuitive only if we assume that a pleasurable experience cannot also involve a genuine physiological stress response. In fact, the stress response is not inherently negative. It is a biological system that activates in conditions of challenge, intensity, and arousal as well as danger.

Wuyts and colleagues noted that BDSM interactions can be compared in this respect to other activities that are both stressful and rewarding: long-distance running, riding roller coasters, and watching horror films all involve activating the stress response system in service of an ultimately pleasurable experience. The cortisol elevation in submissives reflects the real physical and psychological intensity of a BDSM scene rather than a contradiction of its pleasurability. That Dominants did not show the same cortisol increases is consistent with the different role they play: directing and controlling the scene rather than experiencing its physical and psychological intensity in the same way as the submissive.

Endocannabinoids and the Reward System

Endocannabinoids are naturally occurring compounds produced by the body that interact with the same receptor system as cannabis. They include anandamide (from the Sanskrit word for bliss) and 2-arachidonoylglycerol (2-AG). The endocannabinoid system plays roles in pain modulation, pleasure, appetite, memory, and emotional regulation. Elevated endocannabinoid levels have been associated with the pleasurable feelings produced by exercise, including the phenomenon commonly known as runner’s high.

The finding that both submissives and Dominants showed elevated endocannabinoid levels during BDSM interactions provides a direct biological indicator of pleasure activation. For submissives, increases were associated particularly with impact play. For Dominants, increases were associated with power play rather than impact play, which is consistent with the psychological account of Dominance as fundamentally about authority and control rather than about physical sensation. This role-specific pattern is one of the most interesting aspects of the Wuyts et al. (2020) findings: the biology of BDSM is not uniform across participants but reflects the different psychological and physical experiences of the Dominant and submissive roles.

Endorphins: Expected But Elusive

Beta-endorphins are endogenous opioid peptides produced by the body that bind to opioid receptors and produce pain relief and feelings of pleasure. They have long been theorised as central to the pleasurable aspects of impact play and pain play in BDSM, and the subjective experiences that practitioners describe, including the characteristic altered state sometimes called subspace, have often been attributed partly to endorphin release. The Wuyts et al. (2020) study did not find the significant beta-endorphin increases that the researchers had predicted. This finding should not be dismissed but should be held appropriately: the study was a pilot study with a limited sample size, and the absence of a finding in a small sample does not constitute strong evidence that endorphin involvement is absent. It is a finding that requires further investigation with larger samples before firm conclusions can be drawn.

The Systematic Review: Wuyts and Morrens, 2022

In 2022, Wuyts and Morrens published a systematic review in the Journal of Sexual Medicine that brought together all existing literature on the biology of BDSM. The review analysed ten studies meeting their inclusion criteria and concluded that there is evidence for cortisol changes in submissives as a result of BDSM interactions, suggesting involvement of the physiological stress system, and that endocannabinoid changes implicate the pleasure and reward system. In Dominants, biologically measured pleasure appeared to be dependent on power play rather than pain play. The review noted that oxytocin was largely unchanged across studies and that the endorphin picture remained unclear.

Crucially, the review also noted that in recent years the perspective on BDSM has shifted from viewing it as a pathological and taboo niche practice toward viewing it as a healthy form of intimacy. The biological evidence contributes to this shift by demonstrating that BDSM produces recognisable reward-system activation: these are not disordered responses but the same biological systems that activate during any intensely pleasurable and physically or psychologically demanding human activity.

Altered States of Consciousness: The Ambler Study

While the Wuyts studies addressed hormonal responses, Ambler, Lee, Klement, Loewald, Comber, Hanson, Cutler, Cutler, and Sagarin (2017) addressed a different and equally important question: do BDSM activities actually produce the altered states of consciousness that practitioners frequently describe? The study, published in the journal Psychology of Consciousness: Theory, Research, and Practice, assigned fourteen experienced BDSM practitioners randomly to either the top role (the Dominant: the person providing stimulation, orders, or structure) or the bottom role (the submissive: the person receiving stimulation or following orders) for a BDSM scene.

The results documented two distinct, role-specific altered states. Topping was associated with an altered state that matched the characteristics of Csikszentmihalyi’s (1991) flow: a state of complete absorption in an activity, in which awareness of everything outside the task dissolves and performance feels effortless and intrinsically rewarding. Athletes, musicians, surgeons, and chess grandmasters describe flow. The finding that Dominants in BDSM scenes enter comparable states is significant. It positions skilled Dominant practice not as an exercise of casual control but as a demanding, absorbing craft that produces the same neurologically distinctive experience as elite performance in other domains.

Bottoming was associated with a different altered state, one that matched Dietrich’s (2003) model of transient hypofrontality. This model describes a temporary reduction in activity in the prefrontal cortex, the brain region associated with executive function, self-monitoring, planning, and deliberate rational thought. Transient hypofrontality has been documented during intense physical exercise and other absorbing activities. When prefrontal activity is reduced, self-consciousness diminishes, internal narrative quietens, and experience becomes more immediate and less filtered. This neurological model offers a coherent biological account for the subjective descriptions practitioners give of subspace: the quieting of internal chatter, the sense of floating or detachment, the dissolution of ordinary self-awareness into a more immediate and unmediated state of experience.

The Ambler et al. (2017) study was small, with fourteen participants, and the authors themselves described it as preliminary. The findings should be understood as promising rather than definitive. However, the specificity of the role-differentiated results, the use of validated psychological measures (the Flow State Scale and a Stroop test measuring executive function), and the consistency of the findings with both subjective practitioner accounts and broader neuroscientific frameworks give them considerable theoretical credibility that warrants further investigation.

What Subspace Is, Biologically

Subspace is the term practitioners use to describe the altered psychological and emotional state that submissives may enter during intense BDSM scenes. It is characterised subjectively by a sense of floating or detachment, a dissolution of ordinary self-consciousness, an experience of profound present-moment awareness, and, in many accounts, a sense of deep peace, vulnerability, and connection with the Dominant. The biological account of subspace that emerges from the research combines several elements: the cortisol-mediated stress response documented by Wuyts et al. (2020), the endocannabinoid-driven pleasure activation, and the transient hypofrontality documented by Ambler et al. (2017).

Together, these mechanisms suggest that subspace is produced by a combination of physiological stress-response activation, reward-system stimulation, and a temporary quieting of the executive and self-monitoring functions of the prefrontal cortex. The result is an experience that practitioners describe in terms strikingly similar to the states produced by meditation, intense exercise, and certain altered states induced by other means. This is not coincidental. The brain does not have a dedicated subspace circuit. It has systems that produce particular kinds of experience under particular kinds of conditions, and BDSM creates conditions that activate those systems in specific and recognisable ways.

The aftercare requirement that experienced practitioners know well, the period of careful, warm, attentive care following an intense scene, has a biological rationale. Coming down from the hormonal and neurological state of subspace involves a cortisol reduction, a settling of the reward system, and a gradual return of ordinary prefrontal function. This transition can produce the emotional vulnerability and potential distress known as sub drop. Understanding subspace biologically helps explain why aftercare is not an optional luxury but a physiological necessity: the body and the brain need time and support to return to baseline after the specific demands of a BDSM scene.

Domspace: The Dominant’s Altered State

Less discussed than subspace but equally real is the altered state that experienced Dominants sometimes describe, variously called domspace or top space. The Ambler et al. (2017) finding that Dominants enter a flow-like state during scenes is consistent with practitioner accounts of deep absorption, heightened focus, and a sense of seamless competent action in which the Dominant’s attention is entirely on the submissive and the unfolding scene. Flow, as described by Csikszentmihalyi (1991), is intrinsically rewarding and is associated with peak performance and deep engagement. The Dominant in a BDSM scene who enters flow is not disengaged or detached. They are maximally present and maximally absorbed in the demands of their role.

The endocannabinoid elevation found specifically in response to power play in Dominants by Wuyts et al. (2020) is consistent with this picture: the biological reward for the Dominant is activated by the experience of authority and control, not by physical sensation in the way that impact play activates the submissive’s reward systems. This role-specific biology underlines a point that experienced BDSM practitioners know well and outsiders often miss: Dominance is not a passive or lesser role. It is a demanding, skilled, and richly rewarding practice with its own specific neurological and hormonal signature.

Important Limitations of the Current Research

The biological research on BDSM is genuinely interesting but genuinely limited, and intellectual honesty requires saying so clearly. The total number of published studies examining biological responses during BDSM is small. The largest single study, Wuyts et al. (2020), used 35 BDSM couples and 27 controls, which is a modest sample by the standards of biological psychology research. Most studies have been conducted in Western European or North American contexts and cannot be assumed to generalise to BDSM practitioners in other cultural settings. The field is also complicated by the difficulty of studying sexual and intimate behaviour in controlled conditions without the experimental setting itself altering the behaviour being studied.

The Ambler et al. (2017) study used only fourteen participants, making it genuinely preliminary. The specific hormonal pathways producing subspace remain incompletely characterised. The role of oxytocin, the bonding hormone, is unclear: Wuyts and colleagues found no significant overall changes in oxytocin, but this finding may reflect the limitations of measuring a hormone known for its context-sensitivity in a small and varied sample. The endorphin hypothesis remains unresolved. These gaps are not reasons to dismiss the research but reasons to hold its findings with appropriate scientific humility and to support the further research needed to develop a more complete account.

What the current research does clearly support is the biological reality of BDSM as an experience: these are not imaginary states produced by placebo or wishful thinking but measurable changes in hormonal and neurological function consistent with the subjective experiences that practitioners describe. The framework of pathology is not supported by the biology. The framework of a demanding, rewarding, and biologically grounded human practice is.

Myths and Misconceptions

Myth: The pleasure in BDSM is not real; practitioners are just pretending to enjoy pain.
Reality: Wuyts et al. (2020) found measurable activation of the endocannabinoid reward system in both Dominants and submissives during BDSM interactions. These are biological markers of real pleasure activation, not performance.
Myth: Subspace is just endorphins.
Reality: The biology of subspace appears to involve a combination of cortisol-mediated stress activation, endocannabinoid reward stimulation, and the transient hypofrontality documented by Ambler et al. (2017). The specific role of endorphins remains unclear from current research. Subspace is likely a multi-system neurobiological state rather than the product of a single hormone.
Myth: BDSM is biologically harmful.
Reality: The biological profile documented in research matches that of other intensely engaging and physically demanding rewarding activities: the stress-response activation, reward-system engagement, and altered neurological states are comparable to those produced by endurance exercise, creative performance, and meditation. The systematic review by Wuyts and Morrens (2022) explicitly framed BDSM as a healthy form of intimacy rather than a pathological practice.
Myth: Dominants do not experience anything significant during scenes.
Reality: Ambler et al. (2017) found that Dominants entered flow states during BDSM scenes, and Wuyts et al. (2020) found endocannabinoid increases in Dominants specifically associated with power play. The Dominant role has its own distinct and biologically measurable altered state.
Myth: The science is settled on the biology of BDSM.
Reality: The science is early, small-scale, geographically limited, and contains significant unresolved questions. The existing research is promising and important, but the honest position is that the biological account of BDSM remains incomplete and requires substantially more research before strong conclusions can be drawn.

What Professionals Need to Understand

For healthcare providers, psychotherapists, and mental health professionals, the biological research on BDSM has several practical implications. The existence of measurable stress-response activation during BDSM scenes means that practitioners may present with the physiological markers of stress in clinical contexts related to their BDSM practice without this indicating pathology. Understanding that cortisol elevation is a normal feature of intense BDSM scenes, rather than evidence of distress requiring treatment, requires basic familiarity with this research.

The transient hypofrontality model of bottoming has implications for clinical conversations about consent: a submissive who is deeply in subspace has reduced executive function and reduced capacity for the kind of deliberate rational decision-making that consent frameworks typically assume. This is not a reason to pathologise subspace but a reason to understand why negotiation and limit-setting must happen before scenes begin, not during them. Safe words and pre-negotiated limits function as the rational decision-making capacity that transient hypofrontality temporarily reduces. The biology makes clear why they matter.

The sub drop phenomenon, the emotional vulnerability and potential distress in the hours and days following intense scenes, also has clear physiological roots in the return from the hormonal and neurological state of subspace to baseline. Clinicians who encounter clients experiencing post-scene emotional difficulties should understand this physiological dimension and avoid pathologising a normal part of the BDSM experience that is managed through appropriate aftercare.

Reader Reflection

Consider how you think about the relationship between physical intensity, stress, and pleasure. We accept without difficulty that runners experience the stress response as pleasurable, that horror film audiences enjoy fear, and that the discomfort of a cold bath or challenging exercise can produce wellbeing. The biology of BDSM suggests that the same systems are at work in a different context. Does that framing change how you think about why people seek these experiences? And for those who practise BDSM: does understanding the biological architecture of subspace or flow change how you think about what you are doing and why it matters?

Practical Takeaways

BDSM produces measurable, role-specific biological changes. Submissives show cortisol and endocannabinoid increases; Dominants show endocannabinoid increases linked specifically to power play. These are real biological responses, not imaginary or performed ones.
Subspace has a coherent neurobiological account. The combination of stress-response activation, reward-system stimulation, and transient hypofrontality (temporary reduction in prefrontal executive function) offers a biologically grounded explanation for the altered state practitioners describe.
Dominance involves genuine altered states, specifically flow. Ambler et al. (2017) found that Dominants enter Csikszentmihalyi’s flow state during BDSM scenes. This is the same state documented in elite athletes, performers, and skilled practitioners of demanding crafts.
Aftercare has a biological rationale. The physiological state of subspace involves hormonal and neurological changes from which the body needs time and support to return. Sub drop is not purely psychological but has physiological roots.
The research is promising but limited. All existing studies are small, most are Western, and many key questions remain unresolved. Findings should be presented as what they are: important early evidence, not settled science.
For professionals: pre-scene negotiation is physiologically essential. The transient hypofrontality of deep subspace means that meaningful consent decisions cannot be made during an intense scene. Negotiation must happen beforehand, and this has a clear neurobiological basis.

Conclusion

The science of BDSM is young, limited in scale, and full of unresolved questions. But what it has already established is worth stating clearly. BDSM produces real, measurable, role-specific biological changes consistent with a demanding, pleasurable, and neurologically distinctive human experience. The stress response activation in submissives, the reward-system engagement in both Dominants and submissives, and the altered states of consciousness documented in both roles are not curiosities or anomalies. They are evidence that BDSM works the way practitioners say it works: as an experience that engages the body and brain at a deep level, producing states of intense pleasure, altered consciousness, and profound connection that have a coherent biological architecture.

The old question, what went wrong to produce this, was always the wrong question. The right question, what is actually happening here, is beginning to get the serious scientific attention it deserves. The answers so far are, by any reasonable assessment, fascinating. The answers still to come, with larger samples, greater diversity, and more sophisticated neuroimaging, will be more fascinating still.

References

Ambler, J.K., Lee, E.M., Klement, K.R., Loewald, T., Comber, E.M., Hanson, S.A., Cutler, B., Cutler, N., and Sagarin, B.J. (2017). Consensual BDSM facilitates role-specific altered states of consciousness: A preliminary study. Psychology of Consciousness: Theory, Research, and Practice, 4(1), 75-91. https://doi.org/10.1037/cns0000097
Csikszentmihalyi, M. (1991). Flow: The Psychology of Optimal Experience. HarperPerennial.
Dietrich, A. (2003). Functional neuroanatomy of altered states of consciousness: The transient hypofrontality hypothesis. Consciousness and Cognition, 12(2), 231-256.
Lecuona, O., Martinez-Barajas, O., Gimeno-Martin, A., Hernansaiz, A., Carrillo-Molina, C., Alcolea-Cantero, R., Rodriguez-Carvajal, R., and de Rivas, S. (2024). Not twisted, just kinky: Replication and structural invariance of attachment, personality, and well-being among BDSM practitioners. Journal of Homosexuality, 72(6), 1079-1108. https://doi.org/10.1080/00918369.2024.2364891
Richters, J., de Visser, R.O., Rissel, C.E., Grulich, A.E., and Smith, A.M.A. (2008). Demographic and psychosocial features of participants in bondage and discipline, “sadomasochism” or dominance and submission (BDSM): Data from a national survey. Journal of Sexual Medicine, 5(7), 1660-1668. https://doi.org/10.1111/j.1743-6109.2008.00795.x
Wuyts, E., De Neef, N., Coppens, V., Fransen, E., Schellens, E., Van Der Pol, M., and Morrens, M. (2020). Between pleasure and pain: A pilot study on the biological mechanisms associated with BDSM interactions in dominants and submissives. Journal of Sexual Medicine, 17(4), 784-792. https://doi.org/10.1016/j.jsxm.2020.01.001
Wuyts, E. and Morrens, M. (2022). The biology of BDSM: A systematic review. Journal of Sexual Medicine, 19(1), 144-157. https://doi.org/10.1016/j.jsxm.2021.11.002