Researchers at University Hospital Zurich and the University of Zurich report that intimate physical contact combined with intranasal oxytocin was associated with modestly faster skin wound healing and lower stress hormone levels in healthy romantic couples.
Social bonds and physical health
Close romantic partnerships have often been linked to better physical health and lower mortality, with quality of the relationship often serving as a stronger predictor of outcomes than relationship status alone. Repeated supportive, affectionate, and intimate interactions in couples have been proposed as one route through which immune function and longevity may improve.
Physical contact represents a central channel for social support during stress, and experimental studies have associated affectionate touch with reduced autonomic activation, lower cortisol, and less subjective stress.
Couple-based interventions that cultivate relationship quality, particularly cognitive-behavioral approaches, have improved both relationship functioning and health outcomes in targeted clinical populations such as individuals with cancer, chronic illness, or mental health conditions, while preventive interventions for the general population remain less frequently studied.
Oxytocin has been considered a neuropeptide mediator of positive social interaction effects on physical and psychological well-being. Animal and human experiments have linked affectionate touch with increases in endogenous oxytocin and have shown that exogenous oxytocin can enhance touch sensitivity and dampen stress responses.
In the study, “Intranasal Oxytocin and Physical Intimacy for Dermatological Wound Healing and Neuroendocrine Stress,” published in JAMA Psychiatry, researchers conducted a double-blind, randomized, placebo-controlled clinical trial to examine how repeated oxytocin administration, a brief couple interaction exercise, and naturally occurring physical intimacy relate to wound healing and stress responses.
Couples were recruited for a preregistered clinical trial at University Hospital Zurich, Switzerland. Participants included 80 healthy heterosexual couples, for a total of 160 participants with a mean age of 27.6 years and a mean relationship duration of almost four years, most of whom were employed and university educated.
Love hurts
Couples attended three laboratory visits over one week. During the first visit, researchers collected questionnaires and urine samples and created four standardized suction-blister wounds on each participant’s forearms using a vacuum-and-heat protocol that separated the dermal-epidermal junction.
Two blisters had tops removed at the first visit and two at the 24-hour visit, with all wounds covered by hydrocolloid bandages.
Oxytocin and placebo dosing
Around 50 minutes after wounding, each partner self-administered a nasal spray containing either intranasal oxytocin or placebo. The oxytocin spray delivered three puffs per nostril for a total dose of 24 IU in the lab, and received sprays for home use at a daily dose of 32 IU administered as two puffs per nostril twice daily for five days. Placebo sprays were identical in composition apart from the absence of oxytocin.
About 45 minutes after spraying, couples were randomly assigned to either a structured interaction, the Partner Appreciation Task (PAT), or an unstructured interaction condition (nPAT).
PAT comprised a 10-minute, video-recorded conversation in which partners used a list of 23 positive relationship characteristics, such as trust, joint planning, and dyadic coping, to guide mutual positive feedback, gratitude, and attention to valued aspects of the relationship. In the control condition, couples spoke freely for 10 minutes while being videotaped.
Wound severity was scored using a revised Photographic Wound Assessment Tool (revPWAT). Two independent raters evaluated each wound for granulation tissue type, granulation tissue amount, wound edges, and skin variability such as erythema, encrustation, or pigmentation. Each dimension received a score from 0 to 4, with total wound severity ranging from 0 to 16. Assessments occurred at one hour, 24 hours, and seven days after wounding.
Intimacy tracking and stress biology
Researchers complemented the laboratory protocol with a five-day assessment using a handheld iDialogPad device. Across six prompts per day, participants indicated whether they had interacted with their partner since the previous entry and classified those interactions as conversation, affectionate touch, sexual activity, conflict, or other categories.
Each prompt also captured momentary emotional state, including a rating on a 5-point scale from very stressed to very relaxed, as well as recent eating, drinking, and sports activity.
Participants also collected saliva samples for cortisol measurement at waking, 30 minutes later, 2.5 hours, 8 hours, 12 hours, and bedtime. Samples were frozen for later analysis.
Oxytocin findings
Wound severity scores declined over time, indicating healing over the seven-day period. Effects of oxytocin alone and PAT alone on revPWAT scores were not significant, and interactions between these factors did not reach significance either.
A three-way interaction among time, oxytocin, and PAT emerged, suggesting that oxytocin was associated with better wound healing for couples instructed to perform the Partner Appreciation Task, but not for those in the unstructured interaction condition.
Sensitivity checks that removed two influential cases weakened the PAT-related oxytocin effect, which then no longer met thresholds for statistical significance.
Intimacy findings
Analyses then focused on physical intimacy measured in daily life through ecological momentary assessment. Models predicting healing between 24 hours and seven days after wounding, adjusted for baseline wound severity, tested affectionate touch and sexual activity separately. In both cases, oxytocin alone and the intimacy measures alone showed no significant main effects on wound severity.
For affectionate touch, a three-way interaction among time, oxytocin, and touch indicated that more frequent daily affectionate touch in the oxytocin group predicted greater improvement in wound healing, whereas affectionate touch in the placebo group showed no such association. Sensitivity analysis retained this effect at a similar magnitude with a statistically significant result.
For sexual activity, a parallel three-way interaction showed that higher levels of daily sexual activity in the oxytocin group were associated with better wound healing, with no corresponding pattern in the placebo group.
After removal of influential cases, this interaction is below significance levels.
Intimacy, cortisol, and perceived stress
Models probing how perceived stress relates to intimacy found that oxytocin administration did not significantly change the likelihood of affectionate touch or sexual activity when examined across the ecological momentary assessment period.
Relaxation ratings predicted affectionate touch and sexual activity, suggesting that participants tended to engage in physical intimacy at times when they already felt more relaxed.
Cortisol analyses showed no main effect of oxytocin administration on aggregated daily cortisol secretion. Cortisol declined across study days, and the number of affectionate touch episodes showed no significant relationship with cortisol. In contrast, more frequent sexual activity across the day was associated with lower daily cortisol levels, independent of oxytocin assignment and other covariates.
Oxytocin takeaways
Investigators concluded that intranasal oxytocin did not function as a simple standalone enhancer of wound healing or stress regulation. Oxytocin showed no consistent effects on healing, intimacy, or cortisol.
Associations with better wound outcomes only appeared when oxytocin coincided with structured positive interaction with naturally occurring affectionate touch and sexual activity.
Authors frame oxytocin as a social amplifier, with a role in modulating the impact of intimate interactions rather than a direct therapeutic agent on its own. Observed links between intimacy, oxytocin, cortisol, and wound healing could provide a basis for future work on interventions that jointly address relationship processes and neurohormonal modulation in health and recovery contexts.
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More information:
Ekaterina Schneider et al, Intranasal Oxytocin and Physical Intimacy for Dermatological Wound Healing and Neuroendocrine Stress, JAMA Psychiatry (2025). DOI: 10.1001/jamapsychiatry.2025.3705
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