The experiment enrolled 72 university students aged 19 to 30 — 36 women and 36 men — all fluent readers of the Quran and in general good health, recruited at Bayburt University in Türkiye. The study was led by psychology-of-religion researcher Süheyb Okur of the university’s Faculty of Theology, working with physiotherapy researcher Bülent Bayraktar of its Faculty of Health Sciences. The sample size was fixed in advance using G*Power software to deliver 80 percent statistical power at a 95 percent confidence interval, and participants were randomly assigned to one of two matched groups. The experimental group spent exactly five minutes reciting verses 195 through 200 of Surah Al-i Imran from a Mushaf, the bound physical copy of the Quran, aloud, clearly, and in the measured cadence demanded by Tajwid recitation rules. The control group simply rested for five minutes in an isolated, quiet room with eyes closed, avoiding sleep, speech, and any deliberate cognitive task — a passive baseline chosen to isolate the combined effect of vocalization, breath control, and focused reading against the body’s homeostatic state. Because salivary biochemistry is easily perturbed, participants avoided food, drink, tooth brushing, and tryptophan-rich foods such as red meat, eggs, fish, nuts, seeds, and yogurt for an hour beforehand, and samples were collected between 08:00 and 09:00 to control for cortisol’s natural daily rhythm.

Behind the design sits an explicit neurotheological framework that the authors present as a testable model rather than a loose metaphor. Recitation, they argue, is a compound mind-body intervention built from three interacting components. The first is rhythmic respiration and vocalization: the paced breathing and articulated sound required by Tajwid are exactly the kind of controlled breathing known to evoke the relaxation response, tilting the autonomic nervous system away from sympathetic fight-or-flight arousal toward parasympathetic dominance — which in turn suppresses the hypothalamic-pituitary-adrenal axis, the endocrine cascade whose downstream output is cortisol. The second is focused cognitive attention: decoding Arabic script, retrieving Tajwid rules from memory, and sustaining concentration on a complex sacred text is demanding mental work, comparable in kind — if not in duration — to the sustained attention of mindfulness meditation, a practice repeatedly linked to structural change in the brain. The third is affective-spiritual connection, the felt reward of fulfilling a sacred duty and connecting with the text’s meaning. Earlier neuroimaging work has shown that intense religious experiences, from prayer to scripture reading, reproducibly activate reward-processing regions including the nucleus accumbens and caudate nucleus — precisely the circuitry through which dopamine exerts its motivational pull.

Each component was then mapped onto a specific molecule. Cortisol, a steroid hormone produced in the adrenal cortex, is the classic chemical signature of the stress response, although it also governs energy metabolism, blood sugar regulation, immune function, blood pressure, and aspects of memory formation and retrieval. Serotonin, popularly nicknamed the happiness neurotransmitter, modulates mood, sleep, appetite, learning, and memory, and low serotonergic tone is implicated in depression and anxiety. Dopamine, the principal currency of the brain’s mesolimbic reward pathway, drives motivation, pleasure, movement control, and attention, and its imbalance underlies disorders ranging from Parkinson’s disease to addiction. NDNF is the dark horse of the quartet: a secreted neurotrophic protein involved in neuronal survival, development, differentiation, synaptic plasticity, and neuroprotection, with essentially no prior study in any behavioral or spiritual context. All four compounds were measured in saliva using human-specific sandwich ELISA kits, with absorbance read at 450 nanometers, intra-assay coefficients held below 8 percent and inter-assay coefficients below 10 percent, and samples centrifuged at 2,000 g for 20 minutes before storage at minus 80 degrees Celsius.

The biochemical results were strikingly consistent. Salivary NDNF in the recitation group climbed from a mean of 1,106 picograms per milliliter before the session to 1,359 afterward, while resting controls drifted only from 1,099 to 1,106 — a group-by-time interaction of F(1,70) = 117.05, p < .000, the strongest of its kind reported in the study. Serotonin rose from 4.82 to 5.50 nanograms per milliliter in the reciters against a slight drift from 4.59 to 4.77 in controls, with an interaction of F(1,70) = 6.52, p < .013. Dopamine jumped from 7,559 to 8,583 picograms per milliliter while the resting group moved only from 6,405 to 6,720, its interaction reaching F(1,70) = 12.07, p < .001. Cortisol moved the opposite way: reciters fell from 2.01 to 1.85 nanograms per milliliter even as the resting group’s levels rose from 2.01 to 2.15, an interaction of F(1,70) = 70.00, p < .000. A three-way mixed analysis of variance confirmed that the NDNF and dopamine patterns held across sex, while serotonin and cortisol both showed significant interactions involving sex — a hint that men and women may fine-tune those two signals differently during vocal practice.

Correlational analysis wove the four markers into a coherent physiological network, and the numbers land where the theory predicts. NDNF was strongly and negatively coupled to cortisol (r = −.734, p < .001), and positively linked to serotonin (r = .395) and dopamine (r = .322). Cortisol correlated negatively with serotonin (r = −.481) and dopamine (r = −.590), while serotonin and dopamine rose in tandem (r = .498) — a pattern consistent with the dense cross-talk described in the basic literature, where serotonergic signaling regulates dopamine release and elevated glucocorticoids erode serotonin function. Self-reported well-being tracked the chemistry in the expected direction, correlating positively with serotonin (r = .323) and dopamine (r = .280) and negatively with cortisol (r = −.236), all statistically significant, while NDNF’s association with well-being was positive but non-significant (r = .185). Read as a whole, the network describes a brain sliding out of defensive mode and into a state more permissive for trophic maintenance and reward signaling — the molecular shadow of a relaxation response, captured in saliva.

Then came the twist that complicates the story. Immediately after the intervention, all participants completed the seven-item Warwick-Edinburgh Mental Well-Being Scale, a validated, unidimensional instrument adapted into Turkish, with a Cronbach’s alpha of 0.727 in this sample. The passive resting group scored significantly higher — a mean of 26.47 against 24.22 for the reciters — and the difference held under two-way analysis of variance (F(1,68) = 5.277, p = .025), with no effect of gender. The study’s fifth hypothesis, that the neurochemical gains would surface as higher self-reported well-being, was flatly rejected. The authors offer layered explanations. Reciting scripture in an observed, experimental setting may have induced performance anxiety — worry about delivering a correct Tartil recitation — that counteracted the practice’s immediate spiritual benefits, a pressure the resting group never faced. Recitation is also, by the study’s own framing, cognitively demanding work: five minutes of intensive decoding and articulation may be briefly fatiguing where ordinary rest is purely restorative. And the measurement tool itself may share the blame, because trait-oriented well-being scales are slow to register the minute-scale fluctuations that salivary biomarkers capture with ease.

The NDNF result may prove the study’s most durable contribution. No previous research has examined Quran recitation in relation to this molecule, and its sharp rise — roughly 20 percent within five minutes — alongside a strong inverse coupling to cortisol fits a growing literature suggesting that contemplative practices can bias the brain toward plasticity and repair. The authors interpret the pattern as objective evidence of a reparative shift: as stress physiology is downregulated, conditions improve for the trophic signaling that supports neuronal survival and synaptic maintenance. The parallel surges in serotonin and dopamine complete the picture, with the spiritual satisfaction of a devotional act plausibly engaging the mesolimbic reward pathway and the rhythm of measured vocalization recruiting autonomic circuits shared with slow-breathing relaxation techniques. The cortisol data carry one more nuance: levels fell after recitation but rose slightly after passive rest, suggesting the recitation may have buffered a mild anticipatory arousal that even quiet resting did not prevent.

The caveats are substantial. Every participant was a student at a single Turkish university who already knew how to read the Quran and presumably carried some baseline of religious belief; the researchers did not measure degrees of religiosity and included no non-believer comparison group. Because the hypothesized dopamine reward depends heavily on the subjective spiritual value of the text, the authors caution that the same neurochemical response may not generalize to people outside the tradition or unfamiliar with its cultural context. The intervention was a single five-minute laboratory session, the sample was modest, and the general well-being questionnaire may have been too blunt to detect acute state changes that a dedicated state-anxiety or mood inventory would have caught. Salivary measurements, meanwhile, capture peripheral signals whose relationship to central neurotransmitter release remains indirect — a reminder that saliva provides a proxy, not a window, into the living brain.

Future work, the team argues, must escape the one-shot design. Longitudinal protocols with repeated sessions would test whether transient neurochemical spikes consolidate into trait-level well-being and durable neuroplastic adaptation, and whether the performance anxiety of a single supervised session fades with practice. To separate the active ingredients — rhythmic vocalization, cognitive processing, and spiritual meaning — the authors propose multi-arm trials adding listening-only, silent reading, and secular-text control conditions. For now, the study stands as one of the first controlled demonstrations that a brief, structured vocal-spiritual practice can push stress and neuroplasticity biomarkers in a favorable direction within minutes, while documenting with unusual candor the gap between what the blood reports and what the mind admits to feeling. At the intersection of neuroscience and religious practice, that gap may turn out to be the most interesting finding of all.