Ramadan Fasting Raised BDNF by 47% and Serotonin in 29 Healthy Adults: What the Research Shows

Medical disclaimer: This article summarises published research for informational purposes only. It is not medical advice and is not a substitute for guidance from a qualified health professional. Always consult your doctor before starting any fasting protocol, especially if you have an existing health condition or take medication.

Study at a Glance

What This Study Looked At

Researchers at Shahid Beheshti University in Tehran set out to measure what happens to four key neurochemicals — serotonin, dopamine, BDNF, and NGF — in the blood of healthy adults practicing Ramadan fasting. Ramadan fasting is a form of time-restricted eating in which all food and drink are avoided from dawn to sunset, creating a daily fasting window of approximately 15–17 hours. This makes it directly comparable to the 16:8 and 18:6 protocols that millions of people practice worldwide. The study is one of the few to directly measure neuroprotective proteins in human blood during a structured intermittent fasting period, making it valuable for anyone interested in intermittent fasting's effects on brain health.

Who Was Studied

Participant profile: 29 adults — 22 women (76%) and 7 men (24%). All were healthy with no reported chronic conditions. Blood was drawn at three time points: 2 days before Ramadan (baseline), day 14 of Ramadan (mid-fast), and day 29 of Ramadan (end of the month).

How Ramadan fasting works: Participants abstained from all food and water from the Fajr (dawn) prayer to the Maghrib (sunset) prayer — approximately 15–17 hours per day. Eating occurred only during the nighttime window. This is a naturally occurring, culturally practiced form of daily intermittent fasting with a compulsory eating window in the evening hours.

What the Researchers Found

BDNF (Brain-Derived Neurotrophic Factor)

• BDNF rose by 47% by the final day of Ramadan compared to pre-fasting levels — the headline finding of the study.
• The increase was progressive: BDNF at day 29 was significantly higher than at day 14, suggesting the brain-protective effect builds over the duration of the fasting period rather than plateauing.
• The pattern in women (who made up 76% of the sample) matched the pattern in the full group.

Serotonin

• Serotonin — the neurotransmitter most associated with mood stability, emotional resilience, sleep quality, and protection against depression — rose progressively and significantly throughout the full month of Ramadan.
• The progressive increase mirrors the BDNF pattern, suggesting the neurochemical benefits of fasting accumulate with duration.

NGF (Nerve Growth Factor)

• NGF, which supports the survival and maintenance of neurons throughout the nervous system, rose by 23.2% over the full month.
• Like BDNF, the increase was progressive across both measurement points.

What Did Not Change

• Dopamine showed no statistically significant difference at either time point (day 14 or day 29) compared to baseline. The reward and motivation neurotransmitter appears not to be directly modulated by daily intermittent fasting of this duration in healthy adults.

What the Researchers Concluded

The researchers concluded that Ramadan fasting — a structured form of daily intermittent fasting — significantly increased plasma BDNF, serotonin, and NGF in healthy adults over 29 days, while dopamine was unaffected. They proposed that the mood and wellbeing benefits widely reported during Ramadan may be at least partly explained by these measurable neurochemical changes, independent of spiritual or social factors.

What This Means If You Fast

• The brain responds measurably to daily fasting. A 47% rise in BDNF over 29 days is a clinically meaningful change. BDNF supports neurogenesis, protects existing neurons, and is associated with reduced risk of depression and age-related cognitive decline. This study provides direct human evidence supporting fasting's benefits for brain function and focus.
• The mood elevation during fasting is biological, not just willpower. The progressive serotonin rise throughout Ramadan suggests that the calm, focused wellbeing fasters describe isn't just psychological — it has a measurable neurochemical basis that builds over weeks of consistent practice.
• Nerve growth factor supports long-term neurological health. A 23% increase in NGF is relevant for anyone concerned with peripheral nerve health, sensory function, and the neurological effects of aging. Fasting appears to be a non-pharmacological way to support this system.
• The benefits build — they don't plateau. Both BDNF and NGF were higher at day 29 than day 14, with both time points significantly above baseline. This supports treating intermittent fasting as a long-term lifestyle practice rather than a short-term intervention.
• Standard 16:8 fasting windows are sufficient. This study used approximately 15–17 hour daily fasting windows — comparable to a standard 16:8 protocol. Extreme multi-day fasting is not required to achieve neuroprotective effects.
• The euphoria of deep fasting has a biochemical explanation. Many fasters report a distinct sense of mental clarity and elevated mood during extended fasting. This study provides part of the biochemical explanation: rising serotonin and BDNF, not hunger-induced altered perception.

Study Limitations

• Small sample size (n = 29): The findings are promising but need replication in larger, more diverse populations before strong conclusions can be drawn.
• Gender imbalance: 76% of participants were women. While the results in women matched the overall group, the male subsample (n = 7) is too small to draw conclusions about sex-specific differences.
• No independent control group: All participants fasted — there was no group of non-fasting individuals measured in parallel. Changes are relative to each participant's own pre-Ramadan baseline, which limits causal conclusions.
• Cultural and spiritual context: Ramadan occurs within a specific cultural, social, and spiritual framework. Factors including increased communal activity, sleep pattern changes, and spiritual motivation may contribute to neurochemical changes independently of fasting itself.
• No dietary records for the eating window: The study did not track what participants ate during the nighttime eating period. Food quality, caloric intake, and macronutrient composition during refeeding windows could all affect BDNF and serotonin independently.
• No long-term follow-up: The study ended at day 29. Whether BDNF and serotonin elevations persisted after Ramadan ended is unknown.
• Journal impact: Neurology International is a peer-reviewed MDPI journal but not a top-tier journal by impact factor (e.g., NEJM, JAMA, Cell Metabolism). The findings are preliminary until replicated in higher-powered studies.

Source

Bastani A, Rajabi S, Kianimarkani F. (2017). The Effects of Fasting During Ramadan on the Concentration of Serotonin, Dopamine, Brain-Derived Neurotrophic Factor and Nerve Growth Factor. Neurology International, 9(2), 7043. doi:10.4081/ni.2017.7043. PMID: 28713531

Frequently Asked Questions

How much did BDNF increase during Ramadan fasting?

BDNF increased by 47% by day 29 of Ramadan compared to pre-fasting baseline. The increase was progressive — significantly higher at day 29 than day 14 — suggesting the neuroprotective effect builds over the duration of consistent fasting practice.

Does intermittent fasting increase serotonin levels?

This study found that serotonin rose progressively and significantly over 29 days of daily fasting (~15–17 hours/day) in 29 healthy adults. Whether equivalent increases occur with shorter fasting protocols (e.g., less than 30 consecutive days) requires further research, but the biological mechanism is plausible: lower insulin and higher BDNF both support serotonergic function.

What is BDNF and why does it matter for fasting?

BDNF (Brain-Derived Neurotrophic Factor) is a protein that promotes the growth of new neurons, protects existing brain cells, and strengthens synaptic connections. Higher BDNF is associated with better memory, improved mood, reduced risk of depression, and protection against age-related cognitive decline. Fasting, exercise, and certain dietary patterns are among the most accessible non-pharmacological ways to elevate it.

Can a 16:8 fast raise BDNF the way Ramadan fasting does?

The fasting windows in this study (~15–17 hours) overlap directly with a 16:8 or 18:6 protocol. The key variable that may differ is duration: Ramadan involves 29 consecutive days of daily fasting. Whether shorter-term 16:8 practice (a few weeks rather than a full month) produces comparable BDNF increases is an open research question — but the fasting window itself is directly comparable.

Why didn't dopamine change in this study?

Dopamine synthesis and regulation respond primarily to novel stimuli, rewards, and movement — not to nutritional state in the same direct way as serotonin and BDNF. In healthy adults with no dopamine-related conditions, daily intermittent fasting appears not to acutely modulate dopamine levels. Longer or more intensive fasting protocols (48–72 hour fasts) may have different effects on dopamine receptor sensitivity, which this study was not designed to capture.

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