The Effect of Melatonin Supplement on High Arterial Blood Pressure: An Overview from Clinicaltrials.gov

Introduction

Blood pressure is the force exerted by the blood against the walls of the arteries as the heart pumps it throughout the circulatory system. It is typically measured in millimeters of mercury (mmHg) and expressed as two values: systolic pressure over diastolic pressure. High blood pressure, also known as hypertension, is a significant global health concern contributing to an increased risk of cardiovascular diseases, stroke, and other adverse health outcomes. Hypertension affects an estimated almost one-third of the adult population worldwide, making it a critical public health issue.¹ As a result, interest has been growing in identifying novel therapeutic strategies and dietary supplements that may help regulate blood pressure and mitigate the risks associated with hypertension.^2,3 One such dietary supplement that has gained attention in recent years for its potential impact on arterial blood pressure is melatonin.^3,4

Melatonin is a hormone produced by the pineal gland primarily at night, and it plays a vital role in regulating the circadian rhythm and sleep-wake cycle.^5,6 Beyond its role in sleep regulation, melatonin has been suggested to possess various cardiovascular benefits, including the potential to lower blood pressure.⁴ This has led to a surge in research investigating the relationship between melatonin supplementation and arterial blood pressure.^4,7 Many studies have shown that melatonin’s impact on blood pressure regulation can be multifaceted. It is believed to influence blood pressure through its interaction with various physiological pathways, including the renin-angiotensin-aldosterone system (RAAS), nitric oxide (NO) production, and sympathetic nervous system (SNS) activity.⁸ Several studies showed that melatonin administration can reduce blood pressure by modulating the activity of these pathways. For example, melatonin has been found to inhibit the release of renin and aldosterone, which are key regulators of blood pressure.⁷ Additionally, melatonin’s antioxidant properties may help protect vascular endothelial cells from oxidative stress, further contributing to its potential antihypertensive effects.⁸ In this study, we used results from ClinicalTrials.gov to examine the effectiveness of melatonin on high arterial blood pressure.

Methods

Search Strategy

On October 10^th, 2023, a thorough investigation was performed on ClinicalTrials.gov to identify all relevant studies regarding the effect of melatonin as a supplementary intervention for hypertension and associated indications. The term “melatonin and hypertension” was entered into the search engine website to generate pertinent results. The utilization of such a specific search query aimed to generate a focused and refined set of results, contributing to the comprehensive understanding of the current landscape of research on melatonin’s role as an intervention for hypertension and related conditions.

Reviewing Search Results

The procedure for identifying appropriate clinical trials relied on specific criteria detailed in the area of interest of the research. The inclusion criterion for clinical trials investigating hypertension was that such trials were required specifically to demonstrate the effect of melatonin as a treatment. Clinical trials that did not demonstrate the effect of melatonin as a treatment were excluded from the review.

Data Extraction

Several data, including study title, type, intervention details, status, and outcome, were collected from the website.

Results

Analysis of the Number of Clinical Trials Relevant to the Review

An inclusive search of the ClinicalTrials.gov website on October 10th, 2023, indicated 13 registered trials specific to hypertension. These identified clinical trials were carefully documented and focused on the potential of melatonin as a supplementary treatment for hypertension.

Only three of the thirteen registered trials focused on the impact of melatonin, thus aligning with our inclusion criteria and research objectives – Table 1. The three clinical trials are reported as completed, have results, and are interventional and observational. Table 1 details the study titles, conditions, statuses, enrollment sizes, interventions, and outcome measures. The data gathered from these three clinical trials will assist our understanding of the potential risks and benefits of melatonin in relation to hypertension.

Table 1 Data from https://clinicaltrials.gov, Updated on October 10th, 2023

There were 93 participants in the included clinical trials and all of the studies were in Phase II of the clinical trials.

Discussion

In recent years, clinical trials investigating the effects of melatonin supplements on human blood pressure have yielded mixed results.^3,12 Some studies have reported a modest reduction in blood pressure with melatonin supplementation, particularly in individuals with hypertension or at risk of developing hypertension.¹² However, the magnitude of the blood pressure-lowering effect varies among studies, and not all have demonstrated a significant impact.¹³ Factors such as dosage, duration of supplementation use, and the baseline blood pressure of participants may contribute to the variability in study outcomes.^13,14 Regarding safety and contraindications, melatonin is generally considered safe when used for short-term purposes, such as adjusting sleep patterns. However, the long-term safety of melatonin supplements, especially in high doses, is still a subject of ongoing research.¹⁵ Individuals with specific medical conditions or those taking medication should consult with healthcare professionals before starting melatonin supplementation due to potential interactions and side effects.

Conclusion

Melatonin’s potential as a dietary supplement for regulating arterial blood pressure is a subject of ongoing research and debate. While some evidence suggests a favorable impact, more extensive and rigorous studies are needed to establish its effectiveness and safety as an antihypertensive agent. As our understanding of melatonin’s mechanisms and its relationship with blood pressure continues to evolve, it holds promise as a complementary approach to managing hypertension, but cautious optimism should guide both research and clinical practice.