Research Appraisals
Evidence-based critical appraisals of the latest medical research, systematically evaluated using Oxford CEBM methodology.
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PloS one
Effects of peppermint (Mentha x piperita L.) oil on cardiometabolic outcomes in patients with pre- and stage 1 hypertension: A placebo randomized controlled trial.
Hypertension represents the predominant risk factor for cardiovascular disease morbidity and mortality; with significant healthcare utilization and expenditure. Pharmaceutical management is habitually adopted; although its long-term effectiveness remains ambiguous, and accompanying adverse effects are disquieting. Peppermint, which is rich in menthol and flavonoids, may exert potential benefits relevant to hypertension. This trial aimed to explore the effects of twice-daily peppermint oil supplementation in individuals with pre- and stage 1 hypertension. A 20 day, parallel randomized, placebo-controlled trial was adopted (NCT05561543). 40 individuals with pre- and stage 1 hypertension were randomly assigned to receive 100 μL per day of either peppermint oil or peppermint-flavoured placebo. The primary trial outcome was the between-group difference in systolic blood pressure from baseline to 20 days. Secondary outcome measurements were the between-group differences in anthropometric, haematological, diastolic blood pressure/resting heart rate, psychological wellbeing, and sleep efficacy indices. Statistical analysis was conducted on an intention-to-treat basis using baseline-adjusted linear regression models comparing post intervention values between trial arms with the corresponding baseline value entered as a covariate; adjusted mean differences (b), 95% confidence intervals, and effect sizes (d) were calculated. In relation to the primary outcome, adjusted systolic blood pressure at 20 days was significantly lower (b = -8.48 mmHg, 95% CI = -14.24 to -2.73, d = -0.94) in the peppermint trial arm (baseline = 130.05 mmHg, 20 days = 121.97 mmHg) than in placebo (baseline = 130.93 mmHg, 20 days = 131.05 mmHg). Loss to follow-up (N = 1) and adverse events (N = 1) were low, both occurring in the peppermint arm, and compliance was very high in the peppermint (93.3%) trial arm. Given the substantial health and economic burden associated with hypertension worldwide, these findings suggest that twice-daily peppermint supplementation may represent a simple, low-cost, and well-tolerated strategy to support blood pressure reduction in this population. Trial registration ClinicalTrials.gov NCT05561543.
27 Apr 2026
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Acupuncture for primary hypertension: a systematic review and meta-analysis of randomised controlled trials
OBJECTIVE: This systematic review and meta-analysis evaluated the efficacy and safety of acupuncture for primary hypertension, based on randomised controlled trials (RCTs) published between 2015 and 2024. METHODS: We searched seven major databases for RCTs comparing acupuncture to control interventions. The primary outcomes were changes in systolic blood pressure (SBP) and diastolic blood pressure (DBP). Meta-analyses utilised random-effects models, and the Cochrane Risk of Bias tool assessed study quality. RESULTS: Seven RCTs (n = 812) were included. Acupuncture was associated with lower SBP [mean differences (MD) = -6.73 mmHg, 95% confidence interval (CI): -8.84 to -4.62] and DBP (MD = -6.59 mmHg, 95% CI: -9.42 to -3.76). Heterogeneity was substantial for SBP (I2 = 73.3%) and considerable for DBP (I2 = 90.9%). Notably, the SBP analysis included seven studies, whereas the DBP analysis included six studies, and the similar absolute pooled reductions should be interpreted cautiously, given the small and not fully overlapping study sets. Exploratory subgroup analyses suggested blood pressure reductions across several acupuncture modalities, though each subgroup contained very few studies. Adverse-event reporting was limited and inconsistent across studies. Formal tests for publication bias were underpowered given the small number of included studies. CONCLUSIONS: Acupuncture may have blood pressure-lowering effects in patients with primary hypertension, but the evidence is limited by substantial heterogeneity, a small number of studies and considerable variation in intervention type and exposure. Larger, well-designed, multi-centre RCTs with standardised protocols and longer follow-up are needed to confirm these findings and establish optimal treatment parameters. High blood pressure (hypertension) is a major health concern worldwide. Acupuncture, a component of traditional Chinese medicine, has been used to manage blood pressure, but evidence of its effectiveness remains limited. This review examined seven recent randomised controlled trials involving 812 participants to assess whether acupuncture reduces blood pressure in people with primary hypertension. The findings suggest that acupuncture may reduce both systolic and diastolic blood pressure; however, the included studies were few and varied considerably in the type of acupuncture used, the number of treatment sessions (ranging from a single session to 60 sessions over 12 weeks) and the populations studied. Reported side effects were minor, such as temporary pain at the needle site, though safety reporting was incomplete. Therefore, while the results are encouraging, they are not definitive. Further large-scale, rigorously designed trials are needed before firm conclusions can be drawn about the role of acupuncture in hypertension management.
20 Apr 2026
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