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Head-to-head evidence comparison — which supplement is right for you?
B-Complex and Melatonin are closely matched across evidence, studies, and safety.
Verdict
Probably helps
5 of 8 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
19 of 24 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both B-Complex and Melatonin have evidence — compare verdict strength side-by-side.
1 capsule daily (per label)
Morning with breakfast
Methylated B-complex (methylcobalamin, methylfolate)
0.5-1mg
30-60 minutes before bed
Immediate-release tablet or sublingual
B vitamins may interfere with sleep if taken in evening
Take B vitamins in morning, melatonin 30-60 minutes before bed.
2-4 weeks
4-8 weeks
Immediate
Same night
1-3 days
Next morning
First week
Dosage exploration of combined B-vitamin supplementation in stroke prevention: a meta-analysis and systematic review
The American journal of clinical nutrition (2024) · Meta analysis · n=76664
In areas without and with partial folic acid fortification, combined B-vitamin supplementation significantly reduced the risk of stroke by 34% [RR: 0.66; 95% confidence interval (CI): 0.50, 0.86] and 11% (RR: 0.89; 95% CI: 0.79, 1.00), respectively.
A Comparative Study Evaluating the Effectiveness of Folate-Based B Vitamin Intervention on Cognitive Function of Older Adults under Mandatory Folic Acid Fortification Policy: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Nutrients (2024) · Meta analysis · n=42768
The meta-analysis on the effects of folate-based B vitamin supplementation on cognitive function showed a significant overall impact (Z = 3.84; p = 0.0001; SMD, 0.18; 95% CI, 0.09, 0.28).
A Systematic Review and Meta-Analysis of B Vitamin Supplementation on Depressive Symptoms, Anxiety, and Stress: Effects on Healthy and 'At-Risk' Individuals
Nutrients (2019) · Meta analysis · n=2015
Regarding individual facets of mood, B vitamin supplementation benefited stress (n = 958, SMD = 0.23, 95% CI = 0.02, 0.45, p = 0.03).
Melatonin in cancer treatment
The Cochrane database of systematic reviews (2025) · Meta analysis · n=126
We downgraded the certainty of the evidence because of high risk of bias, small sample size, the width of the 95% confidence interval, and indirectness due to inadequate reporting of cancer type.
Comparative Efficacy, Tolerability, and Acceptability of Donanemab, Lecanemab, Aducanumab, Melatonin, and Aerobic Exercise for a Short Time on Cognitive Function in Mild Cognitive Impairment and Mild Alzheimer's Disease: A Systematic Review and Network Meta-Analysis
Journal of Alzheimer's disease : JAD (2024) · Meta analysis · n=4599
Melatonin may be a better potential disease-modifying treatment for cognitive decline in mild AD and MCI.
Melatonin for sleep disorders in people with autism: Systematic review and meta-analysis
Progress in neuro-psychopharmacology & biological psychiatry (2023) · Meta analysis · n=595
According to the global analysis, the wake after sleep onset and night awakening parameters were not statistically significant.
Multiple meta-analyses show small but statistically significant benefits for cognitive function in older adults and stroke prevention populations. Effect sizes are modest (SMD ~0.15-0.18). Benefits may be more pronounced in B-vitamin deficient populations.
Based on meta-analyses showing 7-12 minute reduction in sleep onset. Higher doses showed diminishing returns and increased morning grogginess. Sublingual forms may be more effective at lower doses.
AI-estimated from published studies. Interpret as directional guidance.
Both B-Complex and Melatonin are closely matched — the best choice depends on your specific health goals.
For estrogen & progesterone balance, B-Complex has a higher relevance score (85 vs 70).
B vitamins may interfere with sleep if taken in evening Take B vitamins in morning, melatonin 30-60 minutes before bed. Consult a healthcare provider for personalized advice.