#Meta Analysis
Articles tagged #Meta Analysis on Vitalspell.
Vitamin D at 5,000 IU reduced depression symptoms most in new dose-response analysis
A 2026 meta-analysis of 15 RCTs finds vitamin D supplementation significantly reduces depressive symptoms, with 5,000 IU per day showing the greatest effect. Reductions in PTH and TNFα point toward anti-inflammatory mechanisms.
Caffeine improves attention by small but real margins, finds largest meta-analysis to date
A meta-analysis of 31 randomised trials and 1,455 participants found that acute caffeine intake produces modest but reliable improvements in both attention accuracy and reaction time. The dose-response curve tells a more nuanced story: more caffeine keeps speeding you up, but accuracy peaks and then declines.
GLP-1 receptor agonists reduce sleep apnea severity by 14 events per hour
A 2026 meta-analysis of four randomized controlled trials finds that GLP-1 receptor agonists reduce the apnea-hypopnea index by 13.9 events per hour, lower body weight by 12.5 kg, and improve blood pressure in patients with obstructive sleep apnea and obesity.
L-theanine plus caffeine improved attention within two hours, meta-analysis finds
L-theanine combined with caffeine produced small-to-moderate gains in attention switching and digit vigilance within two hours of ingestion, a meta-analysis of 15 RCTs found. The benefits were real but modest, and confidence intervals revealed substantial uncertainty around the effect sizes.
Saffron and ginseng improve erectile function, meta-analysis of 14 trials finds
A 2025 systematic review of 14 randomized trials found that saffron and ginseng consistently improved erectile function, while Tribulus terrestris and maca lacked sufficient evidence. The analysis, covering 1,227 men, is the most comprehensive assessment of herbal ED supplements to date.
