Research synthesisModerate evidenceSmall effect8 studies · 5 beneficial · 3 neutral · 0 harmful
Across 8 studies (5 beneficial, 3 neutral, 0 harmful), vitamin D supplementation shows a small but statistically significant reduction in triglyceride levels in certain clinical populations. The beneficial effect was consistently small in magnitude across most positive studies, with effects typically observed at around 6 weeks (median 42 days in one RCT). The evidence is strongest in people with metabolic disorders such as type 2 diabetes, MASLD, MAFLD, and gestational diabetes; no benefit was seen in obese/overweight children or PCOS patients.
- Studied populations: people with metabolic disorders (e.g., type 2 diabetes, metabolic dysfunction-associated steatotic liver disease [MASLD], metabolic-associated fatty liver disease [MAFLD], gestational diabetes mellitus)
Caveats: Most studies are meta-analyses pooling heterogeneous populations, doses, and durations, which may obscure subgroup differences. Only one study reported a specific dose (1000 IU/day), and no form data were extracted; one meta-analysis using vitamin D2 alone found no effect, suggesting form may influence outcomes. The evidence is predominantly from clinical populations with underlying metabolic conditions, so benefit in healthy individuals or those with normal triglyceride levels remains unclear.
Generated Jul 14, 2026