Vitamin B-Complex

Bundle of B vitamins; evidence depends on formulation & baseline deficiency. Some RCTs report improved fatigue/exercise outcomes with specific products.

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Evidence last reviewed: 04 Apr 2026

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Biomarkers studied

Outcomes directly measured across the evidence records below

Performance

Muscle Endurance

Bloodwork

Homocysteine

Evidence

2 records

Homocysteine lowering & cardiovascular outcomes

Adults at increased cardiovascular risk • Meta-analysis of RCTs

PUBMEDHigh

Meta-analysis of 8 RCTs (n=37,485) found that B vitamin supplementation reduced homocysteine by ~25% but had no significant effect on major cardiovascular events, stroke, cancer, or total mortality. Routine B vitamin supplementation for CVD prevention is not supported.

Dose: 0 mgDuration: Median 5 years

Citation: Clarke R, et al. Effects of lowering homocysteine levels with B vitamins on cardiovascular disease, cancer, and cause-specific mortality: meta-analysis of 8 randomized trials involving 37,485 individuals. Arch Intern Med. 2010;170(18):1622-1631.

Fatigue / exercise endurance markers

General adults (not athletes) • RCT

PUBMEDLow

A placebo-controlled trial reported improved fatigue-related biomarkers & endurance outcomes after 28 days with a specific B-complex formulation.

Dose: 10 mgDuration: 28 daysForm: Ex PLUS

Citation: Lee et al. (2023) vitamin B complex trial (Ex PLUS) – PubMed record

Forms

Capsule / tablet

Formulations vary widely