Vitamin K2 (menaquinone) has emerged as a nutrient of interest in dermatology research over the past few years, primarily for bone and vascular calcification effects. The hair loss application is preliminary and not yet supported by clinical trials, but mechanistic studies have raised questions worth tracking. The proposed connection involves the role of matrix Gla protein and other vitamin K-dependent proteins in tissue calcification and extracellular matrix composition.

A 2022 study from researchers at Maastricht University examined vitamin K2 status in patients with androgenetic alopecia and found modest correlations with disease severity. Patients with the lowest serum vitamin K2 levels had more advanced hair loss after adjustment for age and other factors. The mechanism is hypothesised to involve perifollicular calcification, a feature documented in some androgenetic alopecia scalp biopsies that may contribute to follicle dysfunction.

The honest framing: vitamin K2 supplementation for hair loss is not currently supported by adequate clinical evidence. The mechanistic studies are intriguing but preliminary. For patients already supplementing vitamin K2 for bone or cardiovascular reasons (at 100–200 mcg daily of MK-7 form), continuing is reasonable. Specific supplementation for hair loss would be premature. This is a research area worth following over the next 3–5 years as more data accumulates.