Kat Fu

Testosterone and sperm aren’t just fertility metrics—they’re early biomarkers of how your body is aging. This article breaks down the overlooked role of vitamin B12 in male hormone health, sperm motility, and DNA integrity. Backed by human studies, mechanistic data, and actionable testing tips, it makes the case for using B12 status as an early signal for biological decline.

A standard vitamin B12 blood test often misses the earliest signs of decline. If you’re optimizing for cognitive function, energy, and longevity, you need deeper markers. This guide breaks down the 3 tests that reveal what total B12 can’t.

B12 brain fog might seem harmless—but new research suggests it could be an early warning sign of cognitive decline. Here’s what to watch for before it’s too late.

Vitamin D hair loss is often reversible. Here are 5 proven steps to restore density, fix deficiencies, and support your scalp from the inside out.

This step-by-step guide reveals my vitamin D protocol after five years of tracking. I cover how much vitamin D3 you should take daily, why sunlight alone isn’t enough, and what optimal vitamin D levels actually look like—plus the exact mistakes that kept my levels low. Backed by test results and years of refinement, this is your shortcut to a smarter, seasonal strategy.

Vitamin D for memory loss is no longer just a theory. New research reveals how this neuroactive compound protects your brain from inflammation, cognitive decline, and neurodegeneration—making it essential for long-term brain health and performance.