He’s not just tired. He’s depleted. And it might be vitamin D.

You’ve probably heard that vitamin D is important. But what most couples don’t realize is just how much it matters especially for men over 40. If your partner is constantly run down, moody, prone to colds, or flat in the bedroom, low vitamin D may be the missing piece.

Standard physicals don’t test it. HUSBAND does.

What Is Vitamin D?

Vitamin D is technically a hormone. It’s made in the skin when exposed to sunlight, and it influences more than 1,000 genes across the body. While it’s often associated with bone health, vitamin D is deeply involved in immune function, testosterone production, inflammation control, mood regulation, and metabolic health.

| This isn’t just about getting more sun. It’s about unlocking the hormonal foundation of energy, mood, and resilience. |

Why It Matters for Men 40+

By age 40, vitamin D levels tend to decline—especially in men who work indoors, live in northern latitudes, or carry extra body fat. Deficiency in men can look like:

• Low mood or “winter blues”

• Increased illness or poor immune recovery

• Stubborn belly fat or metabolic issues

• Low testosterone and reduced sperm quality

• Joint pain and bone stiffness

Vitamin D supports testosterone synthesis in the Leydig cells, and without it, hormonal decline accelerates—even if he’s doing everything else right.

What the Research Says

• Men with low vitamin D tend to have lower testosterone levels

• Supplementing with vitamin D has been shown to improve testosterone in overweight men

• Low vitamin D is linked to higher inflammation, weaker immunity, and greater cardiovascular risk

• Optimal vitamin D supports muscle strength, mitochondria, and cognitive function all keys to aging well

| You’re not just preventing deficiency. You’re building the platform for performance. |

Why HUSBAND Tests It

Every HUSBAND kit includes a test for Vitamin D (25-hydroxy D) which is considered the most accurate marker of his D status. We check this alongside testosterone, cortisol, and inflammation to see how he’s fueling the system.

Then we optimize it.

The HUSBAND Morning Formula includes vitamin D3 in its bioavailable form, paired with cofactors like magnesium and (when indicated) vitamin K2. If he’s deficient, we adjust based on the data—not guesswork.

What to Expect

Once vitamin D is optimized, most men notice:

• Improved energy and mood

• Fewer infections or long colds

• Increased strength and workout recovery

• Better libido and hormonal resilience

• Less joint pain and inflammation

What Experts Say

Dr. Rhonda Patrick, PhD, a leading expert in nutritional biochemistry, emphasizes that vitamin D is a critical regulator of immune function and gene expression. She notes that low vitamin D isn’t just a seasonal issue but that it’s a silent epidemic contributing to fatigue, low mood, inflammation, and hormone imbalance in men. Her advice? “Test, optimize, and recheck because vitamin D affects almost every system in the body.”