Vitamin D: The One Nutrient I Wish I’d Taken Seriously Ten Years Ago

Vitamin D: The One Nutrient I Wish I’d Taken Seriously Ten Years Ago

I used to think vitamin D was just “the sunshine thing” that old people worried about for their bones. Then I moved to the Pacific Northwest, started working from home, and slowly turned into a tired, achy, moody mess who got sick every time someone sneezed within a 50-foot radius. My blood test came back at 19 ng/mL. The doctor didn’t sugarcoat it: “You’re basically running on empty.”

Six months after fixing it, I feel like someone quietly turned the brightness up on my entire life. Here’s everything I’ve learned the hard way so you don’t have to.

Why Vitamin D Is Weirdly Important (Even If You’re Young and Healthy)

It’s not really a vitamin — it’s a hormone your skin makes when UVB rays hit it. And it controls over 1,000 genes.

Real things that tank when you’re low:

• Mood (seasonal depression is literally vitamin D deficiency with extra steps)

• Immune system (I went from 4–5 colds a winter to maybe one)

• Testosterone in men and estrogen balance in women

• Insulin sensitivity (low D makes it harder to stay lean)

• Bone density, muscle strength, even how fast you recover from workouts

How Much Do You Actually Need?

Forget the outdated 600 IU on the milk carton.

Current 2026 consensus from people who actually study this:

• Minimum to avoid deficiency: 30–40 ng/mL

• Sweet spot for most benefits: 50–70 ng/mL

• Most adults need 4,000–6,000 IU per day October–April if you live north of Atlanta

I take 5,000 IU daily from October to May and 2,000 IU the rest of the year. My last test was 62 ng/mL — best I’ve ever felt.

The Easiest Ways to Get It (Ranked by Real Life)

1. Sun → 15–30 minutes of midday summer sun in shorts and T-shirt = 10,000–20,000 IU (free, but impossible in winter for half the planet)

2. Supplements → D3 in oil (softgels or drops) with a fatty meal = 90 % absorption

3. Food → salmon, sardines, egg yolks, fortified milk = nice bonus but nowhere near enough alone

4. Tanning beds → yes, the “bad” ones with UVB actually work (controversial but effective in moderation)

5. Mushrooms exposed to UV light → vegan option, but you’d have to eat a mountain

My Exact Routine That Took Me From Deficient to Optimal

• October–April: 5,000 IU D3 + K2 softgel with breakfast (fat from eggs or avocado helps absorption)

• May–September: 2,000 IU + 20 minutes of sun most days

• Once a year blood test in late winter (costs ~$40 without insurance)

• Magnesium supplement at night (vitamin D uses up magnesium — most people are low in both)

The Supplements I Actually Worth Buying in 2026

After trying 20+ brands:

• Thorne Vitamin D-5,000 + K2 → my daily go-to, tiny softgel, no taste

• NOW Foods 5,000 IU softgels → cheapest that isn’t garbage

• MaryRuth’s liquid drops → for kids or anyone who hates pills

Skip anything without third-party testing and anything that’s just D3 powder in a dry tablet — absorption is terrible.

Signs You’re Probably Low (I Had Almost All of These)

• You get sick all winter

• You’re tired even after 8 hours of sleep

• Your mood crashes when daylight saving ends

• You sweat on your forehead a lot (weird but classic in kids, still applies to adults)

• Lower back or leg pain that no one can explain

• Hair falling out more than usual

The Bottom Line

Vitamin D deficiency is the most common nutritional problem on earth, and fixing it is one of the highest-ROI things you can do for your health. It’s literally free sunlight or a 30-cent pill that makes everything else (sleep, workouts, diet, mood) work better.

I wasted years thinking “I’ll just get outside more.” Spoiler: I didn’t.

Now I treat vitamin D like brushing my teeth — non-negotiable, takes 3 seconds, and keeps the rest of my body from falling apart.

Get your levels tested once. If they’re under 40 ng/mL, fix it.

Your future self will send you a thank-you note from a much happier, healthier body.