Why You’re Probably Not Getting Enough Vitamin D (and How to Fix It)

If there’s one vitamin I see people missing more than any other, it’s vitamin D. Even people who swear they’re “in the sun all the time” or “take supplements every day” often come back with low levels on their labs. Why? Because vitamin D isn’t just a vitamin—it’s a hormone, a metabolic workhorse, and one of the most misunderstood health essentials we have. And if you’re deficient (most adults are), your body will tell you—if you know how to listen.

Let’s start with the truth: The only way to know if you’re truly deficient is with blood testing. A simple lab will show whether your levels are optimal, low, or stubbornly low even after supplementing—an early warning sign of absorption or conversion issues that you absolutely should address. Thankfully, this isn’t complicated. It just requires knowing what to look for.

So what does vitamin D deficiency feel like? Your muscles may weaken. Your bones may ache. You may notice fractures, slower recovery, fatigue, brain fog, or a dip in immunity. Your kidneys and brain—which help metabolize vitamin D—may whisper signs of strain. And if you have fair skin, spend most of your time indoors, or live in northern regions (looking at you, winter), you’re in the highest risk group.

But here’s the part most people don’t realize—many supplements simply don’t work well. Aging digestive systems, the wrong form of vitamin D (D2 instead of D3), poor absorption, lack of magnesium, clothing that blocks UVB rays, or barely-there sunlight exposure all add up.

The good news? You can fix this quickly with a few simple strategies:

• Get outside more, early morning and later afternoon sunlight. UVB rays are strongest from late morning to early afternoon. Just 10–30 minutes of sun exposure—arms and legs out—can make a real difference.

• Use UVB lamps if you live in cold or low-light regions. Safe, targeted, and effective (with guidance).

• Choose highly bioavailable vitamin D3.Liquid or sublingual forms absorb far better—especially for older adults or those with gut issues.

• Pair vitamin D3 with magnesium and vitamin K2.Magnesium converts D into its active form.K2 directs calcium into your bones—not your arteries.D3 and K2 are the power duo your bones, muscles, heart, and immune system depend on.

• Eat vitamin D–rich foods. Fatty fish, egg yolks, liver, and fortified dairy or plant milks.

This isn’t complicated. It’s just overlooked. And correcting vitamin D deficiency is one of the fastest ways to improve energy, immunity, muscle strength, mood, and long-term health—especially as we age.

Ready to find out if your vitamin D levels are working for you—or quietly holding you back? Get your levels tested, optimize your supplement strategy, and unlock better energy, immunity, and longevity starting today. Subscribe to 10 Minute Longevity