Should You Really Be Taking Vitamin D? Why Low Levels Aren’t the Full Story
Vitamin D has been praised for years as a cure-all: for immunity, mood, hormones, fatigue, and more.
And yet… many women are taking vitamin D faithfully and still feel exhausted, inflamed, and stuck.
For years, I’ve advised against daily high-dose vitamin D supplementation. Not because vitamin D isn’t important, but because the conversation around it has become overly simplified.
And when physiology gets oversimplified, symptoms get worse, not better.
Vitamin D Isn’t the Problem — It’s Often the Signal
In the functional health space, vitamin D is often treated like this:
“If this one blood marker is low, take this amount of vitamin D.”
But the body doesn’t work in isolation.
Low vitamin D is often a reflection of deeper metabolic stress, not the root cause itself.
Some common contributors to low vitamin D status include:
Limited sun exposure
Lack of movement
Poor absorption
Chronic inflammation
Obesity
Low magnesium
Low boron
Insufficient calcium intake
Glutathione deficiency
Gut imbalances
Environmental toxin exposure
Certain medications
In many cases, supplementing vitamin D without addressing these factors is like pouring water into a leaking bucket.
Why High-Dose Vitamin D Can Backfire
Vitamin D behaves more like a hormone than a vitamin.
When taken in excess, especially without adequate magnesium, vitamin A, and proper mineral balance, it can disrupt calcium metabolism and contribute to symptoms like:
Fatigue
Anxiety or restlessness
Muscle weakness
Sleep disruption
Increased inflammation
For women with thyroid dysfunction, this matters even more. Vitamin D supplementation can alter mineral relationships that directly affect thyroid hormone signaling, meaning the very thing you’re taking to feel better may actually be contributing to the problem.
A Safer, More Supportive Way to Improve Vitamin D Status
Nature usually gets it right.
The primary source of vitamin D is sunlight, and the way your body responds to sun exposure is very different from how it responds to a synthetic supplement.
Vitamin D also occurs naturally in whole foods, paired with the cofactors your body needs to use it properly.
One of my favorite food-based sources is cod liver (and high-quality cod liver oil). It naturally contains:
Vitamin D
Vitamin A
Omega-3 fats
All of which work together to support inflammation, immune function, and hormone balance.
Not all cod liver oils are created equal. Brands I trust include:
You can use code HEALTHWEALTH for 10% off.
What About Winter Months?
When sunlight is limited, infrared light therapy can be a helpful tool, but quality matters.
I personally use the SaunaSpace Glow Infrared Therapy Light because it mimics natural sunlight and is easy to use while working or relaxing.
You can use my code HEALTHWEALTH for an additional 10% off.
The Bigger Picture
If you’re supplementing vitamin D but still feel exhausted, inflamed, or off, it’s not because you’re doing something wrong.
It’s because supplementation without context and data often creates more confusion than clarity.
Inside my Functional Medicine Nutrition Program, we use HTMA testing and blood labs to understand mineral status, nutrient needs, and metabolic patterns, so recommendations are personalized, strategic, and supportive.
Because healing isn’t about taking more, it’s about taking what your body actually needs.
In your corner,
Karri