'Vitamin' D...is it really what you've been told?
Posted by Emily on Jan 13th 2026
It has been brought to my attention that not everyone wants to read a scientific article every day. That's my jam, but perhaps it isn't yours.
I cant really do this subject much justice without getting into the technical side of things at least a little, but I've hopefully made it as easy to read as possible.
What would you think if I told you vitamin D doesn't exist?
I can hear the bristling now...but allow me to explain before you hit the unsubscribe button!
A vitamin is something that, by definition, your body cannot create.
You can and do create hormone D.
Before entering the body, this compound is known as a secosteroid hormone precursor.
Calcitriol, 1,25-(OH) D3, and calcidiol, 25-(OH) D3, are just two well-known forms of the twelve major human D3 forms - but all forms of D3 are precursors to hormones - never true vitamins.
Secosteroid D (whether D2 from plants or D3 from animals or skin) must undergo enzymatic conversion steps in the body - first in the liver to calcidiol (25-hydroxy D3) and then mainly in the kidneys to calcitriol (1,25-dihydroxy D3).
At no stage does D2 or D3 act like a vitamin - it does not serve as a coenzyme or simple nutrient. It functions as a prohormone immediately on entering the body.
The only reason it was historically called a vitamin is because early researchers didn’t understand that it functions as a hormone. There is no valid scientific reason for labeling it a vitamin.
From the moment it is produced in the skin or ingested from food, it is part of a hormonal pathway - not a vitamin pathway.
Now, with that out of the way, we can progress onto the meatier stuff -
The problem with using synthetic D3
The widespread push to supplement synthetic D3 ignores a critical fact: the body does not passively allow unused hormone precursors to float around unchecked. Every drop of supplemental D3 demands action - forcing the body to absorb more calcium, altering mineral balances, and overriding normal hormonal feedback loops. This chronic override creates metabolic chaos that can smolder under the surface for years before showing up as serious disease.
At this point, you might be saying to yourself “Ok, then I can just take more calcium supplements to mitigate some of the effects” - but that would actually compound the problem. Here's why...
Supplementing synthetic calcium alongside synthetic D3 only deepens the problem. Hormone D forces the body to pull more calcium into the bloodstream whether it needs it or not. Adding extra calcium into that system accelerates soft tissue calcification, pushing minerals into arteries, kidneys, joints, and brain tissue. Synthetic calcium, like carbonate or citrate, is poorly regulated by the body, behaving more like a pollutant than a nutrient. Instead of balancing mineral metabolism, combining D3 and calcium supplements supercharges the breakdown of the body's natural checks and balances. (More to come on calcium supplements soon!)
“But what about K2?” People ask...
Well, let’s address that.
Adding synthetic K2 to the mix does not solve the underlying issue either. While K2 is important in natural physiology, it is now being used pharmaceutically to force calcium back into bones without addressing why calcium was mismanaged in the first place. This bypass approach can temporarily shuffle calcium around, but it does not restore the natural hormone-driven regulation between magnesium, potassium and calcium. Worse still, chronic K2 supplementation can thicken the blood and raise clotting risk - especially in people with inflammation, sluggish detox, or synthetic D3 already in play. Without fixing the root causes, like mineral imbalances, liver stress, kidney burden or systemic inflammation, forcing calcium into bones or tissues with K2 just masks dysfunction and can strain the system even further over time.
So what exactly happens when you override the body with synthetic hormone D?
These aren’t rare side effects - they’re direct physiological outcomes of disrupting the body's mineral regulation and hormonal feedback. The results can range from subtle dysfunction to serious long-term damage.
Soft tissue calcification:
Supplemental D3 forces higher calcium absorption even when the body doesn’t want it, leading to soft tissue calcification in arteries, kidneys and joints.
Magnesium depletion:
D3 activation uses up large amounts of magnesium, worsening deficiency and impairing hundreds of enzymatic processes.
Immune suppression:
Excess D3 supplementation suppresses the natural immune system over time, making people more vulnerable to infections and chronic illness.
PTH suppression:
Artificially raising blood calcium and calcidiol levels can suppress parathyroid hormone, harming bone remodeling and regulation of minerals long-term.
Feedback system damage:
High blood levels of D3 disrupt the body’s natural feedback systems for maintaining hormonal balance, causing dependency and further dysregulation.
Covering up root causes:
Supplementing D3 doesn’t solve the underlying reason for low hormone D activation, like liver stress, inflammation, kidney issues or lack of magnesium. It just masks over it while the root causes worsen.
Hijacking natural regulation:
Supplementing with synthetic D3 hijacks the body’s built-in hormonal regulation and can lead to calcification, immune dysfunction, mineral depletion and worsening hidden illness over time.
Some conditions known to be linked to long-term D3 supplementation misuse:
Vascular calcification - artery hardening and increased risk of heart attack
Kidney stones and renal calcification - buildup of calcium in the kidneys
Osteoporosis - bones weaken over time, despite artificially elevated calcium
Autoimmune worsening - immune dysregulation increases rather than improves
Chronic infections - suppressed innate immunity leaves the body more vulnerable
Arthritis - joint calcification and inflammation from displaced minerals
Atherosclerosis - accelerated plaque buildup in the arteries
Tissue fibrosis - stiffening and scarring of organs like liver or lungs
Hypertension - rising blood pressure from vascular damage
Neurodegeneration - calcification in the brain combined with magnesium depletion
So what can you do to raise your D3 levels?
That is a loaded question in itself. Given that there are 12 major forms of D3 and only 1-2 are ever tested for, you really have no way of knowing if your levels are 'where they should be'. The question of having the right numbers depends on there being a 'right number' already established and tested for. There is not.
Some things you can do to support sufficient stored and active forms of D3:
Take a magnesium complex to activate your stored D.
Our 6-magnesium complex is an incredible source of 6 forms of available magnesium. The capsules each contain at least twice the amount you find in most supplements. Each bottle also has 90 capsules. Contrast this with the majority of magnesium supplements that contain 30-60 capsules at half the volume, for the same price or more, and this is an incredible deal!
Eat grass-fed and finished animal products
You can supplement up to approximately 20% of your stored D by eating grass fed and finished organ meats, a good source of cod liver oil that is not rancid and doesn't contain added vitamin A or hormone D (there are currently only three or four that are confirmed to be good sources in America ), grass-fed butter and grass-fed aged cheeses are also wonderful sources.
What about those of us in the northern regions?
There is the common belief that those of us in the northern regions, like the northern United States or Canada, cannot get enough D3 from sunlight in the winter months. But it is absolutely possible to maintain healthy D3 levels even while living here! Traditionally, people in these areas thrived with excellent D3 status by spending regular time outdoors, eating diets rich in cholesterol and nutrient-dense animal foods, and building strong reserves during the sunnier months. Our bodies have a fantastic ability to store plenty. That stored D can be activated any time we need it.
It is not the lack of sun alone that leads to low D3 — it is the combination of modern indoor lifestyles, processed foods, mineral depletion and chronic inflammation that disrupt the natural system. When the body is supported properly, it is fully capable of maintaining strong D3 function year-round, no matter the latitude.
Whatever you choose to do, I hope this information helps you to make an informed decision about how to best support your body's needs.
Some links you might find interesting:
Vitamin D and cardiovascular disease: is the evidence solid?https://pubmed.ncbi.nlm.
Vitamin D Supplementation and Cardiovascular Disease Risks
https://jamanetwork.com/
D supplementation and mild hypercalcemia
https://emedicine.medscape.
New study links excessive amounts of vitamin D to onset of atrial fibrillation
https://www.eurekalert.org/