Why I stopped taking my old magnesium

I’m going to tell you something most dentists won’t.

For 40 years, I watched patients do everything right — brush twice a day, floss, cut the sugar — and still lose enamel. Still grind their teeth at night. Still wake up exhausted. Still come back with more sensitivity, more recession, more damage.

But, in many cases, the problem wasn’t their toothbrush or floss.

It was a mineral deficiency that almost nobody tests for — and that according to NHANES data, 48% of American adults have right now without knowing it.

Magnesium.

I know. You’ve probably heard of it. You might even already take it.

But what I’m about to share changed the way I practice dentistry, and it might change the way you think about your teeth, your sleep, and your brain.

Your teeth may not be able to repair themselves without it.
Magnesium is part of your enamel. A 2016 study in Acta Biomaterialia found that magnesium ions react with tooth enamel through a process called dissolution and re-precipitation — literally restructuring the crystal lattice at the surface — and the result was harder, more resilient teeth. A follow-up study in Acta Biomaterialia (2020) confirmed it: approximately a 20% increase in nanohardness.

But here’s where it gets scary…

When your magnesium is low, your saliva loses the ability to deposit calcium and phosphate back into your enamel. That process — remineralization — is how your teeth fix tiny cracks and damage every single day. Without enough magnesium, that repair system can slow to a crawl — or stall entirely. You could have the best brushing routine on the planet, and your enamel may still be losing ground.

Think about that. Your body has a built-in tooth repair system. And most people may have accidentally turned it off.

Your brain is shrinking. Magnesium may slow it down.
A 2023 study in the European Journal of Nutrition (Alateeq et al.) tracked over 6,000 adults ages 40–73 and measured magnesium intake against brain volume on MRI. The finding stopped me cold: people consuming higher magnesium had brains that appeared approximately one year younger by age 55. Larger total volume. Fewer white matter lesions. Better-preserved regions for learning and memory.

One year younger. From a mineral that costs pennies a day.

Women saw even greater neuroprotective benefits in the Alateeq study — and the reason is alarming. Between 30 and 40% of menopausal women have clinical hypomagnesemia (low magnesium) without knowing it. Estrogen helps regulate magnesium retention, so when estrogen drops during perimenopause and menopause, magnesium plummets with it. And magnesium is what allows your body to actually use vitamin D — so if you’re supplementing vitamin D (as most women over 40 are told to), it may not even be working without adequate magnesium. It’s a cascading failure that almost nobody is connecting the dots on.

Wow! Larger brains. Fewer lesions. Measurably younger structure. And this wasn’t a small study — it was over 6,000 people tracked with MRI. The researchers even found that the neuroprotective benefits of higher magnesium were greater for women than men across every measure they looked at.

If you’re worried about staying sharp as you age — about memory, about focus, about your brain just… working — this one mineral may matter more than almost anything I’ve seen in 40 years of reading research.

This could be why you’re grinding your teeth at 3am.
A double-blind, placebo-controlled clinical trial published in the Journal of Research in Medical Sciences (Abbasi et al., 2012) gave subjects 500mg of magnesium daily for 8 weeks. The results: statistically significant increases in sleep time, sleep efficiency, and melatonin levels — and significant decreases in cortisol (the stress hormone) and sleep onset latency. They fell asleep faster. They stayed asleep longer. Their stress hormones dropped.

When my patients started sleeping better, something unexpected happened: they stopped grinding and clenching at night.

The jaw relaxed. The enamel stopped cracking. The sensitivity dropped.

I take magnesium every night, 1–2 hours before bed. If I skip a dose — especially when traveling or in a new time zone — I notice.

Now — important caveat from a dentist who’s been trained in sleep medicine: magnesium is not a substitute for treating a sleep breathing disorder. If you snore, gasp, or stop breathing at night, that’s a different conversation entirely, and you need to see an AADSM-trained dentist or sleep physician or you can even start with a consultation with a myofunctional therapist. But for the millions of people who don’t get enough magnesium — who lie awake, who wake at 2am, who never feel rested — this mineral is the first thing I’d look at.

Sleep isn’t just about energy. Sleep is when your body repairs. Your brain activates the glymphatic system — clearing beta-amyloid and tau proteins linked to Alzheimer’s and cognitive decline. Your mouth restores its protective mineral balance. Cut your sleep quality, and everything downstream suffers — blood sugar, anxiety, cravings, blood pressure. I’ve seen it in thousands of patients.

Here’s what terrifies me about most magnesium supplements.
After I realized how critical magnesium was, I started taking a popular brand. Good label. Strong reviews. I felt good about it.

Then I read the independent lab results.

I pay for a membership to ConsumerLab — an independent lab that’s been testing supplements since 1999. They’re not sponsored by any brand. They buy products off the shelf, test them for purity, potency, and contamination, and publish the results. Think of it like Consumer Reports, but for supplements. Their testing has flagged multiple popular magnesium products for contamination with lead, cadmium, and arsenic. The very thing I was taking to protect my health may have been quietly adding to my toxic load. I stopped immediately.

And that’s not the only problem. Most supplements contain just one form of magnesium. But your body uses magnesium in hundreds of different processes — your brain needs a different form than your muscles, which need a different form than your bones and teeth. Taking just one form is like putting gas in your car but never changing the oil, the coolant, or the brake fluid.

There are seven critical forms, and each one targets something different. Most products give you one. Maybe two.

Here’s what most people don’t realize until it’s too late.
You can’t necessarily feel when a magnesium deficiency is happening.

Standard blood tests don’t even catch it — only about 1% of your body’s magnesium is in your blood serum, and NHANES hasn’t even measured serum magnesium levels in its national health survey since 1974. You could be deeply deficient and your labs would look perfectly normal. The medical system literally isn’t looking for it.

By the time you notice the sensitive teeth, the brain fog, the jaw pain, the insomnia — it’s possible that, by that point, you’ve been running on empty for years. And every day without enough magnesium is a day your teeth, your brain, and your sleep fall a little further behind.

Here’s how deep this goes:

A 2017 randomized clinical trial (Tarleton et al., PLOS One) found that magnesium supplementation produced clinically significant improvements in both depression and anxiety — and the effects showed up in just two weeks. Whoa.

A dose-response meta-analysis in BMC Medicine (Fang et al., 2016) found that every additional 100mg/day of dietary magnesium was associated with a 22% lower risk of heart failure. A separate meta-analysis in Diabetes Care found a similar dose-response: every 100mg/day increment was linked to a 14% reduction in type 2 diabetes risk across 13 cohort studies involving over 536,000 people.

And a landmark 2018 paper in the Open Heart journal called subclinical magnesium deficiency “a principal driver of cardiovascular disease and a public health crisis.” Not a contributor. A principal driver. And that’s a peer-reviewed cardiovascular journal saying it.
This is not something you fix later. Later is how people end up with cracked molars at 55, or early cognitive decline, or a mouth full of dental work that could have been avoided.

What I personally take — and why I switched.
After the heavy metal scare, I spent months researching. I needed a magnesium that was third-party tested for purity, and that contained all seven forms so my brain, my muscles, my bones, my teeth, and my nervous system were all actually getting what they needed.

I found one. It’s the only one I’ve come across that checks every box — and it passed ConsumerLab’s independent testing for purity, potency, and heavy metals.

You can see exactly what it is and why I vetted it here, but I will say this:

Since switching, my teeth are less sensitive. My sleep is deeper. My wife and I both take it. It is perhaps the one supplement that if I were forced to drop everything else, I’d keep.

See the exact magnesium I take every night.

Nearly half of us are deficient. Almost none of us know it. And the consequences are silent until they’re not.

— Dr. Mark Burhenne (Dr. B)

P.S. I’ve had patients tell me this one change — just getting the right magnesium — did more for their teeth than years of expensive dental work combined. I wish I could go back and tell every patient I’ve ever had. Instead, I’m telling you.

Further Reading & Citations

My previous deep dives on magnesium:

• Why I Stopped Taking My Old Magnesium — the heavy metals story and what I switched to
• Once I Read This Study, I Never Skipped a Day of Taking This Mineral — the brain volume research that changed everything for me
• When My Teeth Get Sensitive, This Is EXACTLY What I Do — my full protocol for sensitivity, starting with magnesium
• I Kept Seeing This Weird Symptom in My Patients — Until I Finally Figured Out Why — how saliva quality connects to magnesium status

Studies cited in this newsletter:
1. Jia et al. (2016). “Diagenesis-inspired reaction of magnesium ions with surface enamel mineral modifies properties of human teeth.” Acta Biomaterialia, 37, 174–183. PubMed

2. Jia et al. (2020). “Magnesium incorporation into primary dental enamel and its effect on mechanical properties.” Acta Biomaterialia, 120, 190–200. PubMed

3. Alateeq, K., Walsh, E.I. & Cherbuin, N. (2023). “Dietary magnesium intake is related to larger brain volumes and lower white matter lesions with notable sex differences.” European Journal of Nutrition, 62(5), 2039–2051. PubMed

4. Abbasi, B. et al. (2012). “The effect of magnesium supplementation on primary insomnia in elderly: A double-blind placebo-controlled clinical trial.” Journal of Research in Medical Sciences, 17(12), 1161–1169. PubMed

5. Tarleton, E.K. et al. (2017). “Role of magnesium supplementation in the treatment of depression: A randomized clinical trial.” PLOS One, 12(6), e0180067. PubMed

6. Fang, X. et al. (2016). “Dietary magnesium intake and the risk of cardiovascular disease, type 2 diabetes, and all-cause mortality: a dose-response meta-analysis of prospective cohort studies.” BMC Medicine, 14, 210. PubMed

7. Dong, J.Y. et al. (2011). “Magnesium intake and risk of type 2 diabetes: meta-analysis of prospective cohort studies.” Diabetes Care, 34(9), 2116–2122. PubMed

8. DiNicolantonio, J.J., O’Keefe, J.H. & Wilson, W. (2018). “Subclinical magnesium deficiency: a principal driver of cardiovascular disease and a public health crisis.” Open Heart, 5(1), e000668. PubMed