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Magnesium: A Metabolic Workhorse Key to Longevity. Are You Getting Enough of it?

In our research, we continue to come across top longevity experts (e.g., Peter Attia, Rhonda Pattrick, and Ben Greenfield to name a few) who state that most people are likely deficient in magnesium. Considering how important it is for our health, we decided to dig deeper. Here is a quick tour of what we found.

Magnesium’s Role In The Body

Magnesium is critical for the normal functioning of your metabolism. 

  • It is the second most abundant mineral inside each of our cells. 
  • It is involved in more than 300 enzymatic reactions in our metabolism and activates over 1,300 metabolic pathways.

From a longevity perspective, magnesium plays key roles in mitochondrial function (one of the hallmarks of aging) and overall cell health: 

  • the creation of new mitochondria as well as the repair of mitochondrial damage due to oxidative stress depends on enzymes that require magnesium as a co-factor;
  • magnesium plays an essential role in the production of ATP, the energy produced by the mitochondria to power the cell,
  • inadequate levels of magnesium can lead to increased production of reactive oxygen species inside cells which can lead to cellular malfunction and decline
  • magnesium acts as a “gatekeeper” in the cell membranes by modulating the exchange of materials coming in (nutrients) and leaving the cell (cellular waste). It does so by regulating what is known as the sodium/potassium pump. 

In terms of overall health, magnesium plays an important role in most key biological functions:

  • Brain chemistry: magnesium is critical to preserving neuronal function during periods of downtime (i.e. when the brain is not asking neurons to fire). In the absence of magnesium, calcium steps in and over-excites neurons when it is not required. This has effects on mood and sleep regulation; 
  • Heart & vascular function: magnesium is required for the normal electrical activity of the heart, it widens blood vessels allowing for better circulation and inhibits blood platelet aggregation;
  • Immune system function: magnesium plays a role in the reduction of inflammation, protects against infection, is critical in the synthesis of glutathione (antioxidant) and aids in detoxification in cells and tissues by removing heavy metals 

The list goes on, but you get the idea. You can think of magnesium as an integral element of your entire operating system. 

Magnesium Supplement Biochemical Process

The “Silent” Magnesium Deficiency

Most American adults are deficient in magnesium (we’ve seen experts/studies citing ranges from 56% to 80% of the population). This is measured against the current RDA (Recommended Daily Allowance) levels of magnesium which are ~400 mg/day for a healthy adult. In practice, the level of deficiency is probably higher if we adjust for the fact that RDA levels are set at the minimum consumption amounts needed to avoid obvious negative consequences. Optimal magnesium levels will be higher. 

So, how come this isn’t a bigger deal when it comes to public health? Enter the concept of “subclinical magnesium deficiency.” Most cases of magnesium deficiency go undetected because you are unlikely to show any symptoms unless your levels are severely low. 

This can be attributed to two adjustments that your boy makes when magnesium levels are low: (1) your kidneys, which typically excrete about 5% of your magnesium contents, will limit excretion if you are running low; and (2) it is believed that when key micronutrients are scarce in your metabolism, a triage response gets triggered that prioritizes critical metabolic functions (i.e., ATP production) at the expense of those that are more important in the long-term, such as DNA repair. This implies that the damage caused by low magnesium levels may take some time to manifest itself and will impact longevity.

Another factor that obscures detection of magnesium deficiency is the fact that the most common tests for it measure serum magnesium. But 99% of magnesium in your body is located in bone, muscle, and soft tissues, where it's harder to measure. Moveover, when serum magnesium is low, your body compensates by pulling magnesium ouf of red blood cells in tissues and bones to put into the blood serum. 

This means that your serum magnesium can test as normal, even if the levels in bones and tissues are low. The “gold standard” for testing magnesium levels is therefore the “magnesium loading test.” It is not commonly used as it requires you to collect your urine over a 24-hour period after receiving a magnesium sulfate injection. The next best test is measuring magnesium levels in red blood cells (RBC magnesium). And here you run into a circularity: doctors usually only order the RBC magnesium test when there is reason to believe that you might have a magnesium deficiency.

Why Are We Deficient?

If you are deficient in magnesium, there are likely to be multiple factors at play. 

The first and most important is diet. You might not be eating enough magnesium-rich foods.

  • magnesium is a key component of chlorophyll, which means it is found in high levels in green vegetables such as spinach, kale, broccoli, swiss chard, etc. (we did find much discussion about the fact that widespread soil erosion has depleted plants from much of their mineral wealth, so even if you are loading up on this, you might not be getting the mineral contents you expect. This requires more research.)
  • magnesium also abounds in nuts & seeds such as pumpkin and chia seeds (by far), almonds, cashews and peanuts
  • Lesser amounts are founds in fish (salmon, tuna), avocados, and dark chocolate

See a more complete list here.

Even if you are eating plenty of magnesium-rich foods, there are other factors that may be depleting your magnesium levels. Among these are:

  • calcium imbalance: too much calcium depletes the amount of magnesium present. Many common foods promote this imbalance (e.g., cheese has a 26:1 calcium/magnesium ratio, yogurt 11:1; dairy 7:1). This extends to the use of antacids
  • Exposure to chronic stress and lack of sleep will deplete magnesium stores
  • Alcohol consumption increases the excretion of magnesium

How To Supplement Magnesium

The best way to know if you need more magnesium is to measure (see above). Setting that aside, considering how critical magnesium is for your optimal health and that the therapeutic band (safe zone) for magnesium supplementation is pretty broad, taking a supplement might make sense (see disclaimer below). 

There are many forms of magnesium based on the molecules (typically salts) that it is bound to. Known as chelations, these bindings are necessary to stabilize the mineral while in pill format, to transport it inside the body, and to prevent cross-reaction with other minerals. While most magnesium supplements will contribute to increased levels of the mineral in your metabolism, some applications seem to be more effective than others depending on your objectives. 

Here is a high-level overview:

Magnesium Oxalate/Oxide

Can be effective in increasing magnesium levels but its relatively low bioavailability (<10%) means most of it will stay in your intestine, giving it a powerful laxative effect

Magnesium Citrate

Most common form, due to higher bioavailability (25-30%), water solubility and relatively lower cost. Notable effects: eases muscle cramping, fatigue, laxative effect

Magnesium Chloride

Typically contains only 10-15% magnesium but is well absorbed. It is used to chelate other minerals such as iron and other heavy metals. As a result, it is often used for detoxes, sleep, relaxation of the mind & body, elevating mood, and constipation.  It also helps with cramping. 

Magnesium Glycinate

Readily bioavailable. Glycinate crosses the blood-brain barrier so can be effective in improving sleep, mood and reducing stress. It is generally a more expensive option. 

Magnesium L-Threonate

Readily bioavailable. L-Threonate crosses the blood brain barrier so it can be effective in improving sleep, mood, and stress. Has been used in treatment of PTSD

Magnesium Orotate

Helps with delivery to cell membranes. Supports DNA and RNA cycle, muscle repair & relaxation

Magnesium Monoaspartate

This form is less common but presents high bioavailability (42%)

Right-sizing Dosage & When to Take

According to Dr. Peter Attia, the therapeutic window for magnesium supplementation is pretty wide and as long as you have healthy kidney function it is unlikely that you can over do it, particularly because as you increase the dose you will trigger a laxative response.  In his experience most people will be able to tolerate ~400mg of magnesium oxide or magnesium citrate.  For his personal routine, he takes: 500mg of magnesium oxide and 2-4 pills of SlowMag in the morning and 2 pills of Magtein (i.e. magnesium L-Threonate) before bedtime (yep, that sounds like a lot of Mg!),

We came across one interesting recommendation for landing on the right dose of magnesium coming from David Asprey: start with a low dose and increase it gradually until you hit the point where you trigger the laxative response, and then dial it back. 

Please share with us your experiences with magnesium and any suggestions on anything we left out!

This content is general in nature and for informational purposes only. Nowgevity content is not intended to constitute medical or other professional advice and should not be considered a substitute for professional medical advice, diagnosis, or treatment. Always consult your doctor or other qualified healthcare provider with any questions you may have regarding a medical condition, procedure, or treatment, whether it is a prescription medication, over-the-counter drug, vitamin, supplement, or herbal alternative. Never disregard professional medical advice or delay in seeking it because of something you have on Nowgevity’s website or emails. Reliance on any information provided herein is solely at your own risk.


  1. Research Breakdown on Magnesium- (paywall)
  2. Magnesium Supplementation: Everything You Need To Know About Dosing Magnesium, Timing Magnesium, Forms Of Magnesium & More
  3. A Magnesium Primer
  4. Subclinical magnesium deficiency: a principal driver of cardiovascular disease and a public health crisis
  5. 20 Magnesium Benefits + Side Effects, Dosing, Sources
  6. Peter Attia - Magnesium Supplementation
  7. Best magnesium to supplement (based on current evidence) | Rhonda Patrick
  8. 3 Mechanisms for Magnesium Deficiency
  9. Maximizing Your Mitochondria with Magnesium
  10. Magnesium Fact Sheet for Health Professionals

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