Magnesium Deficiency Test: From Blood to Hair—Which Test is Best?

Imagine waking up every morning feeling tired, despite a full night’s sleep. Your muscles cramp unexpectedly, and you find yourself struggling to relax, even after a long day. Your energy seems to be drained by mid-afternoon, and you can’t shake the constant feeling of anxiety or irritability. For years, you chalk it up to stress, lack of sleep, or maybe even aging. But what if the real culprit behind your symptoms is something as simple as a magnesium deficiency?

Magnesium, often referred to as the “calming mineral,” is involved in over 300 biochemical reactions in the body. Yet, many of us aren’t getting the magnesium we need, leading to a host of symptoms like muscle cramps, insomnia, and fatigue. If any of this sounds familiar, you may be wondering: how do I know if I have a magnesium deficiency?

There are several ways to test your magnesium levels, but each has limitations. In this article, I’ll walk you through the most common methods for testing magnesium levels and explain why a unique type of hair test called Hair Tissue Mineral Analysis (HTMA) might be the best option for assessing your magnesium status.

Common Magnesium Deficiency Tests

Before diving into HTMA, let’s take a look at the most common ways to assess magnesium levels, along with their limitations. Keep in mind that magnesium is not part of the routine electrolyte panel, so testing for magnesium usually only occurs if a deficiency is suspected.

1. Blood Test (Serum Magnesium Test)

The most widely used test to assess magnesium levels is the serum magnesium blood test. This test measures the amount of magnesium circulating in the bloodstream, which gives a snapshot of magnesium availability at a given moment.

• Limitations: Only about 1% of the body’s total magnesium is found in the blood (and only 0.3% is in the serum), with most of it stored in the bones and tissues. This means that a blood test might show “normal” levels even when there’s a deficiency at the cellular level. This can lead to missed or delayed detection, especially in cases of chronic magnesium deficiency.

2. Urinary Magnesium Test

The urinary magnesium test measures the amount of magnesium excreted in your urine over 24 hours. It’s based on the idea that magnesium is eliminated from the body through urine, and that less will be eliminated during a deficiency.

• Limitations: Your kidneys can influence how much magnesium gets excreted, and if you’re dehydrated or have kidney issues, the results may not tell you the full story. Additionally, urinary magnesium is another short-term test that can be influenced by dietary intake of magnesium, making it less reliable for assessing chronic deficiencies.

3. Red Blood Cell (RBC) Magnesium Test

Unlike the serum test, which measures blood plasma, the red blood cell (RBC) magnesium test measures the amount of magnesium in red blood cells. Since magnesium is predominantly stored in cells, this test can offer a better reflection of intracellular magnesium levels. The RBC magnesium test is mostly offered by more holistic-minded doctors and functional medicine practitioners.

• Limitations: While the RBC magnesium test can provide more insight into cellular magnesium status, it still does not offer a complete picture of long-term magnesium status, since the body pulls magnesium from muscles to maintain normal blood levels. The RBC magnesium test is also not as widely available as a standard blood test.

4. Magnesium Load Test

In some cases, a healthcare provider may recommend a magnesium load test, which involves administering a dose of magnesium and then measuring how much is excreted in the urine over 24 hours. If the body retains magnesium, it could indicate a deficiency.

• Limitations: This test is not commonly used due to its inconvenience and limited availability. It can also be affected by variables such as hydration status and kidney health, which can skew results. And, as seen with the urinary magnesium test, the magnesium load test provides only a short-term assessment.

Hair Tissue Mineral Analysis (HTMA): The Most Comprehensive Magnesium Deficiency Test

Now let’s talk about Hair Tissue Mineral Analysis (HTMA)—a test I’ve been using for over 10 years to assess magnesium levels in the body.

What is Hair Tissue Mineral Analysis (HTMA)?

HTMA involves analyzing a sample of hair to measure the levels of magnesium and other essential minerals. This test offers a unique advantage because minerals are deposited in the hair over time, giving you a long-term view of your magnesium status. It is also more reflective of magnesium levels in the tissues, which is where approximately 99% of magnesium in the body resides.

Why HTMA is the Best Magnesium Deficiency Test

1. HTMA Shows Long-Term Magnesium Levels. If you really want to understand your magnesium status, you need more than the snapshot that blood tests provide. HTMA offers a unique, long-term view of your magnesium status by providing a 3-4 month history of your magnesium levels. This long-term view gives a more complete picture of your magnesium status and can help detect chronic magnesium deficiencies that are missed by blood or urine tests.

2. HTMA Measures Magnesium at the Cellular Level. Magnesium is mostly stored in your bones and tissues, not the blood. HTMA measures magnesium in hair tissue, offering a more accurate reflection of the body’s magnesium stores.

3. HTMA Offers Early Detection of Magnesium Deficiency. Hair is a non-essential, excretory tissue, so the body will avoid depositing magnesium there during deficiencies. This makes HTMA an excellent early indicator for magnesium deficiency.

4. HTMA Reveals Other Mineral Imbalances. Magnesium doesn’t work in isolation—it interacts with other minerals like calcium, potassium, and sodium to maintain balance in the body. HTMA measures a wide range of minerals, which gives you a more holistic view of your health. For example, if you have symptoms of magnesium deficiency, it might be because your calcium-to-magnesium ratio is off. HTMA can reveal these imbalances and provide additional insight into what might be causing your symptoms.

5. HTMA Can Help Provide Personalized Nutrition Recommendations: HTMA is part of a larger system called mineral balancing. Practitioners can use HTMA test results to recommend specific supplements, dietary changes, or lifestyle adjustments tailored to your needs. This gives you a more holistic approach for addressing magnesium deficiency and your health concerns.

6. HTMA is Non-Invasive and Convenient. HTMA requires only a small sample of hair, making it an easy, non-invasive test that you can do at home. There is no need for fasting or other preparatory measures.

Three Types of Magnesium Imbalances on a HTMA

Besides an outright magnesium deficiency, HTMA provides insight into other types of magnesium imbalances. This includes a relative magnesium deficiency (high calcium/magnesium ratio) and biounavailable magnesium (high magnesium). Each of these have different causes and require different methods for correction.

Limitations of HTMA

One problem with HTMA is that it is not an easy test to interpret. Developing a nutrition program based on HTMA results is not as simple as supplementing with all minerals that appear low on the test. So it’s important to find a practitioner who has experience with mineral balancing and designing nutrition programs using HTMA. Click here to learn more about ordering a Hair Tissue Mineral Analysis.

It’s also crucial that the testing laboratory does not wash the hair sample at the lab, which has been shown to skew magnesium levels. There are only a handful of hair analysis labs that use the correct procedure.

Can You Just Take Magnesium Supplements if You Suspect a Deficiency?

In many cases, the answer is yes. Magnesium supplements can work wonders for those who are deficient. However, long-term magnesium supplementation without considering other vitamins/minerals can potentially create imbalances that lead to new symptoms.

Final Thoughts

Magnesium deficiency is an often overlooked cause of many health problems because it is not tested routinely. Even when it is tested, standard blood tests often miss chronic magnesium deficiencies. With Hair Tissue Mineral Analysis (HTMA), you can get a more complete picture of your magnesium status, while also identifying other mineral imbalances.

HTMA has been instrumental in my own case of magnesium deficiency, which was largely induced by mercury toxicity from amalgam dental fillings. Using HTMA, I’ve also been able to identify severe magnesium deficiencies (and other mineral imbalances) in children with autism, ADHD, and other developmental disorders, as well as adults with migraines, muscle cramps, insomnia, and other magnesium deficiency disorders.

If you suspect a magnesium deficiency or want to ensure you’re maintaining optimal magnesium levels, consider doing a HTMA with an experienced practitioner. This simple hair test can lead to life-changing improvements in how you feel.