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The Ultimate Guide to Transdermal or Topical Magnesium


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We get a lot of questions about our transdermal magnesium products (now under the brand name, Bolton’s Naturals). 

That’s why we’ve written this Ultimate Guide to using transdermal magnesium, otherwise known as topical magnesium, magnesium chloride, or magnesium oil.

Get all of your questions answered here.


What Do We Mean By Transdermal Magnesium?


As discussed, there are many different terms for transdermal magnesium. But whether the label says “transdermal”, “topical”, or “magnesium oil”, these are all products for external use.

Transdermal literally means “through the skin”. So, transdermal magnesium products are designed to be absorbed through the skin.

Today, we’re more aware than ever that the substances we apply to the skin are absorbed into the bloodstream. That’s why some medications are delivered through a skin patch, and it’s also why we need to be careful about what products we apply to our face and body.

But we can also use natural transdermal products therapeutically. People have been using minerals like magnesium topically for thousands of years. Ancient Romans and their predecessors may not have known that minerals could explain their healing baths, but they knew that long soaks in certain waters were beneficial to health.

What Is Magnesium Chloride?

Magnesium Chloride

Transdermal magnesium products are made primarily with magnesium chloride.

Magnesium chloride is what’s called a ‘magnesium salt’. It’s a compound of the mineral, magnesium, and the essential electrolyte, chloride.

Magnesium is used in hundreds of processes across the body. It’s essential for chemical reactions, the production and transport of energy, synthesis of protein, transmission of nerve signals, muscle function, healthy DNA, and more.1

Chloride is found in all body fluids, and it is responsible for maintaining pH balance, transmitting nerve impulses and regulating fluid into and out of cells.

You may have also heard of magnesium chloride hexahydrate (MCH) lately, and wondered whether it’s the same compound. MCH is chemically produced in a lab, in contrast to the magnesium chloride we use, which is harvested directly from seawater.

Hexahydrate means “without water” and when MCH transdermal brands make magnesium spray, cream or “oil”, they rehydrate these lab-produced magnesium flakes.

What difference does it make? MCH only includes magnesium chloride without the 90+ naturally occurring trace minerals found in magnesium chloride from seawater. There’s reason to believe that these trace minerals in seawater are also beneficial to our health.

Is Magnesium Chloride A Natural Product? 


Magnesium chloride liquid is a natural product, extracted from brine or seawater. Ours comes from salt evaporation ponds along the coast of southern California. The Dead Sea in the Jordan valley is another well-known source.

The ocean water captured in the ponds is allowed to sit for several months until it becomes a concentrated form of magnesium chloride. Ours also contains 80 to 90 other trace minerals, naturally occurring in ocean water.

Liquid magnesium chloride can be added to other solutions, like the massage gel we use in our Magnesium Chloride Gel or the oils we use in our Magnesium Balm.

Magnesium chloride is popularly known as “magnesium oil” because it feels viscous, and slippery, like oil. However, it’s not actually an oil. We add magnesium chloride to gels and oils so it stays on the skin longer, and because oils have a moisturizing effect that offsets the sometimes drying effect of magnesium chloride.

Magnesium chloride is also available in ‘flakes’, a solid, crystallized format used for baths, like Epsom salts. The flakes are prepared by heating the magnesium chloride liquid until the water is completely evaporated. In the process, the chemical structure of the product changes and it becomes a less concentrated form of magnesium chloride.

Who Needs Magnesium?


We all need magnesium every day. And most of us aren’t getting enough through diet.

Magnesium can help with nerves, muscles, heart, hormones, bones, teeth, and more. It provides relief from stress, improves sleep, reduces pain and has innumerable benefits. That’s because magnesium is an essential mineral for health.

Athletes and anyone with chronic body pain, or Restless Leg Syndrome tend to love transdermal magnesium. If you have cramps (PMS-related or otherwise), you’ll appreciate the muscle-relaxing effects.

Children can use transdermal magnesium, just as they can take Natural Calm magnesium orally. Kids of all ages need magnesium and they often don’t get enough through diet.

We’re often asked if our magnesium products are safe during pregnancy. Unless you have a serious health condition, you can feel confident taking magnesium at a normal dose. Magnesium is great for pregnancy-related cramping and to keep blood pressure low, essential for a healthy, full-term delivery.

Transdermal magnesium is suitable for almost anyone. To learn more about the safety and benefits of supplemental magnesium, read Dr. Carolyn Dean’s book, The Magnesium Miracle.

Why Choose Transdermal Magnesium?

Transdermal Magnesium Massage

Many people think of topical magnesium as a treatment for sore muscles. It is that, and much more.

Topical magnesium can support better sleep, relief from stress, pain, tension, plus the long-term protective effects for heart health and more.

Here’s why you might want to add magnesium chloride to your regime:

  • Athletes and customers with severe muscle tension, cramping and Restless Leg Syndrome choose topical magnesium as a fast-acting form of relief.
  • Customers with migraines and headaches apply it to the neck and skull for pain reduction.
  • Topical magnesium chloride is handy to keep in a gym bag, at your bedside or desk for quick application.
  • Children who won’t take magnesium orally can benefit from magnesium chloride therapy when added to the bath.
  • Some people find relief from skin conditions, like eczema and acne when they use transdermal magnesium.
  • Magnesium chloride is antibacterial, and users find it reduces body odour and helps speed the healing of wounds.
  • Magnesium applied topically may prevent or reverse skin damage from aging and sun exposure.

See also the section below on magnesium as a laxative, and why transdermal magnesium is different.

Should I Use Topical Magnesium, Oral Magnesium, Or Both?

Magnesium Chloride Liquid

Typically people use either Natural Calm or Bolton’s Naturals Magnesium Chloride (formerly MagTherapy) based on personal preference.

Some people like to take their magnesium as a drink. Others like to apply it to their skin.

If you have sensitive bowels, you may prefer transdermal magnesium. All magnesium is a natural laxative, but transdermal is less so, which means people who already struggle with too much regularity sometimes prefer topical magnesium.

In terms of absorption, there is no clinical data comparing magnesium citrate (Natural Calm) to transdermal magnesium chloride. Based on testimonials, it seems clear that both are very helpful for sleep, stress, tension and pain relief.

Both are also fast-acting.

According to some reports, magnesium chloride is absorbed transdermally in just 90 seconds. The only faster way to absorb magnesium is intravenous. Transdermal magnesium doesn’t make a journey through the stomach and into the small intestine to be absorbed, which may be why it acts so fast.

To put this in context, fans of our Natural Calm magnesium citrate drink powder report that they feel the effects within minutes.

If you’re looking for fast-acting magnesium, either will do.

Do you have to choose between oral and transdermal magnesium? No. Some people take both to maximize their magnesium intake.

Personally, I take Natural Calm every day and use transdermal magnesium when I have muscle tension.

How Should I Use Transdermal Magnesium?


We offer magnesium chloride in a range of formats. Our products vary in concentration and can be used in different ways, but each is fragrance-free and non-staining.

General Tips:

  • Our transdermal magnesium products can be applied to the face, but avoid the inside of the nose or eyes, as this would sting.
  • Use caution on other sensitive areas/mucous membranes.
  • Allow the liquid, gel or spray to sit on the skin for 20 – 30 minutes before rinsing, which is optional.
  • You can use any of your preferred skin products after applying transdermal magnesium.


Note that heat increases the rate at which magnesium is absorbed through the skin. To drive the magnesium deep into a tense, painful area, try a hot compress using any one of the above products.

  • First, spray or rub the topical magnesium into the affected area.
  • Then, take a small towel and wet it in hot water (as hot as comfortable).
  • Place the hot towel over the sore area, on top of the magnesium, and allow the heat of the compress to drive the magnesium into the skin.
  • When the compress cools, repeat.

Magtherapy Magnesium Chloride Liquid and Balm

Magnesium Chloride Liquid

Our most concentrated form of transdermal magnesium, each 1ml of Magnesium Chloride Liquid contains 450mg of magnesium chloride, equivalent to 120mg of elemental magnesium. This product can be applied directly to the skin, swabbed onto the face with a cotton pad, or added to a footbath or full-body bath.

Magnesium Chloride Gel

We’ve combined our magnesium chloride with Amigel, a massage gel, for easy application and to hold the magnesium in a thicker layer on the skin while it absorbs. Each 1ml of gel contains 225mg of magnesium chloride, equivalent to 60mg of elemental magnesium. It is half the strength of our Magnesium Chloride Liquid. Use the gel to massage relaxing magnesium into tight, sore muscles.

Magnesium Chloride Spray

Magnesium Chloride Spray contains Magnesium Chloride Liquid diluted to a 50% concentration with distilled water. It’s ideal for sensitive skin, with each 1ml of spray containing 225mg of magnesium chloride. Available in a spray cap, this product makes it easy to boost your magnesium levels with quick spritzes.

Magnesium Balm

For those who prefer a richer formulation, Magnesium Balm deeply moisturizes while delivering magnesium chloride through the skin.  This emollient balm contains natural coconut oil, raw shea butter, beeswax magnesium – and that’s it. No preservatives, fragrance or artificial ingredients. Like our spray and gel, this formulation is less concentrated than our pure magnesium chloride liquid and can be applied directly to the skin. In fact, it’s ideal for dry, sensitive skin and for massage.

How Much Magnesium Chloride Should I Use?


We like to say, ‘think of magnesium chloride like seawater’. It’s hard to have too much! We don’t think you should sweat over the amount you use. If you’re getting good results – feeling more relaxed, getting relief from pain, and sleeping well – it’s working.

But if you’re keen to measure your magnesium intake, please use the following guide as a reference.

Note that Dr. Carolyn Dean recommends 3 – 4 mg of magnesium per pound of bodyweight, every day. (Magnesium is depleted daily.) A 200 lb man or woman would thus need a total of 600 to 900 mg of magnesium daily, from diet and supplements combined. A 150 lb individual would need between 450 and 600 mg, in total.

Important Definition: When we refer to “elemental magnesium” here, we’re talking about the magnesium your body can effectively absorb.

Magnesium Spray

Magnesium Chloride Liquid:

There is 120 mg of elemental magnesium in 1 ml of our full-strength Magnesium Chloride Liquid. 5 ml, just 1 tsp, delivers 600 mg of magnesium.

Magnesium Chloride Gel:

In each ml of gel, there is 60 mg of elemental magnesium. So, if you were to measure out 1 tsp (5 ml), you could expect to apply 300 mg of magnesium to your skin.

Magnesium Chloride Spray:

In 10 sprays or 1 ml, there is 60 mg of elemental magnesium. Try this (but don’t worry about following it exactly):

  • 12 sprays distributed on the feet and all areas of the legs
  • 8 sprays across the glutes, hips and all areas of the back
  • 6 sprays on the abs, chest, neck and shoulders
  • 4 sprays on the arms
  • 2 sprays on the face (covering the eyes)

32 sprays applied to your entire body delivers over 180 mg of highly absorbable magnesium chloride.

Magnesium Chloride Balm:

Each 1 tsp (5 ml) of balm contains approximately 200mg of magnesium chloride. It is thus the least concentrated of our Bolton’s Naturals (formerly MagTherapy) magnesium chloride products, but you may find you use it more often because of the moisturizing benefits.

A quick note on using our products for children: Most children have sensitive skin, so you’ll want to start with a very dilute solution. Add Magnesium Chloride Liquid to a bath, for a soothing soak. For direct application to the skin, try mixing transdermal magnesium with massage oil (or even common kitchen oil, such as olive or coconut oil) and rubbing it into the skin.

How Much Topical Magnesium Can I Use with My Children?

How Much Topical Magnesium Can I Use With My Children?

There are guidelines on how much magnesium children should get daily:

  • Children aged 1 – 3 need 80 mg of magnesium per day
  • From the ages of 4 to 8 the RDA for magnesium is 130 mg/day 
  • Ages 9 – 13 need 240 mg/day

That said, the exact amount of magnesium that is absorbed through the skin isn’t perfectly known. There just isn’t enough clinical research on the topic and clinical trials are less often conducted using children.

So, finding the right dose can be a matter of trial – though not likely error!

You can think of using topical magnesium like swimming in the ocean, which is full of mineral salts. We don’t worry about how long our children swim in ocean water – likewise, you should feel at ease about the amount of magnesium your kids will absorb using topical magnesium. After all, our magnesium chloride is concentrated seawater.

Yes, 5 ml of balm, for example, contains about 200ml of magnesium – more than children need – but the skin appears to regulate absorption.

Personally, when I use Magnesium Balm with my children (ages 6 and 4), I don’t measure it out. I simply use enough to cover their feet and legs, to help prevent growing pains. We have never experienced adverse effects.

Of course, you should trust your own judgment when you use topical magnesium with children. That may mean starting with a small amount and monitoring how your children sleep, act, and how regular they are. If they are sleeping well, have steadier moods (though let’s face it, they’re kids!), and are comfortably regular, they are probably getting enough magnesium.

When Should I Use Transdermal Magnesium?


Magnesium promotes relaxation and sound sleep. But that doesn’t mean you can only take it at night.

In fact, magnesium is also essential for energy production at the cellular level.

Think of it this way: getting enough magnesium helps you to sleep when you need to and feel rested and relaxed during the day.

Topical magnesium can be applied at any time of day. Use it before a stressful day, after a workout (to replace magnesium lost by sweat), during the day when you feel tension, or before bed to keep muscles and nerves relaxed at night.

How Much is Really Absorbed Through the Skin?


You may hear that 60% of what is applied to the skin is absorbed into the bloodstream. This is, however, too simplistic. Different substances have different absorption rates. When it comes to magnesium chloride, we can look to a study out of the UK.

“This study was designed to test whether the transdermal application of a 31% magnesium chloride formulation could alter serum magnesium levels and whole-body calcium/magnesium ratios. Patients were screened using sophisticated hair analysis to determine pre-treatment levels of cellular magnesium and then again following the adopted protocol for product application. After 12 weeks’ treatment, 89% of subjects raised their cellular magnesium levels with an average increase of 59.7% recorded.”2

Our concentrated Magnesium Chloride Liquid is 78% magnesium chloride, while our spray and gel are 39%, compared to the solution in the study, which was 31%.

Is Transdermal Magnesium as Absorbable as Magnesium Taken Orally?


The absorbability of oral magnesium really varies depending on the type of magnesium and the form of the supplement.

Magnesium supplements are available either as inorganic magnesium salt, an organic magnesium salt, or a magnesium chelate (a combo of magnesium and amino acid). There are proven differences in absorbability, but organic magnesium salts, like Natural Calm, are highly absorbable when taken orally.

Magnesium taken as a liquid, orally, is more absorbable than pills or tablets. That’s because soluble (or dissolvable) magnesium is better absorbed than tablets or pills.

Evidence suggests that transdermal magnesium is better absorbed than many pills or tablets, too. And we know that many experts, including Dr. Carolyn Dean, argue that topical magnesium therapy is a fast, effective way to increase magnesium levels.

What is the Difference Between Epsom Salts and Transdermal Magnesium Chloride?


Epsom salts, commonly used in the bath, are magnesium sulphate. Another inorganic magnesium salt, magnesium sulphate is magnesium + sulphur + oxygen.

Epsom salts are similar to magnesium chloride but less concentrated. Magnesium chloride liquid is highly-distilled topical magnesium.

Both are effective for treating symptoms of magnesium deficiency, but “(a)ccording to the National Institutes of Health, magnesium chloride has approximately 12 percent magnesium available for absorption. Alternatively, magnesium sulfate, or that found in Epsom salt, contains only 10 percent magnesium available for absorption.”3

This isn’t a huge difference, but some experts believe the magnesium in Epsom salts is more quickly excreted through the kidneys than that in magnesium chloride.

Another bonus: those interested in eliminating toxins will be interested to note that magnesium chloride is used for cellular detoxification and tissue purification. In the UK study mentioned above, researchers observed that “78% of patients also showed significant evidence of detoxification of heavy metals following treatment”.2

Can Transdermal Magnesium Be Taken Orally?


Our magnesium chloride liquid, spray, and gel are designed to be used topically.

Some experts recommend taking magnesium chloride orally. The chloride is believed to combine with hydrogen in the stomach to make hydrochloric acid – the very stomach acid required for digestion and absorption of nutrients.

There’s certainly great promise for magnesium chloride as an oral supplement, but at Natural Calm we don’t currently sell the product for internal use or providing dosing information.

There are trace minerals in natural magnesium chloride that may not be safe for oral consumption.

Is There a Laxative Effect When Using Transdermal Magnesium?


If you’re new to the topic, you may not have heard of magnesium as a laxative. Let us explain.

All magnesium taken to excess causes a laxative effect. For most people, this is a welcome side effect; constipation is a common issue. But when diarrhea occurs, it means too much magnesium has been taken at one time. The body is safely excreting the excess magnesium through the bowels. The solution is to take smaller amounts of magnesium at one time.

Some people can’t get enough magnesium orally without also experiencing an unwanted laxative effect. Their bodies move the magnesium through the intestines too quickly, and it isn’t properly absorbed. Sometimes (though in our experience, rarely) taking smaller doses of oral magnesium, intermittently, doesn’t solve the problem.

Transdermal magnesium is less likely to cause a laxative effect. In fact, in our years of selling and using magnesium chloride, we’ve never heard of a case.

However, there are exceptions. In Dr. Carolyn Dean’s book, she recounts a patient who soaked for two hours in several pounds of Epsom salts. (The recommended use is 2 cups for 30 minutes.) The result? Diarrhea.

Epsom salts, again, are not the same as magnesium chloride. The sulphate in Epsom salts has a laxative effect in itself, whereas chloride does not.3

Why Does the Label Say the Product is For Temporary Reduction of Skin Roughness?


Topical magnesium does have skin smoothing properties, and as far as Health Canada is concerned, magnesium chloride is for that purpose. It’s what we’re licensed to print on our label.

But science supports the broader benefits of transdermal magnesium and the practice dates back centuries – if not millennia. As long as people have been bathing in hot springs, they’ve been using transdermal magnesium for a variety of ailments.

How Safe is Transdermal Magnesium?


Like soaking in the sea (the source of our magnesium chloride), there’s rarely such thing as ‘too much’ when it comes to transdermal magnesium.

Magnesium toxicity from magnesium salts is rare because excess magnesium is readily excreted in urine by the kidneys. Anyone with kidney disease should consult a doctor before adding magnesium to their supplement regime.

While it is possible to take a toxic amount of magnesium orally, even with healthy kidneys, we have yet to encounter a story of magnesium toxicity from transdermal supplementation.

As Dr. Dean says in her book, “The very few reports of magnesium “toxicity” are in hospitalized patients put on IV magnesium. Unfortunately, these reports get repeated inappropriately in the media. The reality is that there are only certain people with serious health conditions, who are usually already under a doctor’s care, who are warned not to take magnesium. There are only four contraindications to magnesium therapy: kidney failure, myasthenia gravis, excessively slow heart rate, and bowel obstruction.”4

Here’s why:

  • With kidney failure, there’s an inability to clear magnesium from the kidneys.
  • With myasthenia gravis, intravenous magnesium “could accentuate muscle relaxation and collapse the respiratory muscles”
  • In cases of excessively slow heart rate, magnesium can further slow the heart’s rhythm because magnesium relaxes the muscles of the heart.
  • Where there is bowel obstruction, the main route of elimination of oral magnesium is impeded. 5

How Pure is Your Magnesium Chloride?


Whenever a new batch of our magnesium chloride is released, it is lab-tested to check for petrochemicals, pathogens, agricultural runoff and heavy metals that might be harmful. Our magnesium chloride always tests and is certified clean.

Will Magnesium Chloride Irritate My Skin?


Magnesium chloride is healing and purifies the skin, but may sting if you have skin that is sensitive, irritated or broken.

When applying to cuts, scrapes or inflamed skin, start slowly.

If you have sensitive skin, choose one of the more dilute products, like our Magnesium Chloride Spray, Balm, or Gel. These are less concentrated than our Magnesium Chloride Liquid.

You can also choose to dilute the full-strength liquid by adding it to a foot bath, a full-body bath, or mixing either the full-strength liquid or diluted spray with oil and massaging it into the skin.

Our transdermal magnesium products can be washed off after about 20 – 30 minutes, and you can feel free to follow with a moisturizer.

Find Out More

If this piqued your interest, you can find more helpful details on the product pages, FAQs, and various blog posts, including these articles:

Anything We’ve Missed?

Tell us, does this answer your questions on transdermal magnesium? Is there anything we could make clearer? Leave us a comment.


  1. Dr. Dean, Carolyn. M.D., N.D. The Magnesium Miracle. 2014 Revised and Updated Edition. Ballantine Books, New York.
  2. Watkins K., Josling PD. A pilot study to determine the impact of transdermal magnesium treatment on serum levels and whole body CaMg ratios. Mineral Check, Lenham Heath, United Kingdom, Herbal Research Centre, Battle, United Kingdom.
  3. Livestrong. Epsom Salt Vs. Magnesium Chloride.
  4. Wikipedia page: Magnesium Chloride
  5. Dr. Dean, Carolyn. M.D., N.D. The Magnesium Miracle. 2014 Revised and Updated Edition. Ballantine Books, New York. p. Iviii
  6. Dr. Dean, Carolyn. M.D., N.D. The Magnesium Miracle. 2014 Revised and Updated Edition. Ballantine Books, New York. p. 2

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