Transdermal Magnesium

Did you know that simply taking a bath can increase your magnesium absorption? Take relaxation to the next level with transdermal magnesium.

A staple of the bathroom cabinet, Epsom salt has been long hailed for its ability to relax and ease tired, sore muscles. It comes as little surprise then that the secret to its success lies in its other name, magnesium sulfate.

500 grams of Epsom salt dissolved in a bath of hot water will form magnesium ions that are able to cross the skin barrier into the blood and tissues, with excess excreted by the kidneys [1]. The same is true for soaking feet in a hot bucket of aqueous Epsom salts, and for hot Epsom salt compresses. Swapping showers for baths means your daily routine can also become your daily meditation and magnesium booster, in one!

It is still essential to maintain a diet rich in dark leafy greens, nuts, seeds and wholegrains to guarantee your magnesium intake is in good shape, and so too your amino acid, vitamin and fibre intake. However, since soils are depleted of many minerals including magnesium, and time to prepare foods so often seems scarce, supplementing magnesium may be necessary to ensure your levels are optimum. Baths and regular topical applications will help you achieve this. [See cautions for supplementing at the end of this article.]

A bath in a bottle!

Aqueous magnesium chloride is also absorbed through the skin. It is sometimes labelled liquid magnesium or magnesium oil, a solution that is not oil at all, but does have an oil-like, slippery feel. One such topical magnesium supplement, naturally sourced from Victorian underground aqueducts, is Australian owned Karma Rub.

You can make a preparation of magnesium oil yourself by saturating magnesium chloride salt with water. Magnesium oil can be applied directly to the skin and in ten minutes it will be absorbed. Although it leaves a little salty residue, it has been suggested that the skin absorbs magnesium three times better than the gastro-intestinal tract (which absorbs only 30% of ingested magnesium) [2]. Sufferers of IBS or other gut disease may indeed find it more effective, as diarrhoea and inflammation diminish magnesium absorption by the gut [3]. This is what makes transdermal magnesium a sensible option for magnesium supplementation.

Each method has its own advantages: magnesium oil can be applied directly to the site of pain, and baths have the benefit of being very relaxing. Both methods are obviously appropriate for pain relief, especially post-exercise and in conditions such as arthritis, myalgia, spasms or cramps. However, their benefits are much wider reaching due to the many roles magnesium plays in human biology. A future blog post, Magnesium under the Microscope, will give more detailed information.

So before you reach for the pills, remember it is easy to supplement your magnesium intake and aid muscle relaxation by enjoying more baths or keeping a bottle of magnesium oil at hand. Karma Rub comes in a variety of sizes, making it convenient to keep in your sports bag, handbag or drawer to boost your magnesium on the go, or to apply it when computer posture or a stressful day leads to tight neck and shoulder muscles. For more information visit
Cautions for supplementing
If you opt instead for taking oral supplements, choose a water soluble powder that can be sipped throughout the day. Be mindful that high doses of magnesium will eventuate in diarrhoea which inhibits vital nutrient absorption, so immediately reduce your dosage should that occur.
The kidneys maintain the balance of magnesium in the body via excreting any excess into the urine. If this kidney function is impaired, levels may be significantly impacted and will require monitoring. Persons with kidney disease or dysfunction would be wise to consult their doctors and closely monitor their magnesium levels if planning to supplement their magnesium intake (orally or topically) or even if planning to make changes to their diet. Similarly, if you have diabetes or are taking potassium-sparing diuretics, antibiotics or medications for osteoporosis, seek medical advice before supplementing your magnesium intake.
If you are taking calcium supplements for osteoporosis (or other conditions) talk to your doctor to ensure your magnesium intake is sufficient to maintain a functional (healthy) ratio of calcium and magnesium. Carolyn Dean, M.D., recommends not exceeding a 2:1 intake ratio of calcium to magnesium [4].

Photo credit: HyperHopper via / CC BY

  1. Waring, R., S. Nuttal, and L. Klovrza, Report on Absorption of magnesium sulfate (Epsom salts) across the skin. 2015, School of Biosciences, University of Birmingham.: Birmingham, U.K. . p. 1-3.
  2. Nica, A.S., et al., Magnesium supplementation in top athletes-effects and recommendations. Medicina Sportiva: Journal of Romanian Sports Medicine Society, 2015. 11(1): p. 2482.
  3. Higdon, J., V. Drake, and B. Delage. Magnesium. 2001 October 2013 [cited 2017 27 March]; Available from: <>.
  4. Nutritional-Magnesium. Calcium Magnesium Balance. 2011; Available from:


Acupuncture Syd provides scientific information for the general public on the health aspects of lifestyle factors such as relaxation, rest, mind-set, exercise and diet (including the constituents of foods, beverages and supplements). The information is made available with the understanding that the author and publisher are not providing medical, psychological, or nutritional counselling services on this website. The information should not be used in place of a consultation with a health care professional.

The information on dietary factors and supplements, food, and beverages contained on this website does not cover all possible precautions, side effects, interactions, uses and actions. It is not intended as medical or nutritional advice for individual problems. Liability for individual actions or omissions based upon the contents of this website is expressly disclaimed.


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