occasions, say, in the middle of a heart attack, hospitals may administer intravenous magnesium chloride to relax the heart and cardiovascular system.
However, do we need to let the situation deteriorate into an acute crisis before we get can a big dose of magnesium? The answer is no. We can use the skin to deliver large amounts of magnesium very safely and effectively in order to avoid crisis and maintain optimum magnesium status. The skin, being the largest organ of the body and part of the integumentary system (skin, hair, nails, bones, teeth), can act as a reservoir to store magnesium where the body may draw from it what it needs in a self-regulating manner.
Getting magnesium in via skin
The gentlest way to absorb magnesium transdermally is via bathing. When we have a bath or foot soak with magnesium chloride, the absorption process takes about half an hour and then subsides. If you need to soak for a longer duration, you may get wrinkly skin from too much water ingress, without the benefit of much extra magnesium. Magnesium soaks are a great way to not only absorb magnesium, but also to detox, as the skin also uses the opportunity to release wastes. Another welcome benefit of magnesium soaking is that it helps to promote deeper and more restful sleep.
Magnesium is absorbed effectively into the epidermis with bathing because hot water helps to open up the pores. The heat partly melts the cermides (solid fats in the skin), some of which are lost in the bath water, along with any dust particles and wastes that happen to be present in that outside layer. The epidermis then takes up the magnesium in solution until no more can enter.
You may notice that with profuse perspiration, the same ceramide (skin oil) loss happens and the skin becomes more sensitive as a result. After heating of the skin barrier and consequent loss of skin oils, fatty barrier protection needs to be restored. Younger people with naturally oily skin will find this replenishment relatively easy, but those with a dryer skin type will need some help from plant fats to restore skin barrier protection.
Even when applying pure magnesium oil to dry skin without the help of the hot water of bathing to open skin channels, magnesium deficiency symptoms can be alleviated. A study by Chandrasekaran using only magnesium chloride solution on skin found that it increased hydration, recovery and resilience of the epidermis with significant magnesium uptake into the skin barrier:
“Magnesium ions can penetrate through healthy skin with intact stratum corneum, with significant contribution from hair follicles. At high magnesium concentrations the permeation of Mg2+ into the epidermis increases with time and is significantly higher than the baseline concentration of Mg2+ in the epidermis of untreated controls after 15 minutes of exposure… Magnesium treatment also increased the redox ratio of cells in granulosum and spinosum layer indicating changed metabolic activity.”2
However, there is also a lower threshold of uptake compared to magnesium bathing because of skin’s resistance to taking up all the dissolved magnesium of the magnesium oil. This is why people report magnesium oil as leaving their skin with an itchy sticky residue, which can often deter them from using transdermal magnesium regularly.
Magnesium ‘oil’ is not a lipid fat, as are plant oils. It is a water-based solution which has been called ‘oil’ because magnesium chloride in solution, which structures water molecules in a liquid crystalline formation, feels slippery. Some of the magnesium oil will find lipid partners that are naturally present in the skin, which help to absorb it (and you are lucky if you have the oily skin to do this), but a large part of it encounters skin resistance without enough lipid help, leaving a salty residue on the surface.
To achieve an optimal uptake of magnesium oil via skin it needs to be combined with lipids in the right proportion to suit skin type. As the skin takes up the plant fats with infused magnesium chloride, the nutrients sit inside the skin reservoir until the body takes them up in its own time. The amount of magnesium and lipids able to be taken up by the epidermis will depend on the collagen structure of the skin.
If the skin is very dry, thin and depleted, it becomes overly sensitive to salt stimulation, as with the higher magnesium concentrations. Absorption is limited until the collagen rebuilds and strengthens. In extreme cases of sensitivity, we recommend using more magnesium bathing for the first month, followed up with a fatty magnesium cream (and milder magnesium concentration) to protect the skin barrier.
Not only have researchers found that magnesium ions are transported into the skin layer via pores and hair shafts, but recent studies have also found a cell to cell (transcellular) transport system via the membrane protein channel TRPM7. This means magnesium can travel quickly in the body and is not limited to transport via blood supply.
It makes sense because only 1 percent of total body magnesium is in the blood, and 99% is located in cell storage of muscle and bone. Magnesium needs to be able to be moved efficiently to access the mitochondria of tissue cells for making ATP (adenosine triphosphate) in metabolism.
The tissue cells, holding most of the body’s magnesium reservoirs, can even sacrifice their magnesium to the blood to maintain critical levels for cardiovascular electrolyte support, leaving tissue storage levels low, while blood tests can show magnesium levels in the normal range. Care must be taken not to let the cell storage tanks get too low!
‘Chanzymes’: Cell membrane channel gatekeepers (TRPM7) that are sensitive to magnesium
The enzyme protein channels in the cell membrane that open and close, facilitating the transcellular movement of magnesium, are now referred to as ‘chanzymes’. They are sensitive to the presence of magnesium when it comes knocking, and are associated with the resting state. When magnesium becomes depleted, or adrenalin pushes in more calcium which overtakes magnesium, the channels switch to the tension, or ‘squeezed’, state of contraction.
Interestingly, if you can get enough magnesium uptake it can control the excess calcium of hypercalcaemia. Without enough magnesium, calcium becomes the bully with brute force – stiffening, hardening and cramping muscles (including the smooth muscles in the endothelial linings of blood vessels).
Researchers confirm that; “intracellular Mg2+ binds to this site and stabilizes the TRPM7 channel in the closed state, whereas the removal of Mg2+ favours the opening of TRPM7. Hence, our study identifies the structural underpinnings through which the TRPM7 channel is controlled by cytosolic Mg2+, representing a new structure-function relationship.” 3 Another study found that; “TRPM7 is essential for the control of cellular and whole body Mg2+ homeostasis.” 4
What happens when optimal magnesium is available and the body is in a calm state is that, the cell membrane (via TRPM7) maintains its electrical charge potential to hold in the magnesium and potassium ion. When there is a stress response and adrenalin is released, it pulls out magnesium and pushes calcium into the cell membrane channels of muscle fibres, which has a dehydrating and tightening effect for quick action of the muscles and cardiovascular system.
When calm is restored, calcium is once again moved out of the membrane channels, allowing magnesium back in for relaxation of the muscle. As magnesium brings with it water molecules, it increases hydration inside the cell, consequently relaxing and restoring internal cell transport (nutrients in and wastes out). Magnesium also donates electrons, which assists the antioxidant system to neutralise free radicals.