The transdermal transport pathways
Up to now there are three known transport pathways for the absorption of substances through the skin:
- The volume diffusion, the pathway through the cell cavities (intercellular diffusion)
- The transcellular diffusion, the pathway right through the cells
- The shunt diffusion, the pathway via the skin appendage, in other words via sweat glands and hair follicles.
Even if the pathway of magnesium ions right through the cells is conceivable, the decisive magnesium resorbtion seems to take place via the sweat gland route. To protect the body against high magnesium losses through perspiration, special cells equipped for that purpose are suspected, which actively reabsorb magnesium in the sweat glands. These cells should not only be able to filter magnesium out of the sweat and reabsorb it, but also be able to resorb magnesium supplied externally.
Even if the mechanism is not yet fully understood, there is indeed more and more scientific evidence for this assumption. One imagines that occurring similarly as occurs in the kidney, where specially trained cells actively reabsorb magnesium from the filtered urine and bring it back into the circulation. Certain proteins on the cell membrane are held responsible for the transcellular transport. This should involve a special protein group, that has an increased affinity for magnesium ions, binds these and passes them on after a stable equilibrium is reached.
The extent of the transdermal absorption is dependent on the following factors:
- Moisture condition of the skin
- Size of the treated skin area
- Magnesium concentration on the skin
- Blood circulation through the skin
- Exposure time
Efficacy evidence of transdermal magnesium resorption
The first efficacy proof was produced by the American doctor Norman Shealy. He investigated different transdermal dosage forms of magnesium for six years and, based on the determination of the intracellular magnesium level, was able to prove, that with the transdermal application, magnesium deficiency can be eliminated within a very short time, namely in four to six weeks. Comparable results could be achieved in two weeks with intravenous magnesium therapy, in contrast, with oral magnesium substitution, only after six to twelve months. Apart from that, the ratio of calcium to magnesium improved positively in favor of magnesium. (1)
In a further study, both the blood level as well as the cellular magnesium content were determined with the help of a hair analysis before and after a twelve week transdermal application with a 31 percent saturated magnesium chloride solution. Thereby after a twelve week course of treatment an average rise in the cellular magnesium content of 59.5 percent was determined in 89 percent of the test subjects. With oral magnesium intake, comparable results could first be achieved after nine to twenty four months. Furthermore, all patients showed an average improvement of 25.2 percent in the calcium-magnesium ratio during the test period. As a side effect, clear indications of a detoxification of heavy metals was observed in 78 percent of the test subjects. (2)
At the University of Birmingham it was investigated, whether magnesium can be absorbed from a full bath. Over a period of seven days 19 test subjects bathed for twelve minutes in a one percent magnesium sulfate solution. The magnesium content was investigated both in the blood as well as in the urine. Thereby it was shown, that during the seven day application period the magnesium level rose continuously both in the blood as well as in the urine for 16 of 19 test subjects. For those test subjects that did not register any increase in the blood level, a high rise in magnesium could be determined in the urine. The results of this investigation show, that magnesium can be absorbed from a bath through the skin, and depending on the magnesium status of those concerned, is secreted again via the kidneys. (3)
The most recent study on the transdermal absorption of magnesium is supplied by the renowned Mayo Clinic in Rochester (USA). Here it was investigated, whether magnesium applied transdermally in the form of magnesium oil works for fibromyalgia. 40 women with the clinically determined diagnosis “Fibromyalgia” took part in the study. With the help of a special fibromyalgia questionnaire, the type and manifestation of the complaints were documented on a scale. The data were recorded at the beginning, after 2 weeks and 4 weeks treatment time. Every participant was asked to spray and massage in 4 spray strokes twice a day on the arms and legs for 4 weeks. 24 participants completed the study. For all participants, all complaints improved significantly. (4)
(1) Shealy C.N.: Transdermal Absorption of Magnesium. Southern Medical Association 2005, S.18
(2) Watkins K, Josling PD.: A pilot study to determine the impact of transdermal magnesium treatment on serum levels and whole body CaMg ratios. The Nutrition Practitioner, Spring 2010
(3) Waring RH: Report on Absorption of magnesium sulfate across the skin. School of Biosciences, University of Birmingham. B15 2TT, U.K.
(4) Engen D.J, McAllister S.J., Whipple M.O., Cha S.S., Dion L-J., Vincent A., Bauer B.A., Wahner-Roedler D.L.: Effects of transdermal magnesium chloride on quality of life for patients with fibromyalgia: a feasibility study, 2015, Journal of Integrative Medicine Editorial Office.