Magnesium flakes (magnesium chloride hexahydrate) are popular for topical application. Many consumers assume these flakes can dissolve directly into moisturizing carrier oils, such as coconut or olive oil, to create a single, homogeneous product. This article explores the chemistry that makes this simple dissolution impossible and provides practical methods for using magnesium flakes alongside your favorite carrier oils.
Understanding Why Flakes Do Not Dissolve in Oil
The inability of magnesium flakes to dissolve in carrier oils stems from the fundamental principle of chemistry known as “like dissolves like.” Magnesium chloride is an ionic compound, consisting of positively charged magnesium ions and negatively charged chloride ions held together by strong electrostatic forces. In flake form, it is highly polar and strongly attracted to other polar substances, most notably water.
Conversely, common carrier oils, such as grapeseed, almond, or fractionated coconut oil, are primarily composed of triglycerides. These large molecules are overwhelmingly non-polar, lacking the distinct positive and negative charge separation that defines a polar substance like water.
Since the highly polar magnesium salt is unable to form strong attractions with the non-polar oil molecules, the flakes simply cannot dissolve. When mixed, the magnesium chloride will remain as undissolved solids. If it absorbs atmospheric moisture, it will form a separate, dense liquid layer at the bottom of the oil, preventing the creation of a stable, single-phase solution.
To achieve a stable, combined product, the magnesium must first be converted into a form that can interact with the oil, or the two substances must be applied separately.
The Proper Way to Create Magnesium Oil (The Water Solution)
What is commonly sold as “Magnesium Oil” is not chemically an oil, but a highly saturated aqueous solution of magnesium chloride. The term “oil” is used because the high concentration of dissolved magnesium gives the water a distinctly slick, oily texture when applied to the skin.
To prepare this aqueous solution, dissolve the magnesium chloride hexahydrate flakes in hot water. A common and effective ratio is one part magnesium flakes to one part water by volume, yielding a potent solution.
The process involves bringing the measured water to a boil and then removing it from the heat source. Add the magnesium flakes to the hot water and stir continuously until they are completely dissolved. Using hot water increases the speed and amount of magnesium that can be dissolved, creating a highly saturated brine solution.
Use distilled water to prolong the shelf life of the final product and prevent impurities. Once the solution has cooled completely, transfer it into a glass container, ideally a spray bottle, for easy application. This concentrated water-based solution is the foundation for almost all topical magnesium products.
Methods for Combining Magnesium Solutions with Carrier Oils
Since magnesium flakes cannot be dissolved directly into oils, and the resulting aqueous solution is incompatible with oils, two main methods exist for applying both together. The simplest approach involves layering the products on the skin.
In this method, the aqueous magnesium solution is applied directly and allowed to absorb for 10 to 15 minutes. Once dried, a separate carrier oil, such as jojoba or sweet almond oil, is applied over the same area. This technique allows the skin to benefit from transdermal magnesium absorption while the oil provides moisturizing effects and mitigates the tingling sensation of the salt solution.
Creating a Single Product via Emulsification
For those who desire a single, stable product like a cream or lotion, the process requires emulsification. An emulsion is a mixture of two immiscible liquids, like oil and water, stabilized by a third agent called an emulsifier. The emulsifier acts as a bridge, holding the two phases together in a stable suspension.
Common cosmetic emulsifiers, such as emulsifying wax or Polysorbate 80, are necessary to create a cohesive product. Without a proper emulsifier, the water-based magnesium solution and the oil-based carrier will separate over time, resulting in an unstable product. Formulating a stable magnesium cream is an advanced project requiring precise measurements and proper emulsification techniques.