You always hear beauty gurus say that Milk of Magnesia (MOM), an OTC antacid and laxative, can secretly double as a life-saving foundation primer or mask for those with oily skin types. But does this actually have scientific merit in regards to absorbing facial oil? And are there any drawbacks to this off-label use?
What is MOM’s original purpose?
In its unflavored and most widely-used form, magnesium hydroxide (Mg(OH)2) is the active ingredient, accompanied by water and sodium hypochlorite (NaClO) (1).
Mg(OH)2 acts as an antacid (to counter something like stomach ulcers) via neutralization: Mg(OH)2 will dissociate in water, and the basic hydroxide ions (OH-) will combine with the acidic hydrogen ions (H+) in stomach acid to form water. Hence, neutralization.
As a laxative, Mg(OH)2 relies on the magnesium ions (Mg2+) that form upon dissociation. Because these ions aren’t largely absorbed by the intestinal tract, they will draw water from the surrounding tissues, which will increase the water content of the intestinal tract, resulting in softer and more “passable” fecal matter. Mg2+ ions also cause the release of a compound called cholecystokinin, which similarly results in higher levels of water, electrolytes, and intestinal movement (2).
The other ingredient of importance is sodium hypochlorite (NaClO), otherwise known as bleach. It is in very low concentration and acts as a pH adjuster or buffer. When dissolved in water, NaClO will slowly decompose, releasing chlorine, oxygen and sodium hydroxide.
The reaction of this process is: 4 NaClO + 2 H2O >>> 4 NaOH +2 *Cl2 +O2.
*Keep in mind that the rate of decomposition is extremely slow, so the amount of chlorine gas emitted will probably be negligent. However, it’s best to not inhale bleach for any sustained periods of time.
What attributes are relevant when referring to MOM’s applications in skin care?
Milk of magnesia does indeed has some ability to absorb surface lipids on the skin. Though not many studies have been specifically designed to test this concept, one study suggests that Mg(OH)2 is more adept than magnesia or magnesium oxide (MgO) at facilitating the absorption and separation of wax and stearyl esters, which are similar to compounds found in sebum (3). While this is far from conclusive, it does give some weight to the efficacy of MOM as a “degreaser.”
Furthermore, what little of the bleach content is present, can further “degrease” the skin. As a strong oxidizer, bleach can cause defatting or the chemical dissolution of surface lipids (4), resulting in less oil on the skin.
Are there are drawbacks?
Clearly, the most obvious drawback is that milk of magnesia is quite basic — as are its two main ingredients magnesium hydroxide (Mg(OH)2) and sodium hypochlorite (NaClO). MOM has an overall pH of 10.5, while sodium hydroxide (NaOH), as seen above in the chemical reaction has an astonishingly high pH of 14 (5)!
When the skin is at a basic pH, all kinds of problems related to impaired skin can manifest, such as: contact dermatitis, increased acne (since a basic pH interferes with regular desquamation and allows for bacteria proliferation), and many others. With consistent use, MOM can seriously wreck your skin!
What do I do?!
Relax. If you’ve been applying MOM to the skin, just discontinue use. If you’re bummed out because something so promising isn’t actually so, don’t worry! There are other (better) ways to deal with oily skin, ranging from something as complicated as oral isotretinoin, to something as simple as a pressed powder. There are too many to identify, describe, and analyze! Therefore, keeping in line with this post, here are a few topical “cosmetic” absorbents that can easily replace MOM:
- The Smashbox Anti-Shine ($28.50, Amazon.com) contains a similar, but less basic, compound magnesium aluminum silicate, to absorb excess facial oil. I have personally tried this and it’s quite effective, although you may have some difficulty obtaining it in-stores. For some reason, both Nordstrom and Sephora have pulled it from their shelves. The texture is a slightly thick paste- or spackle-like gel that’s excellent for filling in pores, and can be applied underneath or on top of makeup and/or sunscreen.
- The Hourglass Mineral Veil Primer ($52.00, Amazon.com) contains the powerful absorbents, isododecane and alumina. Furthermore, it contains a gentle mineral-based sunscreen wrapped up in an elegant silicone base, whose texture is simply divine! While pricey, I always have one of these on hand. It’s best used underneath or mixed with makeup and/or sunscreen.
- The OC Eight Professional Mattifying Gel ($27.73, Amazon.com) contains a patented type of acrylate copolymer that allegedly forms “micro-particles that trap facial oils.” While the concept and marketing are impressive, I have yet to try this and therefore, cannot give a wholehearted recommendation.
- The Paula’s Choice Shine Stopper ($21.95, Amazon.com) also contains a type of (meth)acrylate crosspolymer, in addition to a small amount of the absorbent present in the Smashbox Anti-Shine, magnesium aluminum silicate. Coincidentally, the textures of both are also quite similar. Likewise, they perform about the same for my very oily skin type. You’ll want to be careful with these two products, as using too much will cause them to ball up and make a mess.
Ultimately, my personal Holy Grail product is the Hourglass Mineral Veil Primer because it really extends the wear-time of anything I apply over it by a few hours. It also provides decent UVA and UVB protection, which coupled with its silky, water-light texture, makes it a perfect mixing medium for my regular sunscreen.
Have YOU tried MOM before? Let me know what you think either on down below or on my blog!