Milk of magnesia has been used as a primer to help absorb the heavy oils in theatrical makeup, but no evidence suggests that it helps combat acne or reduce sweating.

Milk of magnesia is a common medication that’s available over the counter. It’s used for constipation because it draws moisture into the stools to help them pass through the body.

Some people claim it can also absorb oil and fight acne when it’s used topically as a face lotion. However, there’s not much scientific evidence to back up this claim.

Milk of magnesia contains an ingredient called magnesium hydroxide. Magnesium hydroxide can absorb lipids, such as oil on your face. It also contains sodium hypochlorite, the active ingredient in bleach, another ingredient that can soak up oils. This means that when milk of magnesia is applied to your face, it can absorb some oil and reduce shine.

Some people report that milk of magnesia helps oily skin. They claim it’s useful as a skin primer underneath makeup, and it can break down oil on the surface of your skin. However, there isn’t scientific evidence to back up these claims.

Milk of magnesia does seem to remove oil from the surface of the skin, but it doesn’t stop oil production. It’s also unlikely to fight acne.

Scientific evidence

There’s limited evidence linking milk of magnesia to reduced acne. A letter was published by a single dermatologist in 1975 who reported achieving good outcomes by prescribing topical milk of magnesia along with 250 milligrams (mg) of the antibiotic tetracycline.

No other studies have replicated these results, and, since oral antibiotics are often used on their own to treat acne, it’s possible that tetracycline was the most important factor in the original positive outcomes.

Some beauty bloggers recommend using milk of magnesia as a primer if you have oily skin.

Reportedly, milk of magnesia has been used as a primer in theater for decades because it can help heavy stage makeup stand up to sweating under hot stage lights. It’s sometimes said that this same principle makes it a good choice for people with oily skin.

Milk of magnesia as a primer probably isn’t a good choice for everyone. The tip is only recommended for people with oily skin. It’s not suggested if your skin is dry to normal. Additionally, even if you have oily skin, milk of magnesia might irritate your skin or simply not work well for you.

You can test milk of magnesia on a small patch of skin on your inner elbow or wrist to make sure it doesn’t cause irritation, such as a rash, before trying it as skin care. If your skin remains calm for about 24 hours, you can try using milk of magnesia on your face.

It’s important to remember that there’s no evidence that milk of magnesia is a good addition to an acne skin care routine. However, if you want to add it to your morning skin care to combat oil or as a primer before foundation, you can try it once so you know it won’t cause a rash.

Milk of magnesia can cause a rash in some people. Additionally, milk of magnesia is highly alkaline. This means it can be too harsh for some people’s skin. Using overly harsh skin care products can lead to dryness, redness, acne, and other skin concerns.

Finally, there’s no evidence that milk of magnesia benefits the skin. Although it can absorb oil while it’s on the skin, it doesn’t stop sebum production, and research doesn’t support the claim that it can fight acne.

So, even if it doesn’t harm the skin by causing a rash or dryness ― it might be better to look into products that have been proven to help combat oily skin. For instance, you can look into:

You can also make an appointment with a dermatologist to talk about prescription options.

It’s been claimed that milk of magnesia can absorb oil on the skin’s surface, stopping sweating and fighting acne. Some beauty bloggers also recommend using milk of magnesia as a primer under foundation.

These claims do not have scientific backing. Although milk of magnesia can absorb oil, it doesn’t stop oil production, and there’s no evidence it can fight acne.