Know Your Ingredients: Magnesium Aluminum Silicate

by Gio

magnesium aluminum silicate

What it is
Magnesium Aluminum Silicate, white in color, is a naturally occurring mineral derived from clay.

What it does
Magnesium Aluminum Silicate is a thickening agent: it has the ability to increase the water part of cosmetics.
It is also used as an opacifying agent to reduce the clear appearance of some cosmetic products.
In addition, Magnesium Aluminum Silicate is used as a powder in cosmetics. It can absorb liquids, prevents powder products from becoming clumpy and help other ingredients to apply more smoothly.

Side effects
Magnesium Aluminum Silicate is generally considered to be safe.




Makeup Morsels May 8, 2011 - 1:41 am

Just so you know, I now check ingredient labels after starting to read these posts 🙂 Takes a bit of extra time, but hey, it’s good to know what I’m using, right? Keep them coming!

beautifulwithbrains May 8, 2011 - 7:58 pm

Makeup Morsels, I’m so glad to hear that. Yes, it is important to know what’s in your products so you can choose those that work best for your skintype and avoid those that are useless or even harmful. 🙂

hilarychloe October 2, 2011 - 3:51 am

Weird fact I found this ingredient in pepto bismol along with salicylic acid =/

beautifulwithbrains October 2, 2011 - 7:11 pm

hilarychloe, that’s interesting. Thanks for sharing.

Roestadel Tan May 10, 2017 - 6:09 am

just want to ask if i can use this ingredient in an oil based product such as concealer as slip modifier and filler too?

Gio May 14, 2017 - 3:51 pm

Roestadel, yes you can.

Bill November 4, 2018 - 4:26 pm

“Magnesium Aluminum Silicate is generally considered to be safe.”–but why? The only source listed is a cosmetic site, so they are bound to justify their products…and only on a superficial level. If you look around at other sources that are holistic about such topic, then I guarentee that eyes will be opened. I do not know if you are an advocate of beauty products in the market–couldn’t check because my phone is very low as I am typing, but I still did research prior to this–but even if you aren’t, then I get it that this may seem trivial, which is fine by me. But my main point is to ask that you put down more sources–even if they serve as rebuttals for your point. I think it’s wrong to convince a reader with just one source–don’t you?

Gio November 23, 2018 - 9:25 am

Bill, thank you for your comment. But the source I listed isn’t just a cosmetic site selling their own products. In fact, they don’t sell products at all. According to their about page,” is a comprehensive, informational database containing science and safety information on cosmetics and personal care products – how they work, data to corroborate safety, and science behind commonly used ingredients. Developed and maintained by scientists and subject-matter experts.”

These are real scientists, making conclusions based on results of scientific studies. A lot of holistic sources don’t have the background knowledge to read studies. They read that something is toxic to mice and automatically assume it’s toxic to people. They read that something is toxic at 100% undiluted concentrations and automatically assume it’s bad even at 1% diluted concentration. They read that something is toxic when ingested in high amounts and automatically assume that it’s bad even when you apply a tiny quantity on the surface of the skin, where it won’t penetrate (FYI, the “60% of what you put on your skin is absorbed by the body” is such BS. If a source says that, it’s your cue to run away!!).

In another words, if you want to find proof that something is bad for you, be assured, you will find it. By as any scientists will tell you, it’s the dose that makes the poison. If you want to know if a cosmetic ingredient will kill you need to test it in the same way it’s used in cosmetics (ie, on real human skin, in tiny doses). The source I cited does this and for me, that’s good enough.

Andree March 5, 2019 - 2:20 pm

Thank you for that, Gio.

Gio March 16, 2019 - 12:30 pm

My pleasure!

lizette valle September 3, 2019 - 4:52 pm

Would this ingredient be harmful if it were to be microneedles into the skin? Is the molecule too large to penetrate even then? There is a new korean beauty tx called “BB Glow” which uses micro needles of .05 lengh to microneedle a sort if bb cream into the skin to create a more bright radiant look on the face. I an curious about the toxicity and possible ling term effects. THANK YOU.

Gio September 14, 2019 - 6:23 pm

Lizette, I personally don’t recommend microneedling because most ingredients are meant to stay on the surface of your skin. Even if this were safe, there may be something else that isn’t.


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