Thursday, June 23, 2011

Why did I buy that? Malic acid

Malic acid (aka hydroxybutanedioic acid) is an interesting ingredient. It's considered an alpha hydroxy acid found in things like apples and grapes. It was first isolated in apple juice, and we find a lot of it in unripe fruits, which is what gives those fruits the tartness we associate with lack of ripeness.

Alpha hydroxy acids are found in three categories according to the number of hydroxy groups. AHAs like glycolic acid are monocarboxylic acids, AHAs like malic and tartaric acid are dicarboxylic acids, and AHAs like citric acid are tricarboxylic acids. All three groups will behave like AHAs - making skin seem smoother, reducing the look of fine lines, possibly making pores seem smaller - but the latter two groups tend to be quite harsh on our skin, leading to side effects like rashes or sensitivity.

Most malic acid is derived from apples, so it's likely we'll find some AHA qualities in apple extracts (see yesterday's post). The pH of malic acid can vary between 3.0 and 5.0, so it would be useful as a pH adjuster in place of citric acid.

How do we use it? As a pH adjuster and nothing else. The Cosmetics Ingredient Review has determined that malic acid is only safe as a pH adjuster, and that there is "insufficient data to support other uses", such as use as an AHA. It is considered "safe with qualifications", and as such, we shouldn't be using malic acid in our products as anything but a pH adjuster. (If you'd like to see the official reports, click here (PubMed) or click here (CosmeticsInfo.Org) for more information.)

Join me tomorrow for more fun with fruit extracts - banana!


Robert said...

In Canada, malic acid is not limited as a pH adjuster. Malic acid, along with other Alpha-hydroxy acids (AHAs) such as citric acid, glycolic acid, and lactic acid are permitted at total concentrations equal to or less than 10%, with a pH equal to or greater than 3.5

The inner and outer labels of all leave-on skin products containing AHAs at concentrations equal to or greater than 3% shall carry cautionary statements to the effect: "Use only as directed", "Avoid contact with the eyes", "If irritation persists, discontinue use and consult a physician", etc.

Susan Barclay-Nichols said...

Thank you, Robert, for another interesting comment on one of my posts. It isn't a regulatory thing that it is used as a pH adjuster - this comes from the Cosmetics Ingredient Review panel, and I think it's wise to adhere to their suggestions for safety. We aren't obligated to follow their guidelines, but on this blog, we follow the safety suggestions diligently as we don't want any irritated faces, rashes or sensitivities 'round here.

Besides, it sounds like there are much nicer, milder (if that term can be used about AHAs) AHAs like lactic or glycolic acid. I don't think I'd want to use citric or malic as my first choice.

Anonymous said...

May I know where you bought your malicious acid & banana extract from?

Susan Barclay-Nichols said...

I don't own any malic acid, so I can't make a suggestion. I got the banana extract from Aquarius Aroma & Soaps in Mission, B.C. (click for link).

I like the way your spell checker changed malic to malicious! I've been giggling about that all morning.

Robert Simpson said...

I buy all of my malic acid from