Glycolic acid in formulation

Glycolic acid in formulation
April 11, 2019 Aidee Erhime
salicylic acid

When it comes to favorite exfoliating ingredient, an easy runner-up is Glycolic acid. This is mostly because of its molecular size and its solubility in water.

Skin cell turnover – what it is

In a 28 day cycle, the skin sheds dead skin cells to reveal new skin beneath. This regeneration process slows as aging occurs and the skin can no longer shed these dead cells as effectively as it used to. In order to aid the shedding, certain exfoliators are used.

Exfoliators work by physically or chemically removing the dead cells, thus speeding up the skin cell turn over process. One of these exfoliators is glycolic acid.

Physical vs Chemical exfoliators.

While physical exfoliators work by scrubbing off the first layer of the skin, chemical exfoliators dissolve the bond that hold the dead cells together. Chemical exfoliators penetrate deeper into the skin and do not leave bruising which is often an after effect of using a physical exfoliator too vigorously.

Physical exfoliators could be granular or micro-crystalline while alpha and beta hydroxyl acids are chemical exfoliators.

Why is glycolic acid good for skin?

Glycolic acid contains small molecules, which makes for easier and deeper penetration into the skin. It is however not suitable for all skin types so caution should be exercised when a product containing this ingredient is used on the skin.

Ingredient Chemistry

AHA is a general term that stands for Alpha-Hydroxyl Acid. It comprises a number of chemicals with a carboxylic acid group and a hydroxyl group. They occur naturally in large amounts in citrus fruits and sugarcane. This explains why they are often called fruit acids. Some examples of AHAs include lactic acid, citric acid, kojic acid and glycolic acid.

Glycolic acid has the smallest molecule in this group of AHAs, which makes it easily penetrable into the skin layers.

Molecular formula

C2H4O3

Molecular weight

76.05

Glycolic acid in cosmetics formulation

Very often, glycolic acid is found at a concentration range of 6-10% in over-the-counter skin care products. At this concentration range, glycolic aacid is capable of increasing cell turnover.

Concentration alone does not determine the potency of this ingredient in a product, one also has to check with the overall pH balance of the product. This ingredient works best at acidic pH levels. Therefore its optimum pH value is set at 4-5.5 if the aim of the product is to aid natural skin exfoliation.

Glycolic acid may be included in formulas that look to manage acne and brighten the overall look of the skin.

Concentrations of up to 70% can be found in professional products at medical spas but must be administered by a trained skincare professional.

Is glycolic acid safe?

Generally, when any product usage is abused upon application on the skin or if the concentration is incorrect during formulation, it may cause skin irritation. This much can equally be said for an exfoliating ingredient like glycolic acid.

When used in moderation during formulation and/or application, it can be a great exfoliant. This acid may be used as frequently as twice daily when present in concentration of 4% or less.

In all, it is important to understand why the product is being formulated and have in mind, what skin type or skin issue it is formulated for.

The concentration of glycolic acid in these products should not exceed 10%. Any higher concentration should be administered by a professional ONLY.

When used in moderation during formulation and/or application, glycolic acid can be a great exfoliant

Trade names for glycolic acid

In its pure form, it is named

  • Glycolic acid
  • GlypureÒ

In blends, it is named

  • a-HydroxyAcids ‘AHA’
  • Amidroxy Apple
  • Amidroxy Sugar Cane
  • NAB Apricot Extract
  • Sugar Cane AHA

Warnings on cosmetic products containing glycolic acid

Asides the concentration of the ingredient, it is important to warn users of the effect of sunlight UV rays on glycolic acid. Exposing the skin unprotected to the sun, may cause severe sunburn. Therefore users must be advised to wear sun protection, clothings that cover the skin and limit exposure to the sun.

It is important to warn users of the effect of sunlight UV rays on glycolic acid.

 

Summary

AHAs are a wonderful ingredient in skin care – especially when you’re looking to improve the appearance of skin and to increase moisture and hydration. Choose the right AHA for sensitivity and be sure to label all your products according to FDA recommendations

Further reading

https://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/Drugs/PharmacyCompoundingAdvisoryCommittee/UCM529467.pdf

http://iscd.it/files/ALPHA-HYDROXY-ACIDS-IN-COSMETIC-ERMATOLOGY.pdf

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.563.6221&rep=rep1&type=pdf

Van Scott EJ, Yu RJ. (1989) Alpha hydroxy acids: therapeutic potentials. Canadian J. Dermato/. 1: 108-11 2.

Van Scott EJ, Yu RJ. (1989) Alpha hydroxy acids: treatment of the Aging Skin with Glycolic Acid procedures for use in clinica! practice. Cutis. 43: 122-128.

Moy LS. (1990) The use of glycolic acid in the treatment of various skin disorders.

 

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