The latest ingredient that many have asked me to talk about is glycolic acid.
Glycolic acid (or hydroxyacetic acid) is the smallest alpha-hydroxy acid (AHA). This colourless, odourless, and hygroscopic crystalline solid is highly soluble in water.
Due to its excellent capability to penetrate skin, glycolic acid is often used in skin care products, most often as a chemical peel. Once applied, glycolic acid reacts with the upper layer of the epidermis, weakening the binding properties of the lipids that hold the dead skin cells together. In other words, it denatures the elastin and collagen which allows the outer skin to dissolve, revealing the underlying skin.
Acute doses of glycolic acid on skin or eyes leads to local effects that are typical of a strong acid (e.g. dermal and eye irritation). This acid can form glycolate which is a nephrotoxin. A nephrotoxin is a compound that causes damage to the kidney and kidney tissues.
Glycolic acid also has the potential to cause renal toxicity due to its metabolism to oxalic acid. Glycolic and oxalic acid, along with excess lactic acid, are responsible for the anion gap metabolic acidosis. Oxalic acid readily precipitates with calcium to form insoluble calcium oxalate crystals.
Renal tissue injury is caused by widespread deposition of oxalate crystals and the toxic effects of glycolic acid. Glycolic acid does exhibit some inhalation toxicity and can cause respiratory, thymus, and liver damage if present in very high levels over long periods of time.
Glycolic acid has the same effects as salicylic acid. So, I will say the same thing again: the use of glycolic acid in skincare and therapeutic products is an old method and one that I now suggest outdated. My thoughts are, don’t use it. Its best to feed your skin with nutrients rather than kill it with chemicals.
