Alpha Hydroxy Acids
AHAs action mechanism is not fully known, however the most widely accepted theory is that AHAs remove calcium ions from epidermal cell adhesions by chelation.
This results in loosing up the "glue" that keeps dead cells attached causing the shedding of dead and very dry skin cells. The reduced calcium levels also promote further cell growth while slowing cell differentiation - meaning the appearance of wrinkles is lessened making the skin look younger. AHAs have also been shown to promote collagen and hyaluronic acid production improving plumpness and hydration of the skin.
In general, people tend to see greater effects using AHA chemical exfoliation and the results are longer lasting since AHAs work on the deeper layers of the skin.
Extensive clinical studies have proven alpha hydroxyl acids to be effective anti-aging ingredients.
Alpha Hydroxy Acids (AHA) are some of the most broadly used and researched anti-aging skincare ingredients. Extensive clinical trials have proven alpha hydroxyl acids to be effective at reversing the effects of photo-aging and improving skin tone and texture.
The key benefits of AHAs include:
- Exfoliation: While the mechanisms by which AHAs produce these effects is not fully understood, the most widely accepted theory is that AHAs remove calcium ions from epidermal cell adhesions by chelation. This results in weakening of the intercellular adhesions which has an exfoliating effect by causing the shedding and flaking of dead and dry cells yielding softer skin, lightening of age spots, decreased blemishes and better texture.
- Wrinkle Reduction: AHAs have been found to increase epidermal proliferation and collagen production leading to smoother skin and faded wrinkles. Both in vivo and in vitro, AHA glycolic acid treatment increased the production of collagen and fibroblast proliferation. These effects may be the mechanism by which glycolic acid reverses the process of photoaging.
- Hydration: Due to the water attraction of their hydroxy groups, AHAs increase water retention in deeper layers of the skin restoring hydration resulting in plumper skin with better texture. In addition, AHAs, particularly glycolic acid, have been shown to improve barrier function. This makes AHAs ideal for sensitive skin when used intelligently.
Glycolic acid is the smallest AHA and can be extracted from sugar cane. As such, it penetrates the fastest into the skin layers. Lactic acid has also been proven to provide similar benefits, but with slower penetration. We use it in combination with glycolic acid to complement their respective benefits.
AHA are also less inflammatory than retinol.
Dual Effect:
Studies have shown that at high concentrations (>10%), AHAs can increase photo-damage through a synergistic effect with UV radiation. Studies have shown that Glycolic acid has a photo-protective effect at low concentrations of 10% or less.
We use a low concentration approach proven to have significant net benefits for most skin types including sensitive skins. We combine relatively low AHA concentration with other exfoliants that exfoliate by different mechanisms than AHAs to maximize benefits while minimizing adverse effects.
However, everyone should use caution when using products with AHAs. We do not recommend products containing AHAs for highly sensitive skins – meaning skins that have highly adverse skin reactions to many products, burn easily from sun exposure and/or are otherwise photosensitive should only use poly hydroxy acids (PHAs) because PHAs do not cause irritation.
Since every skin type is unique, always always conduct a patch test before using any skincare products.
Clinical Study: Glycolic and Lactic Acid (8% Treatment)
Appearance Improvement After 22 Weeks of Treatment on Photo-damage Skin (4)
- Self assessment
- Two degrees improvement on medical assessment of severity of damage
(1) Hydroxy Acids, the Most Widely Used Anti-aging Agents Eskandar Moghimipour, et al
(2) The effect of glycolic acid on cultured human skin fibroblasts: cell proliferative effect and increased collagen synthesis S J Kim , Y H Won
(3) Glycolic Acid Treatment Increases Type I Collagen mRNA and Hyaluronic Acid Content of Human Skin Eric F. Bernstein MD ; Jason Lee MD ; Douglas B. Brown MS ; Ruey Yu PhD, OMD ; Eugene Van Scott MD
Glycolic acid modulation of collagen production in human skin fibroblast cultures in vitro, Dermatol Surg, 22:439-441, 1996
(4) Topical 8% glycolic acid and 8% L-lactic acid creams for the treatment of photodamaged skin. A double-blind vehicle-controlled clinical trial.
(5) Lai WW, Hsiao YP, Chung JG, Wei YH, Cheng YW, Yang JH. Synergistic phototoxic effects of glycolic acid in a human keratinocyte cell line (HaCaT). J Dermatol Sci. 2011;64:191-8.
(6) Dual Effects of Alpha-Hydroxy Acids on the Skin Sheau-Chung Tang 1 2, Jen-Hung Yang 3 4
(7) Inhibitory effect of glycolic acid on ultraviolet-induced skin tumorigenesis J T Hong 1, E J Kim, K S Ahn, K M Jung, Y P Yun, Y K Park, S H Lee
(8) Anti-aging cosmetics: Facts and controversies Marcia Ramos-e-Silva, et al
(9) The Truth About Over-the-Counter Topical Anti-Aging Products: A Comperhensive Review Catherine K. Huang, MD, Timothy A. Miller, MD Aesthetic Surgery Journal, Volume 27, Issue 4, July 2007, Pages 402–412
(10) Epidermal and dermal effects of topical lactic acid W P Smith
(11) Alpha hydroxyacids modulate stratum corneum barrier function. E Berardesca 1, F Distante, G P Vignoli, C Oresajo, B Green
(12) Alpha hydroxyacids modulate stratum corneum barrier function E Berardesca 1, F Distante, G P Vignoli, C Oresajo, B Green