Although we have yet to discover a fountain of youth to sip from, many anti-aging steps have become a close second over the years. We cannot stop Father Time but with any luck (and perhaps the right cream), we can maybe slow his pace. With the diversity of products at our disposal nowadays though, it is easy to be unsure about the best route for that youthful glow.
When it comes to anti-aging products, they generally contain a group of ingredients, known as “alpha hydroxy acids” or AHA for short. The use of these acids in anti-aging preparations dates back thousands of years – even Cleopatra herself is said to have showered with sour milk, aka lactic acid! The popularity of alpha hydroxy acids can largely be owed to a credible scientific and medical basis that has proven their ability to reduce wrinkles and fine lines, as well as general skin age appearance.
AHAs have been successful and long-used in the race against the clock but like with most things, they do come with some costs. Often to notice lasting results with alpha hydroxy acid-based products, users must also contend with some unpleasant side effects, such as tingling and burning sensation of the skin, redness, and itching.
With rising awareness of these side effects, the cosmetic industry has now been channeling their efforts into retaining the celebrated anti-aging properties of these products while reducing their other, more irritating qualities. As you may imagine though, this is no easy task and has often resulted in the products’ decreased efficiency. So…Is it all over at you win some, you lose some or is there hope?
Balancing act: The science of AHA efficiency
When it comes to AHA efficiency, there are two variables you must know: High concentration and low acidity. The questions cosmetic industries must contend with to find that happy place between maximized efficiency and little to no side effects all boils down to a careful balance between concentration and acidity – What is the necessary concentration required for lasting skin tone change (No wrinkles over here!)? And what is the lowest pH level that will enable the AHA to perform optimally?
PH is the measure of the concentration of hydrogen ions (H+), also called protons, that are positively charged in water. When it comes to skin vitality, those tiny protons can work magic. Upon being released to the skin, protons encourage skin cell division and increase cell production and in this way, act as your skin’s very own “fertilizer”.
PH units are each differentiated by ten times the concentration of acidity and when a pH level is below 7, a solution is considered acidic. Acid is considered a “free acid” when it has protons stored in its reservoir ready for release.
AHA and Anti-Aging
The problem with many anti-aging cosmetics comes from the tension between increased free acid levels and product efficiency and the increased potential for side effects. Let’s take the case of a solution with a pH varying from 4 to 5. What is important to remember here is that a larger value means weaker acid, and that the amount of free acid and low pH values correlate with more H+ protons. With the solution with a pH from 4 to 5, the concentration of free acid is reduced by 83% as pH increases and as such, effectiveness will decrease. However, if we invert the scale and increase the level of free acid, efficiency will increase but so will side effects.
So how has this problem been addressed? Currently, AHA products sold are limited to an 8% AHA concentration at a pH level of 3.8. This is 4% free acid, and anything beyond this level has been shown to create a significant increase in side effects. Furthermore, clinical data supports that when free acid concentration is 0-2%, the solution only serves as a moisturizer; therefore, a concentration of 4% or more is required to enable the biochemical changes associated with skin smoothness, rejuvenation, and overall anti-aging.