The Dark Side of Acids

By Paul Fister, B.Bus (Mktg), Dip. Form. Chem., Member ASCC

Skincare products formulated with various kinds of acids have been available for over 20 years. The benefits of their regular
application have been thoroughly researched and communicated to the market.

Voices raising concerns about the daily use of acid-containing skincare products were first heard in the mid 1990s. A number of issues have since been raised over the years.

The dangers of excessive sun exposure are well-documented and widely known. Our skin has a natural defence mechanism against UVA and UVB damage. A combination of biochemical adaptation, followed by thickening of the skin and pigmentation (tanning) will result in a significantly delayed onset of erythema. While not desirable, these factors nevertheless afford our skin some level of protection against lasting damage from UV rays. Products and treatments leading to increased turnover of the epidermis will rapidly remove this natural protection. The result will be increased free-radical damage as the skin becomes more vulnerable to UV penetration. Daily use of acid-containing skincare requires a strict regime of sun protection or avoidance, which may not always be achievable.

A number of skin professionals have raised inflammation as a contributing or even leading factor in skin ageing. Dr. Nicholas Perricone states in his book ‘The Perricone Promise’ that “inflammation at the cellular level is the single most powerful cause of the signs of ageing.” It’s claimed that daily application of aggressive products or ingredients such as acids leaves the skin in a constant state of microinflammation. Consumers see the oedema associated with this process and feel excited about the apparent improvement in fine lines and mild pigmentation. In reality, their action will result in excessive free radical activity, followed in the long term by a breakdown of collagen and elastin in the skin, and finally premature ageing.

The Hayflick Limit is a theory that has received much attention. Research by Dr. Leonhard Hayflick has shown that our cells do not divide indefinitely. The DNA in each cell is protected by telomeres. Research has shown that these telomeres shrink with each mitosis (cell division). As they grow shorter each cell eventually reaches a point where it can no longer reproduce – it is said to have reached senescence. Dr. Hayflick stated that each cell may be able to divide about 100 times before senescence sets in.

It is feared that regular daily application of products designed to speed up cell renewal may drive cells to their Hayflick limit prematurely. If so, the outcome will be the opposite of what is desired – premature ageing. Stem cells have also been a popular subject in recent times. This is not surprising since they are the cells that are capable of developing into any type of cell in our body. Research is continuing into the medical applications for stem cell treatments, from cancer to spinal cord injuries. The cosmetic industry has acknowledged the importance of stem cells with the release of a variety of cosmetic products that promise to improve, increase or protect the activity of stem cells in the skin.

Researchers have expressed concern that aggressive treatment designed to speed cell turnover may cause damage to stem cells, or may cause stem cells to specialise when there is no real need. As a result, stem cells may be lost unnecessarily. This could potentially result in hundreds of differentiated cells not being produced, thus accelerating the ageing process.

Another concern related to the use of acids relates to the so-called dark repair process. The human organism has the ability in many areas to repair damaged cells. Enzymes become active without the need for energy from the sun, leading to the term ‘dark repair mechanism’.

UVB rays may lead to changes in a cell’s DNA either directly or through the formation of free radicals. Depending on the severity of the damage caused, three possible outcomes have been determined, as shown in this graphic.

The graphic shows that intensive damage leading to cell death and light damage allowing for repair of damaged DNA will have no consequences. Damage that neither leads to cell death nor can be fully repaired leads to skin problems including age spots, wrinkles and may even result in cancer. As mentioned, the dark repair process does not require energy from the sun – but it does require time for the repair to be effected. It is feared that constant exfoliation may lead to cells that are in the process of undergoing repair to their DNA replicating prematurely, i.e. before the repair is completed. The faulty DNA will then become embedded in the cell and will be passed on to every following generation of that cell. There is some uncertainty surrounding this theory. Some experts suggest that the process of cell division of any cell involved in the dark repair process is automatically arrested.
These examples illustrate the importance of a careful and thorough evaluation of all aspects before embarking on a particular course of action relating to the care of our skin. Moderation and caution would seem to be advised.