TCA in peels and creams - what is it and how does it work
Since chemical peels put me in mind of Sex And The City’s Samantha and her trip to a dermatologist that left her looking as if she’d tried to flee a forest fire in six inch Manolo’s, I approached the whole TCA issue with caution. There may only be 10% TCA in this innocent looking blue and white bottle of TCA Moisture Peel, but what exactly is it?
TCA stands for trichloroacetic acid and although it is routinely used for cosmetic chemical peels, tattoo removal and the treatment of genital warts, the discovery that is synonym is “amchem grass killer”, according to OSHA.gov, did not endear me to it. It seems that like hydroxyphenoxy propionic acid in Algenist’s serum it is an herbicide and is “considered to be a corrosive substance”. I was beginning to fear the worst.
Happily, my worst fears weren’t confirmed. During the 1990s, a fair bit of research was conducted on TCA, mostly because (via chlorine) it can end up in the water system. Reviews of various tests, came up with conclusion that it is “not considered to be carcinogenic to humans” (source).
I was still concerned to know how it works on the skin. TCA peels are considered moderate strength: stronger than glycolic or AHA peels, but gentler than a phenol (I’m think Samantha subjected herself to a phenol). TCA, unlike phenol peels, can be effective for darker skin tones without causing hyperpigmentation problems.
Applying TCA to the skin causes “precipitation of proteins”, which I think has something to do with displacing water from the protein’s surface, and coagulative necrosis of cells in the epidermis. Coagulative necrosis refers to “accidental” cell death, but the key thing is that the architecture of dead tissue is preserved for at least a couple days. This means that cells adjacent to the affected tissue will replicate and replace the cells which have been killed off. A similar process happens to collagen and new collagen will continue to form for several months after a chemical peel. TCA also works as a keratocoagulant that produces a temporary frost or whitening of the skin.
A study on 65 people in Korea (using TCA at 65% or 100% concentrations) showed it to be an effective treatment for acne scars. What interested me about this research was the authors did not want to conduct deep peels because of complications such as damage to adjacent normal skin, but instead used high concentrations of TCA targeted directly on each scar “pressing hard” with a wooden applicator.
Medium depth peels are usually performed with trichloroacetic acid (TCA) in concentrations ranging from 20-35%. Although there are formulations of 50%, they generally not recommended because of the high risk of scarring associated with this depth of penetration. Apparently 10-20% concentrations of TCA will penetrate one–to-two layers of the epidermis.
The concentration of TCA in ClearChoice TCA Moisture Peel is 10%. I started using it a couple of nights ago and am instructed to use it for five consecutive treatments. I’ll report back. But I'm pretty confident that I won't be looking like Samantha.
Ingredients in TCA Moisture Peel: Acqua, organic aloe vera gel, USP glycerin, trichloroacetic acid, vitamin B5, l-carnosine, vitamin E, lecithin, retinyl palmitate, sodium hyaluronate, squalane, NAPCA, chamomile, kojuc acid, alpha arbutin, sage extract, eyebright, magnesium ascorbyl phosphate, grapeseed extract