That was a fortunate strike as a result of salicylic acid is each a keratolytic agent (therefore exfoliator) and an anti-inflammatory agent (it’s the precursor of aspirin). Confronted with energetic beauty merchandise, competing manufacturers instantly regarded for attainable components to formulate exfoliating lotions, and located that fruit acids are good exfoliators, too.
Fruit acids, resembling citric acid, glycolic acid, lactic acid, malic acid and the like, are palatable for shoppers who insist that “pure is nice.” The very fact of the matter is, pure will be fairly irritating to pores and skin.
Irritation was a serious downside because the exfoliating motion is primarily required across the eyes to cut back fantastic traces and wrinkles within the crow’s ft space and within the under-eye zone. Skincare manufacturers have been struggling for years to formulate irritation-free, acid-containing merchandise. Acid-containing merchandise have been marketed with claims as various as “it stings as a result of it’s energetic,” “it removes scars,” “it’s an anti-acne product,” “evens out pores and skin discolorations,” “smooths traces and wrinkles” and “the very best anti-aging ingredient ever.”
It ought to be famous that topical acid-containing merchandise will not be “peeling” merchandise. Peeling is a medical apply that have to be carried out by a dermatologist. Peeling entails aggressively treating the pores and skin with excessive concentrations of phenol or trichloroacetic acid or of mixtures of lactic acid, salicylic acid and resorcinol. To be efficient, peelings would possibly want a number of remedies, every of them needing a number of days or even weeks for the pores and skin to heal.
For causes linked to their chemical construction, the fruit acids quoted above belong to a class known as alpha-hydroxy-acids (AHAs) whereas salicylic acid belongs to a chemical class known as beta-hydroxy-acids (BHAs).
A terrific addition to the panoply of exfoliators was ascorbic acid (AA). However AA, aka vitamin C, is neither an AHA nor a BHA. Quite, it’s concurrently a strong antioxidant, an irreplaceable catalyzer of the maturation of collagen, a stimulator of ceramide synthesis and, nicely, an amazing exfoliator. Being a strong antioxidant makes it in order that ascorbic acid is kind of unstable (it offers an electron to whomever wants one) and quickly adjustments coloration, thus affecting the organoleptic properties of the formulation that incorporates it.
Manufacturers eager about growing vitamin C-containing merchandise designed acceptable packaging such that dry vitamin C was saved in an oxygen-free cap, and could possibly be added to the serum within the jar beneath by hitting the cap; this was an ideal technique developed by Helena Rubinstein for protecting vitamin C from adventitious oxidation, thus permitting one to make use of “contemporary” vitamin C. Sadly, in these situations, “contemporary” vitamin C is obtainable solely when the jar incorporates one single dose of product, in order that one cap-jar mixture had for use for each utility, and this was not economically viable. The profitable technique to ship vitamin C upon topical utility was to synthetize shelf-stable molecules that could possibly be transformed to ascorbic acid by enzymes resident within the stratum corneum, resembling magnesium ascorbyl-phosphate, ascorbyl glucoside, ethyl ascorbic acid and tetrahexyldecyl ascorbate (THD ascorbate).
Each water-soluble (sodium ascorbyl phosphate, magnesium ascorbyl phosphate, ascorbyl glucoside and ethyl ascorbic acid) and oil soluble (ascorbyl esters) are extensively utilized in beauty and therapeutic preparations and one of the vital widespread types is tetrahexyldecyl ascorbate (THD vitamin C, THDC). As an oil-soluble by-product, THDC not solely improves chemical stability, however its lipophilic nature facilitates supply into the dermis and maybe the dermis the place it undergoes intracellular enzymatic conversion to free ascorbic acid (AA). Importantly, free AA have to be launched by THDC earlier than its pores and skin advantages will be realized. Thus, THDC is a precursor of AA. When mixed with different components, THDC has been proven to lower indicators of photodamage resembling pores and skin wrinkling and to cut back hyperpigmentation.
For 25 years, THDC (CAS # 183476-82-6) and ascorbyl tetraisopalmitates (CAS # 183476-6) have been construed as being equal buildings. In actuality, they do signify two totally different chemistries with totally different CAS#s. Whereas each are esters of ascorbic acid, THDC comes from the response of AA with 2-hexyldecanoic acid (CAS# 25354-97-6) whereas ascorbyl tetraisopalmitates derives from response of AA with isopalmitic acid (CAS# 4668-02-7). Due to this fact, they originate from two totally different fatty acids that, when esterified with ascorbic acid, yield two totally different merchandise. This misnomer was just lately corrected by Sytheon working in shut collaboration with the Private Care Product Council (PCPC) and the Chemical Summary Companies (CAS # supplier) (private communication). Not too long ago, Sytheon has additionally demonstrated that the soundness of THDC underneath an oxidant wealthy setting in addition to its pores and skin advantages will be improved by combining it with Acetyl Zingerone. This work was revealed within the Worldwide J Molecular Sciences, 22: 8756, 2021.
That is to say that ascorbic acid precursors haven’t but completed to shock us, and it may be surmised that they are going to proceed being related components for skincare merchandise, helpful in “energetic cosmetics.”
Paolo Giacomoni, PhD
Perception Evaluation Consulting
paologiac@gmail.com
516-769-6904
Paolo Giacomoni acts as an unbiased advisor to the skincare business. He served as govt director of analysis at Estée Lauder and was head of the division of biology with L’Oréal. He has constructed a file of achievements by means of analysis on DNA injury and metabolic impairment induced by UV radiation in addition to on the optimistic results of nutritional vitamins and antioxidants. He has authored greater than 100 peer-reviewed publications and has greater than 20 patents.
