Hydroxypinacolone retinoate (HPR), a cosmetic grade ester of ATRA, is unique in that it processes innate retinoic acid activity, binding directly with retinoid receptors without the need for metabolic breakdown to more biologically active forms. It has been demonstrated to be more stable and cause less skin irritation than retinol. Here, we compared levels of gene transcription by HPR, ATRA, retinol (Rol), retinaldehyde (Ral), and retinyl palmitate (RP) by evaluating binding of the retinoic acid receptor to retinoid acid responsive elements (RARE) in DNA using a RARE reporter assay

Together these data suggest that HPR is an effective alternative to ATRA and other less potent retinoids in the treatment of aging skin without the detrimental side-effects

RARE assay results showed that HPR had greater levels of gene transcription than Rol, Ral, and RP at the same concentrations, and was less cytotoxic to cells at a 10 times higher concentration; however, HPR did not achieve gene transcription levels of ATRA

The NPP regimen, which contained cosmetic ingredients known to affect the appearance of wrinkles, along with moisturizing and skin barrier building components, comparably improved the appearance of fine lines and wrinkles relative to the prescription tretinoin regimen as measured by both expert grading and image analysis in a long-term study, with better tolerability

Based on the findings from the safety and efficacy studies presented here, retinyl propionate alone, and in combination with climbazole, was significantly less irritating than a similar serum containing retinol

RPC treatment visibly and significantly improved mottled hyperpigmentation better than 0.1% retinol in the same moisturizing serum base at 8 weeks, with continued improvement throughout the study.

It is well recognized that the problem with retinol usage is the initial skin reaction during the first few weeks of application. Significant improvement observed with RPC treatment in the earlier weeks of the study indicates that RPC treatment is likely to reduce the incidence of retinoid dermatitis in the initial adjustment period for those sensitive to retinol.

In the present work, we wished to further enhance efficacy potential and minimize any risk of irritation by identifying compounds which could boost RP activity in retinoid responsive models

Additionally, we evaluated the flavonoid content in a Ceratonia siliqua (carob) fruit extract (CS, Silab, France) since flavonoids have been reported to inhibit AKR1B10 and carbonyl reductases, enzymes that can reduce RAL back to ROL

RP in combination with Nam and CS can significantly increase RP activity in retinoid responsive in vitro models. Mechanistically, we believe this is via an increase in cellular NAD+ pools by the precursor Nam which allows for optimized oxidation to tRA via ROL and RAL. Additionally, the total flavonoids present in CS may further boost metabolism efficiency by inhibiting the reduction of RAL back to ROL

all tested retinoids were found overall photosensitive, among which retinol was found the most stable

RP is the most stable form of retinoic acid,18 commonly used as anti-aging due to its effectiveness at regulating epithelial cell growth and differentiation and boosting collagen production. Experimental studies have emphasized the valuable role of RP in increasing skin elasticity, decreasing skin roughness, and preventing the peroxidation of skin lipids.3,19,20 It also enhances the appearance of the skin and reduces keratosis in sun-damaged skin.9,10

The inclusion of RP into nanocarriers for topical treatment of acne is an exciting strategy that can lead to higher stability and enhance skin penetration. Ethosomes are soft phospholipid nanovesicles used for enhanced dermal and transdermal delivery of drugs.21,22 They contain a high ethanol concentration, which improves skin permeation21–24 as it acts as a penetration enhancer. It penetrates intercellular lipids, increases lipid fluidity, and decreases the density of lipid multilayer of the cell membrane,23,24 which increases skin permeability. Therefore, ethosomes permeate easily into the deep skin layers and fuse with skin lipids, leading to drug release in deep skin layers.23,24

In a split-face clinical study, RP ethosomal hydrogel showed comparable efficacy to conventional tretinoin formulation, with a remarkable effect over the marketed tretinoin formulation in reducing non-inflammatory acne lesions. Moreover, it was found to have excellent tolerability with no or minimal local treatment-related skin reactions such as erythema, peeling, burning, and pruritus in treated volunteers compared to the conventional cream.

retinyl retinoate (RetinoX8; Enprani Co. Ltd, Inchon Korea), which was an ester of all-trans-retinoic acid (RA) and all-trans-retinol (ROL). This new synthetic hybrid of retinoid showed enhanced thermal stability and decreased photosensitivity, and exhibited decreased cell toxicity compared with that of retinol in vitro biological activity and dermatology test in a randomized-controlled trial (16, 17). In this report, we investigate skin wrinkle improvement on aged skin by comparison of 0.06% retinyl retinoate cream and 0.075% retinol cream

the adverse effects, such as erythema, edema, scaling, itching, stinging, burning, tightness, and prickling, were not reported in the 0.06% retinyl retinoate cream

All these results combined with the stability of the retinyl retinoate indicated that retinyl retinoate, which was synthesized via a condensing reaction between retinol (hydroxyl end group) and retinoic acid (carboxyl end group), removed the disadvantage of retinol and retinoic acid for application in the cosmetics industry

Ethyl Lactyl Retinoate

Ethyl Lactyl Retinoate

Retinoids and AHAs are often referred to as “gold standard” ingredients due to their ability to rejuvenate the skin by influencing the rate of cell turnover and exfoliation.

Retinoids increase cellular mitosis, stimulate collagen production to thicken and repair the epidermis, normalize melanocyte function, and regulate skin cell metabolism and cellular turnover, thereby improving pigmentation, skin texture and roughness, and fine lines and wrinkles

Tran and colleagues demonstrated that the combination of an AHA (glycolic acid) with a retinoid regimen facilitated better bioavailability and greater delivery of the retinoid while reducing or preventing tolerability issues

Carboxylic acids that consist of a hydroxyl group attached to the alpha position of an aliphatic carbon atom are known as alpha hydroxy acids (AHAs).

Alpha hydroxy acids can also be used successfully as exfoliants for all skin types. They cause desquamation by enhancing the breakdown of corneosomes and diminishing their cohesiveness

Exfoliating products containing the acids show antibacterial, keratolytic, and antioxidant effects, which make them popular in anti-aging treatments