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Keywords:

  • aging;
  • photoaging;
  • cosmeceutical;
  • collagen;
  • vitamin C;
  • photodamage

Summary

Background

Chronic sun exposure causes photoaging, the appearance of prematurely aged skin. This phenomenon is characterized by progressive alteration of the dermal extracellular matrix, including elastin and collagen fibers. While many cosmeceuticals claim to improve the appearance of photoaged skin, data are lacking regarding their ability to induce molecular responses associated with wrinkle effacement, particularly increased collagen production.

Aims

To conduct a meta-analysis to determine whether there was a factor(s) that could predict response to various cosmeceuticals.

Patients/Methods

Hundred subjects enrolled in five separate studies of cosmeceuticals containing: L-ascorbic acid, pentapeptide, α-lipoic acid, yeast extract, or 1% idebenone. Five groups consisting of 16–20 volunteers applied one cosmeceutical to their photodamaged forearms for several weeks. Punch biopsies were obtained pretreatment and post-treatment and analyzed for type I procollagen by ELISA.

Results

Analysis of basal collagenesis reinforced the notion that hypo-collagenesis is associated with photoaging severity, independent of age or gender. Treatment outcome varied greatly among subjects, ranging from no improvement to a 7-fold increase in collagenesis. Retrospective statistical meta-analysis was conducted to determine whether age, gender, type of cosmeceutical, or evidence of hypo-collagenesis in untreated skin could predict responsiveness to cosmeceuticals. Our analysis revealed that subjects with hypo-collagenesis responded 6.4 times more often than subjects with normo-collagenesis.

Discussion

Hypo-collagenesis was the only factor that influenced treatment outcome. This study therefore identifies hypo-collagenesis as the unique parameter predicting anti-aging cosmeceutical treatment outcome. These findings provide a basis for future cosmetic testing and the potential development of custom formula skin care.