In the sun exposed area, the profound changes of the skin so noticeable compare with unexposed area.
The result is thinner growth in the skin (epidermis and dermis) and confirmed wrinkle during pass the time caused declined number of fibroblasts and keratinocytes.

All of this condition resulting for decrease of collagen formation then lead to qualitative fragmentation of dermal collagen fibers in the skin.
This process more significant for older adults.

In some clinical trials and study, topical retinol that contain Retinol acid showed important agent to maintain damaged skin caused by sun exposing.

Increasing glycosaminoglucans and procollagen concentrations effects from retinol, makes the improvement of;
- Fine wrinkling degree
- Tactile roughness, and
- Overall changes severity of natural aged skin.

Reza Kafi, M.D., from the University of Michigan Medical School in Ann Arbor, and colleagues said, “Because accelerated skin aging duet to excessive sun exposure just marked collagen deficiency and effective treatments for photoaging promote procollagen synthesis, we hypothesized that similar therapies might also improve the collagen deficiency found in intrinsic aging. Compare with retinoic acid, the ability of retinol to induce skin irritation is notably less, at least according to a 4-day patch test (an occlusive treatment). Thus, retinol has the potential to deliver retinoic acid-like effects to human skin with improved tolerability.”