Retinol Principle and Effects: Understanding and Using It Correctly

Retinol is a vitamin A derivative ingredient commonly used in cosmetics. After being absorbed into the skin, it undergoes conversion through retinaldehyde to retinoic acid, a process known to affect epidermal cell turnover (renewal cycle). For this reason, it is widely used in products designed to refine skin texture and address wrinkles.

How retinol works in the skin

Epidermal keratinocytes are generated and shed in regular cycles, but as age increases or UV exposure accumulates, this cycle can slow and become irregular. Retinol derivatives are reported to be ingredients that help guide this turnover rhythm into a normal range. In this process, older dead skin cells are cleared more quickly and new cells move to the surface.

Research also suggests involvement in collagen synthesis environments within the dermis, so with consistent long-term use, it is often utilized for skin texture and elasticity care purposes. However, this should be understood as an accumulative management concept over several months rather than an immediate change.

Retinol adaptation period: when do reactions appear and what are they?

When using retinol for the first time, an adaptive reaction commonly called 'retinol purging' may occur. Within 2–3 days of starting use, subtle redness or tightness may be felt, and by days 4–7, exfoliation may become more noticeable or a slightly dry sensation may intensify.

This period is known as a process where the stratum corneum is reorganized as cell turnover accelerates, and typically after 2–4 weeks, the skin adapts to the ingredient and reactions tend to subside. However, the intensity and duration of reactions can vary significantly depending on the concentration used, skin condition, and concurrent products.

Staged home care — navigating the adaptation period comfortably

During the early retinol introduction phase (weeks 1–2), it is safe to apply a small amount only in the evening 2–3 times per week while observing skin reactions. During this period, exfoliation and internal tightness tend to occur together, so establishing a habit of first soothing the skin barrier with a gentle, hydrating formulation can help.

Even after adaptation has progressed somewhat (week 3 onward), retinol can increase photosensitivity, so morning broad-spectrum sunscreen is essential. At night, gradually increase use frequency, but when exfoliation and dryness become pronounced, it is safer to take a break of a day or two and focus on hydration.

Particularly when exfoliation is prominent and internal tightness persists, many experts recommend hydrating care that penetrates deep into the skin rather than heavy creams. Establishing a home care routine tailored to this timing can help make the adaptation period more manageable.

Post-procedure recovery: home care makes the difference

Exfoliation and internal tightness during the retinol adaptation period are similar to post-procedure recovery. Abijou Cream is designed with a 2-STEP post-procedure recovery concept: Ultra Sera-Rich Cream addresses the initial stage when redness and heat sensation remain, while Hydro Re-Boosting Cream targets the phase when redness has subsided but internal tightness and exfoliation persist, each providing hydration and barrier care suited to its timing. This approach can also be referenced for managing dryness and exfoliation during the retinol adaptation period.