Hyperpigmentation

Hyperpigmentation

Three distinct processes produce the darkened patches grouped under hyperpigmentation, and they respond differently. Melasma is hormonally driven and affects 15 to 50 percent of pregnant women, appearing symmetrically on the cheeks, forehead and upper lip. Post-inflammatory hyperpigmentation follows acne or injury and is common in Fitzpatrick skin types IV to VI. Solar lentigines accumulate with cumulative sun exposure. All three end in the same place, excess melanin deposited in the epidermis or dermis, but they begin at different triggers. Five ingredients carry an evidence grade here, all of them Grade C, across 19 studies and about 1,070 participants.

The shared endpoint is tyrosinase, the rate-limiting enzyme of melanin synthesis, together with the transfer of finished melanosomes from melanocytes into surrounding keratinocytes. Ultraviolet light, inflammatory mediators and estrogen signalling each upregulate that pathway. Where the pigment lands determines how stubborn it is: epidermal deposition turns over with the keratinocyte cycle, while dermal deposition sits below the basement membrane and persists far longer.

Glutathione carries the widest base in this set at 6 studies and 350 participants. Its proposed action is a shift in melanogenesis from darker eumelanin toward lighter pheomelanin, along with direct inhibition of tyrosinase. Oral bioavailability is the recurring objection, since glutathione is a tripeptide subject to intestinal hydrolysis, and trials have used varying forms and doses that complicate pooling.

Pine bark extract, or pycnogenol, is supported by 4 studies and 240 participants, and Polypodium leucotomos, grape seed extract and N-acetyl cysteine each rest on 3 studies with 150 to 240 participants. The mechanistic thread running through them is antioxidant rather than direct enzymatic: by reducing ultraviolet-induced reactive oxygen species and the inflammatory signalling that follows, they act upstream of pigment production rather than on the melanocyte itself. That is consistent with the observation that the same compounds appear in the internal photoprotection literature.

A uniform Grade C across every entry is the most important fact on this page. It reflects small samples, short durations and a scarcity of the objective colorimetric measurement that would allow results to be compared between studies. Sun exposure is also the dominant variable in all three subtypes, so any trial that does not standardise ultraviolet exposure is measuring photoprotection and supplementation together.

The practical implication is one of sequence rather than substitution. Broad-spectrum sun protection is the intervention with the strongest support for every subtype, and the graded ingredients here are studied as additions to it. Melasma in particular tends to recur when the hormonal or ultraviolet trigger returns, and dermal pigment resists oral approaches. Persistent or rapidly changing pigmented lesions require clinical evaluation, since a change in an existing spot is also how several serious dermatologic conditions present.