A gentle topical acid that reliably calms facial redness and inflammatory bumps and fades dark patches about as well as the long-standing brightening standard, with far less irritation. It also clears blemishes and the marks they leave. Strengths lie in tone, redness, and clarity — not in smoothing wrinkles or reversing structural aging, where studies are absent. (Full Review)
| Marker | Target | Why |
|---|---|---|
| TSH (thyroid-stimulating hormone) | 0.5–2.5 mIU/L (functional) | Thyroid dysfunction can drive or worsen melasma-like pigmentation |
| 25-hydroxy vitamin D | 40–60 ng/mL (functional) | Low vitamin D is associated with some pigmentary and inflammatory skin conditions |
| Ferritin (iron stores) | 50–150 ng/mL (functional) | Screens for iron status when extensive sun avoidance and diet changes accompany treatment |
Cadence: Tolerance at ~4 weeks, early efficacy at 8–12 weeks, then every 3–6 months for maintenance; any labs repeated every 6–12 months if a relevant condition is managed