Tretinoin microsphere 0.1% is a controlled‑release gel for acne that uses porous microspheres to deliver tretinoin gradually, normalizing follicular keratinization, clearing microcomedones, and improving tolerability compared with conventional creams. Apply a pea‑sized amount nightly to clean, fully dry skin, easing in with alternate‑night use and adjusting frequency as tolerated under dermatology guidance. Expect dryness or purging early, with improvement over 8–12 weeks; in trials, 0.1% reduced total lesion counts by roughly 32–45% at 12 weeks versus vehicle. Daily broad‑spectrum sunscreen and gentle skincare are essential during treatment.