Azelaic Acid for Acne
Topical azelaic acid is an evidence-backed treatment for mild-to-moderate acne, reliably reducing inflammatory lesions; it works about as well as topical retinoids and slightly less well than benzoyl peroxide, so it is often used as a well-tolerated alternative or add-on.
Why this grade7-layer evidence engine
This earns a moderate-evidence (Tier A) grade because regulators and high-quality trials line up cleanly. The US FDA approves azelaic acid 20% cream (Azelex) for mild-to-moderate inflammatory acne vulgaris, the UK's NHS/NICE lists it as a treatment option for acne, and NIH MedlinePlus confirms its use for acne; EFSA is neutral only because azelaic acid is a topical medicine, not a food, and the WHO entry was not found.
The clinical data are consistent. A 2023 systematic review of 43 randomized trials found azelaic acid more effective than vehicle for acne (PMID 37550898), and a double-blind RCT showed a 60.6% lesion reduction versus 19.9% for placebo (PMID 17456913). An older comparative trial confirmed efficacy for papulopustular acne (PMID 2528258).
What keeps this at moderate rather than top tier is its relative potency. A Cochrane review (49 RCTs, 3,880 people) found azelaic acid roughly equal to tretinoin but probably less effective than benzoyl peroxide (PMID 33034949), while a trial versus tretinoin showed comparable improvement with less irritation (PMID 9737831). It also fades acne-related dark marks (PMID 37213446), making it a well-tolerated combination or alternative agent. Higher strengths are prescription-only; over-the-counter cosmetic versions are weaker.
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditable▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.785
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 無高階證據可裁決
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status