Spirulina for Allergic Rhinitis
Spirulina has shown promising relief of allergic-rhinitis symptoms in a few small, mostly dated trials, but the evidence is too thin and unreplicated to recommend it, and no health authority or allergy society endorses this use.
Why this grade7-layer evidence engine
The grade is Weak (Tier C) because the clinical case rests on essentially one adequately designed study. In a 24-week double-blind, placebo-controlled RCT of 150 patients at 2,000 mg/day, spirulina significantly reduced nasal discharge, sneezing, congestion and itching versus placebo (PMID 18343939, P<0.001). It is supported only by a small crossover study that measured a single cytokine (IL-4 fell 32%) rather than symptoms (PMID 15857205), and an 8-week trial of 53 patients that lacked a placebo arm, comparing spirulina against cetirizine (PMID 32773785).
These trials are small, dated, of mixed quality, and have undisclosed funding, and the strongest result has never been independently replicated at scale. Regulators treat spirulina only as a food: the US FDA had no questions on its GRAS status, while EFSA and the WHO/FAO take a neutral stance and flag contamination risk from microcystins and heavy metals rather than endorsing any allergy benefit.
Independent clinical sources are unconvinced. NIH ODS and Cleveland Clinic are cautious, saying it may help but that more human research is needed; Mayo Clinic and Harvard do not address it; and the relevant allergy society does not endorse spirulina for rhinitis. Because spirulina is also immunostimulant, it is inadvisable for people with autoimmune disease or on immunosuppressants. Standard treatments such as intranasal corticosteroids and antihistamines remain far better supported.
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 = 0.422
- 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