Hyaluronic Acid (Sodium Hyaluronate) for Dry Eye Disease
Hyaluronic acid eye drops are a well-established lubricant for dry eye, but the oral supplement version this verdict covers has not been shown to work: the only human trial is a single small, confounded pilot study, so there is no reliable evidence that swallowing HA helps your eyes.
Why this grade7-layer evidence engine
This grade is Unverified because of a route mismatch. Nearly all the strong evidence is for topical HA eye drops, not the oral capsule the verdict is about. Two meta-analyses of eye drops (PMID 33804439, n=2,078; PMID 38895674, n=1,796) found modest improvements in tear stability and corneal staining, and head-to-head RCTs (PMID 36333364; PMID 39931678) showed HA drops perform comparably to comparators. Those are a different product entirely.
For oral HA, the cupboard is nearly bare. The single human trial (PMID 31662894) enrolled just 54 people, was open-label, and gave the treatment group oral plus topical HA while controls got topical alone, so any benefit cannot be attributed to the pill. That one confounded pilot cannot establish efficacy, which is why the engine rates the oral route as unverified rather than supported.
Regulators reinforce the caution. The US FDA stopped reviewing the GRAS notice for oral sodium hyaluronate (GRN 976), partly over published reports of possible drug-like effects, and the EU's EFSA has not authorized any health claim for oral HA. Mayo Clinic addresses only injectable HA, while clinic and society endorsements apply specifically to eye drops. Bottom line: use the drops if advised, but do not expect oral HA to treat dry eye.
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 = 0.7
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (2 篇 > 0 negative)
- tier_strict_requirement_check — | A→B 因 L4 有 ≥1 against | B→U 因 scope.conflation_risk=true 且 L11 獨評較低 (B7-2 tier cap)
- detect_disputes — 偵測到 1 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status