This prospective, open-label, controlled pilot study evaluates oral 10% 35 kDa hyaluronan (HA35) versus four control interventions (C60 grapeseed oil, high-oxidation potential water, normal saline, grapeseed oil) for relief of capsaicin/AITC-induced oral pain and pungent sensation. Healthy participants receive standardized pain induction followed by single oral intervention. Pain/pungency assessed at 3 sec/30 sec/60 sec/90 sec. Safety monitored throughout. Minimal-risk, non-invasive oral study.

This prospective, single-center, open-label, controlled pilot clinical study evaluates the rapid analgesic and anti-pungent effects of oral 10% 35 kDa hyaluronan (HA35) compared with four control interventions in healthy adults with capsaicin/AITC-induced oral pain and pungent sensation.

Eligible participants undergo standardized pain induction:

Capsaicin (chili) challenge: Oral capsaicin exposure induces oral pain. AITC (wasabi/horseradish) challenge: Oral AITC exposure induces pain and pungency.

After induction, participants are assigned to 5 parallel groups:

HA35：20 mL 10% HA35 oral solution Control 1：20 mL 4 mg/L C60 grapeseed oil Control 2：20 mL high-oxidation potential water Control 3：20 mL normal saline Control 4：20 mL grapeseed oil All interventions administered orally, held 3-10 seconds then swallowed.

Outcome assessments:

Oral pain (0-10 NRS) Pungent/irritant sensation (0-10 NRS) Time points: Baseline, 3 sec, 30 sec, 60 sec, 90 sec Safety: Oral adverse events and tolerability monitored throughout. Minimal-risk, non-invasive oral intervention. All procedures follow Declaration of Helsinki; written informed consent obtained.

Inclusion Criteria:

• Age 18-65 years, healthy adults
• Able to tolerate capsaicin/AITC oral challenge
• Able to complete NRS assessments
• Signed informed consent

Exclusion Criteria:

• Oral ulcers, lesions, or mucosal disease
• Known hyaluronan allergy
• Severe systemic disease
• Pregnancy/lactation
• Recent oral analgesic use (≤24h)