Evaluating the Impacts of Methylsulfonylmethane on Allergic Rhinitis After a Standard Allergen Challenge: Randomized Double-Blind Exploratory Study.

Background: The sulfur-containing compound methylsulfonylmethane (MSM) has been used as a dietary supplement for a variety of reported health benefits. Clinical observations and case studies have indicated that MSM may help alleviate allergic rhinitis; however, this effect has not been evaluated under controlled conditions.

Objective: This study aimed to determine the effects of MSM consumption on allergic rhinitis symptoms after provocation with a standardized allergen.

Methods: We recruited healthy participants with a history of allergic nasal congestion to participate in a randomized, double-blind, adaptive-design study. Participants were administered a standardized allergen in clinic to determine the presence or absence of an allergic response. Participant responses were recorded using a recognized measure of nasal patency, peak nasal inspiratory flow (PNIF), and by a visual analog scale to score the severity of their allergy-related nasal symptoms. After we collected baseline nasal responses to allergen, followed by a 1-week washout period, participants returned to the clinic and were exposed to allergen after taking an acute high dose of 12 g of MSM. We then randomly assigned participants to a lower dose of MSM (1 g, 3 g, or 6 g), which they consumed once a day for 14 days. Participants returned to the clinic for repeat assessments while again taking their assigned daily dose of MSM.

Results: All MSM treatment courses significantly reduced visual analog scale average nasal symptoms in a longitudinal comparison across all participants, with low-dose treatments decreasing symptoms by 53.72% (P=.001), and an acute 12-g dose decreasing symptoms by 22.49% (P=.03). Although the acute dose of MSM did not yield significant changes in nasal patency, low "everyday" doses significantly relieved nasal obstruction as indicated by a 17.32% (P=.02) increase in PNIF across all participants. The most effective dose across all measurements was daily consumption of 3 g of MSM, which significantly decreased all nasal symptoms (nasal obstruction, rhinorrhea, watery or itchy eyes and nose, and sneezing) and further was found to significantly (P=.01) increase PNIF.

Conclusions: The MSM study product provided significant relief of allergic rhinitis symptoms and objective nasal obstruction measurements without the occurrence of adverse events. Oral consumption of the study product may reduce the symptoms and onset of allergic rhinitis without the side effects associated with standard-care medication.

Trial Registration: ClinicalTrials.gov NCT02342483; https://clinicaltrials.gov/ct2/show/NCT02342483 (Archived by WebCite at http://www.webcitation.org/73vLKNvAp).