Chronic rhinosinusitis is common, under-recognized when self-diagnosed from symptoms alone, and heavily marketed to with unproven "sinus support" supplements. The best independent human evidence points to a simple, low-cost, low-risk intervention — saline nasal irrigation — as the strongest non-drug option, alongside intranasal corticosteroids and, for severe nasal-polyp disease, biologics led by dupilumab. Most supplement ingredients marketed for sinus health — bromelain, probiotics, NAC, quercetin, curcumin — lack adequate human trial evidence specific to CRS. This article covers what CRS is, how it works, conventional treatment, the supplement evidence claim by claim, safety, interactions, dosing, and funding sources.

Table of contents

• Evidence summary table
• What chronic rhinosinusitis is
• How it works
• Conventional treatment
• Supplement and lifestyle evidence
• What works and what does not
• Risks and side effects
• All interactions
• Who should avoid
• Dosage and how to take
• Animal and in-vitro evidence excluded
• Independent funding
• Frequently asked questions
• Sources

What chronic rhinosinusitis is

Chronic rhinosinusitis (CRS) is inflammation of the nose and paranasal sinuses persisting 12 weeks or longer. It is subclassified into CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). Diagnosis requires at least 2 of 4 cardinal symptoms — nasal blockage/obstruction, nasal discharge (anterior or posterior), facial pain or pressure, and reduced or lost sense of smell (hyposmia/anosmia) — plus objective findings on endoscopy or imaging (Alharthi & Alzarei, Cureus 2024).

Symptom-only survey estimates of CRS prevalence run as high as ~10%, but this overstates true disease because many people with sinus-type symptoms do not meet objective diagnostic criteria. Guideline-based prevalence — requiring both symptoms and objective findings — is consistently under 5% (Alharthi & Alzarei 2024). About one-third of diagnosed CRS patients have nasal polyps. Separately, nasal polyps occur in roughly 1–4% of the general population, and about 25–30% of CRS patients overall have the CRSwNP phenotype (Stevens et al., CRSwNP review, PMC).

How it works

CRS is driven by a combination of epithelial barrier defects in the sinonasal lining, exposure to colonizing or pathogenic bacteria including biofilms and broader microbial dysbiosis, and a dysregulated host immune response (Stevens et al., CRSwNP review, PMC).

In CRS with nasal polyps specifically, eosinophilic, type-2 inflammation tends to dominate — the same inflammatory pathway (interleukin-4, interleukin-13, interleukin-5 signaling) implicated in asthma, allergic rhinitis, and atopic dermatitis. This mechanistic overlap explains why CRSwNP frequently co-occurs with asthma and allergic rhinitis, and why biologic drugs originally developed for type-2 asthma and eczema (dupilumab, omalizumab, mepolizumab) have been tested and shown effective in CRSwNP (Stevens et al., PMC).

Conventional treatment

Intranasal corticosteroids (INCS) are first-line therapy for CRS. A 2025 systematic review of 6 high-quality RCTs totaling 2,339 participants found that INCS and INCS-adjunct regimens consistently improved nasal polyp score, nasal congestion, and quality-of-life measures. Among the agents and adjuncts compared, dupilumab produced the greatest nasal polyp score reduction, at Δ−2.06 versus comparators (Mawkili et al., Cureus 2025). The review's authors are academic with no industry funding disclosed.

For severe CRSwNP that does not respond adequately to INCS, biologic therapy is the escalation step: dupilumab (anti-IL-4/IL-13 receptor), omalizumab (anti-IgE), and mepolizumab (anti-IL-5) are all approved options, with dupilumab showing the strongest effect sizes across symptom, olfactory, and quality-of-life endpoints (Wu et al. 2022).

Other conventional tools include short courses of antibiotics for acute bacterial exacerbations, saline irrigation as a guideline-recommended adjunct at every severity level (see below), and functional endoscopic sinus surgery (FESS) for disease that remains refractory to medical therapy.

Supplement and lifestyle evidence

Among non-drug options, saline nasal irrigation is the strongest-supported, lowest-risk intervention and is the one consistently recommended across CRS guidelines. Intranasal corticosteroids and biologics (dupilumab first) remain the evidence-based drug therapies, supported by independent systematic reviews evaluating competing manufacturer drugs. Vitamin D shows only an inverse association with severity, with no treatment trial to confirm supplementation helps. Xylitol has one small positive pilot. Bromelain has only a mucosal-penetration/pharmacokinetic study — not a clinical-efficacy RCT — so it is graded Insufficient rather than effective. Probiotics, NAC, quercetin, and curcumin all lack adequate human CRS efficacy data.

What works and what does not

Risks and side effects

All interactions

Who should avoid

• Anyone using untreated tap water for nasal irrigation should switch to distilled, sterile, or previously boiled and cooled water because of a rare but serious amoebic infection risk (Chong et al., Cochrane CD011995).
• People on anticoagulants or antiplatelets (warfarin, DOACs, aspirin, clopidogrel) should avoid bromelain supplements without clinician approval, given the theoretical additive bleeding risk from its proteolytic activity (Passali et al. 2018).
• People with pineapple allergy should avoid bromelain because of possible cross-reactivity.
• Anyone expecting probiotics, NAC, quercetin, or curcumin to treat diagnosed CRS should not rely on them in place of saline irrigation, intranasal corticosteroids, or prescribed biologics, since human CRS efficacy evidence for these supplements is inadequate.
• Anyone with persistent symptoms beyond 12 weeks, especially with nasal polyps, facial pain, or smell loss, should seek an ENT evaluation rather than self-treating with over-the-counter supplements alone.

Dosage and how to take

Animal and in-vitro evidence excluded

Much of the promotional literature for quercetin and curcumin in sinusitis rests on rodent or cell-culture data rather than human trials. Per this site's independent-evidence standard, animal studies are excluded from all efficacy and safety conclusions and are not used to support any claim that these compounds treat CRS in humans. Where quercetin or curcumin appear in the tables above, the grade is Insufficient specifically because adequate human CRS trial data do not exist — not because the animal/in-vitro signal is being counted as partial evidence.

Bromelain's human evidence base for CRS is a genuine human study, but it is a pharmacokinetic/penetration study (confirming the compound reaches sinonasal tissue), not a clinical-efficacy trial with symptom outcomes (Passali et al., Acta Otorhinolaryngol Ital 2018). It is listed here for transparency because it is sometimes mistaken for proof of clinical benefit, when it only demonstrates that the ingredient can reach the target tissue.

Independent funding

The strongest evidence in this article comes from sources with no commercial stake in the outcome. The Cochrane review of saline irrigation was conducted under Cochrane's non-profit, methodologically independent review process with no commercial funding identified, which matters because saline is essentially unpatentable and has no large manufacturer lobbying for a positive result — the positive finding reflects the underlying trial data rather than sponsor influence (Chong et al., Cochrane CD011995).

The dupilumab biologic ranking comes from an independent academic network meta-analysis (Sun Yat-Sen University) with no industry funding disclosed, comparing three competing manufacturer drugs (dupilumab, omalizumab, mepolizumab) against each other rather than relying on any single company's own trial data — a structure that reduces the chance that the ranking simply reflects one manufacturer's preferred outcome measures (Wu et al., Int Arch Allergy Immunol 2022). The intranasal corticosteroid systematic review and the vitamin D observational review are similarly academic with no industry funding disclosed (Mawkili et al. 2025; Alharthi & Alzarei 2024).

Frequently asked questions

What is the best non-drug treatment for chronic sinusitis?

Saline nasal irrigation. A Cochrane review of 2 RCTs (116 adults) found large-volume hypertonic saline irrigation improved symptom scores versus usual care over 6 months, and it is the non-drug option most consistently recommended in CRS guidelines (Chong et al., Cochrane CD011995).

Do I need steroids for chronic sinusitis?

Intranasal corticosteroids are first-line drug therapy. A systematic review of 6 high-quality RCTs (2,339 participants) found they consistently improved nasal polyp score, congestion, and quality of life (Mawkili et al., Cureus 2025).

Is dupilumab better than other biologics for nasal polyps?

Yes, based on current evidence. A network meta-analysis of 9 RCTs (1,190 patients) ranked dupilumab best for nasal polyp score, SNOT-22 symptom score, smell, and congestion, ahead of omalizumab and mepolizumab (Wu et al., Int Arch Allergy Immunol 2022).

Does bromelain help sinus infections?

It is not proven to. The only human CRS study on bromelain is a pharmacokinetic study showing it penetrates sinonasal mucosa — it did not measure any clinical symptom outcome, so it cannot be said to relieve sinus symptoms based on current human evidence (Passali et al., Acta Otorhinolaryngol Ital 2018).

Should I take vitamin D for sinus problems?

The evidence does not yet support this as a treatment. Nine observational studies (1,042 patients) found a consistent inverse relationship between vitamin D levels and CRS severity, but no supplementation trial has tested whether correcting vitamin D actually treats CRS (Alharthi & Alzarei, Cureus 2024).

Does xylitol nasal rinse work?

Possibly, but the evidence is very limited. A small randomized crossover pilot (n=20) found xylitol irrigation improved SNOT-20 scores by 2.43 points versus a worsening of 3.93 points with saline alone (p=0.044), but the sample size is too small to be conclusive (Weissman et al., Laryngoscope 2011).

Are probiotics good for sinus health?

Not based on current evidence. A systematic review of randomized controlled trials found no consistent clinical benefit for probiotics in chronic rhinosinusitis (J Laryngol Otol systematic review).

Sources

• Alharthi F, Alzarei A. Chronic rhinosinusitis: prevalence, diagnosis, and the role of vitamin D. Cureus. 2024. PMC11005879
• Stevens WW, et al. Chronic rhinosinusitis with nasal polyps. Journal of Allergy and Clinical Immunology / PMC. PMC4939220
• Mawkili W, et al. Intranasal corticosteroids for chronic rhinosinusitis: a systematic review. Cureus. 2025. PMC12335323
• Wu Q, et al. Biologics for chronic rhinosinusitis with nasal polyps: a network meta-analysis. International Archives of Allergy and Immunology. 2022. PMID 34607329
• Chong LY, et al. Saline irrigation for chronic rhinosinusitis. Cochrane Database of Systematic Reviews. CD011995
• Weissman JD, et al. Xylitol nasal irrigation in the management of chronic rhinosinusitis: a pilot study. Laryngoscope. 2011. PMID 21994147
• The role of probiotics in chronic rhinosinusitis: a systematic review of randomised controlled trials. Journal of Laryngology & Otology
• Passali D, et al. Bromelain pharmacokinetics in sinonasal mucosa. Acta Otorhinolaryngologica Italica. 2018. PMC6036946

Last reviewed: July 6, 2026.