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Rye-Grass Pollen Extract (Cernilton / Cernitin, Secale cereale)
Rye-grass pollen extract (Cernilton) modestly improves self-rated urinary symptoms and nocturia in BPH, and reduced pain in one phase-3 chronic-prostatitis trial — but it does not improve urine flow, and its Cochrane review has been withdrawn.
What the evidence says
Rye Pollen Extract doesn't have enough studies with structured effect-size data yet to pool a verdict. Browse the studies below for individual findings.
Most evidence is from medium-quality randomised trials published 1990–2021 with a typical study size of 139 participants.
Based on 16 studies · 5 RCTs · 1,562 total participants
Confidence
High confidenceBy outcome
Two 2000 systematic reviews of the same 444 men — only two of whose four trials were placebo-controlled — found modest, significant improvement in self-rated urinary symptoms and nocturia but no pooled between-group effect on urine flow, residual volume, or prostate size. The Cochrane update was later withdrawn, later urology reviews conclude phytotherapy is no better than placebo for BPH, and the one high-quality modern RCT is in chronic prostatitis rather than BPH.
No trials currently enrolling · 4 completed on ClinicalTrials.gov
Registered trials show research momentum for Rye Pollen Extract, not proof of effect — a registration is a plan, and posted results are sponsor-reported, not peer-reviewed. They are never counted toward the evidence rating above.
Browse these trials on ClinicalTrials.govClinicalTrials.gov · as of Oct 2026
Rye pollen extract — sold for decades in Europe and Japan as Cernilton or Cernitin — is prepared from the pollen of rye grass (Secale cereale) and related pollens, and is one of the older phytotherapies used for benign prostatic hyperplasia (BPH) and chronic prostatitis. The honest reading of its evidence is narrow.
A 2000 systematic review (MacDonald et al., BJU International, PMID 10792162) pooled only 444 men across four trials of 12–24 weeks — and of those four, only two were placebo-controlled, so the versus-placebo estimates rest on a subset of the 444 rather than all of them.
In those, self-rated urinary-symptom improvement was about 2.4 times as likely on Cernilton as on placebo (RR 2.40) and reduced nocturia (RR 2.05), while producing no improvement at all in peak urine flow, residual volume, or prostate size.
The reviewers flagged the trials as short, small, incompletely reported, and of unknown preparation quality — and the 2011 update of the Cochrane version of that review was subsequently WITHDRAWN, so there is no current Cochrane assessment.
Later urology reviews go further, concluding that better-constructed studies show phytotherapy for BPH is no more effective than placebo.
The strongest single trial is not in BPH at all: a 139-man multicentre, double-blind, placebo-controlled phase 3 study found pollen extract significantly improved pain, quality of life, and total NIH-CPSI score in inflammatory chronic prostatitis/chronic pelvic pain syndrome.
Mechanistically, the lipid-soluble fraction inhibits cyclo-oxygenase and 5-lipoxygenase in vitro at potencies comparable to diclofenac, and the extract suppresses prostatic IL-6 and TNF-α in a rat prostatitis model, which fits the symptom-and-inflammation profile of the clinical results better than any effect on prostate size.
Tolerability is the consistent finding across every trial: adverse events were rare and mild, and a 240-man randomised comparison dosed 1,500 mg/day for four years without reported adverse effects.
The fat-soluble fraction of standardized rye pollen extract dose-dependently inhibited prostaglandin and leukotriene synthesis in vitro, with IC50 values of 0.005 mg/ml (cyclo-oxygenase) and 0.08 mg/ml (5-lipoxygenase) — similar to diclofenac tested in the same system. The water-soluble fraction had no effect (PMID 1904229).
In castrated rats given 17β-estradiol to induce nonbacterial prostatitis, prostatic IL-6 and TNF-α rose 2–3 fold; cernitin pollen extract decreased those cytokine levels dose-dependently and restored the histopathological changes at 1,260 mg/kg (PMID 11523128).
Across nine human continuous cell lines, only the prostate-derived lines were growth-inhibited by the pollen extract Cernitin T-60; non-prostate lines showed variable resistance, and selectivity was more pronounced in hormone-independent models (PMID 1699627). This is in-vitro evidence only — no human study has shown a reduction in prostate size.
In 61 prostate-biopsy candidates given cernitin pollen extract for 30 days, mean serum PSA fell by 0.6 ± 1.4 ng/mL (−7.6 ± 16.1%, p=0.0003), and the change differed significantly between men whose biopsy was later negative versus positive for cancer (PMID 29577437).
How Rye Pollen Extract works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
The primary studied population. Expect modest symptom and nocturia benefit at best, and no change in urine flow or prostate size (PMID 10792162, whose Cochrane version, PMID 10796739, has since been withdrawn). Get a proper urological evaluation rather than self-treating.
This is where the strongest single trial sits — 12 weeks of pollen extract significantly improved pain, quality of life, and total NIH-CPSI versus placebo, with only minor adverse events (PMID 19524353).
Poor candidates for phytotherapy alone. A 2016 urology review concluded that better-constructed studies show these agents are no more efficacious than placebo (PMID 27180172), and an alpha-blocker outperformed pollen extract on flow measures in a 243-man randomised trial (PMID 12094707).
No data. Every trial in the evidence base enrolled adult men with prostate or pelvic-pain conditions; there is no studied indication or safety data outside that population.
Studied together in a 243-man randomised multicentre trial: tamsulosin alone and tamsulosin plus cernitin pollen extract were both more effective than pollen extract alone, and no adverse interaction was reported. Adding pollen extract to an alpha-blocker did not improve on the alpha-blocker's own effect on flow rates (PMID 12094707).
Men receiving antibacterial treatment plus cernilton for 3 months had greater relief of pain and dysuria and better quality of life on NIH-CPSI than men receiving standard antibiotics alone (p<0.05) (PMID 17472001). Neither study assessed interactions or safety, so nothing was reported either way — absence of reported events is not evidence of safety.
Theoretical only, based on in-vitro data: the fat-soluble pollen fraction inhibits cyclo-oxygenase at an IC50 similar to diclofenac tested in the same assay (PMID 1904229). No clinical study has tested co-administration, and no additive adverse effect has been reported in humans.
Tip: A 2000 systematic review reported adverse events as rare and mild across the pooled trials, with a 4.8% withdrawal rate on Cernilton versus 2.7% on placebo (PMID 10792162, whose Cochrane version, PMID 10796739, has since been withdrawn). Stop and consult a clinician if symptoms persist.
Tip: Cernilton N was well tolerated by 97% of 90 patients treated for 6 months (PMID 8499988); a 4-year randomised comparison in 240 men — 120 of them at 1,500 mg/day — reported no toxic or adverse effects (PMID 18649754). If intolerance occurs, discontinue.
Rye Pollen Extract has an evidence score of 4.8/10 — emerging evidence based on 16 indexed studies. Rye-grass pollen extract (Cernilton) modestly improves self-rated urinary symptoms and nocturia in BPH, and reduced pain in one phase-3 chronic-prostatitis trial — but it does not improve urine flow, and its Cochrane review has been withdrawn. Representative study: PMID 10792162.
The commonly studied dose of Rye Pollen Extract is 2 capsules/tablets three times daily (every 8 hours), or 375-750 mg twice daily. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
The best time to take Rye Pollen Extract is in split doses through the day. It can be taken on an empty stomach. Every clinical trial dosed rye pollen extract in divided doses through the day — two capsules every 8 hours in the phase 3 CP/CPPS study (PMID 19524353) and one tablet three times daily for 6 months in chronic prostatitis (PMID 8499988) — without any meal requirement.
Rye Pollen Extract is generally well-tolerated and considered safe for most healthy adults at recommended doses. Reported side effects are uncommon and include any adverse event (all causes), intolerance leading to discontinuation. Use caution if any of these apply to you: Not a substitute for prostate cancer evaluation — an uncontrolled 61-man 30-day pilot reported lower serum PSA (PMID 29577437) — while the larger 240-man 4-year trial found NO significant PSA change (PMID 18649754). The evidence conflicts, so mention it before PSA screening rather than assuming either way.
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Reviewed by Dr. Baher Al Hakim · Last reviewed July 2026 · evidence from 16 studies · how we score · editorial policy
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
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