Can an Enlarged Prostate Shrink Back to Normal Size? What Actually Changes Its Volume
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An enlarged prostate does not shrink back to normal on its own: in the placebo group of a 4-year trial, it grew 14.1 percent.6 Prescription 5-alpha reductase inhibitors can shrink it, by 17.9 percent over 4 years with finasteride, but it regrows after stopping.6 Surgery removes tissue. No supplement has reliably reduced size.8,10
"Shrink your prostate naturally" is one of the most common promises in this market, and one of the least supported. This guide separates two things that most pages blur together: making the prostate smaller, and making the symptoms easier. Many treatments do the second without the first, and that is fine, as long as you know which one you are buying. If you are not sure your symptoms come from the prostate at all, start with our guide to enlarged prostate symptoms.
Key takeaways
- In randomly selected community men, prostate volume grew about 1.6 percent a year on average, faster in men with larger glands.3
- In the 4-year PLESS trial, finasteride cut prostate volume by 17.9 percent (55.9 to 45.8 cc) while the placebo group's grew 14.1 percent (51.3 to 58.5 cc).6
- Dutasteride reduced volume by 26.7 percent at 24 months, versus 2.2 percent on placebo.7
- After 3 months of finasteride, volume fell about 20 percent and returned close to baseline about 3 months after stopping.6
- Saw palmetto did not change prostate size in a one-year trial of 225 men, and beta-sitosterol did not reduce it in a review of four trials.8,10
Can an enlarged prostate go back to normal size on its own?
No source we found describes that happening as a rule. The NIDDK explains that the prostate goes through two growth phases: it doubles in size in early puberty, and it starts growing again around age 25 and "continues throughout life."1 A study that measured 631 men aged 40 to 79 in Olmsted County, Minnesota, by ultrasound, up to four times over almost seven years, found an average growth rate of 1.6 percent a year. Growth rates rose with age and were higher in men who started with larger prostates, and individual men varied widely.3
The clearest picture of the untreated course comes from the placebo groups of drug trials. In PLESS, men with enlarged prostates who took a placebo for four years saw their average prostate volume grow from 51.3 cc to 58.5 cc, an increase of 14.1 percent.6 To put the 1.6 percent figure in everyday terms: for a 40 cc prostate, that is roughly 0.6 cc a year (our calculation from the study's average).3
Why size is not the whole story
Before chasing a smaller prostate, it helps to know that size and symptoms are only loosely linked. The NIDDK says BPH symptoms "may not be directly related to the size of your prostate": a large prostate may cause few problems, and a slightly enlarged one may cause more.1 What men want is usually an easier stream, fewer night trips and less urgency. Shrinking the gland is one route to that, not the goal itself. Our guide to normal prostate size by age shows what the studies measured, and our IPSS score calculator measures what you actually feel.
What shrinks the prostate vs what only eases symptoms
This is the comparison most pages leave out. Each row says whether the option changes volume, what it does for symptoms, and how strong the evidence is.
| Option | Prostate volume | Symptoms | Evidence |
|---|---|---|---|
| Finasteride (5-ARI)6,4 | Down 17.9% over 4 years in PLESS; 15 to 25% at 6 months in general | Score down 3.3 vs 1.3 points on placebo | Large placebo-controlled trials |
| Dutasteride (5-ARI)7 | Down 26.7% at 24 months vs 2.2% on placebo | Improved vs placebo | Three placebo-controlled trials |
| Alpha blockers, such as tamsulosin1,9 | Not described as shrinking the prostate; they relax muscle | Improved; doxazosin cut progression risk 39% in MTOPS | Large placebo-controlled trials |
| TURP surgery4 | Removes tissue; mean size fell from average to small in two trials | Large improvement | Randomized trials |
| Prostate artery embolization4 | Reduces volume, but less than TURP | Similar to TURP in some trials, very uncertain | Small randomized trials |
| Saw palmetto8,11 | No change in the STEP trial | Little to no benefit (Cochrane 2023) | High-certainty evidence of no benefit |
| Beta-sitosterol10 | Did not reduce size | Improved scores and flow in short trials | Four trials, 4 to 26 weeks |
| Nettle root12 | 40.1 to 36.3 cc in one trial, not confirmed | Mixed; see our nettle guide | Weak to modest |
The drugs that do shrink it: 5-alpha reductase inhibitors
Finasteride and dutasteride block the conversion of testosterone to a more potent hormone that drives prostate growth. The previous American Urological Association (AUA) guideline describes the result as "shrinkage of the organ ranging from 15-25% measured at six months," and notes that the larger the gland, the greater the reduction.4 MedlinePlus says these medicines can "reduce the size of the gland, increase urine flow rate, and decrease symptoms."2
How much, and how fast
In PLESS, 3,040 men with moderate to severe symptoms and enlarged prostates took finasteride 5 mg or placebo for four years. Prostate volume, measured by MRI in a subgroup, fell 17.9 percent on finasteride and rose 14.1 percent on placebo. Symptom scores fell 3.3 points versus 1.3. Over the four years, 10 percent of the placebo group and 5 percent of the finasteride group needed surgery, and acute urinary retention developed in 7 percent versus 3 percent.5,6 The finasteride label adds that "a therapeutic trial of at least 6 months was generally necessary" to judge symptom relief.6
Dutasteride showed a similar pattern: across three placebo-controlled trials, prostate volume changed by -26.7 percent on dutasteride and -2.2 percent on placebo at 24 months.7 The MTOPS trial of 3,047 men found that finasteride, alone or with doxazosin, reduced the long-term risk of acute urinary retention and of needing invasive treatment.9
It regrows when you stop
The shrinkage lasts only while you take the drug. The finasteride label reports that in patients treated for three months, prostate volume fell by about 20 percent and "returned to close to baseline value after approximately three months of discontinuation of therapy."6 So "shrink back to normal" with a pill means "keep smaller while on the pill." Do not stop or change a prescribed medicine without your doctor.
The trade-offs
The AUA recommends these drugs for men whose prostate is demonstrably enlarged (over 30 g on imaging, a PSA above 1.5 ng/mL, or enlargement felt on exam), and says men should hear about sexual side effects first.4 In the first year of PLESS, impotence was reported by 8.1 percent on finasteride versus 3.7 percent on placebo, and decreased libido by 6.4 versus 3.4 percent; in years two to four the rates were the same in both groups.6 These drugs also lower PSA by about half, so whoever reads your PSA needs to know you take one.4 Our guide to PSA testing by age covers the test itself.
Treatments that ease symptoms without shrinking the prostate
Alpha blockers such as tamsulosin, alfuzosin and silodosin work differently. The NIDDK describes them as relaxing the muscles of the bladder and prostate, while it describes 5-alpha reductase inhibitors as the medicines that "help stop the growth of or help shrink the prostate."1 They can ease symptoms, but they are not a way to change size. In MTOPS, doxazosin cut the risk of overall progression but did not reduce the risk of retention or invasive therapy, while finasteride did.9 Daily tadalafil, a PDE5 inhibitor, also relaxes muscle rather than shrinking tissue.1 Our guide to natural alternatives to Flomax explains how these drugs compare with herbal options.
Procedures that remove or reduce prostate tissue
Surgery is the most direct way to make the prostate smaller. In the trials reviewed by the previous AUA guideline, mean prostate size after transurethral resection (TURP) fell from average (over 30 to under 80 mL) to small (30 mL or less). Prostate artery embolization "was not as effective in reducing prostate volumes compared with TURP."4 The NIDDK also lists water vapor therapy and the prostatic urethral lift among the less invasive options.1 The 2026 AUA guideline says men considering a procedure should be counseled on "possible effects on sexual function, retreatment rates, and the need for re-evaluation."13
Can you shrink your prostate naturally?
Not on the evidence available. Here is what the research shows for the options most often sold that way:
- Saw palmetto: in the STEP trial, 225 men over 49 took 160 mg twice a day or placebo for a year. There was no difference in symptoms, flow or prostate size.8 The 2023 Cochrane review of 27 studies with 4,656 men concluded that saw palmetto alone "provides little to no benefits" for urinary symptoms.11 See how long saw palmetto takes to work and our saw palmetto dosage guide.
- Beta-sitosterol: a review of four placebo-controlled trials with 519 men found better symptom scores and flow, but "B-sitosterols did not reduce prostate size."10 Our beta-sitosterol review covers the details.
- Stinging nettle root: one Iranian trial reported volume falling from 40.1 to 36.3 cc over six months, but the result has not been confirmed.12 See our nettle root guide.
- Pumpkin seeds and zinc: our pumpkin seed guide covers what its trials measured, and our zinc guide explains why we found no placebo-controlled zinc trial for BPH at all.
Habits matter for symptoms. The 2026 AUA guideline says "Behavioral and lifestyle interventions should be explored before or alongside pharmacologic treatment."13 MedlinePlus lists spreading fluids through the day, avoiding alcohol and caffeine after dinner, avoiding cold medicines with decongestants or antihistamines, keeping warm and exercising.2 None of the sources reviewed here shows that these habits reduce prostate volume. They make the same prostate easier to live with, which is often what matters. Our overview of natural remedies for an enlarged prostate grades each option on symptoms.
Can BPH be reversed?
Not in the sense of returning the prostate permanently to its size at 30. Medicines can shrink it while you take them, surgery can remove tissue, and both can change the course of symptoms: in PLESS, finasteride roughly halved the four-year risk of surgery and of acute retention.5 What you can realistically aim for is control of symptoms and a lower risk of complications, measured with a symptom score rather than a promise. The 2026 AUA guideline says men "should be re-evaluated within six months of treatment initiation, to assess response and treatment-related adverse effects."13
Where a supplement fits
Be wary of any product that promises to shrink the prostate: none of the supplements reviewed here has done that reliably in trials. If a supplement fits anywhere, it is as a possible aid for symptoms, chosen after a checkup, with doses that match what was studied, and judged by your own symptom score after 8 to 12 weeks. Our comparison of prostate supplements vs medication lays out the trade-offs side by side. No supplement treats, cures or prevents BPH.
None of the supplements reviewed here reliably reduced prostate size. ProtoFlow's only ingredient with prostate trials is saw palmetto, at 84.5 mg a day, about a quarter of the dose that showed no change in prostate size in the STEP trial.
The rest is mostly herbs sold for male vitality. Its maker says it "supports the normal functions of the bladder, prostate and reproductive system".
Our review checks that claim against the full label, the published research and the refund terms.
A practical plan for this week
- Score your symptoms with the IPSS and write the total down.
- Ask your doctor whether your prostate size has been measured, by imaging, exam or PSA, since that decides whether a shrinking drug makes sense.
- If you are offered a 5-ARI, ask about sexual side effects, the 6-month timeline and what happens to your PSA reading.
- Start the habits that help symptoms now: fluids earlier, less evening caffeine and alcohol, a medicine cabinet check.
- Recheck the score within six months of any new treatment.
Frequently asked questions
Can an enlarged prostate shrink back to normal size?
Not on its own. The prostate keeps growing slowly through adult life, by about 1.6 percent a year on average in one community study, and in the placebo group of the 4-year PLESS trial it grew 14.1 percent. Finasteride and dutasteride can shrink it by roughly 15 to 27 percent, and surgery removes tissue, but medicines only keep it smaller while you take them.
How can I shrink my prostate naturally?
No natural method has reliably reduced prostate size in trials. Saw palmetto did not change prostate size in a one-year trial of 225 men, and beta-sitosterol did not reduce size in a review of four trials. Habits such as timing fluids and limiting evening caffeine and alcohol can ease symptoms, but none of the sources reviewed shows they shrink the gland.
Does saw palmetto shrink the prostate?
No. In the STEP trial, 225 men took 160 mg of saw palmetto extract twice a day or placebo for a year, and there was no difference in prostate size, symptoms or urine flow. The 2023 Cochrane review of 27 studies concluded that saw palmetto alone provides little to no benefit for urinary symptoms.
How long does finasteride take to shrink the prostate?
The previous AUA guideline describes shrinkage of 15 to 25 percent measured at six months. The finasteride label says a trial of at least 6 months is generally needed to judge symptom relief. In the 4-year PLESS trial, prostate volume fell 17.9 percent on finasteride while it grew 14.1 percent on placebo.
What happens to the prostate if you stop finasteride?
It grows back. According to the finasteride label, in men treated for three months, prostate volume fell by about 20 percent and returned close to its starting size about three months after they stopped. Do not stop or change a prescribed medicine without talking to your doctor.
Does Flomax shrink the prostate?
No. Tamsulosin, sold as Flomax, is an alpha blocker. The NIDDK describes alpha blockers as relaxing the muscles of the bladder and prostate to ease urination, while it describes 5-alpha reductase inhibitors as the medicines that help stop growth or shrink the prostate. Alpha blockers can ease symptoms without changing size.
Can BPH be reversed?
Not permanently. Medicines can shrink the prostate while you take them and surgery can remove tissue, which can greatly reduce symptoms. In the PLESS trial, finasteride roughly halved the four-year risk of surgery and of acute urinary retention. A realistic goal is symptom control and fewer complications, checked with a symptom score.
Sources
- National Institute of Diabetes and Digestive and Kidney Diseases (NIH). Enlarged Prostate (Benign Prostatic Hyperplasia). https://www.niddk.nih.gov/health-information/urologic-diseases/prostate-problems/enlarged-prostate-benign-prostatic-hyperplasia
- MedlinePlus Medical Encyclopedia (NIH National Library of Medicine). Enlarged prostate. Reviewed July 1, 2025. https://medlineplus.gov/ency/article/000381.htm
- Rhodes T, Girman CJ, Jacobsen SJ, Roberts RO, Guess HA, Lieber MM. Longitudinal prostate growth rates during 5 years in randomly selected community men 40 to 79 years old. Journal of Urology. 1999;161(4):1174-1179. https://pubmed.ncbi.nlm.nih.gov/10081864/
- American Urological Association. Management of Lower Urinary Tract Symptoms Attributed to Benign Prostatic Hyperplasia: AUA Guideline (2021, amended 2023), unabridged. Previous version, replaced on May 7, 2026. https://www.auanet.org/documents/Guidelines/PDF/2023%20Guidelines/BPH%20Unabridged%2002-20-24%20Final.pdf
- McConnell JD, Bruskewitz R, Walsh P, et al. The effect of finasteride on the risk of acute urinary retention and the need for surgical treatment among men with benign prostatic hyperplasia (PLESS). New England Journal of Medicine. 1998;338(9):557-563. https://pubmed.ncbi.nlm.nih.gov/9475762/
- Proscar (finasteride) tablets, prescribing information, sections 6.1, 12.2 and 14. DailyMed, U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=6f988153-fc74-4ca4-b29a-111f750c4a4b
- Avodart (dutasteride) capsules, prescribing information, section 14. DailyMed, U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=960797b3-09b1-4d6a-8ece-8b5d918e93e4
- Bent S, Kane C, Shinohara K, et al. Saw palmetto for benign prostatic hyperplasia (STEP). New England Journal of Medicine. 2006;354(6):557-566. https://pubmed.ncbi.nlm.nih.gov/16467543/
- McConnell JD, Roehrborn CG, Bautista OM, et al. The long-term effect of doxazosin, finasteride, and combination therapy on the clinical progression of benign prostatic hyperplasia (MTOPS). New England Journal of Medicine. 2003;349(25):2387-2398. https://pubmed.ncbi.nlm.nih.gov/14681504/
- Wilt T, Ishani A, MacDonald R, et al. Beta-sitosterols for benign prostatic hyperplasia. Cochrane Database of Systematic Reviews. 1999;(2):CD001043. https://pubmed.ncbi.nlm.nih.gov/10796740/
- Franco JV, Trivisonno L, Sgarbossa NJ, et al. Serenoa repens for the treatment of lower urinary tract symptoms due to benign prostatic enlargement. Cochrane Database of Systematic Reviews. 2023;6(6):CD001423. https://pubmed.ncbi.nlm.nih.gov/37345871/
- Safarinejad MR. Urtica dioica for treatment of benign prostatic hyperplasia: a prospective, randomized, double-blind, placebo-controlled, crossover study. Journal of Herbal Pharmacotherapy. 2005;5(4):1-11. https://pubmed.ncbi.nlm.nih.gov/16635963/
- American Urological Association. Management of Lower Urinary Tract Symptoms Attributed to Benign Prostatic Hyperplasia: AUA Guideline (2026). Released May 7, 2026; key statements as published by Guideline Central. https://www.guidelinecentral.com/insights/may-2026-aua-lowerurinarytractsymptoms-guideline-video/
About the author
Alice Hess is a health researcher and wellness writer at ProstateClarity. She is not a doctor, a nurse, a nutritionist or any kind of licensed clinician, and nothing here is medical advice. She started this work because of her father: at 76 he was getting up several times a night, and the research she did for him helped him get back to sleeping through the night. One man's story is not evidence, which is why every guide here is built on published research. She reads labels, primary research and regulatory limits, and publishes the numbers manufacturers leave out. More about her work and how these articles are researched.
Found an error? Write to contact@prostateclarity.com with the sentence and the source that contradicts it. Corrections are made in the article with the date noted.