Dutasteride
Prescription ·Exploratory record · not publication-reviewed ·Updated July 13, 2026
Dutasteride is a dual inhibitor of both type I and type II 5-alpha reductase, resulting in more complete DHT suppression than finasteride (~95% vs ~70%). It is approved for the treatment of BPH (as monotherapy or in combination with tamsulosin as Jalyn) and is used off-label for androgenetic alopecia. Due to its very long half-life, effects persist long after discontinuation.
Exploratory record, not a reviewed medical publication.
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This generated database record has not completed a claim-level review by a qualified human medical reviewer. Bibliography links and evidence labels are not approval. The page remains available for reference and is excluded from search indexing.
What the research says.
A quick, data-only summary. The full evidence, dosing, and sources are below.
Dutasteride is a dual inhibitor of both type I and type II 5-alpha reductase, resulting in more complete DHT suppression than finasteride (~95% vs ~70%). NutriStack rates the supporting evidence as strong. Common adult dosing is 0.5 mg once daily (as prescribed by your physician), though a prescriber sets the actual dose. This profile indexes 10 sources.
The bottom line
Evidence rating strong. Most-documented uses: greater dht suppression than finasteride, significant prostate volume reduction (25-30%), reduces risk of acute urinary retention and bph surgery. 10 sources indexed (2014–2025), with 0 interaction records on file.
How it works, mechanistically.
Core mechanism
Irreversibly inhibits both type I and type II isoforms of 5-alpha reductase, the enzymes that convert testosterone to dihydrotestosterone (DHT). This dual inhibition reduces serum DHT by >90% (compared to ~70% with finasteride). The resulting profound DHT suppression leads to greater prostate volume reduction than finasteride.8
Dosing & protocol.
Absolute bioavailability ~60%; food does not significantly affect AUC. Capsules should be swallowed whole. Extremely long half-life (5 weeks) means drug effects persist for months after discontinuation.
Full safety detail.
Side effects
- Erectile dysfunction
- Decreased libido
- Decreased ejaculate volume
- Gynecomastia and breast tenderness
- Dizziness
- Ejaculation disorders
Contraindications
- Women who are or may become pregnant (teratogenic; absorbed through skin)
- Known hypersensitivity to dutasteride, other 5-alpha reductase inhibitors, or capsule components1,2
- Severe hepatic impairment2
- Pediatric patients
- Blood donation restriction: wait at least 6 months after last dose due to long half-life4
Sources, by evidence tier.
Numbered references. Citations throughout the page link here.
Meta-analyses & systematic reviews
5- 1Efficacy and Safety of Combination Tamsulosin and Dutasteride versus Tamsulosin Monotherapy for Benign Prostatic Hyperplasia: A Meta-AnalysisPMIDYu H, Chen H, Wang X et al. · Archivos espanoles de urologia · 2025
Yu H, Chen H, Wang X et al.. Efficacy and Safety of Combination Tamsulosin and Dutasteride versus Tamsulosin Monotherapy for Benign Prostatic Hyperplasia: A Meta-Analysis. Archivos espanoles de urologia. 2025
- 2Tamsulosin and Dutasteride Combination Therapy for Asian Men With Moderate-to-Severe Lower Urinary Tract Symptoms Secondary to Benign Prostatic Hyperplasia: A Systematic Review of Clinical Considerations That Influence the PrescriptionPMIDYang F, Hashim R, Philippou J · Journal of clinical medicine research · 2024
Yang F, Hashim R, Philippou J. Tamsulosin and Dutasteride Combination Therapy for Asian Men With Moderate-to-Severe Lower Urinary Tract Symptoms Secondary to Benign Prostatic Hyperplasia: A Systematic Review of Clinical Considerations That Influence the Prescription. Journal of clinical medicine research. 2024
- 3Meta-analysis of the efficacy and safety of combination of tamsulosin plus dutasteride compared with tamsulosin monotherapy in treating benign prostatic hyperplasiaPMIDZhou Z, Cui Y, Wu J et al. · BMC urology · 2019
Zhou Z, Cui Y, Wu J et al.. Meta-analysis of the efficacy and safety of combination of tamsulosin plus dutasteride compared with tamsulosin monotherapy in treating benign prostatic hyperplasia. BMC urology. 2019
- 4A Systematic Review and Meta-Analysis of the Effects on Dutasteride Treatment for Reducing Surgical Blood Loss during Transurethral Resection of the ProstatePMIDRen J, Lai S, Jiang Z et al. · Urologia internationalis · 2017
Ren J, Lai S, Jiang Z et al.. A Systematic Review and Meta-Analysis of the Effects on Dutasteride Treatment for Reducing Surgical Blood Loss during Transurethral Resection of the Prostate. Urologia internationalis. 2017
- 5Dutasteride on benign prostatic hyperplasia: a meta-analysis on randomized clinical trials in 6460 patientsPMIDWu XJ, Zhi Y, Zheng J et al. · Urology · 2014
Wu XJ, Zhi Y, Zheng J et al.. Dutasteride on benign prostatic hyperplasia: a meta-analysis on randomized clinical trials in 6460 patients. Urology. 2014
Reference material
5- 6Roehrborn CG et al. Efficacy and safety of dutasteride in the four-year treatment of men with benign prostatic hyperplasia. Urology. 2004;63(4):709-715.Source linkedPMID
- 7Roehrborn CG et al. The effects of combination therapy with dutasteride and tamsulosin on clinical outcomes in men with symptomatic benign prostatic hyperplasia: 4-year results from the CombAT study. Eur Urol. 2010;57(1):123-131.Source linkedPMID
- 8Clark RV et al. Marked suppression of dihydrotestosterone in men with benign prostatic hyperplasia by dutasteride, a dual 5alpha-reductase inhibitor. J Clin Endocrinol Metab. 2004;89(5):2179-2184.Source linkedPMID
- 9Ding Y, Wang C, Bi L et al.. Dutasteride for the Treatment of Androgenetic Alopecia: An Updated Review. Dermatology (Basel, Switzerland). 2024Source linkedPMID
- 10Fertig RM, Gamret AC, Darwin E et al.. Sexual side effects of 5-α-reductase inhibitors finasteride and dutasteride: A comprehensive review. Dermatology online journal. 2017Source linkedPMID
Common questions.
Quick answers about Dutasteride, drawn from the data on this page.
What is Dutasteride?
Dutasteride is a dual inhibitor of both type I and type II 5-alpha reductase, resulting in more complete DHT suppression than finasteride (~95% vs ~70%). It is approved for the treatment of BPH (as monotherapy or in combination with tamsulosin as Jalyn) and is used off-label for androgenetic alopecia. Due to its very long half-life, effects persist long after discontinuation.
What is Dutasteride used for?
Commonly cited benefits of Dutasteride include: Greater DHT suppression than finasteride; Significant prostate volume reduction (25-30%); Reduces risk of acute urinary retention and BPH surgery; Combination with tamsulosin (Jalyn) provides dual mechanism benefit. NutriStack rates the overall evidence as strong.
What is a typical dose of Dutasteride?
A typical adult dose of Dutasteride is 0.5 mg once daily (as prescribed by your physician). The commonly recommended form is Soft gelatin capsule; swallow whole, do not open or chew (drug is irritating to oropharyngeal mucosa). These are general ranges, not personalized advice; confirm the right dose with a clinician.
What are the side effects of Dutasteride?
Reported side effects include erectile dysfunction, decreased libido, decreased ejaculate volume, gynecomastia and breast tenderness, dizziness, ejaculation disorders. This is educational information; check with a healthcare professional before use.
How strong is the evidence for Dutasteride?
NutriStack rates this as Strong, meaning multiple high-quality meta-analyses or systematic reviews converge on the same finding. Full tier criteria are at https://nutristackapp.com/methodology/evidence-tiers.
Use this with your stack
Dutasteride in NutriStack.
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