--- title: "Dutasteride: Research & Side Effects | BodyHackGuide" url: https://www.bodyhackguide.co/compound/dutasteride description: "Dutasteride: mechanism, clinical studies & side effects." lang: en --- Skip to content Compare notes on r/BodyHackGuide (https://reddit.com/r/bodyhackguide) Compare notes with other researchers. Join r/BodyHackGuide (https://reddit.com/r/bodyhackguide) # Dutasteride Skin & Hair: https://www.bodyhackguide.co/wiki#cat-skin-&-hair Status Approved (prescription) Evidence Not graded on a research bench yet Dutasteride is a synthetic 4-azasteroid drug that blocks both type 1 and type 2 steroid 5-alpha-reductase, the enzymes that turn testosterone into dihydrotestosterone (DHT); it was developed at Glaxo Wellcome under the code GG745 and approved by the FDA in 2001 as Avodart for benign prostatic hyperplasia. Reviewed 4 November 2026 01 Overview ## What Dutasteride is Dutasteride is not FDA approved for hair loss, but South Korea approved it for male androgenetic alopecia in 2009 and Japan did so on 28 September 2015 (PMID: 27489426; PMDA list of approved products). In a 917-man phase 3 trial, dutasteride 0.5 mg a day raised hair counts more than finasteride 1 mg a day at 24 weeks, and a pooled analysis of three head-to-head trials found no significant difference between the two drugs in sexual side effects (PMID: 24411083, PMID: 30863034). Serum DHT fell by 94.7 percent with dutasteride against 70.8 percent with finasteride 5 mg in a 399-man trial, and a terminal half-life of about 5 weeks keeps dutasteride detectable in the blood for 4 to 6 months after the last dose (PMID: 15126539; US prescribing information for Avodart). ### How it works ### Two forms of 5-alpha-reductase Testosterone is turned into DHT by the enzyme steroid 5-alpha-reductase, which the US label describes as two isoenzymes: type 2 is mainly active in reproductive tissues, while type 1 also converts testosterone in the skin and liver (US prescribing information for Avodart). Dutasteride is a competitive inhibitor of both types and forms a stable complex with the enzyme that comes apart extremely slowly; it does not bind the human androgen receptor (US prescribing information for Avodart). Finasteride, by contrast, selectively inhibits the type 2 isoenzyme (PMID: 15126539); see BodyHackGuide's finasteride (https://www.bodyhackguide.co/compound/finasteride) guide. Read the full mechanism Show less ### How far DHT falls In a GlaxoSmithKline trial of 399 men with benign prostatic hyperplasia treated for 24 weeks, serum DHT fell by 94.7 percent with dutasteride 0.5 mg a day and 98.4 percent with 5 mg, against 70.8 percent with finasteride 5 mg, and suppression varied less between men on dutasteride (PMID: 15126539). In 99 healthy men treated for a year, DHT suppression was 94 percent with dutasteride 0.5 mg and 73 percent with finasteride 5 mg (PMID: 17299062). The US label reports median DHT falls of 85 percent after 1 week and 90 percent after 2 weeks of daily dosing, with median testosterone about 19 percent higher over 1 to 2 years but within the normal range (US prescribing information for Avodart). In a dose-ranging trial in 416 men with pattern hair loss, scalp and serum DHT fell and testosterone rose as the dutasteride dose increased (PMID: 17110217). ### Why the scalp matters DHT is the main androgen behind androgenetic alopecia (PMID: 24411083), and both isoenzymes are present in hair follicles (PMID: 27549867). The authors of the 416-man dose-ranging trial concluded that both type 1 and type 2 5-alpha-reductase may matter in male pattern hair loss, after the highest dutasteride dose, 2.5 mg, outperformed finasteride 5 mg (PMID: 17110217). ### Pharmacokinetics After a single 0.5 mg capsule, peak serum levels come within 2 to 3 hours, absolute bioavailability is about 60 percent, and the drug is about 99 percent bound to albumin (US prescribing information for Avodart). Dutasteride is broken down by the liver enzymes CYP3A4 and CYP3A5 (cytochrome P450 3A), and its terminal elimination half-life at steady state is about 5 weeks, so serum levels reach about 90 percent of steady state after 3 months of daily dosing and stay detectable for 4 to 6 months after stopping (US prescribing information for Avodart). In Glaxo Wellcome's early single-dose studies in men, the terminal half-life was about 240 hours, against 14 hours in rats and 65 hours in dogs (PMID: 9316864). Dutasteride passes into semen, where levels averaged 3.4 ng/mL after 12 months, about 11.5 percent of the serum level (US prescribing information for Avodart). ### Other hormones Over 52 weeks in healthy volunteers, dutasteride did not change sex hormone binding globulin, estradiol, LH, FSH, free thyroxine or DHEA to a clinically significant degree, while median testosterone rose 17.9 percent at 8 weeks and TSH 12.4 percent at 52 weeks; bone density and blood lipids did not change (US prescribing information for Avodart). ### Studied for - Androgenetic alopecia - Benign prostatic hyperplasia - 5-alpha-reductase pharmacology - Prostate cancer prevention trials - Male fertility - Pharmacoepidemiology ### Benefits listed - Target-area hair count against finasteride 1 mg and placebo at 24 weeks in a 917-man phase 3 trial (PMID: 24411083) - Hair count against placebo over 6 months in a 153-man Korean phase 3 trial (PMID: 20605255) - Total and thin-hair counts against finasteride in a 90-man open-label trial (PMID: 27549867) - Hair thickness over 3 years in a retrospective sample of 60 women (PMID: 25382509) Show 2 more Show less - Serum DHT suppression of 94.7 percent against 70.8 percent for finasteride 5 mg in 399 men with prostate enlargement (PMID: 15126539) - Prostate volume, urinary symptoms and risk of acute urinary retention over 2 years in 4,325 men with benign prostatic hyperplasia (PMID: 12350480) 02 Research Free with email ## What the research shows No research bench grades Dutasteride yet. Benches compare compounds people pair, with the evidence for each. ### Unlock the research summary Enter your email to keep reading. It is free, and it opens these sections on every compound page in this browser. - A summary of the key research - Safety and side effects - A link to the PubMed results You also get the free peptide cheat sheet by email. Unsubscribe anytime. Have an account? Sign in (https://www.bodyhackguide.co/auth) 03 Safety ## Dutasteride side effects and interactions ### Side effects #### Common - Sexual adverse events in 16 percent on dutasteride against 8 percent on placebo over 24 weeks in a 117-man hair-loss trial (PMID: 29667763) - Impotence (4.7 versus 1.7 percent), decreased libido (3.0 versus 1.4 percent) and ejaculation disorders (1.4 versus 0.5 percent) in the first 6 months of the prostate trials (US prescribing information for Avodart) - Breast enlargement or tenderness in 0.5 to 1.1 percent of men per 6-month period in the prostate trials (US prescribing information for Avodart) - Lower total sperm count, semen volume and sperm motility in healthy men (PMID: 17299062) #### Serious events - More Gleason 8 to 10 prostate cancers in years 3 and 4 of the REDUCE trial, 12 versus 1 (PMID: 20357281) - Risk to a male fetus from exposure in pregnancy, for example through handling leaking capsules (US prescribing information for Avodart) - More self-harm and depression in the first 18 months, and somewhat more depression after that, in an Ontario cohort of older men (PMID: 28319231) - Hypersensitivity reactions including angioedema and serious skin reactions reported after approval (US prescribing information for Avodart) - Patches of hair loss at injection sites after dutasteride mesotherapy (PMID: 41346555, PMID: 41779759) ### Who should not use it Contraindications The US label contraindicates dutasteride in pregnancy, states that it is not indicated for women, and says women who are or may be pregnant should not handle the capsules, because dutasteride is absorbed through the skin and feminized the external genitalia of male fetuses in rats and rabbits (US prescribing information for Avodart). Read all the contraindications and cautions Show less Men taking dutasteride should not donate blood until at least 6 months after the last dose, the US label states, so that the drug does not reach a pregnant transfusion recipient (US prescribing information for Avodart). For women, Japan's 2017 hair-loss guideline lists oral dutasteride as contraindicated for female pattern hair loss (PMID: 29863806), and a 2016 Cochrane review of female pattern hair loss called for randomized trials of dutasteride (PMID: 27225981). Dutasteride lowers serum PSA by about 50 percent, and the US label states that any confirmed rise in PSA during treatment may signal prostate cancer even within the normal range for untreated men (US prescribing information for Avodart). In healthy men, dutasteride lowered total sperm count, semen volume and sperm motility, measures of male fertility (PMID: 17299062). Strong CYP3A4 inhibitors are a reason for care: the US label calls for caution with potent, long-term CYP3A4 inhibitors such as ritonavir, because dutasteride is cleared by CYP3A4 and CYP3A5 (US prescribing information for Avodart). In older men starting a 5-alpha-reductase inhibitor, self-harm and depression were more frequent in the first 18 months, and depression stayed somewhat more frequent after that (PMID: 28319231). The US label contraindicates dutasteride after a clinically significant hypersensitivity reaction, such as a serious skin reaction or angioedema, to dutasteride or another 5-alpha-reductase inhibitor (US prescribing information for Avodart). ### Interactions 5 pairings in our record: 2 with a caution and 3 to monitor. - Ritonavir and other strong CYP3A4 inhibitors Caution Dutasteride is cleared by CYP3A4 and CYP3A5, and the US label calls for caution with potent, long-term CYP3A4 inhibitors such as ritonavir because their effect on dutasteride levels has not been studied (US prescribing information for Avodart). - Ketoconazole (oral) Caution The US label lists ketoconazole among CYP3A4/5 inhibitors that may raise dutasteride blood levels, and in rats, ketoconazole given at the same time as dutasteride significantly changed the pharmacokinetics of dutasteride and its active metabolite (US prescribing information for Avodart; PMID: 31835695). Ketoconazole 2 percent shampoo was not detected in plasma in long-term use (US prescribing information for ketoconazole 2% shampoo). - Verapamil and diltiazem Monitor In a population pharmacokinetic analysis, verapamil lowered dutasteride clearance by 37 percent and diltiazem by 44 percent; the US label does not consider the change clinically significant (US prescribing information for Avodart). - Tamsulosin Monitor In the 4-year CombAT trial, ejaculation disorders occurred in 11 percent of men on dutasteride plus tamsulosin against 2 percent on dutasteride alone and 4 percent on tamsulosin alone (US prescribing information for Avodart; PMID: 19825505). - Testosterone Monitor In a 20-week trial in 139 healthy men whose own testosterone production was suppressed with monthly leuprolide injections, dutasteride added to graded testosterone injections did not change gains in fat-free mass, strength, sexual function or hematocrit compared with testosterone alone (PMID: 22396515). This interaction data is compiled from published research and community reports. It may not be exhaustive. Always consult a healthcare professional before combining compounds. Need bloodwork before starting? Full hormone + metabolic panels from Anabolic Insights. Code CHONCH for first-order discount. Order Bloodwork (https://anabolicinsights.ai/?ref=nwm2zjb) 04 Dosing Free with email ## Dosing No dose on record Our record lists no dose for Dutasteride. This section holds what it does list. ### Unlock the Dosing section - Route 05 Prices ## Dutasteride prices No listings We do not track a vendor for Dutasteride yet, so this page states no price. 06 Chemistry ## Chemistry and structure Molecular formula C27H30F6N2O2 Molecular mass 528.5 g/mol CAS number 164656-23-9 Half-life About 5 weeks (terminal elimination half-life at steady state in the US prescribing information for Avodart), with serum levels detectable for 4 to 6 months after the last dose; about 240 hours after single doses in Glaxo Wellcome's early human studies (PMID: 9316864). View on PubChem (https://pubchem.ncbi.nlm.nih.gov/compound/6918296) 07 Related ## Related to Dutasteride ### In the same category - Acetyl Hexapeptide-8Marketed topical cosmetic ingredient Acetyl Hexapeptide-8 (INCI: Acetyl Hexapeptide-3 in older nomenclature, commercially known as Argireline) is a synthetic hexapeptide designed as a competitive inhibitor of the SNARE complex at the neuromuscular junction.: https://www.bodyhackguide.co/compound/acetyl-hexapeptide-8 - AHK-CuPreclinical AHK-Cu is a copper chelating tripeptide related to but distinct from GHK-Cu.: https://www.bodyhackguide.co/compound/ahk-cu - KetoconazoleApproved drug Ketoconazole is a synthetic imidazole antifungal that blocks the fungal cytochrome P450 enzyme lanosterol 14-alpha-demethylase and so stops the yeast or mold from making ergosterol for its cell membrane; it was the first broad-spectrum oral antifungal approved by the FDA, as Nizoral tablets from Janssen in 1981, and is also sold as 2 percent and 1 percent shampoos, creams and foams.: https://www.bodyhackguide.co/compound/ketoconazole - Melanotan 2Discontinued A synthetic melanocortin receptor agonist studied for skin tanning, sexual function, and appetite suppression.: https://www.bodyhackguide.co/compound/melanotan-2 - MinoxidilFDA-Approved Minoxidil is an FDA-approved treatment for pattern hair loss. Originally an oral blood-pressure drug, its hair-growth side effect led to the topical products (Rogaine) at 2% and 5%.: https://www.bodyhackguide.co/compound/minoxidil - Palmitoyl Pentapeptide-4Marketed topical cosmetic ingredient with a small set of human cosmetic trials Palmitoyl pentapeptide-4 is the cosmetic ingredient Pal-KTTKS, a five-amino-acid fragment of the type I collagen propeptide with a 16-carbon palmitic acid chain attached, sold to formulators under the trade name Matrixyl (PubChem CID 9897237; PMID: 8486721).: https://www.bodyhackguide.co/compound/palmitoyl-pentapeptide-4 All compounds (https://www.bodyhackguide.co/wiki) ### Compare Dutasteride - Alternatives to Dutasteride: https://www.bodyhackguide.co/alternatives-to/dutasteride ### Research tools - Peptide Calculator Reconstitution and syringe units: https://www.bodyhackguide.co/tools/reconstitution - Reconstitution Guide How to mix, step by step: https://www.bodyhackguide.co/guides/how-to-reconstitute-peptides - Nasal Spray Calc mL per actuation: https://www.bodyhackguide.co/tools/intranasal - Half-Life Visualizer Decay curves: https://www.bodyhackguide.co/tools/halflife All articles (https://www.bodyhackguide.co/blog) 08 Questions ## Frequently asked questions What is dutasteride? Dutasteride is a 4-azasteroid drug that blocks both type 1 and type 2 5-alpha-reductase, the enzymes that convert testosterone to DHT (US prescribing information for Avodart). Dutasteride was developed at Glaxo Wellcome under the code GG745 (PMID: 9316864). The FDA approved dutasteride in 2001 for benign prostatic hyperplasia (Drugs@FDA NDA 021319). Is dutasteride approved for hair loss? Dutasteride is approved in the US only for benign prostatic hyperplasia, and hair-loss use of dutasteride there is off-label (US prescribing information for Avodart; PMID: 35920739). South Korea approved dutasteride for male androgenetic alopecia in 2009 (PMID: 27489426). Japan approved dutasteride for male pattern hair loss on 28 September 2015 (PMDA list of approved products). How does dutasteride compare with finasteride for hair loss? In a 917-man phase 3 trial, dutasteride 0.5 mg a day increased hair count more than finasteride 1 mg a day at 24 weeks (PMID: 24411083). A 2022 network meta-analysis put the extra gain from dutasteride over finasteride 1 mg at about 7 hairs per square centimeter at 24 weeks (PMID: 35107565). A 2013 network meta-analysis by Gupta and Charrette found no significant efficacy difference between dutasteride and finasteride (PMID: 23768246). Dutasteride lowered serum DHT by 94.7 percent against 70.8 percent for finasteride 5 mg in a 399-man trial (PMID: 15126539). What side effects were reported with dutasteride? In a 117-man hair-loss trial, sexual side effects occurred in 16 percent on dutasteride and 8 percent on placebo over 24 weeks, all mild to moderate and resolved (PMID: 29667763). A meta-analysis of 15 placebo-controlled hair-loss trials found a relative risk of sexual dysfunction of 1.37 with dutasteride that was not statistically significant, and the authors noted that studies of dutasteride were limited (PMID: 30206635). The US label states that dutasteride's sexual adverse reactions may persist after stopping and that the role of dutasteride in this is unknown (US prescribing information for Avodart). Dutasteride also lowered total sperm count and semen volume in a one-year trial in healthy men (PMID: 17299062). How long does dutasteride stay in the body? Dutasteride has a terminal half-life of about 5 weeks at steady state (US prescribing information for Avodart). It stays detectable in the blood for 4 to 6 months after the last dose (US prescribing information for Avodart). Because dutasteride stays in the blood for months, the US label states that men taking dutasteride should not donate blood until at least 6 months after the last dose (US prescribing information for Avodart). What do studies show about dutasteride in women? Dutasteride is contraindicated in pregnancy and not indicated for women in the US label, and dutasteride feminized male fetuses in animal studies (US prescribing information for Avodart). Studies of dutasteride for female pattern hair loss are small: a retrospective sample of 60 women found thicker hair after 3 years (PMID: 25382509), and a 126-woman controlled study tested dutasteride by scalp injection (PMID: 22486925). Japan's 2017 guideline lists oral dutasteride as contraindicated for female pattern hair loss (PMID: 29863806). Does dutasteride affect PSA tests or prostate cancer? Dutasteride lowers serum PSA by about 50 percent within 3 to 6 months (US prescribing information for Avodart). In the 4-year REDUCE trial, dutasteride lowered biopsy-detected prostate cancer by 22.8 percent but was associated with more Gleason 8 to 10 tumors in years 3 and 4, 12 against 1 on placebo (PMID: 20357281). The US label states that dutasteride may increase the risk of high-grade prostate cancer and is not approved for preventing prostate cancer (US prescribing information for Avodart). Free 2026 Peptide Cheat Sheet (PDF) 38 compounds and blends: vial sizes, BAC water volumes, dosing ranges and bloodwork markers. Download Free (https://www.bodyhackguide.co/guides/peptide-cheat-sheet-download) BodyHackGuide (https://www.bodyhackguide.co/) Your biohacking research hub: compound pricing, brain health protocols, dosing tools, and vendor reviews. support@bodyhackguide.co Join our Discord: https://discord.gg/Mhq5UdRYBA r/BodyHackGuide on Reddit: https://reddit.com/r/BodyHackGuide **Affiliate Disclosure:** We rank every vendor on the same public, reproducible methodology (https://www.bodyhackguide.co/vendors/methodology). 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All rights reserved. - Terms: https://www.bodyhackguide.co/terms - Privacy: https://www.bodyhackguide.co/privacy ## Structured data ```json [ { "@context": "https://schema.org", "@type": "BreadcrumbList", "itemListElement": [ { "@type": "ListItem", "position": 1, "name": "Home", "item": "https://www.bodyhackguide.co/" }, { "@type": "ListItem", "position": 2, "name": "Compounds", "item": "https://www.bodyhackguide.co/compare" }, { "@type": "ListItem", "position": 3, "name": "Dutasteride" } ] }, { "@context": "https://schema.org", "@type": "MedicalWebPage", "name": "Dutasteride", "description": "Dutasteride is a synthetic 4-azasteroid drug that blocks both type 1 and type 2 steroid 5-alpha-reductase, the enzymes that turn testosterone into dihydrotestosterone (DHT); it was developed at Glaxo Wellcome under the code GG745 and approved by the FDA in 2001 as Avodart for benign prostatic hyperplasia (PMID: 9316864; Drugs@FDA NDA 021319; US prescribing information for Avodart). Dutasteride is not FDA approved for hair loss, but South Korea approved it for male androgenetic alopecia in 2009 and Japan did so on 28 September 2015 (PMID: 27489426; PMDA list of approved products). In a 917-man phase 3 trial, dutasteride 0.5 mg a day raised hair counts more than finasteride 1 mg a day at 24 weeks, and a pooled analysis of three head-to-head trials found no significant difference between the two drugs in sexual side effects (PMID: 24411083, PMID: 30863034). Serum DHT fell by 94.7 percent with dutasteride against 70.8 percent with finasteride 5 mg in a 399-man trial, and a terminal half-life of about 5 weeks keeps dutasteride detectable in the blood for 4 to 6 months after the last dose (PMID: 15126539; US prescribing information for Avodart).", "lastReviewed": "2026-11-04T22:43:38.154Z", "url": "https://www.bodyhackguide.co/compound/dutasteride", "author": { "@type": "Person", "name": "BioChonch", "url": "https://www.bodyhackguide.co/about", "jobTitle": "Founder & Lead Researcher", "sameAs": [ "https://reddit.com/r/BodyHackGuide", "https://reddit.com/r/BrainHackGuide", "https://reddit.com/r/Biohackingher" ], "worksFor": { "@type": "Organization", "name": "BodyHackGuide", "url": "https://www.bodyhackguide.co" } }, "reviewedBy": { "@type": "Person", "name": "BioChonch", "url": "https://www.bodyhackguide.co/about", "jobTitle": "Founder & Lead Researcher", "sameAs": [ "https://reddit.com/r/BodyHackGuide", "https://reddit.com/r/BrainHackGuide", "https://reddit.com/r/Biohackingher" ], "worksFor": { "@type": "Organization", "name": "BodyHackGuide", "url": "https://www.bodyhackguide.co" } }, "publisher": { "@type": "Organization", "name": "BodyHackGuide", "url": "https://www.bodyhackguide.co" }, "mainContentOfPage": { "@type": "WebPageElement", "cssSelector": "main" }, "about": { "@type": "Drug", "name": "Dutasteride", "alternateName": [ "Avodart", "Avolve", "Zagallo", "GI-198745", "GG745" ], "description": "Dutasteride is a synthetic 4-azasteroid drug that blocks both type 1 and type 2 steroid 5-alpha-reductase, the enzymes that turn testosterone into dihydrotestosterone (DHT); it was developed at Glaxo Wellcome under the code GG745 and approved by the FDA in 2001 as Avodart for benign prostatic hyperplasia (PMID: 9316864; Drugs@FDA NDA 021319; US prescribing information for Avodart). Dutasteride is not FDA approved for hair loss, but South Korea approved it for male androgenetic alopecia in 2009 and Japan did so on 28 September 2015 (PMID: 27489426; PMDA list of approved products). In a 917-man phase 3 trial, dutasteride 0.5 mg a day raised hair counts more than finasteride 1 mg a day at 24 weeks, and a pooled analysis of three head-to-head trials found no significant difference between the two drugs in sexual side effects (PMID: 24411083, PMID: 30863034). Serum DHT fell by 94.7 percent with dutasteride against 70.8 percent with finasteride 5 mg in a 399-man trial, and a terminal half-life of about 5 weeks keeps dutasteride detectable in the blood for 4 to 6 months after the last dose (PMID: 15126539; US prescribing information for Avodart).", "activeIngredient": "Dutasteride", "administrationRoute": "Oral, Intradermal injection (mesotherapy), Topical", "mechanismOfAction": "Two forms of 5-alpha-reductase Testosterone is turned into DHT by the enzyme steroid 5-alpha-reductase, which the US label describes as two isoenzymes: type 2 is mainly active in reproductive tissues, while type 1 also converts testosterone in the skin and liver (US prescribing information for Avodart). Dutasteride is a competitive inhibitor of both types and forms a stable complex with the enzyme that comes apart extremely slowly; it does not bind the human androgen receptor (US prescribing information for Avodart). Finasteride, by contrast, selectively inhibits the type 2 isoenzyme (PMID: 15126539); see BodyHackGuide's finasteride guide. How far DHT falls In a GlaxoSmithKline trial of 399 men with benign prostatic hyperplasia treated for 24 weeks, serum DHT fell by 94.7 percent with dutasteride 0.5 mg a day and 98.4 percent with 5 mg, against 70.8 percent with finasteride 5 mg, and suppression varied less between men on dutasteride (PMID: 15126539). In 99 healthy men treated for a year, DHT suppression was 94 percent with dutasteride 0.5 mg and 73 percent with finasteride 5 mg (PMID: 17299062). The US label reports median DHT falls of 85 percent after 1 week and 90 percent after 2 weeks of daily dosing, with median testosterone about 19 percent higher over 1 to 2 years but within the normal range (US prescribing information for Avodart). In a dose-ranging trial in 416 men with pattern hair loss, scalp and serum DHT fell and testosterone rose as the dutasteride dose increased (PMID: 17110217). Why the scalp matters DHT is the main androgen behind androgenetic alopecia (PMID: 24411083), and both isoenzymes are present in hair follicles (PMID: 27549867). The authors of the 416-man dose-ranging trial concluded that both type 1 and type 2 5-alpha-reductase may matter in male pattern hair loss, after the highest dutasteride dose, 2.5 mg, outperformed finasteride 5 mg (PMID: 17110217). Pharmacokinetics After a single 0.5 mg capsule, peak serum levels come within 2 to 3 hours, absolute bioavailability is about 60 percent, and the drug is about 99 percent bound to albumin (US prescribing information for Avodart). Dutasteride is broken down by the liver enzymes CYP3A4 and CYP3A5 (cytochrome P450 3A), and its terminal elimination half-life at steady state is about 5 weeks, so serum levels reach about 90 percent of steady state after 3 months of daily dosing and stay detectable for 4 to 6 months after stopping (US prescribing information for Avodart). In Glaxo Wellcome's early single-dose studies in men, the terminal half-life was about 240 hours, against 14 hours in rats and 65 hours in dogs (PMID: 9316864). Dutasteride passes into semen, where levels averaged 3.4 ng/mL after 12 months, about 11.5 percent of the serum level (US prescribing information for Avodart). Other hormones Over 52 weeks in healthy volunteers, dutasteride did not change sex hormone binding globulin, estradiol, LH, FSH, free thyroxine or DHEA to a clinically significant degree, while median testosterone rose 17.9 percent at 8 weeks and TSH 12.4 percent at 52 weeks; bone density and blood lipids did not change (US prescribing information for Avodart).", "legalStatus": "Approved (prescription)" } }, { "@context": "https://schema.org", "@type": "FAQPage", "mainEntity": [ { "@type": "Question", "name": "What is dutasteride?", "acceptedAnswer": { "@type": "Answer", "text": "Dutasteride is a 4-azasteroid drug that blocks both type 1 and type 2 5-alpha-reductase, the enzymes that convert testosterone to DHT (US prescribing information for Avodart). Dutasteride was developed at Glaxo Wellcome under the code GG745 (PMID: 9316864). The FDA approved dutasteride in 2001 for benign prostatic hyperplasia (Drugs@FDA NDA 021319)." } }, { "@type": "Question", "name": "Is dutasteride approved for hair loss?", "acceptedAnswer": { "@type": "Answer", "text": "Dutasteride is approved in the US only for benign prostatic hyperplasia, and hair-loss use of dutasteride there is off-label (US prescribing information for Avodart; PMID: 35920739). South Korea approved dutasteride for male androgenetic alopecia in 2009 (PMID: 27489426). Japan approved dutasteride for male pattern hair loss on 28 September 2015 (PMDA list of approved products)." } }, { "@type": "Question", "name": "How does dutasteride compare with finasteride for hair loss?", "acceptedAnswer": { "@type": "Answer", "text": "In a 917-man phase 3 trial, dutasteride 0.5 mg a day increased hair count more than finasteride 1 mg a day at 24 weeks (PMID: 24411083). A 2022 network meta-analysis put the extra gain from dutasteride over finasteride 1 mg at about 7 hairs per square centimeter at 24 weeks (PMID: 35107565). A 2013 network meta-analysis by Gupta and Charrette found no significant efficacy difference between dutasteride and finasteride (PMID: 23768246). Dutasteride lowered serum DHT by 94.7 percent against 70.8 percent for finasteride 5 mg in a 399-man trial (PMID: 15126539)." } }, { "@type": "Question", "name": "What side effects were reported with dutasteride?", "acceptedAnswer": { "@type": "Answer", "text": "In a 117-man hair-loss trial, sexual side effects occurred in 16 percent on dutasteride and 8 percent on placebo over 24 weeks, all mild to moderate and resolved (PMID: 29667763). A meta-analysis of 15 placebo-controlled hair-loss trials found a relative risk of sexual dysfunction of 1.37 with dutasteride that was not statistically significant, and the authors noted that studies of dutasteride were limited (PMID: 30206635). The US label states that dutasteride's sexual adverse reactions may persist after stopping and that the role of dutasteride in this is unknown (US prescribing information for Avodart). Dutasteride also lowered total sperm count and semen volume in a one-year trial in healthy men (PMID: 17299062)." } }, { "@type": "Question", "name": "How long does dutasteride stay in the body?", "acceptedAnswer": { "@type": "Answer", "text": "Dutasteride has a terminal half-life of about 5 weeks at steady state (US prescribing information for Avodart). It stays detectable in the blood for 4 to 6 months after the last dose (US prescribing information for Avodart). Because dutasteride stays in the blood for months, the US label states that men taking dutasteride should not donate blood until at least 6 months after the last dose (US prescribing information for Avodart)." } }, { "@type": "Question", "name": "What do studies show about dutasteride in women?", "acceptedAnswer": { "@type": "Answer", "text": "Dutasteride is contraindicated in pregnancy and not indicated for women in the US label, and dutasteride feminized male fetuses in animal studies (US prescribing information for Avodart). Studies of dutasteride for female pattern hair loss are small: a retrospective sample of 60 women found thicker hair after 3 years (PMID: 25382509), and a 126-woman controlled study tested dutasteride by scalp injection (PMID: 22486925). Japan's 2017 guideline lists oral dutasteride as contraindicated for female pattern hair loss (PMID: 29863806)." } }, { "@type": "Question", "name": "Does dutasteride affect PSA tests or prostate cancer?", "acceptedAnswer": { "@type": "Answer", "text": "Dutasteride lowers serum PSA by about 50 percent within 3 to 6 months (US prescribing information for Avodart). In the 4-year REDUCE trial, dutasteride lowered biopsy-detected prostate cancer by 22.8 percent but was associated with more Gleason 8 to 10 tumors in years 3 and 4, 12 against 1 on placebo (PMID: 20357281). The US label states that dutasteride may increase the risk of high-grade prostate cancer and is not approved for preventing prostate cancer (US prescribing information for Avodart)." } } ] }, { "@context": "https://schema.org", "@type": "Organization", "@id": "https://www.bodyhackguide.co#organization", "name": "BodyHackGuide", "alternateName": "BHG", "url": "https://www.bodyhackguide.co", "logo": { "@type": "ImageObject", "url": "https://www.bodyhackguide.co/logo.png", "width": 512, "height": 512 }, "description": "Evidence-based research reference for peptides and nootropics. 273 compound profiles, interactive dosing calculators, vendor price comparisons, and trust-scored vendor reviews scored on a public, reproducible methodology applied to every vendor. 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