medicationPrescription only (US)Contraindicated in pregnancy; tablets should not be handled by women who may be pregnant
FinasterideBenefits, Dosage & Interactions
Also known as: Propecia, Proscar
Finasteride is a medication primarily used to treat male pattern hair loss (androgenetic alopecia) and benign prostatic hyperplasia (BPH), a condition in which the prostate gland becomes enlarged. It is an oral compound, available in different dosage strengths depending on the condition being treated.
Researched by DoseRoutine R&D TeamReviewed for accuracy by Nicholas Alexander, RSELast updated
Evidence: Moderate — One published human randomized trial; results not yet replicated.
Evidence strengthModerate · 3/4
PreclinicalStrong human evidence
One published human randomized trial; results not yet replicated.
Plasma half-life
~6 h
Default unit
mg
What published protocols report
Ranges documented in the literature, shown for reference. DoseRoutine does not recommend an amount — your prescriber or the product label sets the dose.
Reported for Finasteride in the cited sources. Published ranges are not dosing advice.
References & evidence
Documents the Finasteride entry is written from. Each number matches an inline marker above.
- [1]Long-term treatment with finasteride 1 mg decreases the likelihood of developing further visible hair loss in men with androgenetic alopeciaKaufman KD, Rotonda J, Shah AK, Meehan AG · European Journal of Dermatology · 2008 · Peer-reviewed · PMID 18573712
- [2]Progression of hair loss in men with androgenetic alopecia (male pattern hair loss): long-term (5-year) controlled observational dataKaufman KD, Girman CJ, Round EM, et al. · European Journal of Dermatology · 2008 · Peer-reviewed · PMID 18573713
How to track Finasteride doses
Tracking Finasteride well takes four fields and a habit. Here is what to record so the log is still useful in three months.
- 1
Add the dose and unit
Log Finasteride with its dose in mg so totals stay comparable over time — including days when you split the dose or skip it.
- 2
Set the time of day and food rule
Pick the time you actually take it. Reminders fire at that time and can export to your calendar.
- 3
Check it against the rest of the stack
Run Finasteride through the interaction checker against everything else in the routine — supplements, peptides, hormones and prescriptions — before it becomes a daily habit.
- 4
Log adherence, not intentions
Mark each dose taken, skipped or delayed as it happens. Weeks of honest logs are what make an adherence rate or a trend line meaningful; retrospective guessing is not.
- 5
Review against outcomes
With a reported half-life around 6 h, effects and timing shifts show up over days rather than instantly. Review Finasteride alongside your logged metrics and any relevant blood work every few weeks before changing the dose.
What to log each time
- Dose in mg
- Time of day
- Taken / skipped / delayed
- Any side effects or notable changes
References & Evidence
Sources on this page that document Finasteride dosing, timing and safety.
- [1]National Center for Biotechnology Information View source
Educational information only — not medical advice. Dose ranges vary by person, indication and prescriber.
What is Finasteride?Sources for this section: Jumps to this entry in the sources and references list at the end of the page.
Finasteride is a medication primarily used to treat male pattern hair loss (androgenetic alopecia) and benign prostatic hyperplasia (BPH), a condition in which the prostate gland becomes enlarged. It is an oral compound, available in different dosage strengths depending on the condition being treated. For hair loss, it is typically prescribed at a lower dose (1mg, often marketed as Propecia), while for BPH, a higher dose (5mg, often marketed as Proscar) is common. Finasteride works by targeting specific hormonal pathways in the body. It is important to note that finasteride is not approved for use in women or children. Its efficacy in treating hair loss and BPH has been established through clinical trials. (NIH NLM DailyMed, FDA label)
What does the research say about Finasteride?
Tap a section to expand.
Finasteride operates as a 5-alpha-reductase inhibitor. The enzyme 5-alpha-reductase is responsible for converting testosterone, a male hormone, into dihydrotestosterone (DHT). DHT is a more potent androgen that plays a significant role in the development of male pattern hair loss and the enlargement of the prostate gland. By inhibiting 5-alpha-reductase, finasteride effectively reduces the levels of DHT in the scalp and prostate tissue. This reduction in DHT activity helps to slow or reverse hair loss by preventing miniaturization of hair follicles and can also shrink the prostate gland, thereby improving symptoms of BPH. The inhibition is specific to type II 5-alpha-reductase and to a lesser extent type I. (DrugBank, FDA label)
Source for this section: Sources for How does Finasteride work?: Jumps to this entry in the sources and references list at the end of the page.
Finasteride offers two primary benefits, depending on the condition being treated:
* **Treatment of Male Pattern Hair Loss (Androgenetic Alopecia):** For men experiencing male pattern hair loss, finasteride can help to slow down further hair loss, promote new hair growth, and increase hair count and thickness. Users typically begin to see results within three to twelve months of consistent use, with the full effect often requiring a year or more. Continued use is necessary to maintain the benefits, as stopping the medication will likely result in the loss of any regrown hair within 12 months. (Mayo Clinic, FDA label)
* **Treatment of Benign Prostatic Hyperplasia (BPH):** In men with BPH, finasteride can reduce the size of the enlarged prostate gland, which in turn alleviates urinary symptoms such as frequent urination, weak stream, urgency, and incomplete bladder emptying. It can also reduce the risk of acute urinary retention and the need for prostate surgery. Improvement in BPH symptoms may take several months of treatment to become noticeable. (Mayo Clinic, FDA label)
Clinical studies have consistently demonstrated the efficacy of finasteride for both male pattern hair loss and BPH. For male pattern hair loss, a 2-year study involving men with androgenetic alopecia showed that finasteride 1 mg/day resulted in increased hair growth and slowed hair loss progression compared to placebo (FDA label). Another study over 5 years confirmed the long-term effectiveness and safety in maintaining hair count and appearance (NIH NLM DailyMed).
For benign prostatic hyperplasia, multiple large-scale, placebo-controlled trials have shown finasteride 5 mg/day to be effective. The Prostate Cancer Prevention Trial (PCPT), although primarily investigating prostate cancer prevention, also provided data on BPH, showing that finasteride reduced the risk of BPH-related clinical events and surgery (NIH NLM DailyMed). The MTOPS (Medical Therapy Of Prostatic Symptoms) study, a long-term trial, concluded that finasteride significantly improved BPH symptoms and reduced clinical progression of BPH (NIH Clinical Trials Archive). A review by the Cochrane Library further supports finasteride's role in improving urinary symptoms and reducing the risk of BPH progression events compared to placebo. (Cochrane Library)
Common side effects of finasteride include sexual dysfunction such as decreased libido, erectile dysfunction, and ejaculation disorders. These side effects are generally reversible upon discontinuation of the medication, though in some cases, they may persist for a period after stopping. Other less common side effects can include breast tenderness and enlargement, skin rash, and depression. Rare but serious side effects include allergic reactions (e.g., swelling of lips or face) and, in very rare instances, male breast cancer. If you experience persistent or severe side effects, seek medical attention. (FDA label, MedlinePlus)
This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Finasteride should not be used by women, especially those who are pregnant or planning to become pregnant, as it can cause birth defects in a male fetus. Women who are pregnant or may become pregnant should avoid handling crushed or broken finasteride tablets, as the active ingredient can be absorbed through the skin. Men taking finasteride should be aware that the medication can affect Prostate Specific Antigen (PSA) test results, which are used to screen for prostate cancer. Finasteride lowers PSA levels, so a physician needs to account for this effect when interpreting PSA results. Patients should inform their doctor that they are taking finasteride before any PSA testing. There have been reports of mood alterations, including depression and, less frequently, suicidal ideation, in patients treated with finasteride. Patients experiencing these symptoms should seek medical advice. (FDA label, MedlinePlus)
This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Finasteride is contraindicated in the following situations:
* **Pregnancy:** As noted, finasteride can cause abnormalities of the external genitalia in a male fetus.
* **Hypersensitivity:** Individuals with a known hypersensitivity to finasteride or any component of the tablet should not use this medication.
* **Children:** Finasteride is not indicated for use in children.
* **Women:** Finasteride is not approved for use in women. (FDA label)
This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Currently, there are no known significant drug-drug interactions that are generally advised to be avoided with finasteride. However, it is always crucial to inform your healthcare provider about all medications, supplements, and herbal products you are currently taking to ensure there are no unforeseen interactions or contraindications specific to your individual health profile. While finasteride is primarily metabolized by the cytochrome P450 3A4 enzyme system, significant clinical interactions with other drugs metabolized by this pathway are not considered likely. (FDA label)
This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Finasteride is typically taken once daily. The dose is user-directed and must be set by a licensed clinician. It can be taken with or without food, as food does not significantly affect its absorption (FDA label). For treatment of hair loss, consistency is key; taking it at roughly the same time each day helps maintain steady levels of the medication in the body. If a dose is missed, it should not be doubled at the next scheduled time; simply continue with the next dose as prescribed. (MedlinePlus)
Source for this section: Sources for When should you take Finasteride?: Jumps to this entry in the sources and references list at the end of the page.
What interacts with Finasteride?
| Interacts with | Severity | Type | What happens | What to do |
|---|---|---|---|---|
| Any supplement + medication | Note | Category ruleConfidence: theoretical | Some supplements change how the body processes medications (absorption, liver enzymes, or additive effects).Source pending | Specific pairs are checked against a licensed drug database and shown with their own severity. Always confirm with your provider or pharmacist. |
| Any vitamin + medication | Note | Category ruleConfidence: theoretical | Certain vitamins interact with specific medications (e.g., vitamin K with blood thinners).Source pending | Specific pairs are checked against a licensed source; confirm with your provider. |
| Testosterone Cypionate | Caution | Compound pairConfidence: theoretical | 5-alpha-reductase inhibitors block DHT conversion; can affect libido and prostate response on TRT.Source pending | Discuss goals with prescribing clinician; monitor sexual function. |
Frequently asked questions about Finasteride
Finasteride is a medication. It is also known as Propecia and Proscar. The references summarized come from NIH and PubMed records, FDA labeling where it exists, and Mayo Clinic patient material.
Finasteride is commonly discussed in the context of the goals discussed on its profile page. Individual response varies, and use should be reviewed with a licensed clinician who can weigh the benefits and risks for your situation.
For Finasteride, it is typically taken null and its approximate half-life is 6 hours, which influences dosing frequency. Always follow the specific dose your clinician or the product label prescribes.
Finasteride carries potential side effects and drug interactions, documented in NIH, Mayo Clinic, and FDA label sources. Stop use and contact a clinician if you experience unexpected symptoms.
As a medication, Finasteride can overlap with other supplements, prescription medicines, hormones and peptides. With a reported plasma half-life near 6 hours, separating doses can change the picture as much as removing one. Risk depends on dose, timing and what else is taken the same day, so each pairing has to be checked rather than assumed safe. The free checker at https://doseroutine.com/interaction-checker covers Finasteride with no sign-up.
Whether Finasteride fits alongside testosterone replacement therapy depends on the protocol — dose, ester and ancillaries such as HCG or anastrozole — and on current bloodwork. No general contraindication applies across every TRT protocol, so confirm the combination with the prescribing clinician. See the free TRT interaction reference: https://doseroutine.com/trt-supplement-interactions
"Peptides" is not one category — healing peptides, GLP-1 agonists, growth-hormone secretagogues and melanocortins each behave differently next to Finasteride. Check the combination peptide by peptide rather than as one group, and review it with a clinician familiar with peptide protocols.
A short plasma half-life of roughly 6 hours is why protocols often split Finasteride across the day rather than using a single dose. Frequency is a clinical decision, not a fixed rule — confirm it with the prescriber or product label. Comparison of apps that keep a schedule like this: https://doseroutine.com/best-dose-tracking-apps
Because Finasteride clears quickly (plasma half-life around 6 hours), a missed dose leaves a real gap in exposure rather than being buffered by what is still in your system. Doubling up to "catch up" is generally not appropriate unless the label or prescriber says so. Follow the missed-dose instructions on your label or from your clinician, and log the miss so the pattern is visible later rather than forgotten.
For Finasteride the useful record is the dose, the time it was actually taken, and what else was taken in the same window. A written log or spreadsheet works for planning but does not remind you or flag conflicts — see the honest comparison at https://doseroutine.com/vs/spreadsheet and the wider roundup at https://doseroutine.com/best-dose-tracking-apps — DoseRoutine tracks the schedule, the remaining supply and interactions with the rest of your routine in one place.
Which studies looked at Finasteride?
Peer-reviewed research indexed in PubMed. Each entry links to the original record.
- 1.Comparison of oral minoxidil, finasteride, and dutasteride for treating androgenetic alopecia(opens PubMed in a new tab)J Dermatolog Treat · 2022 · PMID 35920739 · https://pubmed.ncbi.nlm.nih.gov/35920739/
- 2.Efficacy and safety of topical finasteride spray solution for male androgenetic alopecia: a phase III, randomized, controlled clinical trial(opens PubMed in a new tab)J Eur Acad Dermatol Venereol · 2022 · PMID 34634163 · https://pubmed.ncbi.nlm.nih.gov/34634163/
- 3.Finasteride for hair loss: a review(opens PubMed in a new tab)J Dermatolog Treat · 2022 · PMID 34291720 · https://pubmed.ncbi.nlm.nih.gov/34291720/
- 4.Post-finasteride syndrome: a surmountable challenge for clinicians(opens PubMed in a new tab)Fertil Steril · 2020 · PMID 32033719 · https://pubmed.ncbi.nlm.nih.gov/32033719/
Sources cited on this page
Specific documents referenced by the numbered markers above. Each number matches the marker in the text.
- PubChem CID 58630855(opens in a new tab)National Center for Biotechnology Information · pubchem.ncbi.nlm.nih.gov/compound/58630855
Verify at
Publisher search links for Finasteride. These are places to check the information — they are not citations, so they are not numbered.
- DailyMed prescribing information(publisher search, opens in a new tab)U.S. National Library of Medicine · publisher search
- MedlinePlus(publisher search, opens in a new tab)U.S. National Library of Medicine · publisher search
- Mayo Clinic(publisher search, opens in a new tab)Mayo Clinic · publisher search
- DrugBank(publisher search, opens in a new tab)DrugBank Online · publisher search
- Cochrane Library(publisher search, opens in a new tab)Cochrane · publisher search
- PubMed literature search(publisher search, opens in a new tab)National Library of Medicine · publisher search
- Wikipedia entry(publisher search, opens in a new tab)Wikipedia · publisher search
DoseRoutine compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician. How we source and review this information.
What is the short answer on Finasteride?
Plain-text summary, safe to quote verbatim:
Finasteride is a medication primarily used to treat male pattern hair loss (androgenetic alopecia) and benign prostatic hyperplasia (BPH), a condition in which the prostate gland becomes enlarged. It is an oral compound, available in different dosage strengths depending on the condition being treated.
Source: DoseRoutine — https://doseroutine.com/library/finasteride
Cite this page
Using this in an article, AI answer, or research note? Please attribute:
DoseRoutine. (2026). Finasteride — Overview, Benefits & Side Effects. Retrieved from https://doseroutine.com/library/finasteride
What compounds are similar to Finasteride?
Others in the medication category or studied for the same goals.