Finastid

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Medically reviewed

Marina Burgos

Last updated on 10/01/2026

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Finastid

What is Finastid? Identity, Class, and General Purpose

Property Description
Active ingredient Finasteride
Form Film-coated oral tablet
Pharmacological class 5-alpha reductase inhibitor (5alpha-RI)
General purpose Hormonal modification of androgen-dependent conditions
Origin Synthetic 4-azasteroid compound

Finastid: Identity, Composition, and Class

Finastid is a prescription medicine containing the synthetic active ingredient, Finasteride, which is derived from the 4-azasteroid compound chemical structure. This drug is officially classified as a 5-alpha reductase inhibitor (5alpha-RI), a class specifically designated to target steroid hormone metabolism. The product is manufactured as a single-ingredient oral tablet for systemic administration, which ensures the active substance is absorbed into the bloodstream to affect target tissues throughout the body.

What is the General Purpose of a 5-Alpha Reductase Inhibitor?

The fundamental purpose of Finastid is to address conditions that are reliant on the powerful androgen Dihydrotestosterone (DHT). It achieves this by acting as a competitive inhibitor of the Type II 5-alpha reductase enzyme, which prevents the conversion of the less potent hormone Testosterone into DHT. This inhibitory action leads to a significant and sustained reduction in the concentration of DHT in serum and target tissues, a process clinically recognized for its ability to modify the underlying hormonal drivers of these conditions. The general therapeutic goal of this hormonal modification is to manage or slow the progression of specific androgen-dependent tissue conditions in adult males.

The Distinction of a Single-Ingredient, Systemic Medicine

Finastid is defined by its form as a single-ingredient product, focusing its therapeutic impact exclusively on the enzyme inhibition pathway. The oral route of intake ensures a systemic effect, delivering a consistent reduction of DHT across all relevant androgen-sensitive tissues. This systemic approach is a core feature that distinguishes it from localized or non-prescription treatments, providing a standardized method for achieving therapeutic concentrations.

Regulatory References

  1. (NIH)

What side effects are possible with Finastid?

Possible Side Effects and Safety Information

The safety profile for Finastid (Finasteride) is defined by officially documented adverse reactions categorized by frequency and the body system affected. These classifications are established through regulatory documentation based on clinical trial data and post-marketing surveillance.

Key safety observations are frequently categorized under Reproductive System and Breast Disorders and Psychiatric Disorders.

Official Adverse Reactions and Frequencies

Classification Examples of Documented Effects
Common (may affect up to 1 in 10 men) Decreased libido, erectile dysfunction, decreased volume of ejaculate.
Uncommon (may affect up to 1 in 100 men) Depression, ejaculation disorder, breast tenderness, breast enlargement (gynecomastia), rash.
Not Known (Post-marketing reports) Hypersensitivity reactions (e.g., swelling of the face/lips), anxiety, suicidal ideation, testicular pain, male breast cancer, persistent sexual dysfunction.

Serious Safety Signals and Constraints

Official regulatory sources note that sexual dysfunction, including decreased libido and erectile dysfunction, has been reported to persist after discontinuation of treatment. Serious adverse reactions documented in post-marketing reports include cases of male breast cancer and the potential for suicidal ideation.

Regarding specific populations, Finastid is contraindicated for women who are or may be pregnant, due to the risk of causing external genital abnormalities in a developing male fetus. The medication is not indicated for use in the pediatric population.

Finally, Finasteride causes a reduction in serum Prostate-Specific Antigen (PSA) levels, a constraint that must be accounted for when interpreting diagnostic test results.

Overdose and Emergency Response

Overdose and When to Seek Help

Official government regulatory information provides specific guidance on Finastid (finasteride) overdose, emphasizing a high safety threshold based on clinical trials.

Documented Overdose Findings

Overdose Parameter Official Regulatory Status
Documented Presentations No specific adverse effects or symptoms have been reported in clinical trials following acute overdosage.
High Dose Exposure Patients have tolerated single oral doses of up to 400 mg and multiple doses of up to 80 mg/day for three months without documented adverse effects.
Antidote No specific antidote or pharmacological reversal agent is listed in regulatory product information.

Emergency Response Guidance

In the event of a suspected overdosage, the required action is to seek immediate medical advice, even if the person displays no signs of discomfort or illness. This is standard regulatory instruction for suspected high-dose exposures.

Management of finasteride overdose, if clinically necessary, is defined as symptomatic and supportive. Until further experience is obtained beyond the high doses tested in clinical trials, no specific treatment can be universally recommended by regulatory agencies. Therefore, the priority is to contact a healthcare professional or a Poison Control Centre immediately for guidance.

Therapeutic Uses of Finastid

Main Uses of Finastid

Finastid is a medication primarily prescribed for the management of two distinct conditions: androgenetic alopecia (male pattern hair loss) and benign prostatic hyperplasia (BPH).

Benign Prostatic Hyperplasia (BPH)

In men with benign prostatic hyperplasia, the prostate gland becomes enlarged, which can compress the urethra and lead to various urinary symptoms. Finastid helps manage this condition by:

  • Reducing Prostate Size: The medication works by lowering the levels of dihydrotestosterone (DHT), a hormone that contributes to prostate growth. This reduction in size helps alleviate pressure on the urinary tract.
  • Improving Urinary Flow: As the prostate gland shrinks, patients typically experience improved urine flow and a decrease in the force required to urinate.
  • Reducing Urinary Symptoms: Common symptoms such as the frequent urge to urinate, nighttime urination (nocturia), and the sensation of incomplete bladder emptying are often diminished.
  • Lowering Risk of Complications: Long-term use can reduce the likelihood of acute urinary retention and the eventual need for surgical intervention related to prostate enlargement.

Male Pattern Hair Loss (Androgenetic Alopecia)

Finastid is also indicated for the treatment of male pattern hair loss, a condition characterized by the thinning of hair on the scalp. Its benefits in this area include:

  • Stabilizing Hair Loss: The primary benefit for many users is the slowing or stopping of further hair thinning and loss.
  • Promoting Regrowth: In many cases, the medication can stimulate the regrowth of hair in areas that have begun to thin, such as the vertex (crown) and the middle of the scalp.
  • Increasing Hair Density: By inhibiting the production of DHT in the scalp—the hormone responsible for shrinking hair follicles—the medication helps maintain thicker, healthier hair strands.

Mechanism of Action and Benefits

The efficacy of Finastid across both conditions stems from its role as a 5-alpha reductase inhibitor. By blocking the conversion of testosterone into the more potent androgen dihydrotestosterone (DHT), it addresses the hormonal root cause of both prostate enlargement and hair follicle miniaturization. This targeted approach allows for the management of chronic conditions through consistent, long-term hormonal regulation.

Eligibility and Restrictions for Use

Official Eligibility Status for Finastid

Finastid is authorized for use exclusively in adult men and is subject to several explicit regulatory restrictions defining who can and cannot use the medicine.

Eligibility Status Regulatory Requirement
Approved Population Adult men, including those with renal insufficiency.
Absolute Contraindication All females must not use this medicine, especially those who are or may be pregnant.
Age Restriction Not indicated for use in children and adolescents under 18 years of age.
Comorbidity Caution Caution is advised in patients with liver function abnormalities (hepatic impairment), as clinical data on pharmacokinetics in this population is unavailable.
Drug Prohibitions Use is contraindicated for patients with a known hypersensitivity or those concurrently taking another 5-alpha reductase inhibitor.

Regulatory documents define Finastid as contraindicated in women due to the potential risk of external genitalia abnormalities in a male fetus, and they are advised not to handle crushed tablets. Use is also officially not indicated for children, restricting eligibility to the adult male population. Patients with specific excipient intolerances, such as total lactase deficiency, are also excluded from use.

What should I know about interactions with other medicines?

Interactions with other medicines and products

The interaction profile for Finastid (Finasteride) is defined by its generally low potential for causing clinically meaningful drug interactions and a specific prohibition related to its pharmacological class. All interaction statements are derived strictly from official government regulatory documents.

Interaction Scope Official Regulatory Statement
Formal Restrictions Co-administration with any other 5-alpha reductase inhibitor (5α-RI) is formally prohibited. This includes other strengths of Finasteride or Dutasteride.
Metabolic Interactions No drug interactions of clinical importance have been identified with the cytochrome P450 (CYP) enzyme system. Finastid does not appear to affect this metabolic system.
Tested Compounds Clinical studies found no clinically meaningful interactions with various tested compounds, including: antipyrine, digoxin, propranolol, theophylline, and warfarin.
Exposure Modification Finastid is metabolized by CYP3A4. Inhibitors and inducers of this enzyme are probable to affect Finastid's plasma concentration. However, official regulatory documents state that the resulting change in exposure is unlikely to be of clinical significance based on safety margins.
Food & Timing Rules No mandatory timing or separation requirements are documented. The medicine can be taken with or without food, and no interaction is documented with alcohol consumption.
Population Notes The effect of hepatic insufficiency on the medicine's pharmacokinetics has not been formally studied in patients with liver impairment.

This official interaction profile is structured by a single, explicit contraindicated combination concerning other 5α-RIs, while simultaneously establishing a low risk for pharmacokinetic alterations with most other commonly administered medicines. The absence of strict timing constraints allows for flexible administration.

Mechanism of Action

Finastid (Finasteride) operates exclusively by modulating the metabolism of sex hormones at the enzymatic level. Its entire mechanism of action is dependent on interrupting a specific conversion pathway, leading to a sustained alteration of the local hormonal environment.

Targeted Inhibition of the 5-Alpha Reductase Enzyme

Finastid functions as a specific, competitive inhibitor of the Type II 5-alpha reductase enzyme (5alpha-R Type II), which is responsible for converting Testosterone into the potent androgen, Dihydrotestosterone (DHT). The drug forms a stable complex with the enzyme, initiating a cascade that results in a significant reduction of the concentration of DHT in androgen-sensitive tissues.

Mechanism of Time-Dependent Tissue Regression

The withdrawal of the potent DHT growth signal causes cells in affected tissues to slow their proliferation, leading to the cellular regression of tissue volume and a reduction in cellular activity. Because this physiological effect relies on the physical reversal of tissue structure rather than rapid receptor blockade, the mechanism requires chronic inhibition over many months to manifest its full physiological effects.

Limitations of Partial Androgen Modification

The inhibition is not absolute because Finastid exhibits minimal activity against the 5alpha-R Type I enzyme, which remains active and results in partial systemic DHT suppression. Furthermore, the mechanism is entirely reversible; upon drug cessation, the underlying hormonal stimulus returns, leading to the eventual restoration of the baseline tissue volume and activity.

Dosage and Administration Information

How to Use Finastid

The usage of Finastid is standardized through an official, fixed-dosing protocol for long-term oral administration. The medicine is administered via the oral route as a film-coated tablet.

Standardized Dosing and Frequency

Indication Official Daily Dose Frequency
Benign Prostatic Hyperplasia (BPH) 5 mg Once daily
Male Pattern Hair Loss 1 mg Once daily

Treatment is structured as a long-term commitment, as sustained daily intake is necessary to initiate and maintain the intended effect. For male pattern hair loss, the period to observe the initial effect is typically three months or longer. If administration is discontinued, the established effect will gradually reverse within 9 to 12 months.

Administration Conditions and Handling

Instruction Type Official Requirement
Timing Administered with or without meals.
Preparation The tablet must be swallowed whole; it should not be crushed, broken, or chewed.
Missed Dose Skip the missed dose and resume the normal once-daily schedule with the next dose; do not take a double dose.

Population-Specific Usage: No routine dosage adjustment is required for older adults or patients with renal impairment. The medicine is not indicated for use in the pediatric population (under 18 years).

Recent Clinical Evidence

Research Evidence / Overview of studies for Finastid

Research Evidence for Use in Benign Prostatic Hyperplasia (BPH)

Research exploring Finastid was evaluated through large-scale, long-term studies, primarily through Randomized Controlled Trials (RCTs). These studies were used in research exploring how symptoms change over time in adult men who had symptomatic BPH and a physically enlarged prostate gland. Outcomes related to systemic or functional imbalance were examined, including objective measurements of prostate size (volume), the rate of urinary flow, and the outcomes related to perceived discomfort.

Studies report how symptoms evolved in the observed populations over extended periods, with some findings reporting measured changes in prostate volume. The research also monitored outcomes describing episodic or acute changes and clinical progression, such as pre-defined endpoints related to serious BPH-related events. Findings describe patterns observed in the studies over follow-up periods that extended for several years, which contribute to the long-term evidence landscape measured during the study period.


Research Evidence for Use in Male Pattern Hair Loss (Androgenetic Alopecia)

Research exploring Male Pattern Hair Loss (Androgenetic Alopecia) has examined Finastid primarily through double-blind, placebo-controlled clinical trials. These studies were applied in research contexts involving fluctuating or unstable symptoms, particularly focusing on younger adult men who presented with mild to moderate hair thinning and loss. Research examined outcomes related to physical discomfort and patient-reported outcomes describing perceived discomfort.

The trials included objective measures to monitor hair characteristics, including the counting of hairs in a target area of the scalp and the review of standardized photographs by investigators. Trials reported measurements of changes in hair count within the target scalp area over the 1-year assessment period. These findings help contextualize how patients reported their experience and contributed to the broader evidence landscape for this condition.


Long-Term Studies and Durability of Evidence

For BPH, studies observing responses over defined time intervals tracked outcomes up to 7 to 10 years, and some research reports data show patterns observed during these extended observation periods for up to 15 years. For the hair loss indication, research describes a distinct pattern: the measurements observed are not permanent, and studies reported that the outcomes typically reverse within approximately one year after participants stopped the treatment.


What is Still Uncertain in the Research Landscape

Follow-up durations were limited in some hair loss trials, and there is limited information for long-term outcomes extending far beyond the initial study periods. The evidence also suggests that the results apply only to the populations studied regarding the specific area of hair loss, as research did not determine whether effectiveness is fully established for areas like the bitemporal recession (receding hairline). Furthermore, studies described variability in findings among the observed patients, which highlights that certainty remains low regarding consistent findings across all individuals.

Key Studies & References

  1. Impact of baseline symptom severity on future risk of benign prostatic hyperplasia-related outcomes and long-term response to finasteride. The Pless Study Group

Frequently Asked Questions (FAQ)

Common questions about Finastid (FAQ)


Q: How quickly is Finastid described as reducing DHT levels?

Official information indicates that the drug rapidly reduces levels of Dihydrotestosterone (DHT) in the serum and tissues. Significant suppression of DHT concentration is generally reached within 24 hours after a patient takes the first dose.


Q: What is the official warning regarding pregnant women handling Finastid tablets?

Official warnings state that pregnant women or women who may become pregnant should not handle Finastid tablets that have been broken, crushed, or damaged. This precautionary measure is due to the potential risk of absorption of the medicine, which may cause harm to a developing male fetus.


Q: Is there a reported risk of decreased interest in sexual activity associated with Finastid?

Yes, a decreased interest in sexual activity, which is also known as decreased libido, is listed in official documents as a commonly reported adverse reaction in clinical studies. This is a recognized side effect associated with the use of the medicine.


Q: Have there been reports of difficulty achieving or maintaining an erection while taking Finastid?

Yes, difficulty achieving or maintaining an erection (erectile dysfunction) is a commonly reported adverse reaction described in official safety documents. This is listed as one of the possible effects associated with the medicine's use.


Q: Are the sexual side effects sometimes reported to persist after stopping Finastid?

Post-marketing reports have been reviewed by regulatory agencies and include cases where sexual dysfunction continued even after patients discontinued the medicine. These persistent effects have involved issues such as decreased libido, erectile dysfunction, and ejaculation disorders.


Q: What is described in official documents about the effect of Finastid on ejaculation volume or function?

Official documentation reports decreased volume of ejaculate is a common adverse reaction. Ejaculation disorder is also listed as an uncommon adverse reaction associated with the use of the medicine.


Q: Has Finastid been linked to reports of testicular discomfort or pain?

Testicular pain is an adverse reaction that has been reported during post-marketing surveillance of the drug. Such reports contribute to the medicine's overall safety profile.


Q: Are there different rates of sexual side effects reported for the 1mg and 5mg strengths?

Yes, clinical trial data indicates a difference in reported frequency based on the dosage. The official data shows that the reported frequency of some sexual adverse effects is slightly higher in patients taking the 5 mg dose compared to the 1 mg dose.


Q: Is a loss of sexual ability a recognized potential side effect of Finastid?

Finastid is associated with several adverse reactions that may collectively result in reduced sexual function. These reported effects include decreased interest in sex, difficulty achieving an erection, and ejaculation disorders, as listed in the official product information.


Q: Does Finastid affect sperm count or sperm quality according to research findings?

Post-marketing reports reviewed by regulatory agencies have included cases of male infertility and/or poor seminal quality. It is noted that normalization or improvement of seminal quality has been reported in some cases after the drug was discontinued.


Q: Can Finastid cause changes in the male breast tissue, such as swelling or tenderness?

Yes, uncommon adverse effects include breast enlargement (gynecomastia) and tenderness. Because serious safety signals have been reported post-marketing, regulatory documents state that any breast changes, such as lumps, pain, or nipple discharge, should be reported to a healthcare professional.


Q: Are mood changes, such as low mood or depression, listed as potential effects of Finastid?

Yes, depression is listed in official documentation as an uncommon adverse reaction. This is part of the established safety profile based on clinical trials and reporting.


Q: Is there information about Finastid being associated with anxiety or cognitive issues?

Post-marketing reports reviewed by regulatory agencies have included instances of anxiety. Furthermore, regulatory guidance has noted reported cognitive issues (e.g., memory dysfunction and 'brain fog').


Q: What has regulatory guidance stated about psychiatric side effects like suicidal thoughts?

Suicidal ideation and behavior have been reported in post-marketing surveillance. Because of these serious reports, regulatory agencies have issued warnings and advise monitoring for changes in mood.


Q: Are family members or friends encouraged to monitor a patient for mood changes while on Finastid?

Regulatory agencies advise that patients should be monitored for any mood changes, including symptoms such as depressed mood or depression. Official warnings state that if a patient experiences such symptoms, they should be evaluated by a healthcare professional immediately.


Q: Have there been reports linking Finastid to problems with memory or 'brain fog'?

Post-marketing data analysis, including reports to regulatory systems, has noted reported cases of memory dysfunction and symptoms described as 'brain fog.' This information contributes to the medicine's long-term safety data.


Q: Are skin reactions like rash or itching known possible side effects of Finastid?

Yes, rash is an uncommon adverse reaction. Hypersensitivity reactions, including itching and hives, have also been reported in post-marketing experience.


Q: Can Finastid affect the results of the Prostate Specific Antigen (PSA) test?

Yes, Finastid is known to cause a reduction in serum Prostate-Specific Antigen (PSA) levels. Official guidance states that this lowering effect must be carefully taken into account when interpreting the results of a patient’s PSA test.


Q: What pre-existing medical conditions are listed as contraindications for using Finastid?

Contraindications for use include a known hypersensitivity or allergy to finasteride or any other component in the tablet. The medicine is also exclusively for adult male patients and is not for use in women or children.


Q: Does having liver function issues affect how Finastid is used?

Caution is advised when Finastid is administered to patients with liver function abnormalities because the medicine is extensively processed in the liver. However, official information also states that the effects of formal liver impairment on the medicine have not been formally studied.


Q: Are there any known interactions between Finastid and herbal or dietary supplements?

While the medicine has a generally low potential for causing clinically meaningful drug interactions, some regulatory guidance notes that certain herbal remedies may potentially affect how Finastid works. Specifically, St. John's wort is an example of an herbal supplement noted in official guidance.


Q: What is the official designation for the condition sometimes referred to by patients as 'Post-Finasteride Syndrome'?

Regulatory and governmental bodies do not officially recognize the patient-coined term 'Post-Finasteride Syndrome.' However, drug labels were updated to include warnings regarding the serious risk of sexual and psychiatric side effects that may persist after the medicine is stopped.


Q: Is Finastid the same as [Brand Name 1] or [Brand Name 2]?

Finastid is the generic name for the active ingredient, which is finasteride. This active ingredient is sold under brand names such as Proscar, typically for the 5 mg strength, and Propecia, typically for the 1 mg strength.

How should Finastid be stored and disposed of?

Finasteride tablets must be stored according to specific regulatory requirements to maintain product stability and safety.

Required Storage Conditions

The medication must be stored at Controlled Room Temperature, between 20 C and 25 C (68 F and 77 F). The tablets must be kept in the original, tightly closed container and protected from both light and excess moisture.

  • Child Safety: Like all medications, Finasteride must be stored out of the reach of children.

️ Handling and Disposal

Official labeling mandates a special handling restriction: Women who are or may potentially be pregnant must not handle crushed or broken tablets. If contact occurs, the area must be washed immediately with soap and water.

Unused or expired Finasteride must be disposed of according to local governmental regulations to ensure proper pharmaceutical waste handling.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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