How Pyrilutamide (KX-826) Works, Results, Usage, and Side Effects

Pyrilutamide (often referred to by its research code KX-826) has recently entered the spotlight as a potential novel treatment for androgenetic alopecia (AGA). This article elucidates the science behind its mechanism, examines clinical evidence, and gauges its prospects in the realm of hair loss interventions.

Close up showing the before and after results using pyrilutamide to treat hair loss and balding

What is Pyrilutamide?

Pyrilutamide is a relatively novel compound being explored for its potential in treating hair loss, specifically androgenetic alopecia, which is commonly known as male and female pattern hair loss. Pyrilutamide belongs to a class of medications known as androgen receptor antagonists. Its primary mechanism of action involves blocking androgen receptors in the hair follicles, thereby inhibiting the effects of dihydrotestosterone (DHT), a hormone associated with hair follicle miniaturization and hair loss in individuals with a genetic predisposition. By preventing DHT from binding to these receptors, Pyrilutamide aims to disrupt the hair loss process and potentially promote the retention and regrowth of hair. However, it’s essential to note that research on Pyrilutamide for hair loss is ongoing, and comprehensive data on its efficacy, safety, and side effect profile may continue to evolve.

History of Pyrilutamide

Pyrilutamide is a relatively recent entrant in the field of hair loss treatment, with its historical development still in the early stages. Its journey began with the discovery of its androgen receptor antagonist properties, signifying its ability to counteract the effects of androgens, particularly dihydrotestosterone (DHT). DHT is a hormone closely associated with hair loss, particularly in individuals with androgenetic alopecia, or male and female pattern hair loss.

Researchers and scientists recognized the potential of Pyrilutamide for addressing hair loss concerns, stemming from its mechanism of action in blocking androgen receptors. By inhibiting DHT’s binding to these receptors in hair follicles, Pyrilutamide aimed to disrupt the hair loss process at the molecular level. This promising attribute led to the initiation of clinical trials and research studies specifically designed to investigate Pyrilutamide’s effectiveness and safety as a treatment for hair loss.

The Role of DHT in Androgenetic Alopecia

Dihydrotestosterone (DHT) is a hormone derived from testosterone, and it plays a significant role in hair loss, particularly in androgenetic alopecia (male and female pattern baldness). In individuals with a genetic predisposition to hair loss, hair follicles in certain areas of the scalp are sensitive to DHT. When DHT binds to receptors in these follicles, it can lead to a process known as miniaturization. This process causes the hair follicles to shrink over time, resulting in thinner and shorter hair growth cycles. Eventually, the affected follicles may stop producing hair altogether, leading to baldness in those areas. Therefore, DHT is a key factor in the development and progression of hair loss, and treatments often target its effects to mitigate or reverse the condition.

How Pyrilutamide Treats Hair Loss

Pyrilutamide holds promise for individuals grappling with androgenetic alopecia, commonly known as male and female pattern hair loss. Its potential as a hair loss solution lies in its intricate mode of action at the molecular level, which include:

  • Androgen Receptor Antagonism: Pyrilutamide functions as a potent and selective androgen receptor antagonist. In the context of hair loss, androgenetic alopecia is often associated with the hormone dihydrotestosterone (DHT), which plays a central role in follicular miniaturization—the gradual shrinking of hair follicles. DHT binds to androgen receptors in hair follicles, initiating a cascade of events leading to hair thinning and loss. Pyrilutamide’s primary mode of action involves competing with DHT for binding to these androgen receptors. By blocking the receptors, Pyrilutamide prevents DHT from attaching and initiating the signaling pathways that lead to follicular miniaturization.
  • Interruption of Miniaturization Process: The key objective of Pyrilutamide is to interrupt or slow down the process of follicular miniaturization. By preventing DHT from binding to androgen receptors, Pyrilutamide aims to maintain the size and function of hair follicles. This preservation can lead to the production of thicker, healthier hair strands and potentially promote the retention of existing hair.
  • Molecular Affinity: Pyrilutamide’s effectiveness is also influenced by its molecular affinity for androgen receptors. It has a high specificity for androgen receptors in the scalp, ensuring that its action is concentrated in the area of application. This specificity bolsters its efficacy and minimizes potential systemic effects or disruptions.

Empirical Evidence

Kintor USA’s clinical trial on Pyrilutamide holds significant weight in establishing the compound’s potential:

  • Trial Design: The clinical trial spanned six months and aimed to assess the safety and efficacy of Pyrilutamide. This double-blind, placebo-controlled study included men between the ages of 18 to 65, all diagnosed with AGA.
  • Noteworthy Outcomes: At the conclusion of the trial, those treated with Pyrilutamide demonstrated a marked increase in hair count compared to the placebo group. More specifically, an average increase of about 14 hairs per square centimeter of the targeted scalp area was observed.
  • Safety Metrics: Beyond its efficacy, the trial underscored Pyrilutamide’s safety. The majority of participants reported minimal to no side effects, making it a well-tolerated treatment option.
Pyrilutamide trial results from kintor

Results using Pyrilutamide (KX-826) showed significant increase in hair when compared to the placebo group.

Kinto Pharmaceutical Trials

Phase 1/1b Clinical Trials

Recently, a phase-1 clinical trial was conducted in the United States, following a randomized, double-blind, placebo-controlled, parallel-group, and dose-escalation design. This trial enrolled 40 healthy adult male participants diagnosed with androgenetic alopecia.

The objective of this study was to assess the safety, tolerability, and pharmacokinetics of pyrilutamide, a topical androgen receptor antagonist. The participants received multiple ascending doses of pyrilutamide, ranging from 3mg to 96mg.

Throughout the study, the blood concentration of pyrilutamide among the subjects remained remarkably low. Importantly, no severe adverse drug events were reported, indicating a favorable safety profile associated with pyrilutamide.

Phase 2 Clinical Trials

Multiple clinical trials have been conducted to evaluate the efficacy of pyrilutamide in treating hair loss. In 2020, the first phase 2 clinical trial took place in China, involving a multi-regional randomized placebo-controlled study. This trial included 120 male subjects diagnosed with androgenetic alopecia, who were randomly assigned to four dose groups: 2.5 mg (0.25%) of pyrilutamide twice a day, 5.0 mg (0.5%) once a day, 5.0 mg (0.5%) twice a day, and a placebo group. The outcome measured was the change in non-vellus target area hair count (TAHC) from baseline after six months of treatment.

Participants receiving pyrilutamide 0.5% solution applied twice daily demonstrated a statistically significant improvement in total area hair count compared to the placebo group. There was an increase of 22.73 hairs per cm2 in the pyrilutamide group, whereas the placebo group only experienced an increase of 15.34 hairs per cm2. Based on these promising results, the 0.5% pyrilutamide solution was selected for further investigation in phase 3 clinical trials.

In December 2022, another phase 2 clinical study focusing on the treatment of female pattern hair loss (female AGA) was published. This study included 119 female subjects with AGA who were randomly assigned to four treatment groups with varying doses of pyrilutamide. Results indicated that the pyrilutamide 0.5% solution applied once daily significantly increased hair count by 11.39 hairs per cm2 from baseline after 24 weeks of treatment, with improvements observed as early as the end of week 12. Like previous phase 2 trials, pyrilutamide exhibited a favorable safety profile.

The most recent phase 2 trial conducted in the United States reported its results in May 2023. This trial was a randomized, double-blind, placebo-controlled study involving 123 male patients with male pattern alopecia. The study demonstrated an increase in target area hair count by approximately 10 hairs per cm2 from baseline after 24 weeks of treatment with the 0.5% pyrilutamide solution applied twice daily. The results were both statistically and clinically meaningful, demonstrating a favorable safety profile. The company plans to proceed with subsequent FDA meetings on the Phase 2 trial results and initiate Phase 3 clinical trials in the United States and globally.

Phase 3 Clinical Trials

In November 2021, the Phase 3 clinical trial protocol for evaluating pyrilutamide as a treatment for male androgenetic alopecia received approval. This trial is a randomized, double-blind, placebo-controlled, multi-regional study set to take place across 26 dermatology centers in China.

As of March 2023, a total of 740 male patients have been enrolled in this extensive study. Its primary objective is to assess the efficacy and safety profile of pyrilutamide in addressing male pattern hair loss. The trial is scheduled to run for a duration of 24 weeks with an additional 4-week follow-up period. The primary endpoint of the study is to observe the change in non-vellus target area hair count (TAHC) from baseline at the conclusion of week 24.

The Chinese Phase 3 trials of KX-826 (Pyrilutamide) yielded satisfactory, but not exceptional, results. The trials, free from serious side effects or adverse events, showed positive hair growth over 24 weeks compared to the baseline. However, in comparison with the placebo group, the total area hair count (TAHC) improvements in the KX-826 group weren’t statistically significant, though there was a noticeable trend towards efficacy.


User-reported results and experiences with Pyrilutamide for hair loss treatment are limited, as the compound is still relatively new and undergoing clinical trials. It’s important to note that individual responses to hair loss treatments can vary significantly, and anecdotal reports may not provide a comprehensive picture of its effectiveness. Here are some user-reported outcomes and experiences based on early-stage research and anecdotal reports:

  • Halting Hair Loss: Some users may report that Pyrilutamide helped slow down or halt the progression of hair loss. By blocking androgen receptors, Pyrilutamide aims to preserve existing hair follicles, potentially preventing further thinning and balding.
  • Hair Regrowth: In some cases, users may notice hair regrowth in areas where hair had previously thinned or receded. However, the extent of regrowth can vary among individuals.
  • Improved Hair Quality: Users might report that their existing hair appeared thicker and healthier after using Pyrilutamide, potentially leading to increased overall hair density.
Close up showing the before and after results using pyrilutamide to treat hair loss and balding

Before and after results using pyrilutamide to treat hair loss.

How to Use

The application of Pyrilutamide for hair loss typically involves topical use, as it is intended to be applied directly to the scalp. Here are general guidelines for applying:

  • Clean Scalp: Start with a clean and dry scalp. You can wash your hair with a mild shampoo and ensure that the scalp is free from excess oil, dirt, and debris.
  • Measure the Dose: Follow the dosing instructions provided by the manufacturer or supplier. Typically, a small amount of Pyrilutamide solution is applied to the scalp.
  • Apply to Affected Areas: Use a dropper or applicator to apply the Pyrilutamide solution directly to the areas of the scalp where you are experiencing hair loss or thinning. It’s important to target the areas where the hair follicles are sensitive to DHT.
  • Massage Gently: After applying the solution, use your fingertips to gently massage it into the scalp. This helps distribute the product evenly and stimulates blood flow to the follicles.
  • Allow to Dry: Allow the Pyrilutamide solution to dry naturally. Avoid using a hair dryer or heat source to speed up the drying process, as this may reduce effectiveness.
  • Frequency of Use: The frequency of application can vary depending on the product and individual preferences. Most users have reported applying Pyrilutamide once daily.
  • Be Consistent: Consistency in application is essential for potential effectiveness. It may take several months of regular use to see any noticeable results, and individual responses can vary.
  • Monitor for Side Effects: Keep an eye out for any adverse reactions, such as skin irritation, redness, or itching. If you experience any significant or persistent side effects, discontinue use and consult a healthcare professional.


Proper storage of Pyrilutamide is important to maintain its stability and effectiveness. While specific storage instructions may vary depending on the formulation and brand of Pyrilutamide, here are some general guidelines to follow:

  • Check the Product Label: Always refer to the product label or packaging for specific storage instructions provided by the manufacturer. Different formulations may have variations in storage requirements.
  • Store in a Cool, Dry Place: In general, Pyrilutamide should be stored in a cool, dry place at room temperature, typically between 20°C to 25°C (68°F to 77°F). Avoid exposure to excessive heat, humidity, and direct sunlight, as these conditions can potentially affect the stability of the product.
  • Keep the Container Closed: Ensure that the container or bottle is tightly closed when not in use. This helps prevent contamination and preserves the quality of the solution.
  • Protect from Light: Some topical medications, including Pyrilutamide, may be sensitive to light. If the product is in a clear or translucent container, consider storing it in a dark or opaque container or keeping it in a dark drawer or cupboard.
  • Avoid Freezing: Do not freeze Pyrilutamide. Extreme cold temperatures can alter the composition of the solution and may render it ineffective.
  • Keep Out of Reach of Children: Store Pyrilutamide in a location where it is inaccessible to children and pets. This is important for safety reasons.
  • Check Expiry Date: Always check the expiration date on the product packaging. Do not use Pyrilutamide if it has expired, as its efficacy and safety may no longer be guaranteed.
  • Do Not Transfer to Another Container: It’s generally advisable to keep Pyrilutamide in its original container, as these containers are typically designed to preserve the stability of the solution. Transferring the product to a different container may expose it to air or contaminants.

Safety and Side Effects

Based on early clinical trials and studies, here are some potential side effects associated with Pyrilutamide:

  • Skin Irritation: Like many topical medications, Pyrilutamide may cause skin irritation at the application site. Common symptoms can include redness, itching, burning, or dryness. These side effects are usually mild to moderate and tend to subside as the skin adapts to the treatment.
  • Eye Irritation: Care should be taken to avoid contact with the eyes when applying Pyrilutamide. If the medication comes into contact with the eyes, it can cause eye irritation, redness, or discomfort.
  • Dryness and Peeling: Some users may experience dryness and peeling of the skin on the scalp where Pyrilutamide is applied. This can typically be managed with the use of a moisturizer or by adjusting the frequency of application.
  • Hair Changes: Pyrilutamide’s impact on hair texture and color has been reported in some cases. Hair may become softer or lighter in color. The significance of these changes can vary among individuals.
  • Localized Side Effects: Since Pyrilutamide is applied topically, most side effects tend to be localized to the application site. This localized approach minimizes the risk of systemic side effects compared to orally administered anti-androgenic medications.
  • Systemic Absorption: While Pyrilutamide is primarily topically applied, there is the potential for a minimal amount of the medication to be absorbed systemically. The extent of systemic absorption is typically low, but individuals with known systemic health conditions or those taking other medications should consult with their healthcare provider before using Pyrilutamide.
  • Allergic Reactions: Although rare, some individuals may experience allergic reactions to Pyrilutamide. Signs of an allergic reaction can include severe itching, hives, swelling, or difficulty breathing. If you experience any of these symptoms, discontinue use immediately and seek medical attention.


In the dynamic and evolving landscape of hair loss treatments, Pyrilutamide stands poised as a potential paradigm-shifter. Its unique action, bolstered by encouraging clinical trial data, could well make it a cornerstone of future AGA treatments. Yet, as with all promising treatments, the balance of optimism with rigorous scientific validation remains crucial.


  • Product Pipeline. Kintor Pharmaceutical Limited. (n.d.). Kintor.
  • Kintor Pharma Announces Successful Completion of Phase II Clinical Trial of KX-826 for Treatment of Androgenetic Alopecia in the US (2023, 11 May) Kintor.
  • Kintor Pharma: Developing Novel Drugs and Commercialization Platform (2022) Kintor.

Note: This piece serves as an informative overview. Individual responses may vary, and consultation with a qualified medical professional is indispensable before initiating any therapeutic regimen.

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