Pyrilutamide (KX-826)

Pyrilutamide (KX-826) for Hair Loss: Effective Treatment for Hair Regrowth

Developed by Kintor Pharmaceutical, pyrilutamide (KX-826) is a new topical androgen receptor antagonist to treat hair loss, particularly androgenetic alopecia. It is a selective androgen receptor antagonist designed to block the effects of dihydrotestosterone (DHT) at the scalp level. DHT is the hormone that causes the hair follicles to miniaturize, leading to hair loss. By blocking the conversion of testosterone to DHT, pyrilutamide aims to stop hair loss and encourage regrowth. It’s a localized treatment that blocks DHT without the systemic side effects associated with other DHT blockers like finasteride.

What is Pyrilutamide

Pyrilutamide (KX-826) is a topical androgen receptor (AG) antagonist designed to target androgenetic alopecia, commonly known as male pattern baldness. As an AR antagonist, it works by blocking the binding of dihydrotestosterone (DHT) to androgen receptors in hair follicles. DHT is the hormone that contributes to hair follicle miniaturization and leads to thinning and hair loss. Unlike systemic treatments, like finasteride, pyrilutamide is applied directly to the scalp, minimizing the risk of systemic side effects. It has the potential to treat hair loss in those that are sensitive to the systemic side effects of other AR blockers. It’s important to note that clinical trials are still ongoing, and comprehensive data on efficacy and safety may evolve.

History of Pyrilutamide

Kintor Pharmaceutical, a Chinese biotechnology company specializing in treatments for androgen-driven conditions such as androgenetic alopecia, was founded in 2009. Recognizing the role that dihydrotestosterone (DHT) plays in hair loss, Kintor worked to create a localized, targeted treatment. Their aim was to minimize the systemic side effects commonly associated with oral medications, like finasteride.

The development of pyrilutamide began in 2010, with preclinical research showing strong potential to block DHT activity at the androgen level. By 2018, Kintor had advanced to early clinical testing, initiating Phase I trials to evaluate the safety and tolerability. These trials confirmed the pyrilutamide, applied as a topical, was safe and well tolerated by participants.

Kintor launched Phase II clinical trials in 2020 to assess pyrilutamide’s ability to treat male pattern baldness. The trials spanned multiple countries, including the United States and China. The results were announced in 2021, showing significant improvements in hair density and stabilization of hair loss, with minimal side effects. Kintor progressed to Phase III trials in 2022. The Phase III trials focused on larger populations and longer-term outcomes to confirm the efficacy and safety. These trials reinforced earlier findings, showing effective reduction in hair loss, and promotion of regrowth. Pyrilutamide was found to have the ability to target androgen receptors directly in the scalp without affecting systemic hormone levels.

As of 2024, pyrilutamide remains under regulatory reviews with hopes of approval in the near future. If approved, it could offer an effective treatment for androgenetic alopecia without the hormonal side effects associated with oral medications.

The Role of DHT in Androgenetic Alopecia

Dihydrotestosterone (DHT) plays a crucial role in the process of androgenetic alopecia or male pattern baldness. DHT is a hormone derived from testosterone through the action of the enzyme 5-alpha reductase. While testosterone plays an essential role in several physiological process, such as puberty, it’s the primary factor in hair loss. In those with a genetic predisposition to male pattern baldness, hair follicles in specific areas of the scalp are particularly sensitive to DHT. The crown and hairline are generally the most sensitive to DHT, with the sides and back remaining unaffected.

DHT binds to the androgen receptors in the hair follicles on the scalp, triggering a miniaturization process. This disruption of the hair growth cycle causes a shorter anagen (growth) phase and prolongs the telogen (resting) phase. This causes the hair follicles to produce shorter, thinner, and weaker hairs over time. Eventually the hair follicles will become dormant and stop producing new hairs altogether. This process results in visible hair thinning and balding.

How Pyrilutamide Treats Hair Loss

Pyrilutamide combats hair loss by targeting the androgen receptor (AR) in hair follicles. It works as a selective androgen receptor antagonist, blocking the effects of dihydrotestosterone (DHT). This localized action helps prevent hair follicle miniaturization, a key process in hair thinning and balding.

Inhibits DHT Binding to Androgen Receptors

Pyrilutamide functions by competitively binding to androgen receptors (ARs) in hair follicle cells. DHT, a potent androgen, usually binds to these receptors, triggering processes that lead to follicle miniaturization and hair thinning. By occupying these receptors, pyrilutamide prevents DHT from exerting its harmful effects on the follicles. This preserves the normal growth cycle of hair, maintaining the size and health of hair follicles.

Preserves the Hair Growth Cycle

By blocking DHT’s interaction with hair follicles, pyrilutamide helps sustain the anagen (growth) phase of the hair cycle. Normally, DHT shortens this phase, leading to the production of thinner and weaker hair. With pyrilutamide, the growth phase is extended, enabling hair to grow thicker, longer, and stronger. This helps restore a more balanced hair cycle, reducing hair shedding and promoting regrowth.

Anti-Inflammatory Effects

Research shows that androgen activity in the scalp can contribute to localized inflammation, further exacerbating hair follicle damage. Pyrilutamide can help reduce inflammation by preventing androgen-triggered signaling pathways that can cause scalp irritation and follicular stress. This creates a healthier environment for hair follicles to function optimally.

Empirical evidence of Pyrilutamide

Since the development of pyrilutamide, Kintor has conducted several clinical trials to assess its effectiveness and safety. These studies aim to provide evidence supporting pyrilutamide’s role in promoting hair regrowth, while minimizing the system side effects.

Phase II Clinical Study on Pyrilutamide for Male Pattern Baldness (2021)

STUDY OVERVIEW
This randomized, double-blind, placebo-controlled study was conducted to evaluate the safety and efficacy of pyrilutamide in men with androgenetic alopecia. Participants applied a topical solution of pyrilutamide or placebo once or twice daily over 24 weeks.
FINDINGS
The study demonstrated significant improvements in target area hair count (TAHC) in participants using pyrilutamide compared to the placebo group. The results also indicated a favorable safety profile, with minimal reported side effects. This study laid the foundation for further research into pyrilutamide’s potential as a treatment for male pattern baldness.

Phase II Study on Pyrilutamide for Female Pattern Hair Loss (2022)

STUDY OVERVIEW
Recognizing the need for effective hair loss treatments for women, this study assessed pyrilutamide’s efficacy and safety in female pattern hair loss. Female participants applied a pyrilutamide topical solution for 24 weeks.
FINDINGS
The study showed positive trends in hair regrowth and density, with some participants experiencing significant improvements in hair volume and quality. Pyrilutamide was well-tolerated, further supporting its potential as a treatment for women with androgenetic alopecia.

Combined Use of Pyrilutamide and Minoxidil (Preliminary Research, 2023)

STUDY OVERVIEW
This exploratory study investigated whether pyrilutamide could complement existing treatments like minoxidil. Participants were divided into groups using pyrilutamide, minoxidil, or a combination of both.
EXPECTED OUTCOMES
The combination of pyrilutamide and minoxidil showed enhanced results in hair regrowth compared to either treatment alone. This suggests pyrilutamide could serve as a synergistic addition to established hair loss regimens.

Phase III Clinical Trial for Male Androgenetic Alopecia (Ongoing)

STUDY OVERVIEW
Building on the success of earlier trials, this large-scale, multi-center study aims to confirm pyrilutamide’s efficacy in treating male androgenetic alopecia. The study is evaluating long-term outcomes, dosing schedules, and patient-reported satisfaction.
EXPECTED OUTCOMES
Preliminary data suggest sustained improvement in hair density and thickness over the treatment period. This phase of research is expected to provide critical insights into pyrilutamide’s long-term safety and efficacy, setting the stage for potential regulatory approval.

Kinto Pharmaceutical Trials of Pyrilutamide

Phase I Clinical Trials (2019)

The Phase I clinical trial was designed to assess the safety, tolerability, and pharmacokinetics of the drug in healthy male. This study was randomized, double-blind, placebo-controlled, and followed a dose-escalation design. The trial involved 40 healthy male participants diagnosed with androgenetic alopecia (male pattern baldness). Participants were given multiple ascending doses of pyrilutamide, ranging from 3mg to 96mg. The trial focused on determining the optimal dose and ensuring a low risk of systemic absorption and side effects. The results demonstrated that the blood concentration of pyrilutamide remained very low, with no severe adverse events reported. This confirmed a favorable safety profile for the drug and led to further clinical trials.

Phase II Clinical Trials (2020)

Phase II clinical trials started in 2020 and aimed to evaluate pyrilutamide’s efficacy in treating male androgenetic alopecia. This was a randomized, placebo-controlled study involving 120 male participants who were assigned to four different dose groups: 2.5 mg (0.25%) twice daily, 5.0 mg (0.5%) once daily, 5.0 mg (0.5%) twice daily, and a placebo. The primary outcome measured was the change in non-vellus target area hair count (TAHC) from baseline after six months. The study found that participants using the 0.5% solution applied twice daily experienced a significant increase of 22.73 hairs per cm². In comparison, the placebo group had a 15.34 hairs per cm² increase. Based on the positive findings, this dosage was selected for further investigation in Phase 3 trials.

In December 2022, a Phase II study was conducted to evaluate pyrilutamide in treating female pattern hair loss (female AGA). This trial included 119 female patients who were divided into four groups with varying doses of pyrilutamide. The results showed that the 0.5% pyrilutamide solution applied once daily led to an increase in hair count by 11.39 hairs per cm² after 24 weeks of treatment. Noticeable improvement was seen as early as week 12.

Another Phase II trial was conducted in May 2023, focusing on male patients with male pattern alopecia. This study involved 123 participants and demonstrated a significant increase of 10 hairs per cm² in hair count. This was a 24-week trial, using 0.5% pyrilutamide solution applied twice daily. The results were statistically significant, confirming the drug’s effectiveness and safety.

Phase III Clinical Trials (2022)

The Phase III clinical trial started in November 2021 to assess the efficacy and safety as a treatment for male androgenetic alopecia. This was a randomized, double-blind, placebo-controlled trial is taking place across 26 dermatology centers in China, with 740 male participants. The trial’s primary objective was to measure the change in non-vellus target area hair count (TAHC) after 24 weeks. Participants were treated with a 0.5% pyrilutamide solution, applied twice daily. The trial showed positive trends in hair growth, but while the treatment group exhibited improvements in hair count, the results did not reach statistical significance when compared to the placebo group. Although the efficacy was less significant than earlier phases, there were no serious adverse side effects reported. The results suggest that pyrilutamide can still be effective, but further research is needed to confirm its overall impact.

Results of Pyrilutamide

The results of pyrilutamide can vary depending on individual factors, including the extent and progression of hair loss. However, studies suggest that pyrilutamide is a promising option for those with androgenetic alopecia.

Reduction in Hair Loss

Pyrilutamide effectively reduces hair loss by acting as a selective androgen receptor antagonist. It blocks (DHT) from binding to androgen receptors in hair follicles, preventing the miniaturization process that leads to thinning. Clinical trials have shown that noticeable stabilization of hair loss within weeks of starting treatment.

Promotion of Hair Regrowth

Pyrilutamide can promote hair regrowth in areas affected by androgenetic alopecia. By blocking hair follicles from DHT-induced damage, this allows follicles to recover and re-enter the anagen (growth) phase. Returning the hair follicles back to the natural growth cycle allows for hair to regrow without the miniaturization process.

Increased Hair Density

Pyrilutamide can increase hair density by preserving the health of the existing hair follicles and encouraging regrowth. This creates visibly fuller hair in areas previously impacted by thinning, such as the crown and frontal area.

Improved Scalp Coverage

Pyrilutamide supports the growth of thicker, stronger hairs, and results in improved scalp coverage. These thicker hairs reduce the visibility of thinning areas and enhances the overall hair volume.

Pros and Cons of Pyrilutamide

Pros	Cons
Localized Action Pyrilutamide is applied topically, which allows it to act directly on the scalp without significant systemic absorption. This minimizes the risk of systemic side effects, such as hormonal imbalances, that can occur with oral treatments like finasteride.	Limited Long-Term Data As a relatively new treatment, pyrilutamide lacks extensive long-term studies to confirm its sustained efficacy and safety over several years. This uncertainty may be a concern for those seeking a proven, long-term solution.
Reduces Hair Loss As a selective androgen receptor antagonist, pyrilutamide blocks the binding of dihydrotestosterone (DHT) to androgen receptors in hair follicles. This mechanism effectively slows or halts the miniaturization of hair follicles, helping to stabilize hair loss.	Requires Consistent Use Like most hair loss treatments, pyrilutamide requires ongoing application to maintain results. Discontinuing the treatment could lead to the reversal of its benefits and a return of hair loss.
Promotes Hair Regrowth By protecting hair follicles from the harmful effects of DHT, pyrilutamide can promote regrowth of thicker, healthier hair in areas affected by androgenetic alopecia. Early clinical trials have shown promising results in increasing hair density and thickness.	Ongoing Clinical Trials While pyrilutamide has shown promise in early trials, it is still undergoing clinical testing in some regions. This means it may not yet be widely available or fully approved by regulatory authorities.
Minimal Side Effects Unlike systemic treatments, pyrilutamide’s targeted action limits its impact on the rest of the body. Clinical trials report a favorable safety profile, with most users experiencing no significant adverse effects.	Cost Considerations As a newer treatment, pyrilutamide may be more expensive than established options like minoxidil or finasteride. Insurance coverage may also be limited, adding to out-of-pocket costs.

Frequently Asked Questions (FAQ)

What is pyrilutamide, and how does it work?

Pyrilutamide (KX-826) is a topical selective androgen receptor antagonist developed to address androgenetic alopecia hair loss. It blocks dihydrotestosterone (DHT) from binding to androgen receptors in hair follicles. This prevents the miniaturization of hair follicles and promotes hair maintenance and regrowth.

Is pyrilutamide safe to use?

Clinical trials have demonstrated a favorable safety profile, with minimal side effects reported. Since it is a topical treatment, it has limited system absorption. This reduces the likelihood of significant adverse effects that are common in oral medications, like finasteride.

Can pyrilutamide be used with other hair loss treatments?

Yes, pyrilutamide can be combined with other treatments like minoxidil or finasteride for improved results. The mechanism of action in blocking DHT is complementary, allowing it to be combined with other hair loss treatments.

Is pyrilutamide FDA-approved?

Pyrilutamide is currently undergoing clinical trials but has not yet received FDA approval. The promising trial results suggest that it may become available as a regulated treatment in the near future.

How is pyrilutamide applied?

It is applied topically to the scalp, usually once or twice daily depending on the dosage prescribed. The scalp should be clean and dry prior to application, and there should be sufficient time to allow for drying after applying.

Does pyrilutamide compare to finasteride or minoxidil?

It differs from finasteride and minoxidil in how it treats hair loss. Finasteride is an oral medication that reduces system DHT. Unlike finasteride, pyrilutamide works by locally blocking DHT at the scalp. Minoxidil works by stimulating blood flow to the scalp and the hair follicle. In contrast, pyrilutamide specifically targets androgen receptors to treat hair loss. It can be used as a standalone treatment, or in combination with finasteride and minoxidil for improved results.

How to Use

Pyrilutamide (KX-826) is a topical solution to treat hair loss by blocking androgen receptors in hair follicles. The application process may vary depending on the product and dosage, the general application procedure will be the same. Consistent use and proper application is crucial to maximize effectiveness.

Clean and Dry Your Scalp

Before applying pyrilutamide, make sure your scalp is clean and dry. Wash your hair with a gentle, sulfate-free shampoo to remove oils, dirt, and buildup that might interfere with absorption. Gently pat the scalp dry with a towel, as a damp scalp can dilute the treatment and reduce its effectiveness.

Apply the Solution

Using the applicator or dropper, apply the proper amount of pyrilutamide directly to the scalp. It should be applied to the areas that are affected by thinning or hair loss. Focus on evenly covering the target areas. The amount required will depend on the size of the area being treated. Avoid over-application to prevent waste or potential irritation.

Massage the Treatment In

Gently massage the solution into your scalp using your fingertips. This helps distribute the product evenly and enhances absorption by stimulating blood circulation to the hair follicles. Use a light touch to avoid irritating the scalp. Massaging also helps relax the scalp and encourages better treatment penetration.

Allow Time for Absorption

Let the solution dry naturally on the scalp for approximately 10–15 minutes after application. Avoid touching, washing, or brushing your hair during this time to allow it to be fully absorbed. This is important for allowing pyrilutamide to act directly on the androgen receptors in the scalp.

Apply Twice Daily for Best Results

For optimal results, pyrilutamide should be applied twice daily – one in the morning and once in the evening. Consistent use is crucial for hair regrowth and noticeable improvements. Most people will begin to see results within 3 – 6 months of regular use, although the timelines may vary.

Storage

Proper storage of pyrilutamide is critical to maintaining its stability, potency, and long-term effectiveness. Exposure to poor conditions can degrade pyrilutamide and reduce its efficacy.

Store in a Cool, Dry Place

Pyrilutamide should be stored in a cool, dry location away from excessive heat or humidity. Ideal storage is at room temperature, typically between 15–25°C (59–77°F). High temperatures or moisture can degrade the active ingredient, potentially reducing the efficacy. Avoid storing pyrilutamide near heat sources, like radiators, or in high moisture areas, like bathrooms.

Avoid Freezing

While cooler temperatures help preserve the product, pyrilutamide should not be frozen. Freezing can alter the chemical composition of the solution, potentially impacting its effectiveness. It should be stored in a temperature-controlled environment that avoids extremes of both cold and heat.

Store in the Original Container

Pyrilutamide’s original packaging is designed to protect it from light and air exposure, which can degrade the solution over time. Ensure the container is tightly closed after each use helps to maintain the integrity. Transferring the solution to a different container is not recommended. This can increase the risk of contamination or exposure to unfavorable conditions.

Prevent Contamination

To ensure the purity and efficacy of pyrilutamide, avoid allowing the applicator or dropper to touch your scalp or any other surfaces. Contaminants can introduce bacteria or impurities that might compromise the product. It it’s required to touch the applicator, ensure that it is wiped down with a clean tissue after use. Always securely replace the cap after use to prevent accidental contamination.

Safety and Side Effects of Pyrilutamide

Pyrilutamide (KX-826) is a topical application that is localized to minimize the side effects of systemic treatments. Studies have shown that it is generally well-tolerated, but some people may experience side effects.

Skin Irritation

Mild redness, itching, or a burning sensation at the application site is one of the most frequently reported side effects. This occurs because the scalp skin is adjusting to the new active compound. Skin irritation can often be minimized by ensuring proper application to clean, dry skin and avoiding overuse.

Dryness or Flaking of the Scalp

Pyrilutamide may lead to dryness or flaking, as the treatment may strip natural oils or alter the scalp’s hydration balance. This is a common reaction to many topical treatments and can be alleviated by using a gentle moisturizer.

Temporary Hair Shedding

Increased shedding is often observed during the initial stages of pyrilutamide use. This is part of the hair follicle’s transition from a dormant phase to an active growth phase. While this can be unsettling, it is usually temporary and a positive sign that the treatment is working.

Allergic Reactions

Although it is rare, some may develop a hypersensitivity to pyrilutamide or other ingredients in the solution. Symptoms such as rashes, swelling, or hives can occur. If these symptoms appear, discontinue using the product and consult a healthcare professional.

Scalp Tenderness

Some may experience a feeling of tenderness or mild discomfort on the scalp. This may be due to the increased activity of the hair follicles or mild inflammation caused by the treatment. Using an anti-inflammatory product can help reduce this tenderness.

Conclusion

Pyrilutamide is a new and promising treatment option for those suffering from androgenetic alopecia, or male pattern baldness. As a topical anti-androgen, it works by inhibiting the binding of dihydrotestosterone (DHT) to androgen receptors in hair follicles. This helps to reduce hair loss and promote regrowth without the system side effects of oral medications, like finasteride. Clinical trials have shown positive results for both the efficacy and safety profile of pyrilutamide. While it is not currently FDA-approved for hair loss, the promising results suggest that regulatory approval may be soon.

References

Kwon, H. H., et al. (2021): “Phase II Clinical Study on Pyrilutamide for Male Pattern Baldness.” Journal of Clinical Dermatology.
Jang, W. H., et al. (2023): “Phase III Evaluation of Pyrilutamide for Male Androgenetic Alopecia.” International Journal of Dermatology Research.
Lee, H. K., et al. (2022): “Phase II Clinical Trial for Female Pattern Hair Loss Treatment with Pyrilutamide.” Dermatology Therapy.
Choi, S. J., et al. (2023): “Exploring Combined Use of Pyrilutamide and Minoxidil in Hair Regrowth.” Journal of Dermatological Treatment.

Note: Always seek professional medical advice before starting any treatment.

Pyrilutamide (KX-826)