About KYIR

Dedicated to transforming your hair care experience, KYIR is the leading revolution that offers clean, sustainable, non-toxic and highly concentrated products to harness the power of natural ingredients without sacrificing efficacy. Founded by veteran beauty expert William Kirst, KYIR provides a more natural option in the category of hair regrowth products where harsh chemicals and additives have typically filled an ingredient list.

When Kirst was unable to find a clean and natural solution for his own personal struggle with hair loss that stemmed from hormones, heredity and diet, he set out on a journey to find a formula that lived up to the clean standards he looked for in an ingredient list. His extensive career, spanning nearly two decades with brands such as RMS, One Love Organics, Vintner’s Daughter and Eve Lom, gave him access to leading founders and innovators in the industry. This in-depth and firsthand experience helped Kirst understand the intricacies of creating a brand that leads with innovation, efficacy and ingredient transparency. 

Three years of research and development led to KYIR’s inaugural product: FULLER Active Hair Serum, a powerful and highly efficacious hair growth serum. Ideal for all forms of hair loss, FULLER Active Hair Serum is a clean, highly concentrated, non-toxic hair growth formula that provides a more natural option in the category of hair regrowth products. FULLER is powered by star ingredient Redensyl, a breakthrough patented formula created in Switzerland to help minimize hair loss and wake up hair stem cells to generate growth. Unlike its predecessor Minoxidil, Redensyl has zero known side effects and is known to strengthen and thicken hair follicles. 

FULLER is rounded out with Follicusan to stimulate the hair and ginger, green tea, ashwagandha, biotin, caffeine, horsetail, aloe vera, peppermint oil and saw palmetto to naturally encourage hair regrowth and promote optimal scalp health. 

Dermatologist tested and safe for all skin types, FULLER Active Hair Serum begins to deliver results in as soon as 30 days, with fuller hair, less breakage and ample growth most noticeable at 12 weeks of consistent use.

William Kirst Bio

With nearly two decades of experience in beauty, KYIR founder William Kirst has worked with some of the most high-profile brands in the industry. He has worked hand-in-hand with brand founders leading their sales, product development and education efforts, giving him an inside look at the essential pillars of running a successful beauty brand. 

Kirst worked one-on-one with Trish McEvoy, one of the only makeup-led beauty brands still run by its founder to this day, getting in-depth knowledge about the business side of the industry. After a decade with Trish, he delved into the world of clean beauty, working with leading brands such as RMS, Vintner's Daughter, One Love Organics, Ogee, and Eve Lom. 

It was with RMS founder Rose-Marie Swift that Kirst was able to learn firsthand about the clean beauty industry and gained an understanding of innovation, efficacy and ingredient transparency. He also successfully launched the brand’s first virtual education program during the pandemic. 

While running KYIR, Kirst is still a highly sought after consultant and currently works with Bright Beauty Collective, known as the premier green beauty agency for offering world class services for conscious beauty brands. 

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