Your Cloud Medical Team


At Cloud Medical, we offer advanced Direct Primary Care with a Functional Medicine approach provided by Board-Certified family physicians and practitioners.  We are healthcare providers devoted to helping you live your best life!

We are focused on establishing closely connected, trusted, lasting relationships with our patients.  And we provide the most sophisticated diagnostics and health care programs available, for surprisingly affordable rates. Whether you are an elite athlete, a weekend warrior, or a busy parent trying to keep up with your kids, we would love to support and facilitate your optimal health.  We are genuinely interested in getting to know you as a person and developing a trusted relationship with you over time.  

We love what we do.  We love where we live. And we live by what we preach. We are here for you if you get sick and need to get back to your baseline as quickly as possible, but our true purpose is in helping you go from your current baseline to the best and healthiest version of yourself — that’s the kind of healthcare that we believe you deserve. We’d be honored to serve you as your key healthcare advocates and champions for your wellness over your entire lifetime.

“My goal for each of my personal patients is to be an ever-available champion for your best interests and an advocate for your health—to help you unlock your greatest potential toward optimal vitality and quality of life.” – David Z. Tusek, MD



David Z. Tusek, MD Founder / CEO

Dr. Tusek is a board-certified family physician who also has experience as an emergency room doctor.  He is a member of the Academy of Sports Medicine, the American Academy of Anti-Aging Medicine, and the Institute of Functional Medicine.

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Dr. Tusek relishes the close connectivity with his Cloud-DPC patients, whether they are training for the Olympics, dealing with an illness, or simply trying to lose a few pounds.  He believes that enhancing your quality of life is just as important as extending the quantity of your years.    

Dr. Tusek combines expertise in advanced diagnostics and optimization of brain and body function using a broad-based approach, blending cutting edge technologies with a natural orientation.  He uses a wide variety of gentle, needle-based therapies to treat musculoskeletal and neuromuscular conditions and injuries (including PRP and botox).  He performs various office-based surgeries, cryosurgeries, and treatments of minor trauma.  In 2004, he became one of the first practitioners in Colorado to offer bio-identical hormone implants, and has been working closely with compounding pharmacies (those pharmacies that prepare personalized medications for patients), to provide the purest, most effective forms of natural therapies.

In 2009, Dr. Tusek co-founded one of the nation’s first DPC programs, which he sold in 2016.  He then went on to launch Cloud Medical DPC, and currently oversees several other healthcare ventures including Cloud Collective.

As a previous member of the steering committee of the Direct Primary Care Coalition based in Washington, DC, Dr. Tusek is a recognized leader in healthcare transformation, and was invited to the White House to discuss the future of American medicine.  He was named among the “Top Doctors in Concierge Medicine” and is a former qualifier for the Ironman Triathlon World Championships in Kona, Hawaii.  He enjoys skiing, cycling, and spending time with his wife and two daughters in the playground that is Colorado.



Charles Tawa, MD

Dr. Tawa received his medical degree from the Université Scientifique et Médicale in Grenoble, France, and completed his family practice residency at the University of Massachusetts.

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His experience includes serving as Chief of the Family Practice and Trauma departments at Kaiser Permanente, and as a staff physician with Boulder Family Practice.  Board certified in Family Medicine, Dr. Tawa founded Boulder Family Practice in 2005, which merged with Cloud Medical Center in 2016.

Dr. Tawa is beloved by his patients who have entrusted him with comprehensive family care, including pediatric, adolescent and adult primary care, women’s wellness care, in-office procedures and related prevention services.  A member of the Colorado Medical Society, Dr. Tawa is also certified in Acupuncture.  He enjoys spending time with his family and traveling when he’s not fulfilling his original calling: providing exemplary care for, and establishing lasting relationships with his patients.




Sheila Kupersmith, FNP-BC

Sheila works as a partner with her patients to help them meet their health and wellness goals.  She strives to use the safest, least invasive methods first, with a focus on wellness and disease prevention.  

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Sheila is a Board Certified Family Nurse Practitioner trained in a variety of integrative modalities that support health and healing.  She has over 20 years of experience working with all ages in primary care and integrative medicine.

In addition to conventional family practice medicine, Sheila’s training includes studies in botanical medicine, nutrition, stress reduction, Ayurveda, homeopathy, wellness coaching, and energy medicine.  She is currently in the process of obtaining certification in functional medicine through the Institute for Functional Medicine.  She has studied Herbalism with Susun Weed, Matthew Wood, and David Hoffman, as well as with Tieraona Low Dog in her Fellowship Program, and in her Foundations in Herbal Medicine course.

Sheila graduated from the University of Arizona’s Integrative Medicine Fellowship Program in 2012, and received training as a Wellness Coach through Mayo Medical School.  Some of her additional integrative studies have included education through the SCRIPPS Center for Integrative Medicine, the Center for Spirituality and Healing at the University of Minnesota, Jeremy Sherr’s Dynamis School for Homeopathy, Food As Medicine at the Center for Mind Body Medicine, Reiki level I and II, and Balancing Point Energy training.

Sheila’s Master’s Degree in Nursing training was completed at the University of Massachusetts in Amherst, and undergraduate studies were done at the University of Minnesota.  She enjoys spending time with her husband, two sons and friends, being outdoors, and cooking healthy meals with family and friends.



Ariel Radack Krassner – Operations

As an ever-evolving human, Ariel’s number one value in life is the expansion of consciousness and therefore, human potential.

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Ariel’s academic, professional and life path has taken her back and forth between science and practice, with a center of gravity that revolves around the question, “What does it mean to live a meaningful life?”  And while the interpretation of the word “meaning” springs eternal, she values health of the body, mind and soul as foundational and nowadays (or currently), more possible than ever. 

Ariel has an indominable curiosity for what works to create exceptional quality of life, and in this way, she is somewhat of a functionalist.  As Chief People Officer at Cloud Medical Center, she helps optimize the human realm for our members, staff and the greater communities that Cloud connects with.  Reach out to her with any non-clinical questions, comments, concerns, or just to connect!




Aleisha Walker – Office Manager

Aleisha has an extensive background in healthcare administration and management and brings over ten years of direct experience in this field.

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At Cloud Medical Center, she manages the billing department and supports our offices to function smoothly and efficiently.  When you call in to schedule an appointment, you will most likely be greeted by this wonderful woman. 

Given her professional background, Aleisha knows the importance of a well-designed healthcare system and supports our team to always strive for the best.  When she is not in the office, you will find her happily riding a horse, or teaching the Hunter/Jumper style of riding and competing.  Animals, and specifically horses, have been a lifelong passion for Aleisha, and is something she will always make time for.  But when this busy woman is ready for rest, she gives herself play time, which often means playing with her new puppy!





Melinda Kilpatrick  – MA / Reception / Admin

Melinda is Cloud Medical Center’s “master of all things clinical,” also known as the Senior Medical Assistant to providers David, Sheila and Susie.

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She is one of those inspirational women that strive for 110% in everything she does and greets the challenges of a fast-paced work environment with grace and agility. 

In 2001, Melinda was certified as a Medical Assistant and Phlebotomist.  She brings with her the wisdom and experience of almost two decades of clinical service.  While she has many professional skills, when seeing Melinda in action, you might first notice her superior ability to carefully oversee the vital feedback channels that support our team’s ability to care deeply for our patients. 

Melinda works to embody the values of optimal health in her own life, and places family at the top of her list of importance.  During her time off, you will certainly find her spending quality time with the people she loves, either outdoors or on some kind of fun adventure.



Denise Holtz  – MA / Reception / Admin

Denise is both Medical Assistant and Administrator at Cloud Medical Center, which means she is a woman of many talents.

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Among these talents is the ability to administer nearly painless injections and calm a child or anxious adult while doing so.  Her drive to work in the field of healthcare stems from a deep motivation to help people in whatever way they are needing it.  In her work at Cloud, she is a master “anticipator” and prides herself in being the woman behind the scenes, helping the whole system run smoothly. 

Denise is a mother of four grown children and a proud grandmother to five grandchildren.  Her family is her number-one priority and passion.  She believes that health and well-being is the ticket to leading a full, enriched life.  This enables her innate ability to address health issues whenever and however they are needed.

When Denise is recharging her batteries, you might find her out in her flower garden or taking a walk along a mountain stream.




Zen Nickel – Reception

Zen is a highly motivated individual who is plugged into the current issues and requirements for optimal healthcare in this country.

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She is interested in the quality of life and healthy habits, which led to her obtaining a degree in Physiology at the University of Colorado in 2015.  Zen’s long-term goals of specializing in health and wellness may expand her educational path, as she is driven by a desire to become a healer and a champion for the complete well-being of others. 

In her position as receptionist at Cloud Medical Center, Zen works to help patients feel welcomed, heard, and secure in their journey to optimal health.  When scheduling or coming in for an appointment at the Peloton office, you will be greeted by her warmth and compassion. 

Zen values “vulnerability” as a trait to be admired.  She knows that it leads to growth and enjoys supporting others to step into their full potential.  She is passionate about living and all that life offers, whether she is hanging out with her family, dancing, singing, or enjoying time in nature.




Lori Anderson – Lab

Lori is one of Cloud Medical Center’s highly skilled phlebotomists.  She offers the convenience of this service both in our offices as well as through a mobile lab.

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Her career in healthcare began with surgical technology, where she quickly became aware that she was much better suited to working in the person-centered aspects of healthcare.  She cherishes her direct interaction with her patients, and they appreciate her gentle and efficient bedside manner.

Lori holds an Associate of Applied Science (AAS) degree and a Certification in Phlebotomy.  She has also received a Meritorious Service Medal Citation in recognition of saving the life of a 9-year-old drowning victim.

Lori continually seeks to embody integrity, compassion, and excellence in everything she does, and enjoys keeping her finger on the pulse of the latest healthcare research.

She is passionate about her faith and the precious time spent with her family.




Our 3 Locations


Lofts at the Peloton
3601 Arapahoe Ave Unit D176
Boulder, CO 80303
(38th & Arapahoe)


Highland City Club
885 Arapahoe Ave
Boulder, CO  80302
(9th & Arapahoe)



Prospect New Town
2017 100 Year Party Ct
Longmont, CO 80504


Or Call Us: (303) 848-3800
Longmont Fax: (303) 848-4910

Boulder Fax: (720) 745-4820


(303) 848-3800