Providers

William Billica, MD, is a functional and integrative medicine specialist making a difference for patients’ wellness in Fort Collins, Colorado, at Tri-Life Health, PC. He takes a unique approach in treating patients living with autoimmune diseases, chronic pain, hormone imbalance, vitamin deficiencies, mood disorders, addictions, and more.

Dr. Billica attended undergraduate and medical school at the University of North Carolina Chapel Hill School of Medicine as a Morehead Scholar. He then completed his family medicine residency at the Banner Good Samaritan Medical Center in Phoenix, Arizona.

After finishing his education and training, Dr. Billica was a faculty fellow at Duke University in Durham, North Carolina, and later served as faculty at the Good Samaritan Family Practice Residency program in Phoenix and held a faculty appointment to the University of Arizona in Tucson. He was also a department chairman of family medicine at Banner Good Samaritan Medical Center from 2000 until 2004.

Throughout his career, Dr. Billica has won several awards for his excellence in teaching. He was also named a “Top Doc” in Phoenix, Arizona, many years in a row. He continues to use his keen skill at Tri-Life Health, PC, to educate patients about their treatments and the conditions that affect them.

At Tri-Life Health, PC, Dr. Billica routinely uses his skills in functional medicine to deliver cutting-edge treatments like detoxification, IV therapy, neurotransmitter restoration, ozone and stem cell therapies, and hormone replacement therapy to his patients.

Kaylyn Wilson is an ANCC certified Family Nurse Practitioner who graduated from Regis University’s Loretto Heights School of Nursing. She worked as a primary care provider while studying functional medicine and attending integrative and functional medicine conferences. She joined Tri-Life Health in December 2022 to provide care for individuals across the lifespan with a functional medicine approach. She has a passion for preventive medicine and for working alongside patients to optimize their health.

She focuses on finding the root cause of illness and in improving the health of each person as an individual. She cares for patients with chronic fatigue, hormone imbalance, mold/biotoxin illness, gastrointestinal illness, autoimmunity, headaches/migraines, cognitive decline, chronic illness, Lyme disease, other infections, and more.

She specializes in ozone injections, preventive medicine, resolving nutritional deficiencies, improving gut health, and hormone replacement. In her spare time, she enjoys many outdoor activities with her husband including kayaking, mountain biking, and camping.

Julie Harstine is an ANCC-certified Family Nurse Practitioner and Functional Medicine Academy Certified Practitioner (FMACP) who graduated from Indiana Wesleyan University. With more than 30 years of clinical experience—including 13 years in hospital and critical care medicine and 17 years in outpatient internal medicine—Julie brings extensive expertise in caring for patients with complex acute and chronic conditions.

Passionate about helping people navigate complex health challenges, Julie embraces functional medicine as her primary therapeutic approach while integrating the best of conventional and functional medicine. By looking beyond symptoms to uncover the root causes of illness, she seeks to understand how the body’s interconnected systems including metabolism, hormones, digestion, immune function, brain health, inflammation, and environmental exposures—work together to influence health. Her goal is to create personalized plans that restore function, optimize wellness, and support lasting healing.

Julie believes the body was designed to heal when given the proper support. Her mission is to help patients move beyond symptom management to restore vitality, renew hope, and fully engage in the people and experiences that matter most.

“I hear you. I believe you. And I want to help you not just feel better—but truly thrive.“— Julie Harstine, MSN, APRN, FNP-C, FMACP

Aimee Smith is a Master Nutrition Therapist from Nutrition Therapy Institute and is Board Certified in Holistic Nutrition at Tri-Life Health in Ft. Collins, Colorado. Aimee is also a Level-1 certified practitioner in GI Functional Nutrition through Restorative Wellness Solutions. She has acquired extra training for perimenopause and ways to support women during a vital change in life.

She spent a 29-year career as an RN in the hospital setting watching people get sicker while dealing with her own health issues which makes her a compassionate partner in discussing and providing individualized wellness options for optimal health after a detailed health assessment. Aimee wants to help have a more positive impact on the health of others through education, diet, & lifestyle. She combines her nursing knowledge with nutrition and lifestyle changes to help people live their best lives.

She believes the best way to true, vibrant health is what we put in our bodies, removing barriers to healing, giving the body what it needs to ultimately heal and thrive while focusing on the body, mind, and soul of each individual so people can thrive and live with vitality.