Meet The Performance
Medicine Team
We’re not your typical healthcare team. At Performance Medicine, we combine modern medicine, fitness, and nutrition to help you feel your best from the inside out. Together, we’re redefining what it means to live healthy, strong, and fully alive at every age.
Our team is united by one mission: helping people perform at their best through personalized, preventative healthcare. Whether it’s hormones, recovery, nutrition, or longevity, we create strategies that build lasting strength and better health for life.
Medical Director + Co-Founder
Dr. Ryan Joseph, DO, MS, FACEP
Dr. Ryan Joseph spent over a decade in emergency medicine before founding Performance Medicine to take a more proactive approach to health. After years of treating preventable conditions, he saw the need for care that builds strong foundations instead of just fixing problems.
His focus now is helping patients optimize hormones, performance, and longevity through personalized, evidence-based care that blends medicine, movement, and lifestyle.
Outside the clinic, Dr. Ryan enjoys training for Hyrox and CrossFit competitions, spending time with his wife and two boys, and staying active in the San Antonio community.
Clinical Director + Co-Founder
Rob Guzman
Rob Guzman brings a unique background in engineering, fitness, and business to Performance Medicine. After running his own successful gym for a decade, he saw the power of combining science, strategy, and consistency to transform health.
Rob’s passion is helping people take ownership of their well-being through smart nutrition, movement, and mindset that support long-term performance and vitality.
When he’s not working with the team or patients, Rob enjoys training, mentoring others in business, fitness, and faith, serving at his local church, and spending quality time with his wife and two kids.
Nurse Practitioner
Karina Owens, MSN, APRN, FNP-C
Karina Owens is a board-certified Nurse Practitioner with a background in ICU, ER, urgent care, and family medicine. She’s passionate about helping patients—especially women—balance hormones, improve energy, and feel their best in every season of life.
With a practical and compassionate approach, Karina focuses on whole-person care that empowers people to take control of their health and live with confidence and vitality.
Outside of work, Karina loves staying active, spending time outdoors with her husband and three children, and finding balance between family, faith, wellness and everyday life.
Nurse Practitioner
Garrett Dyer, MSN, APRN, FNP-C
Garrett Dyer is a board-certified Nurse Practitioner with a background in Family Practice and experience in both Cardiology and Hospice. Caring for patients at the end of their life profoundly shaped how he views healthcare. He saw firsthand how often we treat disease only after it has already taken hold, sometimes at the expense of quality of life.
That experience led him to focus on preventive health and wellness. He believes in a proactive approach that prioritizes optimizing health, lifespan, and helping patients stay ahead of chronic disease rather than reacting to it.
Outside of work, he is an active outdoorsman who enjoys fishing, hiking, and mountain biking. He is an avid golfer and runner. His goal, both personally and professionally, is simple: stay strong, stay active, and help others do the same so they can fully enjoy life with the people they love.
Registered Nurse
June Luna, RN
June Luna: Coming Soon
Executive Patient Care Coordinator
Stella Guzman
Stella Guzman serves as our Executive Patient Care Coordinator, keeping Performance Medicine running seamlessly behind the scenes. She oversees daily operations, coordinates appointments between patients and our medical team, and ensures every touchpoint reflects the excellence and care we’re known for.
With over two decades of experience in customer service and client relations, Stella brings both professionalism and warmth to every interaction. She’s passionate about healthcare and fitness that truly heals, care that promotes wholeness, longevity, and lasting vitality, and she’s committed to helping patients feel seen, supported, and empowered in their journey.
Outside of the clinic, Stella loves being a mom, spending time with those she loves, and traveling to experience new places.