Sasha Castillo
MSN, FNP-BC · Family Nurse Practitioner
Functional Medicine Specialist · ANCC Certified
Sasha built RENEW on a simple but radical belief: that every patient deserves to be heard, to have their labs analyzed through a lens that actually reflects optimal health, and to leave with a plan that treats the cause, not just the symptoms.
20+
Years Clinical Experience
100%
Personalized Plans
6
Integrated Services
★ 5.0
Patient-Rated Care
A Career Built on
Going Further for Patients
Sasha's path to founding RENEW wasn't a straight line — it was 20+ years of deliberately seeking out the harder questions and the clinical settings where she could learn the most.
LVN → RN → Advanced Practice
Sasha began her nursing career as an LVN — learning hands-on patient care at its most direct level. Driven by conviction that she could do more for her patients, she continued her education while working clinically, earning her Associate Degree in Nursing from South Texas College and then her Master of Science in Nursing with a Family Nurse Practitioner specialization from Walden University. That journey from LVN to Advanced Practice Registered Nurse was never just about credentials — it was about earning the depth of knowledge needed to truly advocate for patients in a way a bedside nurse alone cannot.
Building Clinical Depth at DHR
Before becoming a Nurse Practitioner, Sasha spent 14 years at DHR Health — one of the Rio Grande Valley's largest healthcare systems. Her roles spanned the Pre-Operative Department, clinical health informatics, and Quality & Compliance, where she gained systems-level insight into how healthcare institutions function, where they succeed, and critically, where they fail patients. This gave her a perspective most clinicians never develop — and it directly shapes how RENEW is run today.
Community-Centered Care at V Express Care
As a Nurse Practitioner with UT Health RGV at V Express Care, Sasha expanded her practice to include community-based, continuity-of-care focused medicine — honing her ability to quickly identify patterns, triage complex presentations, and prioritize patient education and empowerment above symptom management.
Where the Root-Cause Conviction Crystallized
Sasha's most recent clinical position before founding RENEW was with Rio Grande Pain Team — working daily with patients in chronic pain who had been through multiple providers and multiple disappointments. Watching patients receive temporary relief instead of lasting resolution confirmed what she had long suspected: functional medicine wasn't an alternative approach. It was the missing layer that conventional care consistently skipped.
Building the Practice She Wished Existed
RENEW is the culmination of everything Sasha learned in two decades of nursing — what works, what gets skipped, what patients desperately need and rarely receive. Located in McAllen, Texas, RENEW offers functional medicine, IV therapy, nutraceuticals, medical weight loss, hormone care, and aesthetics under one roof — coordinated by one practitioner who knows your full picture. Sasha is not a practitioner who manages your symptoms and sees you in six months. She is a partner in your health.
The Way Sasha
Approaches Every Patient
Root Cause, Not Symptom Management
Your symptoms are signals, not the problem. Sasha looks at the full picture — labs, lifestyle, history, and nutritional status — to find what is actually driving the issue, and address it directly.
Patient Education & Empowerment
Sasha believes patients who understand their own bodies make better decisions. Every visit includes an explanation — not just a protocol. You leave knowing why, not just what.
Faith-Infused, Whole-Person Care
Sasha's faith is foundational to her practice. She sees every patient as a whole person worthy of dignity, deep listening, and genuine effort.
Inner Health & Outer Confidence
Feeling well and feeling confident are connected. Sasha offers aesthetic treatments as a natural extension of caring for the whole person — inside and out.
"For I know the plans I have for you… plans to give you hope and a future."
— Jeremiah 29:11
Education, Certifications
& Professional Associations
Education
Master of Science in Nursing
Family Nurse Practitioner
Walden University
Patient Care Technician Certificate
South Texas College
Associate Degree in Nursing (RN)
South Texas College
Licensed Vocational Nurse (LVN)
South Texas College
Certifications
ANCC Board Certified
American Nurses Credentialing Center, Functional Medicine
Functional Vitamin, Supplement & Nutrition
IV Infusion & Injectables
Botox & Fillers
Medical Weight Loss
Women's & Men's Hormone Replacement Therapy
Professional Associations
Texas Nurse Practitioners Association
The Institute for Functional Medicine
Clinical Expertise
✦ Disease Prevention & Health Promotion
✦ Restorative Care — All Ages
✦ Pediatric Home Health
✦ Pre-Operative Care
✦ Pain Management
✦ Clinical Health Informatics
✦ Quality Assurance & Compliance
✦ Functional & Integrative Medicine
Real People.
Real Results.
These aren't curated marketing stories. These are your neighbors, right here in the Rio Grande Valley.
"After more than three years of suffering — and two pulmonologists who couldn't help — Sasha found the answer and started me on the right path. Three months later, all my symptoms are gone. I feel better than I ever did."
"My lab numbers improved so significantly that the iron infusion I was scheduled for was no longer urgent. My own doctor told me to keep following Sasha's plan. She pours her love, passion, and faith into everything she does."
"My labs came back "normal" but I felt sluggish and exhausted. Sasha analyzed them through a functional lens, found my iron, Vitamin D, and ferritin were below optimal — within two weeks of her plan, I felt active and awake again."
"Sasha's analysis of my bloodwork led to a treatment plan that significantly improved my health and well-being. Her warm demeanor, trustworthy advice, and comprehensive knowledge make the journey toward wellness a comforting and successful experience."
"For I know the plans I have for you… plans to give you hope and a future." — Jeremiah 29:11
Rio Grande Valley · McAllen, Texas
Ready to Start Feeling
Like Yourself Again?
You don't have to keep living with symptoms that have no clear answer. Book your consultation with Sasha today, and let's find what's actually going on — and what can be done about it.