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 — not just "normal" — and to leave with a plan that treats the cause, not just the symptoms.
With 20+ years in nursing and clinical practice across some of the Rio Grande Valley's most demanding healthcare environments, she brings both the expertise and the compassion to do what most practices won't.
20+
Years in
Nursing & Practice
"She pours love, passion, and faith into the care she provides."
— Erica L., RENEW Patient
20+
Years Nursing
14
Yrs at DHR
7
Certifications
FNP-BC
Board Certified
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, the underserved patients, and the clinical settings where she could learn the most.
LVN → RN → Advanced Practice
Sasha began her nursing career as an LVN — learning the fundamentals of hands-on patient care at its most direct level. Driven by curiosity and a conviction that she could do more for her patients, she continued her education without pausing her clinical work, 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 and most complex healthcare systems. Her roles spanned the Pre-Operative Department, where she cared for patients preparing for surgical procedures, to clinical health informatics and Quality & Compliance, where she gained deep systems-level insight into how healthcare institutions function, where they succeed, and critically, where they fail patients.
This wasn't narrow specialization. She worked across patient safety, regulatory compliance, behind-the-scenes support systems, and the operational infrastructure that determines whether a patient gets exceptional care or falls through the cracks. It gave her a perspective that 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. Working in an express care setting, she honed her ability to quickly identify patterns, triage complex presentations, and prioritize the education and empowerment of patients — not just the management of their acute symptoms.
This role deepened her understanding of community health dynamics in the Rio Grande Valley, and reinforced her belief that truly caring for a patient meant helping them understand their own body — not just handing them a prescription.
Where the Root-Cause Conviction Crystallized
Sasha's most recent clinical position before founding RENEW was with Rio Grande Pain Team, where she worked directly with patients in chronic pain — people who had often already been through multiple providers, multiple treatments, and multiple disappointments. This environment exposed her daily to the inadequacy of symptom-only medicine.
Watching patients receive temporary relief instead of lasting resolution — and seeing how nutrition, deficiencies, and systemic imbalances were almost always factors no one had addressed — confirmed what she had long suspected: functional medicine wasn't an alternative approach. It was the missing layer that conventional care consistently skipped. RENEW was built to fill that gap.
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, and serving patients across the entire Rio Grande Valley, RENEW offers a space where functional medicine, IV therapy, nutraceuticals, medical weight loss, hormone care, and aesthetic treatments all exist 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 — and she built RENEW to prove that the Rio Grande Valley deserves that level of care.
The Way Sasha
Approaches Every Patient
Root Cause, Not Symptom Management
Your symptoms are signals, not the problem. Sasha looks at the full picture — lab values, 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 for their health. 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 not separate from her practice — it is foundational to it. She sees every patient as a whole person worthy of dignity, deep listening, and genuine effort. That ethos defines how RENEW operates at every level.
Inner Health & Outer Confidence
Feeling well and feeling confident are connected. Sasha offers aesthetic treatments not as a vanity add-on, but 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
Sasha's credentials span clinical practice, functional medicine, aesthetics, and advanced nursing — giving RENEW a scope of care few single-practitioner practices can match.
Education
Master of Science in Nursing
Family Nurse Practitioner Specialization
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
What Sasha's Patients
Say About Her Care
"After more than three years of suffering — two pulmonologists, an asthma diagnosis, and an inhaler that made me feel worse — Sasha ordered the right labs, confirmed the diagnosis, and started me on the right regimen. Three months later, all my symptoms are gone. I feel better than I ever did."
Emma M.
Treated: B12 deficiency, fatigue, tachycardia, shortness of breath
"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 the care she provides — and it shows in the results."
Erica L.
Treated: Chronic anemia, iron deficiency, shortness of breath
"My labs came back 'normal' but I felt sluggish, unmotivated, and exhausted. Sasha analyzed them through a functional medicine lens — found my iron, Vitamin D, and ferritin were all below optimal. Within two weeks of her plan, I felt active and awake again."
Jennifer DLC
Treated: Low ferritin, Vitamin D deficiency, fatigue
"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."
Anthony A.
Treated: Low energy, nutritional deficiencies
Phone
(956) 867-2365
Hours
Mon–Fri · 9AM–5PM
Location
500 S. 11th St., Suite 1
McAllen, TX · Directions →
RENEW Health & Wellness · McAllen, TX
Ready to Work with Sasha?
No referral needed. No long waits. Just a thorough conversation, the right labs, and a plan built entirely around you — by a practitioner who has spent 20+ years preparing to do exactly this.