Preventive Health & Diagnostics Clinic

  • Primary Care
  • Unrivaled Primary Care

    Comprehensive personalized care focused on improving your healthspan and increasing your lifespan

  • Hidden Risks
  • Uncover Hidden Risks

    Many health threats go unnoticed until it’s too late. Our deep diagnostic approach uncovers silent issues—like insulin resistance, inflammation, or nutrient deficiencies—so nothing is missed.

  • Optimize Health
  • Optimize Your Health

    Health optimization means going beyond “normal.” We help you function at your highest level through strategic improvements in sleep, exercise, nutrition, and hormonal balance, all tailored to your lifestyle and goals.

  • Prevent Disease
  • prevent Disease

    We identify risk factors early and implement personalized strategies to stop chronic conditions before they start—protecting you from heart disease, cancer, dementia, and metabolic dysfunction.

  • Root Cause
  • Identify the Root Cause

    We focus on understanding the underlying mechanisms behind your symptoms. Through advanced testing and thoughtful analysis, we treat the source of the problem—not just the signs of it.

Unrivaled Primary Care

Comprehensive personalized care focused on improving your healthspan and increasing your lifespan

Uncover Hidden Risks

Many health threats go unnoticed until it’s too late. Our deep diagnostic approach uncovers silent issues—like insulin resistance, inflammation, or nutrient deficiencies—so nothing is missed.

Optimize Your Health

Health optimization means going beyond “normal.” We help you function at your highest level through strategic improvements in sleep, exercise, nutrition, and hormonal balance, all tailored to your lifestyle and goals.

prevent Disease

We identify risk factors early and implement personalized strategies to stop chronic conditions before they start—protecting you from heart disease, cancer, dementia, and metabolic dysfunction.

Identify the Root Cause

We focus on understanding the underlying mechanisms behind your symptoms. Through advanced testing and thoughtful analysis, we treat the source of the problem—not just the signs of it.

Advanced Testing Protocols

  • 100+ lab biomarkers
  • Body Composition Analysis
  • VO2 Max Testing
  • Comprehensive Strength Analysis
  • Advanced Diagnostics

Hormone Replacement Therapy

Our hormone levels naturally decline with age, contributing to the aging process. Hormone replacement therapy is essential to slowing the aging process, preserving vitality, and preventing age-related disease.

Functional Protocols

Our protocols are aimed at optimizing sleep, nutrition, exercise and stress reduction.

Peptide Therapy

Peptide therapies are ever-evolving, cutting edge, customized treatment regimens that promote health optimization and performance


Medicine 3.0


Old School primary Care Optimizing human lifespan, healthspan & performance

Physician Access

No office staff. Only direct access to your physician 7 days a week.

Telemedicine

Consult with your physician via text message, phone call or video chat anytime

Same Day Visits

Peace of mind that you will never have to wait days or weeks to be seen.

Meet Your Physician

John Wenhold D.O. Is the founder of Marathon Direct Primary Care.  He received his medical degree from UNTHSC in Fort Worth, TX and is board certified in Family Medicine. Additionally, he has 8 years of experience as an Emergency Room Physician.

He is an avid endurance athlete and just completed the 2025 Boston Marathon in 2 hours 43 minutes

He is passionate about digital tracking of health metrics in order to optimize his own health.  He hopes to provide the same level of detailed care to his patients

He is licensed in the state of Texas

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Direct Primary Care

Frequently Asked Questions

At Marathon Direct Primary Care, we are not contracted with any health insurance or 3rd party payor.  Instead, our patients pay a monthly membership fee in exchange for unlimited and direct access to Dr. Wenhold.  On average, this will address 90% of a patient’s medical issues.  

Furthermore, Marathon Direct Primary Care is focused on optimizing not only how long you live, but how well you live.  A number of cutting edge treatment modalities and health protocols are available to members.  Additional fees may apply.

A list of all services included with our standard membership are listed in Appendix A of our Standard Patient Agreement Form.  You can also contact us at anytime for more information.

Our office is located within Dominion Place (next to the Tesla dealership).

The address is 23119 W IH10 Suite 18, San Antonio, TX 78257

No.  We do not accept health insurance.  With a monthly membership, you receive comprehensive primary healthcare and have unlimited access to Dr. Wenhold.

We do recommend patients carry some form of a catastrophic health plan. High deductible plans are a great supplement to Direct Primary Care and cover you and your family for catastrophic events. Medical cost-sharing plans or Health shares are also good options to consider. These types of health plans will help cover services that Marathon Direct Primary Care cannot provide, such as hospitalizations, surgeries, and other catastrophic event

Yes.  However, Marathon Direct Primary Care  is not responsible for payments not covered by your insurance company.  Marathon Direct Primary Care has negotiated cash-pay rates with local lab and imaging centers so that paying cash for these services is very affordable.

Marathon Direct Primary Care accepts HSA and FSA funds as a form of payment, however, it is the responsibility of the patient to ensure eligibility of use in accordance with IRS guidelines

The Marathon Direct Primary Care Membership is available to individuals 18-64 years of age

Membership sign up for ages 65+ is currently full.