5
144 Ratings with 143 written Reviews

Overview based on verified provider data
Preferred Provider badge recognizes providers that are committed to transparency, responsiveness and great service to patients, and have earned a high patient satisfaction rating.
![]() | ![]() | ![]() | ![]() |
| Dr. John Andrew Mcmahon, DO | Dr. Penelope Laura Shar, MD | Dr. Barbara L P Mccall | Dr. Alex Nicholas Sisto |
| Internal Medicine | Internal Medicine | Internal Medicine | Internal Medicine |
| Accepts New Patients | |||
| 18 Years of Experience | 37 Years of Experience | 59 Years of Experience | 6 Years of Experience |
| No Virtual Visit Option | No Virtual Visit Option | No Virtual Visit Option | No Virtual Visit Option |
| Speaks Spanish, Chinese | |||
| York , ME | Portsmouth , NH | Sanford , ME | Rye , NH |
| Med School: University Of New England College Of Osteopathic Medicine | Med School: Yeshiva University | Med School: Hahnemann University School Of Medicine | Med School: Drexel University College Of Medicine |
Current Profile | View Profile | View Profile | View Profile |
Dr. John Andrew Mcmahon holds an active medical license in the states of New Hampshire and Maine.
Doctor Of Osteopathy with an active medical license in the state of New Hampshire that expires in 2027 and an active medical license in the state of Maine that expires in 2027.
Graduated from University Of New England College Of Osteopathic Medicine in 2008.
Dr. Mcmahon's NPI number is 1821258062.










Our provider data is gathered directly from physicians and publicly available databases. Providers who verify their profiles gain the ability to update information, offering additional details about their specialties,education, treated conditions, performed procedures, and accepted insurances.
Reviews on Vitals are submitted by users only. Recognizing the valuable insights these reviews offer into a doctor's reputation, we maintain internal policies and protocols to ensure the quality and accuracy of all reviews. Importantly, providers cannot delete or alter reviews independently. Reviews can only be deleted or changed following an internal assessment by our customer service team.
Your feedback is highly valued and we encourage you to contact our support team should you encounter any issues.