Janet Lo, MD
Endocrinology, Diabetes & Metabolism Physician · Boston, MA
Janet Lo, MD is an endocrinology, diabetes & metabolism physician with a practice address in Boston, Massachusetts, and NPI 1639290083, issued on Apr 3, 2007. Check the license (Massachusetts L-221992, as entered in NPPES) on the Massachusetts Board of Registration in Medicine; the Medicare figures below come from public CMS files.
- Name
- Janet Lo
- Credential
- MD
- Primary taxonomy
- Endocrinology, Diabetes & Metabolism Physician 207RE0101X
- License number
- L-221992 MA
Self-reported in NPPES; status is on the state search - Practice location
- Massachusetts General Hospital, Boston, MA 02114
- Phone
- (617) 724-9109
- Enumerated
- Apr 3, 2007
- Record last updated
- Nov 9, 2012 (not updated in 14 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20070719000789); accepts Medicare assignment
- Medical or professional school
- Columbia University College Of Physicians And Surgeons, 2000
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest endocrinology, diabetes & metabolism physician records → All 522 in Massachusetts → Look up another NPI →
Also registered at Massachusetts General Hospital
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Janet Lo in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMassachusetts Board of Registration in Medicine
Search for license L-221992Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
82% fewer Medicare Part D claims than the average endocrinology, diabetes & metabolism physician in 2024
485 Medicare Part D claims for 89 beneficiaries, against an average of 2,630 among the 8,223 providers of this specialty who prescribed in Part D. Brand-name drugs were 51% of claims.
Most prescribed
- Repatha Sureclick133 claims
- Ezetimibe49 claims
- Levothyroxine Sodium49 claims
- Praluent Pen47 claims
- Rosuvastatin Calcium37 claims
- Atorvastatin Calcium26 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Bills Medicare through 2 group practices
- Massachusetts General Physicians Organization IncBoston, MA
- The General Hospital CorporationBoston, MA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Janet Lo among 522 endocrinology, diabetes & metabolism physician records in Massachusetts
Janet Lo, MD is one of 522 endocrinology, diabetes & metabolism physician records with a practice address in Massachusetts. 82% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2007, is newer than 48% of them.
- NPI issued2007 · 48% of these records are older, 40% newer
- In a Medicare fileYes · 82% of these records are
- In the CMS Doctors and Clinicians fileYes · 72% of these records are
- Graduated2000 · median 2002 among the 378 with a school on file
- Record last updated2012 · 60% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RE0101X and a Massachusetts practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Endocrinology, Diabetes & Metabolism Physician providers in Massachusetts
There are 522 endocrinology, diabetes & metabolism physician records in Massachusetts.
All 522 in Massachusetts → Every provider in Boston → Endocrinology, Diabetes & Metabolism Physician nationwide →
The 8 endocrinology, diabetes & metabolism physician records with the nearest ZIP codes
- Joseph Avruch, MDBoston, MA 021141851381941
- Giuseppe Barbesino, MDBoston, MA 021141366432635
- Enrico Cagliero, MDBoston, MA 021141700877347
- William Crowley, MDBoston, MA 021141417947599
- Marie Demay, MDBoston, MA 021141528058153
- Steven Grinspoon, MDBoston, MA 021141457342099
- Janet Hall, MDBoston, MA 021141548251002
- Anne Klibanski, MDBoston, MA 021141518958164
Common questions
What is Janet Lo, MD's NPI number?
Janet Lo, MD's National Provider Identifier (NPI) is 1639290083, issued on Apr 3, 2007. An NPI identifies a provider in billing; it is not a license.
Where is Janet Lo, MD located?
The NPPES record lists a practice address at Massachusetts General Hospital, Boston, MA, 02114. Phone: (617) 724-9109. Providers update this record themselves, so call before visiting.
How can I verify Janet Lo, MD's license?
NPPES lists Massachusetts license number L-221992, as entered by the provider. Search the Massachusetts Board of Registration in Medicine at https://findmydoctor.mass.gov/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Janet Lo, MD prescribe under Medicare Part D?
In 2024, Janet Lo, MD had 485 Medicare Part D claims for 89 beneficiaries; the average among endocrinology, diabetes & metabolism physician prescribers was 2,630. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.