DoctorsProofNPPES directory · verify at state boards

Internal Medicine in South San Francisco, CA

65 verified internal medicine doctors in South San Francisco. Page 1 of 2.

Internists specialize in the prevention, diagnosis, and treatment of adult diseases, often coordinating complex or chronic conditions across multiple systems.

NPPES tenure ≠ clinical experience. "Years on NPPES" is time since the physician first registered a National Provider Identifier, not time practicing medicine. Verify current license status with the state medical board.

Verify a license at the Medical Board of California

Dr. Robert Lo, MD

Internal Medicine

20 yrs NPPES
NPI 1710928999
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2147
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Laura Yang, MD

Internal Medicine

20 yrs NPPES
NPI 1437255502
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Faith Wells, MD

Internal Medicine

20 yrs NPPES
NPI 1194818211
395 OYSTER POINT BLVD STE 512, South San Francisco, CA 94080(650) 826-2945
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Issa Khouri, MD

Internal Medicine

20 yrs NPPES
NPI 1285712885
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registryAccepts Medicare (2024)
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. William Chung, MD

Internal Medicine

20 yrs NPPES
NPI 1083792683
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Michelle Caughey, MD

Internal Medicine

20 yrs NPPES
NPI 1861570475
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Sally Yu, MD

Internal Medicine

20 yrs NPPES
NPI 1669550273
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Adeline Segundo, MD

Internal Medicine

20 yrs NPPES
NPI 1518045152
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Shandra Yoshimi, MD

Internal Medicine

20 yrs NPPES
NPI 1396823977
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Jae Park, MD

Internal Medicine

20 yrs NPPES
NPI 1477631075
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registryAccepts Medicare (2024)
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Jeany Tay, MD

Internal Medicine

20 yrs NPPES
NPI 1598843104
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Timothy Liao, MD

Internal Medicine

20 yrs NPPES
NPI 1114005733
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Stephen Howe, MD

Internal Medicine

20 yrs NPPES
NPI 1497833024
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Hulya Kaymaz, MD

Internal Medicine

20 yrs NPPES
NPI 1295813822
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Grace Lay, DO

Internal Medicine

20 yrs NPPES
NPI 1629156211
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Aruna Chinnakotla, MD

Internal Medicine

20 yrs NPPES
NPI 1093893604
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· $124.97 (2023)

Industry Payments (2023)

Reported by drug and device makers to CMS Open Payments. These payments are legal and disclosed — shown as context, not a judgment.

$124.97

Total received

1

Transactions

1

Paying companies

Top paying companies

VIVUS LLC$124.97

Among the 183,896 internal medicine doctors we've analyzed, about 37% received any industry payment (median $195 among those who did). This doctor's total ranks around the 78th percentile of that group.

Benchmark reflects doctors we've analyzed, not all US internal medicine doctors.

Payments to Aruna Chinnakotla do not imply any wrongdoing. Many are meals, education, or research support.

Dr. Eva Liu, MD

Internal Medicine

20 yrs NPPES
NPI 1538247143
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Ikuko Ogihara, MD

Internal Medicine

20 yrs NPPES
NPI 1740368372
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registryAccepts Medicare (2024)
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. James Gibboney, MD

Internal Medicine

20 yrs NPPES
NPI 1154409779
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Kenneth Lee, MD

Internal Medicine

20 yrs NPPES
NPI 1508944141
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Caroline Tsen, MD

Internal Medicine

20 yrs NPPES
NPI 1902984545
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Alan Le, MD

Internal Medicine

20 yrs NPPES
NPI 1992884647
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registryAccepts Medicare (2024)
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Karl Chan, MD

Internal Medicine

20 yrs NPPES
NPI 1194897942
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Tom Vo, MD

Internal Medicine

20 yrs NPPES
NPI 1033281787
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Liya Dorfman, MD

Internal Medicine

20 yrs NPPES
NPI 1447322250
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Gerald Saliman, MD

Internal Medicine

20 yrs NPPES
NPI 1992877724
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Bambi Menes, MD

Internal Medicine

20 yrs NPPES
NPI 1144394446
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Robert Marshall, MD

Internal Medicine

20 yrs NPPES
NPI 1801960117
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registryAccepts Medicare (2024)
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. David Kim, MD

Internal Medicine

20 yrs NPPES
NPI 1992879274
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Simrat Randhawa, MD

Internal Medicine

20 yrs NPPES
NPI 1225104706
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. James Peros, MD

Internal Medicine

20 yrs NPPES
NPI 1003978719
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Yumi Taylor, MD

Internal Medicine

20 yrs NPPES
NPI 1194888545
269 E GRAND AVE, South San Francisco, CA 94080(650) 777-4400
NPPES public registryAccepts Medicare (2024)
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Christopher Fowler, MD

Internal Medicine

19 yrs NPPES
NPI 1619027414
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Grace Kajiwara, MD

Internal Medicine

19 yrs NPPES
NPI 1528118320
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Joel Manosalva, MD

Internal Medicine

19 yrs NPPES
NPI 1699827824
18 JOSEPH DR, South San Francisco, CA 94080(650) 588-5145
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Rozanda Chou, MD

Internal Medicine

19 yrs NPPES
NPI 1821138355
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registryAccepts Medicare (2024)
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Edward Fang, MD

Internal Medicine

19 yrs NPPES
NPI 1124243845
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Sadhana Sonti, MD

Internal Medicine

19 yrs NPPES
NPI 1780800185
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Patrick Twomey, MD

Internal Medicine

19 yrs NPPES
NPI 1265639454
1 DNA WAY, South San Francisco, CA 94080(650) 225-2580
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Priti Dahya, MD

Internal Medicine

18 yrs NPPES
NPI 1932360492
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Kelly Yeh, MD

Internal Medicine

18 yrs NPPES
NPI 1336304369
1200 EL CAMINO REAL, 2ND FLOOR MODULE 2, South San Francisco, CA 94080(650) 742-3144
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Jennifer Jones, MD

Internal Medicine

17 yrs NPPES
NPI 1447484506
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2304
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Charles Barr, MD

Internal Medicine

17 yrs NPPES
NPI 1861627531
1 DNA WAY, MAIL STOP 66, South San Francisco, CA 94080(650) 225-4867
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Timothy Puri, MD

Internal Medicine

16 yrs NPPES
NPI 1235458092
395 OYSTER POINT BLVD STE 512, South San Francisco, CA 94080(650) 826-2945
NPPES public registryAccepts Medicare (2024)
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Prasanna Durairaj, DO

Internal Medicine

15 yrs NPPES
NPI 1538459540
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2100
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Jennifer Larsen, MD

Internal Medicine

14 yrs NPPES
NPI 1578839486
1200 EL CAMINO REAL DEPT 384, South San Francisco, CA 94080(650) 742-2000
NPPES public registryAccepts Medicare (2024)
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Natalia Bruchanski-Gallagher, MD

Internal Medicine

14 yrs NPPES
NPI 1871856369
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registryAccepts Medicare (2024)
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Matthew Mcclure, MD

Internal Medicine

14 yrs NPPES
NPI 1235493404
270 E GRAND AVE, South San Francisco, CA 94080(650) 246-7389
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. David Martin, MD

Internal Medicine

14 yrs NPPES
NPI 1245585413
300 UTAH AVE, SUITE 150, South San Francisco, CA 94080(650) 873-1115
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Nigar Seven, MD

Internal Medicine

13 yrs NPPES
NPI 1265775563
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registryAccepts Medicare (2024)
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Wendy Tseng, MD

Internal Medicine

12 yrs NPPES
NPI 1609296680
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registryAccepts Medicare (2024)
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Evie Kalmar, MD

Internal Medicine

12 yrs NPPES
NPI 1710397054
395 OYSTER POINT BLVD STE 512, South San Francisco, CA 94080(650) 826-2945
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Barnabas Yik, MD

Internal Medicine

9 yrs NPPES
NPI 1427589266
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· $254.85 (2023)

Industry Payments (2023)

Reported by drug and device makers to CMS Open Payments. These payments are legal and disclosed — shown as context, not a judgment.

$254.85

Total received

2

Transactions

2

Paying companies

Top paying companies

Regeneron Pharmaceuticals, Inc.$133.21
Janssen Biotech, Inc.$121.64

Among the 183,896 internal medicine doctors we've analyzed, about 37% received any industry payment (median $195 among those who did). This doctor's total ranks around the 84th percentile of that group.

Benchmark reflects doctors we've analyzed, not all US internal medicine doctors.

Payments to Barnabas Yik do not imply any wrongdoing. Many are meals, education, or research support.

Dr. Andrew Cheng, MD

Internal Medicine

8 yrs NPPES
NPI 1437659208
601 GATEWAY BLVD STE 350, South San Francisco, CA 94080(650) 487-6486
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Nan Ye Lei, DO

Internal Medicine

8 yrs NPPES
NPI 1265936132
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registryAccepts Medicare (2024)
CMS Open Payments· $30.32 (2023)

Industry Payments (2023)

Reported by drug and device makers to CMS Open Payments. These payments are legal and disclosed — shown as context, not a judgment.

$30.32

Total received

1

Transactions

1

Paying companies

Top paying companies

UCB, Inc.$30.32

Among the 183,896 internal medicine doctors we've analyzed, about 37% received any industry payment (median $195 among those who did). This doctor's total ranks around the 69th percentile of that group.

Benchmark reflects doctors we've analyzed, not all US internal medicine doctors.

Payments to Nan Ye Lei do not imply any wrongdoing. Many are meals, education, or research support.

Dr. Douglas Stewart, MD

Internal Medicine

7 yrs NPPES
NPI 1740748573
701 GATEWAY BLVD STE 380, South San Francisco, CA 94080(877) 688-0992
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Alaap Mehta, MD

Internal Medicine

7 yrs NPPES
NPI 1154982130
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registryAccepts Medicare (2024)
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Jennifer Shieh, MD

Internal Medicine

6 yrs NPPES
NPI 1699302794
1200 EL CAMINO REAL, South San Francisco, CA 94080(408) 728-3101
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Wing Ken Wong, DO

Internal Medicine

6 yrs NPPES
NPI 1982223608
1200 EL CAMINO REAL, South San Francisco, CA 94080(650) 742-2000
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Dr. Keon Pearson, MD

Internal Medicine

6 yrs NPPES
NPI 1386264794
600 GATEWAY BLVD STE 101, South San Francisco, CA 94080(844) 838-3322
NPPES public registry
CMS Open Payments· No payments in 2023

Industry Payments

No industry payments on record in the 2023 CMS Open Payments data. This doctor received no reported payments from drug or device makers that year.

Internal Medicine in South San Francisco, CA — Verified | DoctorsProof | DoctorsProof