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Portrait of Rosalyn Yalow
Photo: US Information Agency (see image credits at the end), Women of Influence, pg. 28 · Public domain via Wikimedia Commons

Nobel Prize in Physiology or Medicine · 1977

Rosalyn Yalow

A nuclear physicist who learned to measure tiny traces of hormones in blood, changing how doctors diagnose diabetes and thyroid disease.

The Nobel citation: “for the development of radioimmunoassays of peptide hormones”
Born
July 19, 1921, New York, NY, USA
Died
May 30, 2011, New York, NY, USA
Shared with
Roger Guillemin, Andrew V. Schally
Affiliation at the time
Veterans Administration Hospital, USA

Medicine prize

1977

Shared with 2 other laureates.

Age that year

56years

Born in 1921.

Headline credited impact

16,000–62,000people benefited

Transfusion recipients spared hepatitis B by donor screening, 2008-2025. How it was built

Sources cited

29

Fact-checked September 24, 2026.

  • She was a nuclear physicist with no medical degree, yet she won half of the 1977 Nobel Prize in Physiology or Medicine, only the second woman ever to win it.
  • Her test could detect less than a trillionth of a gram of the hormone ACTH in a milliliter of blood. Older methods could need as much as 250 milliliters of blood.
  • She and her partner Solomon Berson chose not to patent their test, and they often gave visiting scientists some of their antibodies to take home.
  • Graduate physics programs turned her down, partly because she was a woman and Jewish. At Illinois in 1941 she was the only woman among the 400 members of its engineering faculty.
  • Science rejected the 1956 paper that led to her Nobel Prize, and a second journal took it only after changes. She showed that journal's rejection letter in her Nobel lecture.

The breakthrough

Radioimmunoassay: measuring hormones in a few drops of blood (1959)

Hormones are chemical messengers, such as insulin, that travel in the blood in amounts far too small for 1950s methods to measure. In the 1950s, Yalow and the physician Solomon Berson tested a theory that adult-onset diabetes happens because the body destroys insulin too fast. They injected patients with insulin tagged with radioactive iodine, which let them follow it with radiation counters. The result surprised them. In people already treated with insulin, the tagged insulin lingered longer, because their bodies had made antibodies that grabbed it. Experts then believed a molecule as small as insulin could not trigger antibodies, and journals at first rejected the finding. Yalow and Berson then saw a new use for it. Picture a room with a fixed number of chairs (the antibodies) and a crowd wearing glowing badges (the tagged insulin). Add people without badges (the insulin in a patient's blood sample) and they compete for the chairs. The more of them there are, the fewer glowing people get a seat. By measuring how much glow is seated, you can work out how much untagged insulin was in the sample. In 1959 they used this radioimmunoassay (RIA) to measure insulin in human blood. It could detect about 10 to 20 trillionths of a gram of insulin, and the same idea could measure virtually any substance of biological interest.[2],[3],[4],[6],[21]

“The world cannot afford the loss of the talents of half its people if we are to solve the many problems which beset us.”
Rosalyn Yalow, Speech at the Nobel Banquet in Stockholm, 10 December 1977, on the barriers facing women in science.[5]

What it meant for humanity

Before RIA, doctors could not reliably measure most protein hormones in blood. Measuring the stress hormone ACTH could take as much as 250 milliliters of blood, and the Nobel press release noted that unreliable tests had led research astray. RIA needed only a fraction of a milliliter of blood per sample and made it easy to test hundreds of samples. That made it possible to watch hormone levels rise and fall, not just take a single reading. Use spread slowly at first, then fast: by 1975, more than 4,000 hospital and other clinical labs in the United States were running radioimmunoassays. The method was soon used for vitamins, enzymes, drugs and viruses as well as hormones. According to NobelPrize.org, its precision showed that type 2 diabetes stems from the body using insulin inefficiently, rather than simply from a lack of insulin. By 1977 an RIA for a hepatitis antigen was the method of choice for screening donated blood in American blood banks. Babies gained too. Congenital hypothyroidism, a thyroid hormone shortage at birth, is one of the most common preventable causes of intellectual disability. The first screening programs, starting in Quebec in 1974, tested dried drops of newborn blood by radioimmunoassay. Babies caught this way and treated early generally develop normally. About 39 million newborns a year are now screened. Today most labs use non-radioactive descendants of RIA that rest on the same principle. Yalow and Berson did not patent their method, which the VA credits with helping labs adopt it quickly, and its simplicity carried it even to countries with few scientific resources.

  • RIA could measure less than a trillionth of a gram of the hormone ACTH per milliliter of blood; older biological tests could need as much as 250 milliliters of blood.[4]
  • By 1975, more than 4,000 hospital and other clinical labs in the United States were running radioimmunoassays, almost double the number of a year or two earlier.[3]
  • By 1977, an RIA for hepatitis antigen had become the method of choice for screening donated blood in Red Cross and other US blood banks.[3],[8]
  • Newborn thyroid screening began in Quebec in 1974 using RIA on dried blood spots. It now reaches about 39 million babies a year, 29.6% of all births.[9],[10],[11],[13]
  • Yalow and Berson chose not to patent RIA and trained visiting scientists from around the world, often giving them antibodies to take home.[6],[7],[8]

Impact in numbers

Radioimmunoassay gave medicine a way to measure the body's chemical messengers, and much of modern endocrinology grew from it. Its value is hard to express as one number, because RIA and its non-radioactive descendants now sit inside countless routine tests, from diabetes and fertility work to drug monitoring and blood-bank screening. We therefore count only one well-documented slice: babies found through newborn thyroid screening, which began with radioimmunoassay. We credit Yalow with just 5% of it, because Berson co-invented the method and many others built the screening programs. Her decision not to patent RIA helped it spread quickly and cheaply. Her example, and her public insistence that women's talents were being wasted, also widened the door for women in science.

HealthFundamental scienceWomen's rights

Each number is the laureate’s credited share of a real-world outcome, cumulative to 2025. The whole outcome, the share of credit, and the reasoning are shown so you can check the arithmetic. Outcomes shared with other laureates are counted once on the impact page.

  • Medium confidenceRippleModeledHealth

    Babies with congenital hypothyroidism found by newborn screening and treated early (1974-2025)

    10,000–25,000

    people benefited, credited share

    That is 5% of 200,000–500,000 people benefited since 1974.

    How this number was built

    Arrigoni et al. (2025): 39.1M babies/yr screened (29.6% of 132.1M births in 2023) and 29.3% in 2014; Ford & LaFranchi: about 71% of babies unscreened. UN births via OWID: 2014-2025 at ~29.5% of 1.65B = 0.49B screened. 1975-2013: coverage rising linearly from 0 (1974) to 29.3% = 0.79B (high) or half that, 0.40B (low). Total 0.88B-1.28B. Incidence 1 in 4,000 (low) to 1 in 2,500 (high), below the 1 in 1,714 seen with lower cutoffs, which add mild cases. Result 220,000-510,000, rounded to 200,000-500,000. Share 0.05: the first screens measured T4 by radioimmunoassay, but the outcome also needed Berson (co-inventor, equal credit), Ekins's competitive-binding thyroxine assay, Dussault and Laberge's program, dried-blood-spot cards, thyroid hormone treatment and later non-radioactive assays.[3],[9],[10],[11],[12],[13],[14]

    Sources: NobelPrize.org; The Journal of Pediatrics (PubMed record); L'Union Medicale du Canada (PubMed record); European Thyroid Journal (via PubMed Central); Best Practice & Research Clinical Endocrinology & Metabolism (PubMed record); Endocrine (via PubMed Central); Our World in Data

  • Low confidenceRippleModeledHealth

    Transfusion recipients spared hepatitis B by donor screening, 2008-2025

    16,000–62,000

    people benefited, credited share

    That is 1% of 1.6–6.2 million people benefited since 2008.

    How this number was built

    2008-2025 only. WHO: 91.8M donations in 2008, 118.5M in 2018; linear between, flat after = 1.99B. Median HBsAg-reactive rates by income group 0.01/0.29/1.96/2.81%, weighted by 2018 donation shares 40/34/24/2% (WHO 2021) = 0.63%: 12.5M units kept out. Infections averted per unit: 0.15 (Allain, Ghana: recipients over 10, often already immune) to 0.5 (Gocke 1972, US: 52% of recipients of antigen-positive blood were infected). Low x 0.9: 11% of donations not screened to standard (WHO 2011). 12.5M x 0.9 x 0.15 = 1.7M, rounded down to 1.6M; 12.5M x 0.5 = 6.2M. Only susceptible recipients count, so no vaccinated child from the vaccine claim is counted. Rough: medians, unconfirmed reactives. Share 0.01 (Blumberg 0.2, Alter 0.05): gel tests missed carriers (s29); her lab's 1970 radioimmunoassay for the antigen became the US blood-bank method (s3); today's tests are later immunoassays.[3],[24],[25],[26],[27],[28],[29]

    Sources: World Health Organization (archived 16 May 2022); World Health Organization; Blood (American Society of Hematology), via PubMed; JAMA, via PubMed; World Health Organization; Virology Journal (BioMed Central), via PubMed Central; NobelPrize.org

The double edge

No serious harm has been traced to Yalow's work, but there are three caveats. First, RIA relies on radioactive reagents. Their perceived hazards, the rules and disposal problems they bring, and their short shelf life pushed labs to switch to non-radioactive labels from about 1980 on. Second, antibody tests can be fooled. In one documented series, 12 women were wrongly diagnosed with cancer because of false-positive results from modern antibody-based tests descended from RIA, and most had needless surgery or chemotherapy. Third, Yalow was a vocal critic of what she called radiation phobia. In the 1980s she argued that fears of low-level radiation were exaggerated. That view remains contested. In 2021 US regulators reaffirmed the no-threshold model she rejected; in 2026, after a presidential order, they proposed moving away from it.

  • Minor

    Radioactive reagents and waste

    Classic RIA uses radioactive labels. A 2000 PNAS paper lists their drawbacks: perceived radiation hazards, regulatory requirements and disposal problems, and a short shelf life. Over the previous two decades, immunoassays had largely switched to non-radioactive labels.[13],[15]

  • Minor

    False results from antibody-based tests

    Immunoassays can be misled by unusual antibodies in a patient's blood. A 2000 Lancet study described 12 women wrongly diagnosed with a pregnancy-related cancer because of false-positive hCG results; most had needless surgery or chemotherapy before the error was found.[8],[16]

  • Minor

    Contested views on low-level radiation

    In a 1983 reappraisal and a 1989 column, Yalow argued that low-level radiation risks were overstated and faulted fellow scientists for not challenging exaggerated claims, which fed 'radiation phobia'. In 2021 the US Nuclear Regulatory Commission reaffirmed the linear no-threshold model, which assumes even small doses carry some risk. In 2026, after a 2025 presidential order, it proposed dropping its 'as low as reasonably achievable' rule, which rests on that model.[17],[18],[19],[22],[23]

Against the odds

Yalow faced no state persecution, but she grew up when American Jews met quotas and closed doors. Most US medical schools limited Jewish admissions from the 1920s, and antisemitism was still pervasive when World War II ended. Her parents had not finished high school, and there were no books at home. The tuition-free Hunter College gave her a start. After she graduated in 1941, graduate physics programs turned her down, at least partly because she was a woman and Jewish. One admissions office was frank about its reason: it believed a Jewish woman would never find work in physics. The University of Illinois finally accepted her, helped by the wartime draft and a Hunter professor's request, on condition that it would not have to find her a job afterward. She was the only woman among the 400 members of its engineering faculty and the first since 1917. When she earned an A-minus in a lab course, the department chairman said it confirmed that women do poorly at lab work. After her doctorate she again met closed doors, since research posts were rarely offered to women. She started her radioisotope lab at the Bronx VA hospital in what had been a janitor's closet.

  • —

    Quota

    In Yalow's youth, most US medical schools used quotas to limit Jewish students. The quotas began in the 1920s, were well entrenched by 1945 and were gone only by about 1970.[20]

  • 1941

    Discrimination

    Graduate physics programs rejected her, at least partly because she was female and Jewish. One admissions office was frank: it believed a Jewish woman would never find work in the field. Illinois took her only after agreeing it would not have to find her a job afterward.[6],[7]

  • —

    Discrimination

    In her first year of graduate school, the physics department chairman looked at her near-perfect grades and said her A-minus in a lab course confirmed that women do not do well at laboratory work.[2]

  • 1945

    Discrimination

    After finishing her doctorate in four years, she again met closed doors: research jobs rarely went to women. She worked as an engineer and then taught physics at Hunter before finding a research post.[6],[7]

  • 1952

    Discrimination

    Veterans Administration policy required women to leave work once they were five months pregnant. Yalow ignored it and returned to her lab about a week after her son was born in 1952.[7]

  • 1956

    Other

    Their finding that insulin-treated patients make insulin antibodies clashed with the expert view of the time. Science rejected the paper, and the Journal of Clinical Investigation accepted it only after they removed 'insulin antibody' from the title.[3],[6]

Jewish background

Both parents JewishIdentified as Jewish, secular

Yalow was born in the Bronx into a Jewish family. Her mother, Clara Zipper, came to America from Germany at age four; her father, Simon Sussman, was born on New York's Lower East Side, then home to many Eastern European immigrants. At the University of Illinois she was one of only three Jewish people among its 400 faculty and teaching assistants. In 1943 she married another of them, physicist Aaron Yalow, the son of an Orthodox rabbi. The couple kept a kosher home, in deference to his wishes according to the Jewish Women's Archive, and she invited her lab assistants to Passover seders.[2],[6],[7],[8]

Key dates

  1. July 19, 1921

    Born Rosalyn Sussman in the Bronx, New York City, to Jewish parents who had not finished high school.[1],[2],[6]

  2. January 1939

    As a Hunter College junior, squeezes into a packed Columbia University lecture hall to hear Enrico Fermi describe newly discovered nuclear fission.[2]

  3. January 1941

    Graduates from the tuition-free Hunter College. After rejections elsewhere, she starts a physics PhD at the University of Illinois in September.[2],[6],[7]

  4. June 6, 1943

    Marries fellow physics student Aaron Yalow, the son of an Orthodox rabbi.[2],[7]

  5. January 1945

    Earns a PhD in nuclear physics at Illinois, supervised by Maurice Goldhaber.[2]

  6. December 1947

    Joins the Bronx Veterans Administration Hospital as a part-time consultant to set up one of its first radioisotope services.[2],[8]

  7. July 1950

    Physician Solomon Berson joins her radioisotope service, months after she left teaching to work at the VA full time. Their partnership lasts 22 years.[2],[7]

  8. 1956

    Yalow and Berson publish evidence that insulin-treated patients make insulin antibodies, after Science rejected the paper.[3],[6]

  9. 1959

    They use radioimmunoassay to measure insulin in human blood, launching the RIA era. The full paper appears in 1960.[2],[3],[21]

  10. April 11, 1972

    Berson dies. At Yalow's request, their laboratory is later named the Solomon A. Berson Research Laboratory.[2]

  11. 1976

    Becomes the first woman to receive the Albert Lasker Basic Medical Research Award.[7]

  12. December 10, 1977

    Receives half of the Nobel Prize in Physiology or Medicine for developing radioimmunoassays of peptide hormones.[1],[4],[5]

  13. 1988

    Receives the National Medal of Science.[7]

  14. May 30, 2011

    Dies in New York at age 89 after a series of strokes.[1],[6],[7]

Sources

  1. 1.Rosalyn Yalow - Facts · NobelPrize.org (Nobel Prize Outreach)
  2. 2.Rosalyn Yalow - Biographical · NobelPrize.org (from Les Prix Nobel 1977, Nobel Foundation, 1978), 1978
  3. 3.Radioimmunoassay: A Probe for Fine Structure of Biologic Systems (Nobel Lecture, 8 December 1977) · NobelPrize.org, 1977
  4. 4.The Nobel Prize in Physiology or Medicine 1977 - Press release · NobelPrize.org (Karolinska Institute), 1977
  5. 5.Rosalyn Yalow - Banquet speech, 10 December 1977 · NobelPrize.org, 1977
  6. 6.Rosalyn Sussman Yalow (1921-2011) (Kahn CR, Roth J; PNAS 109(3):669-670) · Proceedings of the National Academy of Sciences (via PubMed Central), 2012
  7. 7.Rosalyn Yalow (Taitz E, Fields T), Shalvi/Hyman Encyclopedia of Jewish Women · Jewish Women's Archive
  8. 8.Breaking barriers in science: Dr. Rosalyn S. Yalow's legacy · VA News, U.S. Department of Veterans Affairs, 2026
  9. 9.Preliminary report on a mass screening program for neonatal hypothyroidism (Dussault JH et al., J Pediatr 86:670-674) · The Journal of Pediatrics (PubMed record), 1975
  10. 10.Thyroxine (T4) determination by radioimmunological method in dried blood eluate: new diagnostic method of neonatal hypothyroidism? (Dussault JH, Laberge C) · L'Union Medicale du Canada (PubMed record), 1973
  11. 11.Newborn screening for congenital hypothyroidism: worldwide coverage 50 years after its start (Arrigoni M et al.) · European Thyroid Journal (via PubMed Central), 2025
  12. 12.Screening for congenital hypothyroidism: a worldwide view of strategies (Ford G, LaFranchi SH) · Best Practice & Research Clinical Endocrinology & Metabolism (PubMed record), 2014
  13. 13.Improvements in screening test, diagnosis, and outcomes of children with congenital hypothyroidism: lessons learned from 50 years of newborn screening (Salerno M et al.) · Endocrine (via PubMed Central), 2026
  14. 14.Births and deaths per year, World (UN World Population Prospects 2024) · Our World in Data, 2024
  15. 15.Isotope-labeled immunoassays without radiation waste (Shan G et al., PNAS 97:2445-2449) · Proceedings of the National Academy of Sciences (PubMed record), 2000
  16. 16.False diagnosis and needless therapy of presumed malignant disease in women with false-positive human chorionic gonadotropin concentrations (Rotmensch S, Cole LA) · The Lancet (PubMed record), 2000
  17. 17.The contributions of medical physicists to radiation phobia (Yalow RS) · Medical Physics (PubMed record), 1989
  18. 18.Reappraisal of potential risks associated with low-level radiation (Yalow RS) · Annals of the New York Academy of Sciences (PubMed record), 1983
  19. 19.Linear No-Threshold Model and Standards for Protection Against Radiation (petitions for rulemaking; denial), 86 FR 45923 · U.S. Nuclear Regulatory Commission, Federal Register, 2021
  20. 20.Why Did the United States Medical School Admissions Quota for Jews End? (Halperin EC) · The American Journal of the Medical Sciences (PubMed record), 2019
  21. 21.Immunoassay of endogenous plasma insulin in man (Yalow RS, Berson SA) · Journal of Clinical Investigation (PubMed record), 1960
  22. 22.Nobel Prize winner Dr. Rosalyn Yalow, nuclear medicine pioneer and fierce critic of 'no safe dose' myth (includes a transcription of Yalow's 1989 Medical Physics column) · Atomic Insights (Rod Adams), 2017
  23. 23.Reforming and Modernizing the NRC's Radiation Protection Framework (proposed rule), 91 FR 43456 · U.S. Nuclear Regulatory Commission, Federal Register, 2026
  24. 24.Blood safety and availability (fact sheet, Table 1: prevalence of transfusion-transmissible infections in blood donations by income group) · World Health Organization (archived 16 May 2022), 2022
  25. 25.Global Database on Blood Safety: Summary Report 2011 (2008 data: 91.8 million donations) · World Health Organization, 2011
  26. 26.The risk of hepatitis B virus infection by transfusion in Kumasi, Ghana (Allain JP et al., Blood 101:2419-2425) · Blood (American Society of Hematology), via PubMed, 2003
  27. 27.A prospective study of posttransfusion hepatitis: the role of Australia antigen (Gocke DJ, JAMA 219:1165-1170) · JAMA, via PubMed, 1972
  28. 28.Global status report on blood safety and availability 2021 · World Health Organization, 2022
  29. 29.Medical virology of hepatitis B: how it began and where we are now (Gerlich WH, Virology Journal 10:239) · Virology Journal (BioMed Central), via PubMed Central, 2013

Fact-checked on September 24, 2026 by a separate AI fact-checking pass that re-opened the sources, with 10 corrections made. How we check

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