Vitamin B12: History and Discovery

For most of the nineteenth century, a diagnosis of "pernicious anaemia" was a death sentence: patients grew pale, weak, and breathless, and then they died, and no one knew why. The story of vitamin B12 is the story of how that lethal mystery was solved — an unusually well-documented chain of discovery that earned two separate Nobel Prizes and that runs through the lives of real, named people: the London physician who first described the disease, the Boston doctors who found that feeding patients raw liver could save them, the physiologist who worked out why the stomach mattered, the microbiologist whose simple bacterial test cracked the puzzle open, the two industrial laboratories that raced to crystallise the red vitamin within weeks of each other in 1948, the British chemist who mapped its astonishingly complex atomic structure with X-rays, and the two teams who finally built it from scratch. Where the historical record is firm we say so plainly; where priority was a near-tie or a genuine dispute, we mark it as such; and we have verified every name, date, and prize below.

Table of Contents

  1. A Vitamin Named by Its Cobalt Core
  2. The Disease First: Addison and Biermer
  3. Casimir Funk and the Word "Vitamine"
  4. The Liver Cure: Whipple, Minot, Murphy, and the 1934 Nobel Prize
  5. Castle and the Two Factors: Why the Stomach Matters
  6. Mary Shaw Shorb and the Bacterial Test That Cracked It Open
  7. 1948: Two Laboratories Crystallise the Red Vitamin
  8. Dorothy Hodgkin, X-Rays, and the 1964 Nobel Prize
  9. Building It from Scratch: Woodward and Eschenmoser
  10. From Death Sentence to a Drop in a Pill
  11. Research Papers and References
  12. Connections
  13. Featured Videos

A Vitamin Named by Its Cobalt Core

The name vitamin B12 records its place in a sequence. As the family of water-soluble "B" factors was teased apart in the first half of the twentieth century, each newly recognised member was given a number; the anti-pernicious-anaemia factor, isolated relatively late, became the twelfth. When the substance was finally obtained as pure red crystals in 1948 (see below), the chemists who reported it explicitly proposed the designation "vitamin B12" in print — so this is one of the rare cases where we can point to the exact paper that named the vitamin.

Its scientific name, cobalamin, came once the molecule's makeup was understood, and it tells you the single most distinctive fact about this nutrient: at the centre of the molecule sits one atom of the trace metal cobalt. No other vitamin contains a metal ion at its core, and it is the cobalt — bound inside a ring system later named the corrin ring — that gives B12 its deep red colour and its name (cobalt + the chemical suffix). The familiar supplement forms carry this naming through: cyanocobalamin, methylcobalamin, hydroxocobalamin, and adenosylcobalamin all share the -cobalamin root because they share that cobalt heart, differing only in the small group attached to the metal.

Unlike a few of the "B" numbers that were later reclassified or abandoned, vitamin B12 is a genuine, essential vitamin in the strict sense: the human body cannot make it, it is required in tiny amounts, and its absence causes a specific deficiency disease. That disease — and the people who learned to defeat it — is where the real history begins.

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The Disease First: Addison and Biermer

As with several vitamins, the disease was described long before anyone imagined a missing nutrient lay behind it. The first clear medical account belongs to Thomas Addison, a physician at Guy's Hospital in London. He spoke of a fatal "idiopathic" anaemia — an anaemia with no apparent cause — at a London medical meeting in 1849, and set it down more fully in his 1855 monograph On the Constitutional and Local Effects of Disease of the Supra-renal Capsules. Addison described patients who grew steadily paler, weaker, and more breathless until they died, with no bleeding or obvious cause to explain the wasting. (The same celebrated monograph also described the adrenal disorder we now call Addison's disease — a separate condition.) Because he gave the first recognisable clinical picture, the disorder is sometimes still called Addisonian anaemia.

The grim name most people know it by came later. In 1872 the German physician Anton Biermer published a fuller description and introduced the term "progressive pernicious anaemia" — pernicious meaning deadly, because that is exactly what it was. The disease is consequently sometimes labelled Addison–Biermer disease, crediting both men. What matters for our story is the shared verdict of nineteenth-century medicine: this anaemia was reliably, untreatably fatal. Doctors could name it and watch its course, but they could not stop it. That helplessness lasted more than seventy years after Addison, and it is the backdrop against which the breakthroughs of the 1920s landed like a miracle.

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Casimir Funk and the Word "Vitamine"

The very idea that a trace substance missing from the diet could cause a specific disease — the conceptual key that eventually unlocked B12 — owes much to the Polish-born biochemist Casimir Funk. In 1912, working in London on the cause of beriberi, Funk proposed that a class of compounds present in food in minute amounts was responsible for preventing diseases such as beriberi, scurvy, rickets, and pellagra. He believed the protective factor he was chasing was a chemical amine, and he coined the word "vitamine" — from the Latin vita (life) plus amine — to capture the idea of a "vital amine."

Funk's chemistry turned out to be only partly right. When it later emerged that many of these substances are not amines, the trailing "e" was dropped and "vitamine" became vitamin, the spelling we use today. (As it happens, vitamin B12 does contain nitrogen-rich amine-like groups, but that is incidental; the renaming was about the class as a whole.) Funk did not discover B12 — the molecule was decades from being isolated when he wrote — but he supplied the framework and the very word that made it possible to think of pernicious anaemia as a deficiency disease at all. Every milestone that follows is, in effect, the deficiency-disease idea being applied, tested, and ultimately proven on one specific missing nutrient.

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The Liver Cure: Whipple, Minot, Murphy, and the 1934 Nobel Prize

The first genuine defeat of pernicious anaemia did not come from finding the vitamin — that was still twenty years away — but from a startling dietary discovery, and it is the centrepiece of B12's history. It unfolded in two stages, and it earned the people responsible the 1934 Nobel Prize in Physiology or Medicine.

The groundwork was laid by George H. Whipple at the University of Rochester. Studying anaemia in dogs that had been made anaemic by bleeding, Whipple found around 1920 that feeding them liver was the most effective way to drive the regeneration of red blood cells. His dogs did not have pernicious anaemia, and Whipple was not initially studying that disease — but his work pointed a bright arrow at liver as something powerfully blood-building.

The decisive human step came in Boston. The physicians George R. Minot and William P. Murphy, of Harvard Medical School, reasoned that if liver rebuilt blood in Whipple's dogs, it might help their dying pernicious-anaemia patients. They put patients on a regimen of large amounts of lightly cooked liver — and the results were extraordinary. In their landmark 1926 paper in the Journal of the American Medical Association, "Treatment of pernicious anemia by a special diet," they reported that patients who would otherwise have died went into prompt, marked remission. A reliably fatal disease had, for the first time, been controlled. The treatment was demanding — patients had to eat roughly half a pound of liver every day — but it worked, and that changed everything.

In 1934 the Nobel Prize in Physiology or Medicine was awarded jointly to Whipple, Minot, and Murphy "for their discoveries concerning liver therapy in cases of anaemia." They were among the first Americans to win the prize in this category. It is worth being precise about what they had and had not found: they had discovered a cure — that something in liver reversed the disease — without yet knowing what that something was. The active ingredient was still hidden inside the liver, unnamed and unisolated. Naming and extracting it would occupy the next two decades, helped along by an industrial chemist, Edwin Cohn, who by 1928 had concentrated liver into an injectable extract many times more potent than the food itself — sparing patients the daily plates of liver.

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Castle and the Two Factors: Why the Stomach Matters

If liver cured the disease, why did pernicious-anaemia patients develop it in the first place — and why could some not be cured by liver taken by mouth? The answer came from another Boston physician, William Bosworth Castle, in a series of ingenious experiments carried out in the late 1920s — he conceived the idea around 1927, presented preliminary results in 1928, and published the landmark study in 1929. Castle suspected the problem lay not in the diet alone but in the stomach.

His experiment was as direct as it was unforgettable. Castle had healthy volunteers (including, by his account, himself) swallow beef muscle; after about an hour he recovered the partly digested stomach contents and fed that to patients with pernicious anaemia. Their blood improved — yet feeding the patients beef muscle alone, or normal gastric juice alone, did not work. Castle concluded that two things were needed together: an "extrinsic factor" supplied by food (present in beef muscle, and we now know it as vitamin B12 itself), and an "intrinsic factor" made by the normal stomach. Pernicious-anaemia patients, he reasoned, had stomachs that failed to produce the intrinsic factor, so even a B12-rich diet could not be absorbed.

Castle was exactly right, and his framework still organises the textbook account today. The "extrinsic factor" is dietary vitamin B12; the "intrinsic factor" is a protein secreted by the stomach's parietal cells that B12 must bind to in order to be absorbed in the small intestine. Pernicious anaemia is, at root, an autoimmune failure of intrinsic-factor production. Castle did not share the 1934 Nobel Prize — that honoured the liver-therapy discovery — but his two-factor insight explained why liver worked and laid the physiological foundation for everything that followed. It also explained the puzzle of absorption that still shapes how B12 deficiency is treated, from injections that bypass the gut to the high-dose oral tablets that exploit a small amount of passive uptake.

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Mary Shaw Shorb and the Bacterial Test That Cracked It Open

By the 1940s, everyone knew there was a potent "anti-pernicious-anaemia factor" hiding in liver, but no one could purify it — for a maddening reason. The only way to test whether a given liver fraction contained the factor was to inject it into a human patient and watch their blood over days or weeks. That made the chemists' trial-and-error purification agonisingly slow: you cannot run hundreds of test-tube experiments if each "test" is a sick person.

The bottleneck was broken by an American microbiologist, Mary Shaw Shorb. Working at the University of Maryland in the mid-1940s — reportedly on a grant of only a few hundred dollars — Shorb realised that a strain of bacteria, Lactobacillus lactis Dorner, needed the same liver factor in order to grow. Because the bacteria's growth could be measured quickly and cheaply in the lab, her finding turned an unworkable human bioassay into a fast microbiological assay: a fraction rich in the factor made the bacteria flourish; a depleted fraction did not. Shorb published this work in 1947–48.

The effect on the hunt was immediate and dramatic. Armed with Shorb's test, chemists could finally screen liver extracts at speed and follow the active ingredient as they purified it. Shorb collaborated closely with the Merck team led by Karl Folkers, and by her account the assay let them close in on pure crystals within a matter of months. Mary Shaw Shorb is the often-overlooked figure in this story: she discovered no vitamin and won no Nobel Prize, but without her bacterial yardstick the 1948 isolation might have taken years longer. It is a clean example of how a clever method can be the true turning point in a discovery.

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1948: Two Laboratories Crystallise the Red Vitamin

1948 is the year vitamin B12 became a real, holdable substance — and, in a genuine photo-finish, it happened in two laboratories on two sides of the Atlantic almost simultaneously. This is the closest thing in B12's history to a priority near-tie, and it is best told as exactly that.

In the United States, a team at Merck — Edward L. Rickes, Norman G. Brink, Frank R. Koniuszy, Thomas R. Wood, and Karl Folkers — isolated tiny, intensely red crystals of the active factor from liver and reported them in Science in April 1948 under the title "Crystalline Vitamin B12," the paper that put the name in print. Karl Folkers is usually credited as the senior figure of this group.

In Britain, almost at the same moment, Ernest Lester Smith (generally known as E. Lester Smith), working at Glaxo, independently purified the same red anti-pernicious-anaemia factor from liver and reported it in Nature, also in 1948. The two groups published within weeks of one another, and the standard histories treat the isolation as a near-simultaneous, independent achievement on both sides of the Atlantic rather than a clear single "first." A year later, the purified vitamin was given to a patient with pernicious anaemia and produced the expected dramatic recovery — the final proof that the long-sought factor and the new crystals were one and the same.

Two further facts round out the isolation. First, liver was a poor commercial source — it took enormous quantities to yield a speck of vitamin — and the practical supply problem was solved when B12 was found to be produced in abundance by bacteria such as Streptomyces, reflecting the deeper truth that vitamin B12 is ultimately made only by microorganisms, never by plants or animals themselves. Second, the chemists could now hold the vitamin but still could not draw it: its internal structure was a mystery, because the molecule was far too large and intricate for the chemical methods of the day. Solving that became the next prize — and it went to a remarkable scientist working with X-rays.

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Dorothy Hodgkin, X-Rays, and the 1964 Nobel Prize

Vitamin B12 is the most structurally complex of all the vitamins, and working out how its roughly 180 atoms were arranged defeated conventional chemistry. The problem was solved instead by Dorothy Crowfoot Hodgkin at Oxford, using the technique of X-ray crystallography — firing X-rays through crystals of the vitamin and deducing the atomic arrangement from the pattern of diffracted rays.

Hodgkin began the analysis in 1948, the very year the vitamin was isolated, and the work took years; the full structure was published in 1956, with key results appearing in Nature. It was a tour de force, carried out in collaboration with others — including Kenneth N. Trueblood at UCLA, whose access to early electronic computers helped with the immense calculations the analysis demanded. Hodgkin's structure revealed the cobalt atom at the molecule's heart, held inside a previously unknown ring system that came to be called the corrin ring — an entirely new feature in organic chemistry.

For determining the structures of important biochemical substances by X-ray techniques — vitamin B12 foremost among them — Dorothy Hodgkin was awarded the 1964 Nobel Prize in Chemistry. She remains, to this day, the only British woman to have won a Nobel Prize in a science, and she was the third woman ever to win the chemistry prize, after Marie Curie and Irène Joliot-Curie. With the structure in hand, B12 was no longer a mysterious red crystal that happened to cure a disease; it was a fully mapped molecule whose workings could finally be understood — and, in principle, copied.

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Building It from Scratch: Woodward and Eschenmoser

The last great milestone was to make vitamin B12 in the laboratory entirely from simple chemicals — a total synthesis — and given the molecule's complexity it became one of the most famous feats in the history of organic chemistry. It was accomplished in the early 1970s through a long collaboration between two of the towering chemists of the century: Robert Burns Woodward at Harvard University in the United States and Albert Eschenmoser at ETH Zürich in Switzerland.

The effort was on an almost industrial scale, spanning roughly a decade and drawing on the work of dozens of doctoral and postdoctoral chemists across the two institutions and many nations. The synthesis was announced in 1972 and the work published in the years around 1972–1973. The two laboratories pursued complementary routes to closing the molecule's difficult corrin ring, and the project is famous not only for its success but for the chemistry it created along the way — the insights it generated into how chemical reactions conserve symmetry fed directly into a major body of theory in the field.

A point of accuracy on the Nobel record: Woodward had already received the 1965 Nobel Prize in Chemistry for his outstanding achievements in the art of organic synthesis across many molecules — that prize predates and is not specifically "for" the B12 synthesis. Albert Eschenmoser, widely honoured for his part in the B12 work and for his wider contributions to organic chemistry, did not receive a Nobel Prize. We note this carefully because it is easy to assume the celebrated B12 synthesis must itself have won a Nobel; the accurate statement is that one of its two leaders was already a chemistry laureate.

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From Death Sentence to a Drop in a Pill

Set end to end, the arc of this history is one of the most satisfying in all of nutrition. Within a single century, pernicious anaemia went from a disease that Addison and Biermer could only describe and name as fatal, to one that Minot and Murphy could halt with plates of liver, to one whose mechanism Castle explained, whose active factor Shorb's bacterial test let Folkers and Lester Smith capture as red crystals, whose structure Hodgkin mapped atom by atom, and whose molecule Woodward and Eschenmoser finally built from scratch. Two Nobel Prizes — the 1934 Medicine prize for the cure and the 1964 Chemistry prize for the structure — bracket the achievement.

The human payoff is hard to overstate. A condition that killed reliably for the better part of a century is now, in most cases, fully and cheaply preventable and treatable — with B12 injections, or with the high-dose oral and sublingual tablets made possible once the chemistry was understood. The same scientific understanding underlies the modern recognition that strict vegans and many older adults need supplemental B12, since the vitamin comes ultimately from microbes and is absorbed through the elaborate, fragile pathway Castle first glimpsed.

One honest closing note belongs here, in the spirit of the rest of this page. The history above is the discovery of a vitamin and the conquest of a deficiency disease; it is not a claim that high-dose B12 is a cure-all for unrelated complaints. The detailed, evidence-based account of what B12 does in the body, who is at risk of deficiency, how it is measured, and how it is supplemented is covered on the main Vitamin B12 page and in the companion Vitamin B12 Benefits articles. This page has done its own narrower job: to tell, accurately, the remarkable true story of how humanity came to know this molecule at all.

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Research Papers and References

The list below gathers the landmark primary papers and authoritative reviews behind the discovery story told above, followed by curated PubMed topic-search links into the historical literature. Author names, titles, and journals are given as plain text; only the stable DOI, PMID, or archive link is hyperlinked, and each opens in a new tab. Nineteenth-century works by Addison and Biermer are named in the article as historical sources rather than as modern citations.

  1. Minot GR, Murphy WP. Treatment of pernicious anemia by a special diet. Journal of the American Medical Association. 1926;87(7):470-476. (Landmark-article reprint.) — PMID: 11769340
  2. Rickes EL, Brink NG, Koniuszy FR, Wood TR, Folkers K. Crystalline Vitamin B12. Science. 1948;107(2781):396-397. — doi:10.1126/science.107.2781.396
  3. Smith EL. Purification of anti-pernicious anaemia factors from liver. Nature. 1948;161(4095):638-639. — doi:10.1038/161638a0
  4. Hodgkin DC, Kamper J, Mackay M, Pickworth J, Trueblood KN, White JG. Structure of vitamin B12. Nature. 1956;178(4524):64-66. — doi:10.1038/178064a0
  5. Okuda K. Discovery of vitamin B12 in the liver and its absorption factor in the stomach: a historical review. Journal of Gastroenterology and Hepatology. 1999;14(4):301-308. — PMID: 10207776
  6. Scott JM, Molloy AM. The discovery of vitamin B12. Annals of Nutrition and Metabolism. 2012;61(3):239-245. — doi:10.1159/000343114
  7. The Nobel Prize in Physiology or Medicine 1934 (Whipple, Minot, Murphy) — NobelPrize.org: 1934 Medicine
  8. The Nobel Prize in Chemistry 1964 (Dorothy Crowfoot Hodgkin) — NobelPrize.org: Dorothy Hodgkin
  9. Vitamin B12 discovery and pernicious anaemia — history — PubMed: vitamin B12 discovery history
  10. Intrinsic factor and Castle's experiments — history — PubMed: Castle intrinsic factor history

External Authoritative Resources

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Connections

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