How the WHO Essential Medicines List Is Actually Chosen

A medicine earns a place on the WHO Essential Medicines List not by being new, heavily marketed, or the most advanced option for a disease, but by passing three tests in front of an independent expert committee that meets every two years: the evidence has to show it works, its harms have to be acceptable, and it has to deliver real value against what it costs. Clear all three for a health problem that matters at the population level and a medicine is listed. Fall short on any one, however promising the drug, and it is not.

Key points#

• The list answers a systems question, not a bedside one: what should a health service stock to treat most people, in most settings, well and affordably.
• Nothing is added unless someone applies. The list is built from structured applications that a company, a clinician, a society, or an individual can submit.
• Three criteria decide each case: public health need, evidence of efficacy and safety, and comparative cost and cost-effectiveness.
• Cost is weighed alongside the clinical evidence, not tacked on at the end as a tiebreaker.
• More than 150 countries adapt the WHO template into their own national lists, so the Model List is a starting point, not a final answer.

What "essential" is meant to capture#

WHO defines essential medicines as those that meet the priority health care needs of a population. Read that definition slowly, because the wording sets up everything that follows. The committee is not trying to crown the single best therapy ever devised for a condition. It is asking a narrower and more practical question: given finite budgets and uneven infrastructure, which medicines let a health system treat the greatest number of people effectively and safely at a price it can keep paying.

That population lens explains a lot of the decisions that follow. A drug that produces a marginal benefit at an extreme price may lose to an older, cheaper option that treats far more patients for the same money. The first Model List, published in 1977, held roughly 200 medicines, according to WHO's fact sheet on essential medicines. A dedicated list for children arrived in 2007. The 2025 revision, the 24th edition, carries 523 medicines for adults and 374 for children, per WHO's announcement of that update, and still fits the same test.

Nothing gets added unless someone asks#

The most common misconception you will meet is that WHO scans the pharmaceutical market and hands out places. It does not. The list is application driven from start to finish. A pharmaceutical company, a professional society, a WHO department, a treating clinician, or even a single interested person can file a structured application to add a medicine, change how an existing one is listed, or remove one that no longer earns its spot. Whoever applies carries the work of assembling the evidence and arguing the case. That design matters, because it means the list grows in response to documented need and available data, and it means the burden of proof sits with the applicant rather than with the committee to go hunting.

The three questions every candidate faces#

For each application the committee applies the same criteria set out in its terms of reference: the prevalence and public health relevance of the condition, the scientific evidence of efficacy and safety, and the comparative cost and cost-effectiveness.

The first question is whether the medicine genuinely helps. That means real clinical benefit shown in credible trials, not a tidy mechanism or a surrogate marker standing in for an outcome patients actually feel. The second is whether it is safe enough: the harms have to be well described and reasonable in light of the benefit on offer.

The third question is where the Model List parts company most sharply with a national drug regulator. A regulator asks whether a medicine is safe and effective enough to be sold. The committee asks something further: is it worth listing when compared with the alternatives already on the list. A fully approved medicine can still fail the essential test if a cheaper option delivers a similar result, because every candidate is judged against what it would displace or sit beside.

Why cost lives inside the science, not after it#

It is tempting to picture cost as a final filter, applied once the clinical arguments are settled. That is not how the committee works. Comparative cost and cost-effectiveness are weighed together with efficacy and safety throughout the review. A medicine's price is part of the evidence about its value, not a separate accounting step. This is what lets the list stay affordable enough to be useful in low and middle income settings without pretending that money is beside the point.

A decision made in public#

For a body with this much influence over global procurement, the process is strikingly open. Applications are posted on WHO's website for public review and comment before the meeting. The application itself, the expert peer reviews, comments from WHO technical departments, and submissions from outside groups are all published. You can read the case for and against a given medicine and trace how the committee reached its view. That transparency is a deliberate safeguard, because when a small panel shapes what health systems buy for billions of people, the antidote to suspicion is showing the reasoning rather than announcing the verdict.

Who sits on the committee#

The recommendations come from the WHO Expert Committee on the Selection and Use of Essential Medicines. Its members are drawn from WHO's expert advisory panels for their clinical and technical background, with deliberate attention to geographic and gender balance so that practice from low, middle, and high income settings is all represented. Members declare interests that could color their judgment. The committee's role is advisory: it recommends additions, changes, and deletions, and WHO then adopts the revised lists.

The numbering can trip people up. The committee that met in Geneva from 5 to 9 May 2025 was the 25th such meeting, and its work produced the 24th edition of the main list. It considered 59 applications that cycle.

Core, complementary, and the antibiotic classes#

The list is not a flat inventory. It marks core items, the most cost-effective choices for major health problems that need little added infrastructure, apart from complementary items, which call for specialized training, diagnostics, or monitoring, or carry a less favorable balance of benefit and cost. Layered on top is the AWaRe classification of antibiotics (Access, Watch, Reserve), which steers prescribing toward stewardship and slows the spread of resistance.

What a listing does and does not tell you#

Two limits are worth stating plainly. First, "essential" is a system-level judgment, not a ranking of the best therapies for one patient, and it never substitutes for a clinician's decision about one particular patient. Second, the Model List is a template. More than 150 countries maintain their own national essential medicines lists, adapting WHO's version to local disease burden, budgets, and capacity. The Model List informs procurement, reimbursement, donations, and local manufacturing, but each country decides what it can actually deliver.

Read this way, a listing tells you something specific. It is not a trophy for the most sophisticated molecule. It is a signal that, on the published evidence, a medicine has earned a place in a system built to treat a population well and within its means.