Peru obesity drugs: budget impact explained

In July 2026, Victor J. Vera Ponce published a budget-impact analysis in Obesity Pillars that asked a question most obesity-drug coverage debates never quantify: what would it actually cost Peru if the government decided to fund pharmacotherapy for everyone who qualifies^[1]? The answer, at full coverage, runs from roughly S/9.6 billion to S/143 billion per year depending on which drug and which eligibility criterion you pick.

The study draws on a national health survey covering 76,819 participants and builds two candidate populations. The broad criterion follows the World Health Organization definition of obesity^[3]: 9.04 million Peruvian adults. The pragmatic-priority criterion applies a narrower filter for comorbidities, arriving at 3.67 million. All cost estimates run against both groups.

The drugs in scope and what they would cost

The analysis covers three approved agents: liraglutide 3.0 mg (a once-daily GLP-1 receptor agonist), naltrexone/bupropion extended-release, and phentermine/topiramate extended-release. Semaglutide 2.4 mg, the once-weekly GLP-1 agonist studied in the STEP 1 trial^[4], is quoted separately as a cost-per-patient reference: S/16,804.86 in the first year and S/18,135.52 in maintenance years.

At 100% coverage of the broad criterion population (9.04 million), the annual medication cost figures are:

Liraglutide 3.0 mg: S/142.95 billion. Naltrexone/bupropion: S/23.65 billion. Phentermine/topiramate: S/26.83 billion.^[1]

Narrowing to the pragmatic-priority group (3.67 million) cuts those figures roughly in half: liraglutide to S/57.95 billion, naltrexone/bupropion to S/9.59 billion, and phentermine/topiramate to S/10.88 billion.

Why liraglutide is the most expensive option

The liraglutide figure is the most striking because of the drug's unit cost, not its efficacy relative to alternatives. Semaglutide 2.4 mg, which tends to produce larger weight reductions in trials, is not included in the aggregate projections because it is priced separately in the study as a per-patient cost reference rather than as a scenario modelled at population scale. The gap between the two GLP-1 receptor agonists in the analysis reflects the very different per-dose pricing that governs drug procurement in middle-income countries.

The population context

Peru's obesity burden has been increasing rapidly. A separate 2026 analysis of 257,264 Peruvians surveyed between 2014 and 2024 found that class III obesity (BMI at or above 40 kg/m2) grew at an average of 8.9% per year, and that severe obesity expanded from higher-income groups into middle and lower socioeconomic strata^[2]. That widening distribution is exactly what makes a budget-impact model matter: a condition once concentrated among those who might fund private treatment is now common among populations who would need public coverage.

Globally, the World Health Organization estimated in 2022 that one in eight people lives with obesity and that rates have more than doubled since 1990^[3]. The Region of the Americas has the highest prevalence among WHO regions, at 67% overweight. Peru sits within that regional picture.

What the analysis does and does not say

Budget-impact models estimate medication acquisition costs. They do not account for administration, monitoring, or any offset from reduced downstream costs (hospitalisations, diabetes complications, cardiovascular events). The Vera Ponce analysis is explicit that the numbers represent pharmacotherapy spend only, and that 'budget impact is driven primarily by candidate-population size and annual medication cost.'

The study does not make a recommendation about which drug to choose or whether Peru should fund pharmacotherapy. It gives policymakers numbers for a decision framework. For readers tracking semaglutide specifically: the study's per-patient cost reference for semaglutide 2.4 mg is based on current Peruvian pricing and does not reflect any future negotiated procurement price, which would almost certainly be lower if the drug were included in a national formulary.

What this means for access to GLP-1 medicines in middle-income countries

The STEP 1 trial reported that once-weekly semaglutide 2.4 mg produced a mean 14.9% weight reduction at 68 weeks versus 2.4% on placebo^[4]. That is a clinically meaningful result, but it only benefits patients who can access the drug. In a country where a single year of semaglutide at retail costs more than S/16,000, public coverage is the gating factor for most of the population who would qualify under either the broad or the pragmatic criterion in this analysis.

The Vera Ponce paper is one of a small number of published budget-impact analyses for GLP-1 class drugs in Latin America. Similar analyses exist for high-income settings, but the cost structures differ enough that high-income estimates are not directly portable to Peruvian policy discussions. This paper provides a nationally calibrated starting point.

This article covers research findings and regulatory context for informational purposes. It does not constitute medical advice. Consult a qualified healthcare provider before making any decisions about treatment.

A budget model becomes more useful when its assumptions are tested across several realistic scenarios. Coverage rates, negotiated prices, treatment persistence, and clinical capacity can each change the total substantially. Decision-makers therefore need a range of estimates rather than one retail-price total treated as a forecast.