Observational study finds increased brown fat in patients using angiotensin receptor blockers — Evidence Review

Losartan, a common blood pressure medication, was found to activate energy-burning brown fat via a pathway independent of its cardiovascular effects, according to a large observational study at Rockefeller University. Related research broadly supports the role of ARBs and other pharmacological agents in brown fat activation and metabolic health, though mechanisms and outcomes can differ across drug classes.

• The new study aligns with prior work showing ARBs and other agents (e.g., telmisartan, mirabegron) can modulate adipose tissue, improve metabolic markers, and influence brown fat activity, but highlights a distinct, non-blood-pressure-related mechanism for losartan 5 6 7 9.
• Other studies have demonstrated that brown fat activation—whether through β-adrenergic agonists, mineralocorticoid receptor antagonists, or ARBs—is associated with improved insulin sensitivity, reduced visceral fat, and better cardiovascular outcomes, supporting the potential therapeutic value of targeting brown fat 1 2 3 10 13.
• While most prior research focused on metabolic and cardiovascular endpoints, this study is among the first to link brown fat to psychiatric health, and it calls attention to both potential benefits and possible adverse associations (e.g., osteoporosis, skin diseases) that require further exploration 10 13.

Study Overview and Key Findings

Growing interest in brown adipose tissue (BAT) is driven by its role in burning energy and influencing metabolic health, but pharmacological strategies to activate BAT in humans have been limited. This new observational study leverages over 100,000 patient records and PET/CT scans from Memorial Sloan Kettering Cancer Center, providing one of the largest datasets to date examining the link between antihypertensive medications and brown fat in clinical populations. By identifying a previously unrecognized effect of losartan on brown fat, and distinguishing its action from blood pressure lowering, the research opens possibilities for new therapeutic approaches beyond hypertension.

Property	Value
Study Year	2026
Organization	Rockefeller University, Memorial Sloan Kettering Cancer Center
Journal Name	Nature
Authors	Nicolás Gómez-Banoy, Jorge A. Barrero, Luiza Rachel Pinheiro de Carvalho, Caroline S. Jiang, Tara Doma Lama, Nakul Karandikar, Mascha Koenen, Tiffany Lam, Kaja Plucińska, Ksenia Morozova, Stephanie Chahwan, Gustavo Barraza, Burcin Agridag Ucpinar, Jennifer E. Liu, Rohit Sharma, Daniel Lafontaine, Heiko Schöder, Paul Cohen
Population	Patients taking angiotensin receptor blockers
Sample Size	n=100,000
Methods	Observational Study
Outcome	Brown fat activity, metabolic effects, psychiatric health
Results	Patients on ARBs had more brown fat detected on scans.

Literature Review: Related Studies

To contextualize the new findings, we searched the Consensus database of over 200 million research papers using the following queries:

1. ARB blood pressure drug brown fat
2. angiotensin receptor blockers fat metabolism
3. brown adipose tissue hypertension treatment effects

The related studies address several major questions about brown fat biology, pharmacological activation, and links to metabolic health:

Topic	Key Findings
How do ARBs and related drugs affect brown fat and metabolism?	- Telmisartan, an ARB, activates PPARγ, reduces visceral fat, and improves insulin resistance, while losartan and valsartan show variable effects 5 6 7 9. - ARBs generally improve adipose tissue function and glycemic control 8 12.
What are the effects of pharmacologic brown fat activation in humans?	- β2- and β3-adrenergic agonists (salbutamol, mirabegron) increase brown fat activity, resting energy expenditure, and may reduce body fat and improve cardiometabolic profiles 1 3 4.
What is the clinical significance of brown fat in cardiometabolic health?	- Presence of BAT in humans is associated with lower prevalence of type 2 diabetes, dyslipidemia, and cardiovascular diseases, especially in overweight/obese populations 10 13 14.
Are there additional health associations or risks linked to brown fat?	- Brown fat activity may be linked to reduced psychiatric disease (as newly reported), though some data also suggest potential associations with osteoporosis and skin disease, warranting further study 10 13.

How do ARBs and related drugs affect brown fat and metabolism?

Existing research shows that certain ARBs, especially telmisartan, possess metabolic actions beyond blood pressure reduction, including improvement in insulin sensitivity and modulation of adipose tissue. While telmisartan is a partial PPARγ agonist, losartan's mechanism appears distinct and is newly implicated in brown fat activation. The new study adds to the evidence that ARBs can influence adipose tissue biology, but suggests that losartan may act via a separate pathway from blood pressure control.

• Telmisartan reduces visceral fat and improves glucose metabolism, outperforming other ARBs like valsartan in preclinical and clinical studies 6 7.
• Both losartan and telmisartan modulate the hepatic renin-angiotensin system, leading to reduced liver fat and better glycemic control in obesity models 9.
• ARBs improve adipose tissue function and insulin sensitivity by reducing inflammation and promoting adiponectin production 8 12.
• The new study is among the first to show that losartan activates brown fat in humans, and does so independently of its antihypertensive effect.

What are the effects of pharmacologic brown fat activation in humans?

Several agents beyond ARBs can pharmacologically activate brown fat in humans, with clinical trials demonstrating increased energy expenditure and improved metabolic outcomes. However, side effects and receptor specificity remain challenges. The new study on losartan complements this literature by suggesting a new, potentially safer pharmacological route to BAT activation.

• β2-adrenergic agonists (e.g., salbutamol) and β3-adrenergic agonists (e.g., mirabegron) activate human BAT, increase glucose uptake, and may reduce body fat mass and serum LDL-cholesterol 1 3.
• Mirabegron increases BAT activity, energy expenditure, and metabolic rate, but also raises heart rate and blood pressure at higher doses; combining with β1-blockers may mitigate cardiovascular effects 3 4.
• Existing BAT-activating agents act through sympathetic pathways, while losartan's mechanism appears distinct and non-cardiovascular.

What is the clinical significance of brown fat in cardiometabolic health?

Brown adipose tissue has emerged as a protective factor against metabolic and cardiovascular diseases in both animal and human studies. The new study reinforces previous findings by showing that patients with more brown fat have better metabolic and cardiovascular profiles, and extends these associations to psychiatric health.

• Large cohort studies confirm that BAT is associated with lower odds of type 2 diabetes, dyslipidemia, coronary artery disease, and hypertension, particularly in overweight/obese individuals 10.
• BAT activation is linked to improved glucose and lipid profiles, and its beneficial effects are more pronounced in those at higher cardiometabolic risk 10 13.
• Brown fat exerts health benefits via thermogenic and endocrine functions, including secretion of protective molecules like FGF21 and 12,13-diHOME 11 13.

Are there additional health associations or risks linked to brown fat?

While much attention has focused on metabolic and cardiovascular benefits, the new study is among the first to systematically assess other health associations with brown fat, including psychiatric and bone health. The findings highlight the need to consider both positive and negative associations as brown fat-targeting therapies are developed.

• Patients with more brown fat were found to have lower rates of anxiety and depression, suggesting a possible link between metabolic and psychiatric health 10.
• Some studies and the new analysis report higher rates of osteoporosis and skin diseases in patients with greater brown fat activity, raising questions about potential trade-offs or confounding factors 10.
• The interplay between brown fat, medication use (including SSRIs), and broader health outcomes remains a largely unexplored area requiring further study.

Future Research Questions

Although the new study provides compelling evidence linking losartan to brown fat activation and broader metabolic and psychiatric health outcomes, several important questions remain. Further research is needed to clarify the mechanisms, long-term effects, and broader safety of targeting brown fat in diverse populations.

Research Question	Relevance
Does activating brown fat with losartan improve metabolic and psychiatric health in people without hypertension?	Understanding whether losartan can safely benefit individuals with normal blood pressure could expand its use beyond hypertension, especially since the mechanism appears independent of cardiovascular effects 5 6 10.
What are the long-term health consequences of sustained brown fat activation in humans?	Long-term effects, including both benefits (e.g., metabolic health) and potential risks (e.g., osteoporosis, skin disease), are not well defined and require prospective studies 10 13.
Which molecular pathways mediate losartan’s effect on brown fat compared to other ARBs?	Elucidating the exact pathways could inform drug development and clarify why losartan, but not all ARBs, have this effect, as well as identify targets for more selective brown fat activation 5 7 9.
How does brown fat activity influence psychiatric disease risk and treatment?	The observed association between brown fat and lower rates of anxiety and depression is novel; understanding causality and mechanisms could reveal new approaches to mental health 10 13.
Are there genetic or demographic factors that predict brown fat responsiveness to pharmacological activation?	Personalizing therapies will require knowledge of which populations are most likely to benefit or experience adverse effects from brown fat-targeting drugs, as suggested by variable responses in the literature 10 12 14.