Rapamycin for aging
Evolving Concepts

Rapamycin for Aging: Lessons in Biology, Ethics, and Scientific Rigor

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Rapamycin for Aging

Rapamycin, a macrolide compound originally developed as an antifungal and later repurposed as an immunosuppressant for organ transplant recipients, is now widely studied for its role as a modulator of the mechanistic target of rapamycin (mTOR) pathway. The mTOR pathway – particularly mTOR complex 1(mTORC1) – is a central regulator of cellular growth, metabolism, and protein synthesis, and is responsive to nutrient availability, energy status, and stress1. Inhibition of mTORC1 has been associated with lifespan extension in multiple model organisms, from yeast and worms to flies and mice, leading to interest in rapamycin as a potential geroprotective therapy to slow the biological processes of aging and reduce the risk of age-related disease2,3.

As enthusiasm surrounding its use in humans grows, our recent mini-review, published in Frontiers in Aging, offers a critical perspective of these findings . We contrast the clinical rigor of rapamycin’s use in epilepsy and rare disease settings with the more speculative and loosely regulated practices observed in the context of longevity and aging research, longevity clinics, and biohackers.

Our review, titled “Rapamycin for Longevity: The Pros, The Cons, and Future Perspectives,” highlights the need for greater caution and rigor in the translation of rapamycin from animal studies and rare disease settings to widespread off-label use in otherwise healthy individuals. We argue that lessons learned from the epilepsy field – specifically, the treatment of monogenic mTORopathies like tuberous sclerosis complex (TSC) has established rapamycin’s safety, dosing, and efficacy parameters through years of basic, pre-clinical, and clinical research, which could inform how longevity research proceeds.

These insights are notably absent in many current off-label uses of rapamycin for aging where dosing regimens, pharmacodynamic targets, and long-term outcomes are poorly defined.  For example, the epilepsy field has long relied on biomarkers such as phospho-ribosomal S6 (p-S6) as a tissue biomarker to assess mTORC1 hyperactivation in resected brain specimens.

This approach remains underutilized in the anti-aging/longevity field. Indeed, in the epilepsy field clear standards have been designed to ensure its use in the correct populations with the maximum amount of safety. In contrast, anti-aging clinics and biohackers often employ rapamycin in ways that lack standardized biomarkers, therapeutic targets, or established endpoints. Unlike the biohacking community’s reliance on self-directed dosing and minimal monitoring, the epilepsy field provides a model for how tissue-level evidence, therapeutic thresholds, and long-term clinical surveillance can, and should, guide mTOR inhibitor use. Our paper urges the aging field to adopt similar strategies – validating tissue or blood-based pharmacodynamic biomarkers, stratifying risk profiles, and defining target populations more clearly.

Our review also highlights the issues of species differences in pharmacokinetics and toxicity, and sex-specific responses including drug metabolism, bioavailability, and half-life, that complicate the direct translation of rapamycin’s effects from model organisms to aging humans. In addition, only a few studies have looked at the potential for mTORC2 inhibition (the sister complex of mTORC1) to drive off-target metabolic effects such as insulin resistance4,5 – which is antithetical to the anti-aging outcomes that are desired by longevity researchers and biohackers alike. While emerging human data suggests that low-dose or intermittent dosing regimens may mitigate some of these concerns, we argue that more research and better patient stratification is needed before rapamycin can be safely and ethically mainstreamed as longevity therapy.

Low-dose rapamycin has been shown to exacerbate uveitis and INF-y producing T cells in experimental uveitis models for example, suggesting that even modest immune modulation may provoke autoimmunity in susceptible indiviudals6. Additionally immune axis shifts are well known in rheumatology pharmacological interventions. For example, TNF-α inhibitors—used to treat RA and inflammatory bowel disease—can paradoxically induce psoriatic lesions in a subset of patients7–9. These responses underscore the nonlinear immune compensation seen with cytokine manipulation. Like anti-depressants, immunomodulators may exhibit tachyphylaxis – diminishing response overtime to successive doses. This is concerning for mTOR inhibitors, which lack alternative options.

Such risks remain largely unaccounted for in the longevity field, where low-dose rapamycin is presumed safer due to its mild pharmacologic profile. Importantly, we raise ethical concerns about the increasing proliferation and online availability of rapamycin through telehealth clinics offering rapamycin prescriptions with little oversight, often without clear patient stratification, standardized dosing, or validated surrogate endpoints. This trend raises concerns about patient safety, informed consent, and the commercialization of speculative science.

Philosophical and regulatory tensions persist around aging as a therapeutic target. Since the FDA does not recognize aging as a disease, clinical trials and approvals remain limited—despite growing links between aging biology and chronic conditions like Alzheimer’s and autoimmunity. These blurred boundaries between prevention and treatment call for clearer aging-related disease classifications.

Figure 1 RapamycinFigure 1: Role of mTOR signaling in physiological processes.

From a neuroendocrine-immunology perspective, this dialogue opens the door to new interdisciplinary inquiries. mTOR pathway signaling interfaces with numerous physiological systems, including hormonal regulation, immune-signaling processes, and neuroplasticity10,11. For instance, mTOR modulates hormones including estrogen signaling and thyroid hormone sensitivity- both of which change with age and contribute to cognitive decline and metabolic dysfunction 12–14. Aberrant mTOR signaling may also contribute to immune dysregulation via cytokine imbalance, supporting rapamycin’s potential utility in certain rheumatologic conditions.

Notably, rapamycin has shown promising results in clinical trials for systemic lupus erythematosus (SLE)15. Given the mechanistic overlap between SLE and tuberous sclerosis complex, rheumatology may benefit from research on rapamycin use. Similarly, aging and studies could gain insights into patient stratification and immune profiling from rheumatologic practice15.

Figure 2 RapamycinFigure 2: Impact of cytokines on mTOR-mediated immune responses.

While TSC2 is more established in autoimmune diseases such as lupus,16–18 emerging evidence suggests that mTORC1 hyperactivation may contribute to metabolic stress phenotypes associated with chronic inflammation and aging, including mitochondrial dysfunction, impaired autophagy, and redox imbalance19–23. Clinically, mTORC1-driven immune activation may overlap with features of age-related inflammatory decline. Chronic autoimmune disorders—including lupus, rheumatoid arthritis, autoimmune thyroiditis, and other connective tissue diseases—commonly exhibit elevated IL-6 and TNF-α, alongside dysregulation of the Th17/IL-23 axis, all of which are also implicated in aging.

Mechanistically, mTORC1 activation promotes Th17 differentiation, enhances IL-17 and IL-23 production, and suppresses regulatory T cell (Treg) function, collectively tipping the immune balance toward inflammation 1,11,15,24–26. Although aging and rheumatologic diseases share biomarkers and mechanistic features—such as elevated IL-6 or mTORC1 signaling—this overlap should not be mistaken for evidence that rapamycin offers durable prevention of age-related immune dysfunction in the absence of disease.

However, this framework may help explain how individuals with mTORopathies exhibit long-term vulnerabilities to diseases of aging and cancer27. Loss-of-function mutations in genes such as TSC1/2 lead to early life hyperactivation of mTORC1 signaling28. This constitutive pathway activation may chronically disrupt immune and endocrine homeostasis that accumulate across the lifespan1,11,29,30. Additionally, mTORC1 hyperactivity in hematopoietic or thyrocyte lineages has been linked to autoimmune phenomena and chronic inflammation, both of which are known contributors to biological aging11,15.

Importantly, cancer – one of the leading causes of mortality in individuals with epilepsy – is also associated with mTOR-driven metabolic reprogramming27,31. Recognizing these shared endocrine-immune features may not only provide mechanistic insight into how mTOR dysregulation bridges neurodevelopmental and degenerative conditions, but also offer novel biomarkers and therapeutic targets for aging interventions.

We hope this piece sparks dialogue across fields – uniting epilepsy researchers, aging scientists, endocrinologists, and immunologists – in a shared mission to responsibly harness the therapeutic promise of mTOR inhibition. Interdisciplinary collaboration will be key in building a safer, more scientifically grounded framework for rapamycin’s use in aging.

The contents of this article were adapted from the author’s publication in Frontiers in Aging: “Rapamycin for longevity the pros, the cons, and future perspectives” by Roark K. and Iffland P.H. (2025).

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Authors Affiliations:

Kelley M. Roark, Department of Neurology, University of Maryland School of Medicine, Baltimore MD, USA. Kelley.roark@som.umaryland.edu

Philip H. Iffland II, Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, USA. piffland@som.umarlyna.edu

Cover Image Credit: (Left Panel): Geroprotective interventions target the Hallmarks of Aging. From: Translational geroscience: A new paradigm for 21st century medicine. Matt Kaeberlein, Transl Med Aging 2017 Sep 27;1:1–4. doi: 10.1016/j.tma.2017.09.004; note there is evidence suggesting that rapamycin targets all nine of the hallmarks of aging to some extent; Figure modified at Rapamycin is the most promising aging intervention we currently have. (Right Panel): Easter Island Heads, from: HistoryExtra | BBC

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