# Autophagy: What Humans Actually Have Evidence For

No, 16 hours of fasting does not cleanly switch on autophagy in humans. The cleanest peer-reviewed muscle-biopsy study (8 healthy men) shows the markers move at roughly 72 hours, not 16, and the randomized 16:8 TREAT trial (n=116) found no weight or metabolic benefit. The "16-hour" figure is mostly mouse data scaled to humans, repeated until it sounded official.

Autophagy won a Nobel Prize and sits on the list of twelve hallmarks of aging. So it is real. But almost everything popular media tells you about switching it on in humans is mouse data with the species quietly cut off. Here is the honest 2026 read for anyone in DACH who cares about living longer.

## On this page

- What Is Autophagy, Really?
- Why Does Autophagy Matter for Aging?
- How Do You Switch Autophagy On? (mTOR Off, AMPK On)
- Does 16 Hours of Fasting Actually Trigger Autophagy?
- Does Eating Less Protein Boost Autophagy?
- Rapamycin, Spermidine, Resveratrol: Which Drugs and Supplements Actually Work?
- Does Exercise Trigger Autophagy?
- Why Is Graz the European Capital of Autophagy Research?
- What Diseases Is Autophagy Actually Connected To?
- Autophagie Kur, Apheresis, Combo Supplements: What Are DACH Clinics Actually Selling?
- Is There Any EU-Authorised Autophagy Health Claim?
- So What Should You Actually Believe?

## FAQ

- When does autophagy actually start during a fast?
- What is the difference between autophagy and apoptosis?
- Which foods or supplements actually activate autophagy?
- Is 16:8 intermittent fasting enough to trigger autophagy?
- What does spermidine actually do?
- Rapamycin and autophagy: what does the evidence actually show?
- Does exercise activate autophagy?
- Are there any EU-authorised autophagy health claims?

## Sources

- Nobel Assembly at Karolinska Institutet. (2016). The Nobel Prize in Physiology or Medicine 2016 — Press release. nobelprize.org
- Tsukada M, Ohsumi Y. (1993). Isolation and characterization of autophagy-defective mutants of Saccharomyces cerevisiae. FEBS Letters. https://doi.org/10.1016/0014-5793(93)80398-e
- Mizushima N, Noda T, Yoshimori T, Tanida I, Ishii T, George MD, Klionsky DJ, Ohsumi M, Ohsumi Y. (1998). A protein conjugation system essential for autophagy. Nature. https://doi.org/10.1038/26506
- Kabeya Y, Mizushima N, Ueno T, Yamamoto A, Kirisako T, Noda T, Kominami E, Ohsumi Y, Yoshimori T. (2000). LC3, a mammalian homologue of yeast Apg8p, is localized in autophagosome membranes after processing. EMBO Journal. https://doi.org/10.1093/emboj/19.21.5720
- Bjørkøy G, Lamark T, Brech A, Outzen H, Perander M, Overvatn A, Stenmark H, Johansen T. (2005). p62/SQSTM1 forms protein aggregates degraded by autophagy and has a protective effect on huntingtin-induced cell death. Journal of Cell Biology. https://doi.org/10.1083/jcb.200507002
- Mizushima N, Komatsu M. (2011). Autophagy: renovation of cells and tissues. Cell. https://doi.org/10.1016/j.cell.2011.10.026
- Klionsky DJ et al.. (2021). Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition). Autophagy. https://doi.org/10.1080/15548627.2020.1797280
- Hansen M, Rubinsztein DC, Walker DW. (2018). Autophagy as a promoter of longevity: insights from model organisms. Nature Reviews Molecular Cell Biology. https://doi.org/10.1038/s41580-018-0033-y
- López-Otín C, Blasco MA, Partridge L, Serrano M, Kroemer G. (2023). Hallmarks of aging: An expanding universe. Cell. https://doi.org/10.1016/j.cell.2022.11.001
- Levine B, Kroemer G. (2019). Biological Functions of Autophagy Genes: A Disease Perspective. Cell. https://doi.org/10.1016/j.cell.2018.09.048
- Levine B, Kroemer G. (2008). Autophagy in the Pathogenesis of Disease. Cell. https://doi.org/10.1016/j.cell.2007.12.018
- Kim J, Kundu M, Viollet B, Guan KL. (2011). AMPK and mTOR regulate autophagy through direct phosphorylation of Ulk1. Nature Cell Biology. https://doi.org/10.1038/ncb2152
- Saxton RA, Sabatini DM. (2017). mTOR Signaling in Growth, Metabolism, and Disease. Cell. https://doi.org/10.1016/j.cell.2017.02.004
- Hardie DG, Ross FA, Hawley SA. (2012). AMPK: a nutrient and energy sensor that maintains energy homeostasis. Nature Reviews Molecular Cell Biology. https://doi.org/10.1038/nrm3311
- Liang XH, Jackson S, Seaman M, Brown K, Kempkes B, Hibshoosh H, Levine B. (1999). Induction of autophagy and inhibition of tumorigenesis by beclin 1. Nature. https://doi.org/10.1038/45257
- Mariño G, Pietrocola F, Eisenberg T, et al.. (2014). Regulation of autophagy by cytosolic acetyl-coenzyme A. Molecular Cell. https://doi.org/10.1016/j.molcel.2014.01.016
- Mariño G, Pietrocola F, Madeo F, Kroemer G. (2014). Caloric restriction mimetics: natural/physiological pharmacological autophagy inducers. Autophagy. https://doi.org/10.4161/auto.36413
- Kraus WE, Bhapkar M, Huffman KM, Pieper CF, Krupa Das S, Redman LM, Villareal DT, Rochon J, Roberts SB, Ravussin E, Holloszy JO, Fontana L, CALERIE Investigators. (2019). 2 years of calorie restriction and cardiometabolic risk (CALERIE): exploratory outcomes of a multicentre, phase 2, randomised controlled trial. Lancet Diabetes & Endocrinology. https://doi.org/10.1016/S2213-8587(19)30151-2
- Waziry R, Ryan CP, Corcoran DL, Sugden K, Caspi A, Moffitt TE, Belsky DW. (2023). Effect of long-term caloric restriction on DNA methylation measures of biological aging in healthy adults from the CALERIE trial. Nature Aging. https://doi.org/10.1038/s43587-022-00357-y
- Stekovic S, Hofer SJ, Tripolt N, Aon MA, Royer P, Pein L, Stadler JT, Pendl T, Prietl B, Url J, Schroeder S, Tadic J, Eisenberg T, Magnes C, Stumpe M, Zuegner E, Bordag N, Riedl R, Schmid A, Kolesnik E, Verheyen N, Springer A, Madl T, Sinner F, de Cabo R, Kroemer G, Obermayer-Pietsch B, Dengjel J, Sourij H, Pieber TR, Madeo F. (2019). Alternate Day Fasting Improves Physiological and Molecular Markers of Aging in Healthy, Non-obese Humans. Cell Metabolism. https://doi.org/10.1016/j.cmet.2019.07.016
- de Cabo R, Mattson MP. (2019). Effects of Intermittent Fasting on Health, Aging, and Disease. New England Journal of Medicine. https://doi.org/10.1056/NEJMra1905136
- Cienfuegos S, Gabel K, Kalam F, Ezpeleta M, Wiseman E, Pavlou V, Lin S, Oliveira ML, Varady KA. (2020). Effects of 4- and 6-h Time-Restricted Feeding on Weight and Cardiometabolic Health: A Randomized Controlled Trial in Adults with Obesity. Cell Metabolism. https://doi.org/10.1016/j.cmet.2020.06.018
- Wei M, Brandhorst S, Shelehchi M, Mirzaei H, Cheng CW, Budniak J, Groshen S, Mack WJ, Guen E, Di Biase S, Cohen P, Morgan TE, Dorff T, Hong K, Michalsen A, Laviano A, Longo VD. (2017). Fasting-mimicking diet and markers/risk factors for aging, diabetes, cancer, and cardiovascular disease. Science Translational Medicine. https://doi.org/10.1126/scitranslmed.aai8700
- Lowe DA, Wu N, Rohdin-Bibby L, Moore AH, Kelly N, Liu YE, Philip E, Vittinghoff E, Heymsfield SB, Olgin JE, Shepherd JA, Weiss EJ. (2020). Effects of Time-Restricted Eating on Weight Loss and Other Metabolic Parameters in Women and Men With Overweight and Obesity: The TREAT Randomized Clinical Trial. JAMA Internal Medicine. https://doi.org/10.1001/jamainternmed.2020.4153
- Levine ME, Suarez JA, Brandhorst S, Balasubramanian P, Cheng CW, Madia F, Fontana L, Mirisola MG, Guevara-Aguirre J, Wan J, Passarino G, Kennedy BK, Wei M, Cohen P, Crimmins EM, Longo VD. (2014). Low protein intake is associated with a major reduction in IGF-1, cancer, and overall mortality in the 65 and younger but not older population. Cell Metabolism. https://doi.org/10.1016/j.cmet.2014.02.006
- Solon-Biet SM, McMahon AC, Ballard JWO, Ruohonen K, Wu LE, Cogger VC, Warren A, Huang X, Pichaud N, Melvin RG, Gokarn R, Khalil M, Turner N, Cooney GJ, Sinclair DA, Raubenheimer D, Le Couteur DG, Simpson SJ. (2014). The ratio of macronutrients, not caloric intake, dictates cardiometabolic health, aging, and longevity in ad libitum-fed mice. Cell Metabolism. https://doi.org/10.1016/j.cmet.2014.02.009
- Miller RA, Buehner G, Chang Y, Harper JM, Sigler R, Smith-Wheelock M. (2005). Methionine-deficient diet extends mouse lifespan, slows immune and lens aging, alters glucose, T4, IGF-I and insulin levels, and increases hepatocyte MIF levels and stress resistance. Aging Cell. https://doi.org/10.1111/j.1474-9726.2005.00152.x
- Cabreiro F, Au C, Leung KY, Vergara-Irigaray N, Cochemé HM, Noori T, Weinkove D, Schuster E, Greene NDE, Gems D. (2013). Metformin retards aging in C. elegans by altering microbial folate and methionine metabolism. Cell. https://doi.org/10.1016/j.cell.2013.02.035
- Harrison DE, Strong R, Sharp ZD, Nelson JF, Astle CM, Flurkey K, Nadon NL, Wilkinson JE, Frenkel K, Carter CS, Pahor M, Javors MA, Fernandez E, Miller RA. (2009). Rapamycin fed late in life extends lifespan in genetically heterogeneous mice. Nature. https://doi.org/10.1038/nature08221
- Mannick JB, Del Giudice G, Lattanzi M, Valiante NM, Praestgaard J, Huang B, Lonetto MA, Maecker HT, Kovarik J, Carson S, Glass DJ, Klickstein LB. (2014). mTOR inhibition improves immune function in the elderly. Science Translational Medicine. https://doi.org/10.1126/scitranslmed.3009892
- Mannick JB, et al.. (2018). TORC1 inhibition enhances immune function and reduces infections in the elderly. Science Translational Medicine. https://doi.org/10.1126/scitranslmed.aaq1564
- Eisenberg T, Knauer H, Schauer A, Büttner S, Ruckenstuhl C, Carmona-Gutierrez D, Ring J, Schroeder S, Magnes C, Antonacci L, Fussi H, Deszcz L, Hartl R, Schraml E, Criollo A, Megalou E, Weiskopf D, Laun P, Heeren G, Breitenbach M, Grubeck-Loebenstein B, Herker E, Fahrenkrog B, Fröhlich KU, Sinner F, Tavernarakis N, Minois N, Kroemer G, Madeo F. (2009). Induction of autophagy by spermidine promotes longevity. Nature Cell Biology. https://doi.org/10.1038/ncb1975
- Eisenberg T, Abdellatif M, Schroeder S, Primessnig U, Stekovic S, Pendl T, et al.. (2016). Cardioprotection and lifespan extension by the natural polyamine spermidine. Nature Medicine. https://doi.org/10.1038/nm.4222
- Kiechl S, Pechlaner R, Willeit P, Notdurfter M, Paulweber B, Willeit K, et al.. (2018). Higher spermidine intake is linked to lower mortality: a prospective population-based study. American Journal of Clinical Nutrition. https://doi.org/10.1093/ajcn/nqy102
- Madeo F, Eisenberg T, Pietrocola F, Kroemer G. (2018). Spermidine in health and disease. Science. https://doi.org/10.1126/science.aan2788
- Wirth M, Benson G, Schwarz C, Köbe T, Grittner U, Schmitz D, Sigrist SJ, Bohlken J, Stekovic S, Madeo F, Flöel A. (2018). The effect of spermidine on memory performance in older adults at risk for dementia: A randomized controlled trial. Cortex. https://doi.org/10.1016/j.cortex.2018.09.014
- Schwarz C, Stekovic S, Wirth M, Benson G, Royer P, Sigrist SJ, et al.. (2018). Safety and tolerability of spermidine supplementation in mice and older adults with subjective cognitive decline. Aging (Albany NY). https://doi.org/10.18632/aging.101354
- Schwarz C, Benson GS, Horn N, Wurdack K, Grittner U, Schilling R, et al.. (2022). Effects of Spermidine Supplementation on Cognition and Biomarkers in Older Adults With Subjective Cognitive Decline: A Randomized Clinical Trial (SmartAge). JAMA Network Open. https://doi.org/10.1001/jamanetworkopen.2022.13875
- Hofer SJ, Daskalaki I, Bergmann M, Friščić J, Zimmermann A, Mueller MI, Bhukel A, Liang Y, Müller-Werdan U, Tavernarakis N, Sigrist SJ, Madeo F, et al.. (2024). Spermidine is essential for fasting-mediated autophagy and longevity. Nature Cell Biology. https://doi.org/10.1038/s41556-024-01468-x
- Schroeder S, Hofer SJ, Zimmermann A, et al.. (2021). Dietary spermidine improves cognitive function. Cell Reports. https://doi.org/10.1016/j.celrep.2021.108985
- Hofer SJ, Liang Y, Zimmermann A, Schroeder S, Dengjel J, Kroemer G, Eisenberg T, Sigrist SJ, Madeo F. (2021). Spermidine-induced hypusination preserves mitochondrial and cognitive function during aging. Autophagy. https://doi.org/10.1080/15548627.2021.1933299
- Pekar T, Bruckner K, Pauschenwein-Frantsich S, Gschaider A, Wantke F, Jarisch R. (2020). The positive effect of spermidine in older adults suffering from dementia. Wiener Klinische Wochenschrift. https://doi.org/10.1007/s00508-020-01758-y
- Morselli E, Maiuri MC, Markaki M, Megalou E, Pasparaki A, Palikaras K, Criollo A, Galluzzi L, Malik SA, Vitale I, Michaud M, Madeo F, Tavernarakis N, Kroemer G. (2010). Caloric restriction and resveratrol promote longevity through the Sirtuin-1-dependent induction of autophagy. Cell Death & Disease. https://doi.org/10.1038/cddis.2009.8
- Madeo F, Tavernarakis N, Kroemer G. (2010). Can autophagy promote longevity?. Nature Cell Biology. https://doi.org/10.1038/ncb0910-842
- Barzilai N, Crandall JP, Kritchevsky SB, Espeland MA. (2016). Metformin as a Tool to Target Aging. Cell Metabolism. https://doi.org/10.1016/j.cmet.2016.05.011
- He C, Bassik MC, Moresi V, Sun K, Wei Y, Zou Z, An Z, Loh J, Fisher J, Sun Q, Korsmeyer S, Packer M, May HI, Hill JA, Virgin HW, Gilpin C, Xiao G, Bassel-Duby R, Scherer PE, Levine B. (2012). Exercise-induced BCL2-regulated autophagy is required for muscle glucose homeostasis. Nature. https://doi.org/10.1038/nature10758
- Menzies FM, Fleming A, Caricasole A, Bento CF, Andrews SP, Ashkenazi A, Füllgrabe J, Jackson A, Jimenez Sanchez M, Karabiyik C, Licitra F, Lopez Ramirez A, Pavel M, Puri C, Renna M, Ricketts T, Schlotawa L, Vicinanza M, Won H, Zhu Y, Skidmore J, Rubinsztein DC. (2017). Autophagy and Neurodegeneration: Pathogenic Mechanisms and Therapeutic Opportunities. Neuron. https://doi.org/10.1016/j.neuron.2017.01.022
- Cuervo AM, Wong E. (2014). Chaperone-mediated autophagy: roles in disease and aging. Cell Research. https://doi.org/10.1038/cr.2013.153
- Vendelbo MH, Møller AB, Christensen B, Nellemann B, Clasen BF, Nair KS, Jørgensen JO, Jessen N, Møller N. (2014). Fasting Increases Human Skeletal Muscle Net Phenylalanine Release and This Is Associated with Decreased mTOR Signaling. PLOS One. https://doi.org/10.1371/journal.pone.0102031
- EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). (2011). Scientific Opinion on the substantiation of a health claim related to spermidine and prolongation of the growing phase (anagen) of the hair cycle pursuant to Article 13(5) of Regulation (EC) No 1924/2006. EFSA Journal. https://doi.org/10.2903/j.efsa.2011.2466
- European Commission. (2020). Commission Implementing Regulation (EU) 2020/443 of 25 March 2020 amending Implementing Regulation (EU) 2017/2470 as regards the specifications of the novel food 'spermidine-rich wheat germ extract'. Official Journal of the European Union (CELEX 32020R0443)

_Full guide: https://longevity-china.com/en/guide/autophagie-autophagy_

---

_Canonical: https://longevity-china.com/en/guide/autophagie-autophagy · Part of Longevity Cities · Updated 2026-05-26_