Longevity Interventions Can Have Benefits and Risks

by Nils Osmar

The information in this article is not intended as, and should not be taken as, medical advice. Interventions like exercising, dietary changes, and taking medications and supplements can have both benefits and side effects, Please consult with a medical professional about any medical concerns. See full Medical Disclaimer

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Health interventions—even those with promising research behind them—can have both benefits and risks. This article surveys the risk-benefit landscape of common anti-aging approaches to help you do your due diligence.

In pointing out the risks, I’m not suggesting that they are a reason to do nothing. As Dr. David Sinclair has observed, if we’re too afraid to try any interventions, we are guaranteed to grow old and die.

Of course we may anyway. But in theory, if we find interventions that work for us, there’s a possibility that we could end up living significantly longer in better health.

There’s also the “longevity escape velocity” concept, popularized by futurists Ray Kurzweil and Terry Grossman, and frequently cited by researchers like Dr. Mike Lustgarten, Ph.D.: the idea that if we figure out and commit to the right intervensions, we could in theory “live long enough to live forever”—staying healthy (and staying in the world) long enough to still be around to benefit from better anti-aging protocols as they emerge.

Part I: The Core Principle—Context Determines Outcome

Before diving into specific interventions, it’s worth noting that the same intervention could in theory help one person and harm another. Variables that matter include:

Age — An intervention beneficial at 60 may be unnecessary or counterproductive at 30
Health status — Pre-existing conditions change the risk calculus entirely
Genetics — Polymorphisms can dramatically affect how you metabolize compounds
Other interventions — Drug-drug and supplement-supplement interactions are real
Timing — When you take something (fed vs. fasted, morning vs. evening) matters
Dosage — The dose makes the poison, and the medicine

For Example…

Starting with some interventions that are generally promoted as “healthy”:

Exercise can build strong muscles, reduce cancer and heart disease risk, and stave off sarcopenia. But under some circumstances, it can result in injuries, overtraining syndrome, or even cardiac events in people with undiagnosed conditions.
Fasting has been shown to promote autophagy and increase lifespan in lab animals. But under some circumstances it can result in nutritional deficiencies, muscle loss, or metabolic disruption. People have even died during prolonged unsupervised fasts.
Sun exposure in proper amounts promotes vitamin D synthesis and has mood benefits, but excessive exposure increases UV radiation damage and is associated with a higher risk of skin cancer.
Staying hydrated supports blood pressure regulation and cellular function, but drinking extreme amounts of water can cause hyponatremia—a potentially fatal condition.
Very low calorie diets are associated with longer lifespan in lab animals, but also with weakened immune function, lower bone density, and reduced sex drive.
Extreme diets (all plant, all animal, low protein, or excessively high protein) could turn out to have benefits and risks in some individuals

Part II: Intervention Deep-Dives

Senolytics (Dasatinib + Quercetin, Fisetin)

What they do: Senolytic compounds selectively clear senescent (“zombie”) cells—cells that have stopped dividing but refuse to die, secreting inflammatory factors that damage surrounding tissue.

Potential benefits:

Animal studies show improved physical function, reduced inflammation, and extended healthspan
Early human trials suggest potential for reducing frailty and improving specific conditions

Potential risks:

Quercetin can interact with certain medications (antibiotics, blood thinners)
Dasatinib is a chemotherapy drug with known side effects including fluid retention, fatigue, and blood count changes
Long-term effects of repeated senolytic treatment in humans are unknown
Some senescent cells may serve protective functions we don’t fully understand

Potential problems: These interventions are still largely experimental in humans. If you’re taking dasatinib, it’s recommended that you should work with a physician who can monitor blood counts and other parameters. Quercetin and fisetin are more accessible but could in theory interact with medications in unknown ways

mTOR Modulators (Rapamycin)

What it does: Rapamycin inhibits the mTOR pathway, a nutrient-sensing system that regulates cell growth. When mTOR is chronically activated (as often happens in diets that are high in either carbohydrates or protein, or in people who are nibbling constantly), there is evidence that its activation could accelerate aging.

Potential benefits:

Extends lifespan 9-14% in mice when started in mid-life
The PEARL trial (2024) found that low-dose intermittent rapamycin (5-10mg/week) was well tolerated over one year and showed sex-specific improvements in lean tissue mass and quality of life
Some evidence suggests improved immune function in older adults
Anecdotal reports of benefits for conditions like frozen shoulder and other inflammatory issues

Potential risks:

Immunosuppression at high doses (this is its primary medical use in transplant patients)
Potential for glucose intolerance and lipid changes
Impaired wound healing in high doses
Commonly reported side effects such as mouth sores
Long-term effects of chronic mTOR inhibition in healthy humans remain unknown
Most human data comes from transplant or cancer patients on much higher doses

Rapamycin is a prescription medication. Off-label use for longevity might turn out to have benefits, or unknown risks. The optimal dosing schedule remains an open question—most longevity-focused protocols use intermittent low doses (5-7mg weekly) (adjusted depending on whether we are taking compounded or generic rapamycin). People taking it should stay aware that it has not been confirmed as having benefits in long-term human trials.

NAD+ Precursors (NMN, NR)

What they do: Nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR) are precursors to NAD+, a coenzyme critical for cellular energy production and sirtuin activation. NAD+ levels decline with age.

Potential benefits:

Animal studies show improvements in metabolism, endurance, and various aging markers
Human trials have generally shown the compounds are well-tolerated and do raise NAD+ levels
Some studies suggest improvements in metabolic parameters

Potential risks:

Long-term safety data in humans is limited
Theoretical concerns about promoting cancer growth in those with existing malignancies (NAD+ supports cellular energy in all cells, including potentially cancerous ones) (The concern that is usually raised is not so much that having higher NAD+ levels would result in new cancers, but rather that that some types of existing cancers might grow faster if we’re taking them)
Some individuals report insomnia or overstimulation
Quality control issues with some supplements

NAD boosters are among the more popular “longevity supplements,” but there is no solid evidence to suggest that they increase lifespan. And evidence of human evidence for healthspan extension remains limited. My personal policy is to source them from manufacturers with third-party testing. We don’t really know the long-term risks or benefits from taking them; some people who take them take periodic breaks for this reason.

Autophagy Activators (Spermidine, Fasting)

What they do: Autophagy is the cellular “cleanup” process that removes damaged proteins and organelles. Spermidine (found in wheat germ, aged cheese, mushrooms, and supplements) and fasting both activate this process.

Potential benefits:

Dietary spermidine intake correlates with reduced cardiovascular disease risk and lower blood pressure in observational studies
Animal studies show lifespan extension
Fasting triggers autophagy and has metabolic benefits

Potential risks—and an important nuance:

A 2022 Chinese cohort study found that high serum spermidine levels were associated with a five-fold increased risk of stroke
However, this refers to endogenous serum levels, which may reflect different biological processes than dietary intake
Dietary spermidine from foods appears to have protective cardiovascular associations, while very high circulating levels may indicate other metabolic issues
This discrepancy highlights an important principle: food-form compounds don’t always behave identically to isolated supplements

Spermidine from dietary sources (wheat germ, aged cheese, mushrooms, fermented soy) appears to be beneficial and safe. Supplement forms may warrant more caution, particularly at high doses. As with many interventions, the dose and delivery method matter significantly.

Amino Acids & Peptides (Glycine, Taurine)

Glycine + NAC (GlyNAC)

What it does: Combining glycine and N-acetylcysteine provides the precursors for glutathione synthesis—glutathione being the body’s primary intracellular antioxidant, which declines with age.

Potential benefits:

A randomized controlled trial at Baylor College of Medicine found that 16 weeks of GlyNAC supplementation in older adults improved glutathione levels, reduced oxidative stress, improved mitochondrial function, reduced inflammation, and improved physical function including gait speed and muscle strength
The supplementation also appeared to reverse multiple hallmarks of aging
Benefits declined after supplementation stopped, suggesting ongoing use may be needed

Potential risks:

Generally well-tolerated in studies
NAC can interact with certain medications
Individual responses vary

GlyNAC is one of the more promising and accessible interventions with human RCT data. Standard doses in studies were approximately 100 mg/kg/day each of glycine and NAC. The main risk that I’m aware of is that we may be buying the components from sellers who are lying about the levels of these ingredients in their supplements.

Taurine

What it does: Taurine is a semi-essential amino acid involved in numerous biological functions. A 2023 Science paper reported that circulating taurine levels decline approximately 80% over the human lifespan.

Potential benefits:

The Singh et al. (2023) study found taurine supplementation extended median lifespan 10-12% in mice and improved healthspan markers in monkeys
Mechanistically, taurine reduced cellular senescence, protected telomeres, supported mitochondrial function, and reduced inflammation
In humans, higher taurine levels correlated with fewer cases of type 2 diabetes, lower obesity levels, and reduced inflammation

Important update—conflicting evidence:

A 2025 NIH study published in Science (Fernandez et al.) found that in longitudinal data from humans, monkeys, and mice, taurine levels often increased or remained constant with age—not decreased. If this is borne out, there would be no reason to supplement.
The relationship between taurine and health outcomes was inconsistent across cohorts
This doesn’t negate the potential benefits of supplementation but highlights that taurine’s role as an “aging biomarker” is more complex than initially reported

Taurine has a strong safety profile and is found in many foods (especially poultry, shellfish and meat). Supplementation appears safe, but the evidence for dramatic lifespan or healthspan benefits in humans remains preliminary.

Other Popular Compounds

EGCG (Green Tea Extract)

What it does: Epigallocatechin gallate (EGCG) is the primary polyphenol in green tea, with antioxidant and potential metabolic benefits.

Potential benefits:

Associated with reduced cardiovascular risk, improved metabolic markers, and potential cancer-protective effects in observational studies
May support healthy liver function at moderate doses

Significant risks:

The European Food Safety Authority concluded that EGCG doses at or above 800 mg/day from supplements have been shown to cause statistically significant increases in liver enzymes
Multiple case reports document serious liver injury from green tea extract supplements, including cases requiring liver transplantation
Risk appears elevated when:
- Taking supplements on an empty stomach
- Taking high doses (>800mg EGCG/day)
- Combining with weight loss/fasting regimens
- Certain genetic variants affect individual susceptibility
- Reported deaths in some individuals taking it as a supplement

Critical distinction: Traditional green tea consumption appears safe—the liver toxicity risk is primarily associated with concentrated extract supplements, especially at high doses or during fasting. Drinking green tea is not the same as taking green tea extract capsules.

If I were using EGCG supplements, I would stay below 800mg/day, take itwith food, monitor liver function tests, and avoid combining itwith aggressive weight loss protocols. Drinking green tea appears to be the safest way to obtain beneficial amounts of EGCG.

Metformin

What it does: A diabetes medication that improves insulin sensitivity and may have effects on cellular aging pathways.

Potential benefits:

Epidemiological data suggests diabetics on metformin may have lower all-cause mortality than non-diabetics not on metformin
The TAME (Targeting Aging with Metformin) trial is underway to test aging-related outcomes

Potential risks:

Can cause gastrointestinal side effects
May blunt some exercise benefits (particularly muscle hypertrophy)
Risk of vitamin B12 deficiency with long-term use
Risk of lactic acidosis (rare but serious), especially with kidney impairment

Metformin requires a prescription. People considering it for longevity should discuss it with their doctors and weigh whether they’re already achieving similar benefits through lifestyle interventions (exercise, diet, fasting).

Part III: The Supplement Quality Problem

Beyond the inherent risks and benefits of specific compounds, there’s a systemic issue: the supplement industry is not well regulated.

Amazon’s low-cost supplements are notorious for sometimes containing none of the claimed ingredients, wrong doses, or contaminants
ConsumerLab and independent testing labs routinely find discrepancies between labels and contents
Heavy metal contamination, microbial issues, and mislabeling are real concerns

What you can do:

Look for supplements verified by third-party testing organizations (NSF International, USP, ConsumerLab, Informed Sport)
Buy from established companies with reputations to protect
Be aware that if a supplement is suspiciously cheap, there’s may be a reason
Consider the source: some supplements are more reliably produced than others

Part IV: Interactions and Unknowns

We don’t know the long-term effects of taking multiple supplements together. Do they enhance each other’s benefits? Cancel them out? Create unforeseen problems?

Some known concerns:

Pathway conflicts: Interventions that activate mTOR (like leucine for muscle building) may conflict with interventions that inhibit mTOR (like rapamycin or fasting). Timing these appropriately matters.
Polypharmacy effects: Drug-supplement and supplement-supplement interactions are understudied
Cumulative effects: Taking 15 different supplements means 15 different risk profiles and countless potential interactions

A reasonable approach: Start interventions one at a time, give each adequate time to assess effects, and don’t assume that more is better. Complexity increases risk.

Part V: How to Know If It’s Working

Biomarker Testing

One way to get objective data on whether your approach is working is periodic testing. The Levine PhenoAge test uses nine standard blood biomarkers—albumin, creatinine, glucose, C-reactive protein, lymphocyte percentage, mean cell volume, red cell distribution width, alkaline phosphatase, and white blood cell count—combined with chronological age to estimate your biological age and 10-year mortality risk.

This measure, developed by Dr. Morgan Levine and colleagues at Yale, has been validated in large populations to predict mortality and age-related disease risk better than chronological age alone. It’s accessible through standard blood tests.

Other biological age measures exist, including DNA methylation-based clocks (like GrimAge), but PhenoAge offers the advantage of using routine, affordable bloodwork.

What to test:

The nine PhenoAge biomarkers can be obtained through standard CBC, CMP, and hs-CRP tests
Many longevity-focused individuals test quarterly or semi-annually
Life Extension, Labcorp, Quest, and other labs offer these panels
Track changes over time rather than fixating on single measurements

Functional Markers

Beyond blood tests, pay attention to functional measures:

Strength: Can you maintain or build muscle? Grip strength is highly predictive of all-cause mortality.
Cognition: Are you maintaining mental sharpness?
Sleep: Is your sleep quality preserved?
Energy: How do you feel day-to-day?
Recovery: How quickly do you bounce back from exercise or illness?

Summing Up…

The longevity field is evolving rapidly. What we know today could end up being overturned by tomorrow’s research. The example spermidine (where dietary and serum levels may have opposite associations) illustrate this.

This doesn’t mean we should do nothing while we wait for perfect knowledge. A thoughtful approach might be to:

Do our due diligence — Research interventions before adopting them
Start conservatively — Lower doses, one change at a time
Monitor objectively — Use biomarker testing to track effects
Stay flexible — Be willing to adjust based on new evidence or personal response
Work with knowledgeable practitioners — Especially for prescription interventions
Source quality products — The supplement market requires skepticism
Remember individual variation — What works for someone else may not work for you

The goal isn’t to eliminate all risk—that would mean eliminating all action. The goal is to take informed risks in service of the possibility that we might live longer, healthier lives—and perhaps, as some suggest live long enough to still be here when improved interventions come along.

Disclaimer

Nothing shared or written here should be considered a substitute for medical care or medical advice. This article is intended for educational purposes to help readers make informed decisions in consultation with their healthcare providers.

Bibliography

General Longevity & Aging

Sinclair DA, LaPlante MD. Lifespan: Why We Age—and Why We Don’t Have To. Atria Books, 2019.
Kurzweil R, Grossman T. Fantastic Voyage: Live Long Enough to Live Forever. Rodale Books, 2004.

GlyNAC / Glutathione

Kumar P, et al. “Supplementing Glycine and N-Acetylcysteine (GlyNAC) in Older Adults Improves Glutathione Deficiency, Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Physical Function, and Aging Hallmarks: A Randomized Clinical Trial.” J Gerontol A Biol Sci Med Sci. 2023;78(1):75-89. PMID: 35975308. https://pubmed.ncbi.nlm.nih.gov/35975308/
Kumar P, et al. “Glycine and N‐acetylcysteine (GlyNAC) supplementation in older adults improves glutathione deficiency, oxidative stress, mitochondrial dysfunction, inflammation, insulin resistance, endothelial dysfunction, genotoxicity, muscle strength, and cognition.” Clin Transl Med. 2021;11(3):e372. PMID: 33783984. https://pubmed.ncbi.nlm.nih.gov/33783984/

Rapamycin

“Rapamycin for longevity: the pros, the cons, and future perspectives.” Front Aging. 2025. https://www.frontiersin.org/journals/aging/articles/10.3389/fragi.2025.1628187/full
Hoopes G, et al. “Safety and efficacy of rapamycin on healthspan metrics after one year: PEARL Trial Results.” medRxiv. 2024. https://www.medrxiv.org/content/10.1101/2024.08.21.24312372v1
Kraig E, et al. “A randomized control trial to establish the feasibility and safety of rapamycin treatment in an older human cohort.” Exp Gerontol. 2018;105:53-59. PMID: 29408453. https://pubmed.ncbi.nlm.nih.gov/29408453/
Hands JM, Lustgarten MS, et al. “What is the clinical evidence to support off-label rapamycin therapy in healthy adults?” Aging. 2025. https://www.aging-us.com/article/206300/text

Taurine

Singh P, et al. “Taurine deficiency as a driver of aging.” Science. 2023;380(6649):eabn9257. PMID: 37289866. https://www.science.org/doi/10.1126/science.abn9257
Fernandez ME, de Cabo R, et al. “Is taurine an aging biomarker?” Science. 2025. https://www.science.org/doi/10.1126/science.adl2116
NIH News Release: “NIH researchers conclude that taurine is unlikely to be a good aging biomarker.” June 2025. https://www.nih.gov/news-events/news-releases/nih-researchers-conclude-taurine-unlikely-be-good-aging-biomarker

Spermidine

Zheng L, et al. “Serum Spermidine in Relation to Risk of Stroke: A Multilevel Study.” Front Nutr. 2022;9:843616. PMID: 35464025. https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2022.843616/full
Eisenberg T, et al. “Cardioprotection and lifespan extension by the natural polyamine spermidine.” Nat Med. 2016;22(12):1428-1438.

EGCG / Green Tea Extract

EFSA Panel on Food Additives and Nutrient Sources. “Scientific opinion on the safety of green tea catechins.” EFSA Journal. 2018;16(4):5239. https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2018.5239
LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. “Green Tea.” National Institute of Diabetes and Digestive and Kidney Diseases, 2020. https://www.ncbi.nlm.nih.gov/books/NBK547925/
Acosta L, et al. “Hepatotoxicity with High-Dose Green Tea Extract: Effect of Catechol-O-Methyltransferase and Uridine 5′-Diphospho-glucuronosyltransferase 1A4 Genotypes.” J Diet Suppl. 2023. PMID: PMC10060436. https://pmc.ncbi.nlm.nih.gov/articles/PMC10060436/

PhenoAge / Biological Age Testing

Levine ME, et al. “An epigenetic biomarker of aging for lifespan and healthspan.” Aging (Albany NY). 2018;10(4):573-591. PMID: 29676998. https://pmc.ncbi.nlm.nih.gov/articles/PMC5940111/
Liu Z, et al. “A new aging measure captures morbidity and mortality risk across diverse subpopulations from NHANES IV: A cohort study.” PLoS Med. 2018;15(12):e1002718. https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002718

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“Health interventions” Can Have Both Benefits and Risks