An introduction to nutraceuticals and longevity research

Disclosure. MDS Labs sells products formulated around aging-related pathways. Everything in this guide applies to them: evidence about an ingredient’s mechanism is not evidence that a finished product slows aging.

Lifespan, healthspan and biological age

Lifespan is how long you live. Healthspan is how long you live in good health. Much of aging research aims at healthspan: delaying the point at which multiple age-related conditions arrive. Biological age refers to attempts to measure how far aging processes have progressed, independent of the calendar. Those measures are research tools; changing one is not yet proof that health or survival will change.

The hallmarks of aging

A widely cited framework proposes twelve hallmarks of aging. To count, a process must appear with age, accelerate aging when experimentally worsened, and offer a chance to slow aging when targeted ¹. They are:

• Genomic instability
• Telomere attrition
• Epigenetic alterations
• Loss of proteostasis
• Disabled macroautophagy
• Deregulated nutrient-sensing
• Mitochondrial dysfunction
• Cellular senescence
• Stem cell exhaustion
• Altered intercellular communication
• Chronic inflammation
• Dysbiosis

The hallmarks are interconnected ¹, which is both the promise and the problem: changing one process may ripple into others in ways that are hard to predict.

Three research threads, and where the evidence stands

Cellular senescence

Senescent cells stop dividing but persist and release inflammatory signals, and they accumulate with age ¹. Drugs designed to clear them are being studied in early clinical trials for specific diseases. They are prescription drugs under investigation, not supplements.

Where it stands: an active research area, not established, and not a supplement strategy.

NAD+ metabolism

NAD+ is a molecule central to energy metabolism, and NAD+ precursors have been proposed as a way to support function with age. In a 2 x 6-week randomized crossover trial, nicotinamide riboside was well tolerated and raised NAD+ metabolism in healthy middle-aged and older adults; possible effects on blood pressure and arterial stiffness were flagged for future trials rather than shown ³. In a 10-week randomized trial, nicotinamide mononucleotide increased muscle insulin sensitivity in postmenopausal women with prediabetes who were overweight or obese ⁴.

Where it stands: NAD+ precursors raise NAD+ in people. Evidence for meaningful health outcomes is limited to small, short trials in specific groups. Raising a marker is not the same as slowing aging.

Nutrient-sensing and mTOR

The mTOR pathway links nutrient availability to growth. The drug rapamycin, which inhibits mTOR, extended median and maximum lifespan in genetically diverse mice even when started late in life, at 600 days of age ². Rapamycin is a prescription immunosuppressant. To our knowledge, no supplement marketed as acting on this pathway has been shown to reproduce that result in people.

Where it stands: strong animal evidence for a drug; no human lifespan evidence for anything.

What did not work

The idea that oxidative damage drives aging led to decades of antioxidant supplement trials. Across 78 randomized trials with nearly 300,000 participants, antioxidant supplements did not reduce mortality ⁵, and beta carotene increased lung cancer in smokers ⁶. A plausible mechanism and a large market were not enough. This history is the best reason for patience with today’s promising mechanisms.

Why mouse results so often fail to translate

• Timescale. Mice live a few years. A human lifespan trial would take decades, so human trials measure markers and function instead.
• Dose and exposure. Doses that work in mice may be unreachable, or unsafe, in people.
• Drugs versus supplements. The strongest animal results come from prescription drugs (such as rapamycin) studied under controlled conditions, not from the supplements marketed alongside them.
• Markers versus outcomes. Raising a marker such as NAD+ ³ is a step along the way, not a destination.

How to read a longevity claim

1. Was it tested in people, or only in cells, worms or mice?
2. Was the outcome a marker, a measure of function, a disease, or survival?
3. Was the human study randomized and placebo-controlled, and how many people were in it?
4. Is the product the same compound, at the same dose, as what was studied?
5. Is the strongest evidence actually about a prescription drug?

Common misconceptions

• “It extends lifespan.” In mice, perhaps. We know of no supplement shown to extend human lifespan.
• “It reverses biological age.” Changing an aging marker has not been shown to change how long or how well people live.
• “It is a natural version of a longevity drug.” Sharing a pathway does not make two compounds equivalent in effect, dose or safety.

Practical takeaways

1. Treat longevity science as research in progress, and enjoy it as that.
2. The interventions with the deepest human evidence for health in later life are not supplements: physical activity, sleep, diet quality, not smoking, and managing blood pressure and blood sugar are worth discussing with a clinician first.
3. Be most skeptical of products that cite mouse lifespan studies as if they applied to you.

Technical layer: geroscience trial design

Because survival trials in humans are impractical, geroscience relies on intermediate endpoints: physical function, multimorbidity, biomarkers of specific hallmarks, and disease-specific outcomes in conditions thought to be driven by aging processes. A consistent benefit across several such diseases would strengthen the case that an intervention targets aging itself, not one disease. That has not yet been shown for any intervention.

Rapamycin’s mouse result is notable because it used genetically heterogeneous mice rather than a single inbred strain, which reduces the chance that a finding is specific to one inbred strain ².