While everyone is talking about longevity, far fewer people focus on something far more important: the immune system and its aging.
With age, it’s not only how we look or feel that changes—how our body defends itself changes too. Naive T cells decline, “exhausted” immune cells accumulate, and chronic low-grade inflammation appears, better known as inflammaging.

But a new clinical study published in Nature Aging offers hope that part of this process can be reversed—in just 28 days.

What is Urolithin A?

Urolithin A (UA) is a natural metabolite produced when the body breaks down ellagitannins—compounds found in pomegranates and certain berries.
There’s a catch, however: most people cannot produce UA on their own, because this depends on a specific gut microbiota.

That’s why UA is used directly as a well-studied dietary supplement, known for one key property:
its ability to activate mitophagy—the process that recycles damaged mitochondria.

And when mitochondria work better, the immune system works better too.

The new clinical trial: 50 participants, 28 days, clear results

The study included 50 healthy adults (ages 45–70) who received either 1,000 mg of UA daily or a placebo.
After four weeks, the results were striking:

1. More “young” CD8+ T cells

Urolithin A increased the number of naive CD8+ T cells—the cells that protect us against new infections and are essential for adaptive immunity.

2. Fewer “exhausted” cells

The marker of cellular exhaustion TOX was reduced.
In other words, immune cells became more functional, better prepared, and more resilient.

3. Metabolic rejuvenation

Immune cells in the UA group:

• used less glucose,

• shifted toward fatty acid and amino acid oxidation,

• increased mitochondrial biogenesis (higher PGC-1α).

This is a metabolic profile typically seen in younger, more resilient T cells.

4. Stronger innate immunity

UA increased:

• NK cells (the first line of defense against viruses and tumors),

• non-classical monocytes (key players in immune surveillance).

Monocyte phagocytosis of E. coli also improved significantly.

5. A balanced inflammatory response

No pathological increase in inflammatory cytokines was observed.
On the contrary, trends pointed toward a calmer, better-regulated immune profile.

What does this mean for longevity?

Immune aging is one of the main drivers of overall biological aging.

If we can:

• restore naive T cells,

• reduce cellular exhaustion,

• improve mitochondrial function,

• normalize inflammation,

…then we can improve not only immunity, but healthy aging as a whole.

This study shows exactly that:
Urolithin A is not just a supplement—it is an intervention targeting a fundamental mechanism of aging.

Why does this matter to us at Mitopia?

At Mitopia, we believe longevity begins with energy—and energy begins with mitochondria.
Urolithin A is one of the most thoroughly studied compounds in this field, which is why it is a central component of Fundamentals by Mitopia.

This study only confirms what science and practice have been showing for years:
optimal mitochondrial function is the key to a stronger, younger, and more resilient immune system.

Urolithin A is one of the few compounds with:

• a clear mechanism of action,

• human clinical data,

• a rapid effect on the immune system,

• an excellent safety profile.

All of this—in just 28 days.

As science continues to uncover the secrets of aging, UA is emerging as one of the few real, practical tools that work with the body, not against it.

Source:
Greten, T. F. et al. Effect of the mitophagy inducer urolithin A on age-related immune decline: a randomized, placebo-controlled trial. Nature Aging (2025). doi:10.1038/s43587-025-00996-x.