Head to head
Spermidine against Urolithin A
Autophagy against mitophagy, both sold as food-derived longevity compounds. Urolithin A has randomised human trials showing improved muscle function in older adults; spermidine's human case is mostly population association.
Column A
SpermidineSpermidine
A natural polyamine that induces autophagy, linked in population studies to lower mortality and studied for cardiovascular and cognitive aging.
Column B
Urolithin AUrolithin A
A gut-derived compound that triggers mitophagy and has improved muscle function in older adults in human trials, one of the better-evidenced longevity supplements.
Side by side, on the facts we can check
| Attribute | Spermidine | Urolithin A |
|---|---|---|
| Category | Longevity | Muscle & Performance |
| FDA status | Sold as a supplement / food component; not an approved drug | Sold as a supplement (GRAS); not an approved drug |
| Half-life | Short | Several hours |
| Molecular weight | 145.2 Da | 228.2 Da |
| Mechanism | Induces autophagy by inhibiting acetyltransferase activity, helping cells clear damaged components associated with aging. | Induces mitophagy, clearing damaged mitochondria and improving the quality of the cellular energy supply, especially in muscle. |
| Human studies cited | 1 | 3 |
| Legal status, US | Sold as a dietary supplement | Sold as a dietary supplement |
Frequently asked questions
What is the difference between Spermidine and Urolithin A?
Spermidine: A natural polyamine that induces autophagy, linked in population studies to lower mortality and studied for cardiovascular and cognitive aging. Urolithin A: A gut-derived compound that triggers mitophagy and has improved muscle function in older adults in human trials, one of the better-evidenced longevity supplements.
Which has stronger research evidence, Spermidine or Urolithin A?
This database does not grade compounds. It counts what was run in people: 1 of the 3 studies cited on the Spermidine profile were human work, against 3 of 3 for Urolithin A. Those counts are of our own citation lists and understate any larger literature, and neither is a recommendation.
Are Spermidine and Urolithin A FDA-approved?
Spermidine: Sold as a supplement / food component; not an approved drug. Urolithin A: Sold as a supplement (GRAS); not an approved drug.
Related posts
Blog articles that cover Spermidine or Urolithin A, newest first.
Reviewed Sep 2026. This page sets two published records side by side. It is educational, it is not medical advice, and it contains no dosing protocols or recommendations for personal use.