Is Urolithin B legal in the United Kingdom?

Sold on the reputation of urolithin A, which has human trials. Urolithin B has none: the muscle result is C2C12 cells and mice given 10 micrograms a day through an implanted osmotic pump for 28 days.

Urolithin B is one of the compounds gut bacteria make from the ellagitannins in pomegranate, walnuts and berries. It is structurally simpler than urolithin A and has a different reported action: rather than mitophagy, the 2017 paper that put it on the map described it as a regulator of muscle protein balance acting through the androgen receptor.

Mechanism: In muscle cells and mice, an increase in protein synthesis with repression of the ubiquitin-proteasome degradation pathway, with the androgen receptor implicated genetically and pharmacologically and crosstalk to mTORC1 signalling, possibly through AMPK. This is a different proposed mechanism from urolithin A, which is sold and studied as a mitophagy activator.

Regulatory history: Not an approved drug. Sold as a supplement ingredient and as a research chemical. No registered human trial has administered it.

Licenses medicines for the UK market. A compound without a marketing authorisation is an unlicensed medicine, which can only lawfully be supplied for human use through a prescriber under the specials scheme, not sold as a research product.

The classification above is the The Longevity Archive reading of Medicines and Healthcare products Regulatory Agency listings for Urolithin B at the reviewed date, not a legal opinion. Rules change, and importing, prescribing and possessing a compound can each be treated differently. Check the regulator directly before acting on anything here.