Lithocholic Acid
Lithocholic acid is a bile acid made by gut bacteria, and in late 2024 it made headlines as a molecule that reproduces some of the benefits of calorie restriction. The work is real but it is in mice, worms and flies; the mouse lifespan gain was small and mostly not statistically significant, and the same molecule is one of the more toxic bile acids.
Don't take lithocholic acid as a supplement. It is an animal-stage research lead with no human data, and it damages the liver in several animal species.
What it is
The liver makes two main bile acids from cholesterol. Gut bacteria then rework them: a few specialist species turn one of them, chenodeoxycholic acid, into lithocholic acid, a "secondary" bile acid. The genes for that step turn up in most people, but in well under 1% of their gut bacteria.[1] How bacteria reshape bile, and why it matters for metabolism, is covered on Bile, microbiome and metabolic health.
The calorie-restriction study
The headlines came from one large study. Lithocholic acid rose in the blood of mice kept on calorie restriction, and older mice given it in their drinking water for a month got several of restriction's benefits: better muscle repair after injury, stronger grip and better insulin sensitivity. It worked by switching on AMPK, the cell's energy sensor; in mice, worms and flies lacking AMPK the effects disappeared. In worms and flies it also extended lifespan.[2]
The mouse lifespan result is much weaker than the coverage suggested. The same paper tested it in three groups of mice given lithocholic acid from middle age. Median lifespan was about 5–13% longer across the six comparisons of males and females, but only one of the six, barely, reached statistical significance. The authors themselves called the gain "consistent, albeit nonsignificant". A mammalian lifespan effect is not established, no other group has reported one, and there are no human data.
Why you should not take it
Lithocholic acid is one of the more toxic bile acids. Fed to rabbits and monkeys it damages the liver. The human liver largely neutralises it by attaching a sulfate group, but that is no reason to add more.[3]
The cancer picture is mixed rather than reassuring. In a standard two-year study in rats and mice it did not cause cancer on its own,[4] but in rats, bile acids placed in the colon promoted tumours started by another carcinogen.[5]
What to do
- Skip any product selling lithocholic acid as a calorie-restriction mimic or anti-aging supplement.
- Treat the study as biology, not advice. It shows a bacterial bile acid can act on an energy-sensing pathway in animals; it does not show that taking it helps people.
- For the habits that actually support a healthy bile system — a fibre-rich diet, regular movement and a healthy weight — see Bile, microbiome and metabolic health.
Further reading
- Qu Q, et al. Lithocholic acid phenocopies anti-ageing effects of calorie restriction. Nature 2025 — the source study, including the mouse lifespan cohorts.[6]
- Hofmann AF. Detoxification of lithocholic acid, a toxic bile acid: relevance to drug hepatotoxicity. Drug Metab Rev 2004.[7]
- National Toxicology Program. Bioassay of lithocholic acid for possible carcinogenicity. Natl Cancer Inst Carcinog Tech Rep Ser 1979.[8]