What is pentadecanoic acid?

A saturated fatty acid with 15 carbon atoms, often written C15:0. It is present in trace levels in dairy fat and some fish and plants, and it is sold as a supplement.

Is C15:0 an essential fatty acid?

It has been proposed as one, in a 2020 paper whose studies were financed by companies that employ its lead author. Being essential would mean the body needs it from food and cannot make enough; that proposal has not been tested in people.

Has C15:0 been tested in people?

In small trials only. A 12-week trial of 30 young adults found blood levels rose with no significant adverse events, meaning no notable side effects. A trial of 88 women with fatty liver found adding C15:0 to a healthy diet lowered LDL cholesterol further.

Does C15:0 slow aging?

No human study has measured aging, lifespan or age-related disease in people taking C15:0. The longevity comparisons come from experiments on human cells in a dish.

Were the studies independent?

Mostly not. The 2020 animal studies were financed by companies co-founded by and employing the lead author, and the 2024 human trial was supported by the same company, which supplied the capsules. The 2024 trial was also partly funded by the NIH.

Are supplements checked before they are sold?

In the US, supplement makers are responsible for evaluating safety and labeling before marketing, and the FDA can act against unsafe or mislabeled products after they reach the market. This is general information rather than medical advice.

Can pentadecanoic acid reverse aging? What the evidence shows

Pentadecanoic acid, or C15:0, is a fatty acid found in dairy fat and sold as a supplement with longevity claims. No study in people has tested whether it slows or reverses aging, and the research behind the claims was largely funded by the company that sells it.

No. No study in people has tested whether pentadecanoic acid slows or reverses aging. The fatty acid, usually written C15:0 and sold as a supplement, has been compared with longevity drug candidates in human cells grown in a dish, and has shown effects in obese mice and rabbits. The human trials so far are small, short and did not measure aging at all.

The research also has a notable feature: most of the work behind the claims was financed by the company that sells C15:0. That does not make it wrong, but it is the kind of evidence that needs independent confirmation before anyone can say what the supplement does.

What pentadecanoic acid is

Pentadecanoic acid is a saturated fatty acid with an odd number of carbon atoms, 15 rather than the usual even numbers. Odd-chain fatty acids like it are present in trace levels in dairy fat and some fish and plants, which is why blood levels in people partly reflect how much dairy fat they eat.

It is a saturated fat, the family that, as a group, raises the LDL (bad) cholesterol level. Individual fatty acids within that family behave differently, though, and C15:0 appears in very small amounts compared with the saturated fats most people eat.

Where the anti-aging idea comes from

The modern interest traces largely to one research group. A 2020 paper reported that higher circulating concentrations of odd-chain fatty acids are associated with lower risks of cardiometabolic diseases, meaning heart disease, stroke and diabetes. Its own experiments were in animals: obese mice on a high-fat diet, rabbits on a high-fat, high-cholesterol diet, and rats for safety testing. In those animals, the authors reported that C15:0 attenuates inflammation, anemia, dyslipidemia, and fibrosis, meaning unhealthy blood fat levels and tissue scarring.

On that basis, the authors proposed C15:0 as a potential essential fatty acid, one the body needs from food. The paper’s competing-interests statement notes that its lead author is a co-founder of and employed by Epitracker, Inc and Seraphina Therapeutics, Inc, which financed studies in this paper.

A 2023 paper from the same lead author went further. It used human cells in a dish to compare C15:0 with three longevity-enhancing candidates: acarbose, metformin and rapamycin, drugs studied for their effects on aging in animals. C15:0 and rapamycin shared 24 activities across 10 cell systems, including anti-inflammatory effects. Cell experiments show what a substance can do to cells; they cannot show that a supplement slows aging in a person.

What human trials of pentadecanoic acid have tested

The first placebo-controlled trial in people was published in 2024 in the Journal of Nutrition. Its authors noted that C15:0 supplementation has not been studied in humans before. It was a double-blind, randomized, controlled, 2-arm trial of 200 mg C15:0 or placebo daily for 12 wk in young adults with overweight or obesity.

The trial was small: in total, 20 participants received C15:0 supplement and 10 received placebo. Blood C15:0 levels rose, which was the main aim, and no significant adverse events occurred, meaning no notable side effects were reported. Among the half of the C15:0 group whose blood level passed a set threshold, liver enzyme levels fell and hemoglobin rose compared with those who did not reach it. The authors describe these as potentially relevant improvements in clinical indices, warranting further study, a signal to test rather than a result. The project was also supported by Seraphina Therapeutics including the provision of C15:0 supplements and matching placebo, alongside partial funding from the National Institutes of Health.

A second trial, TANGO, tested C15:0 alongside diet in 88 Chinese women with fatty liver disease, who were randomly assigned to 1 of the 3 groups for 12 wk: a Mediterranean-style diet with C15:0, the same diet without it, or their usual diet. Both diet groups achieved greater reductions in body weight than the control group, losing about 4.0 kg with C15:0 and 3.4 kg without it, with similar falls in liver fat. The authors report that C15:0 supplementation lowers LDL-cholesterol and may cause beneficial shifts in the gut microbiome. Most of the benefit came from the diet itself.

Neither trial measured aging, biological age, lifespan or age-related disease.

What the blood-level studies can and cannot show

Much of the enthusiasm rests on observational research: people with more C15:0 in their blood tend to have lower rates of heart disease, diabetes and fatty liver. The TANGO authors note that higher circulating concentrations of pentadecanoic acid (C15:0) are associated with a lower risk for NAFLD, meaning nonalcoholic fatty liver disease.

Those links cannot separate C15:0 from the foods that carry it. Blood C15:0 rises with dairy fat intake, and people who eat more dairy may differ in many other ways. A marker that tracks a food is not proof that the marker itself is doing the work, which is why the question has to be settled in trials.

How supplements like C15:0 are regulated

In the US, dietary supplements do not go through the approval process that medicines do. Under federal law, supplement firms are responsible for evaluating the safety and labeling of their products before marketing. The Food and Drug Administration (FDA) has the authority to take action against any adulterated or misbranded dietary supplement product after it reaches the market.

That means a claim on a label or website about aging has not been checked by the FDA before a product is sold. It also means the quality of the evidence is the main guide to what a supplement does.

What the pentadecanoic acid research cannot tell us yet

The human evidence consists of two trials with 30 and 88 participants, each lasting 12 weeks, in narrow groups: young adults with overweight or obesity, and Chinese women with fatty liver. Neither was designed to detect effects on aging, and neither ran long enough to.

The animal and cell studies that underpin the anti-aging claims were largely financed by the company that sells C15:0, and they have not been independently repeated at scale. Whether C15:0 is essential, whether low levels cause harm, and whether supplements do anything for aging in people are all open questions.

What the pentadecanoic acid evidence adds up to

Pentadecanoic acid is a real nutrient with interesting laboratory results and a plausible link to cardiometabolic health. It has not been shown to reverse aging, slow aging, or extend life in people, and the claims that it might come mainly from studies funded by its seller. Answering the question would take large, independent, long-term trials in people, and none has been reported.