Taurine

The discovery that put it on the map of longevity

The work of Yadav and colleagues measured serum taurine in humans, mice, and monkeys at different ages and found that levels fall by 70 to 80 percent from youth to old age, a steeper decline than that of many other known aging markers; when they supplemented aged mice with taurine, they observed improvements in mitochondrial function, bone mass, muscle mass, immune function, gut microbiota, and behavior, along with the lifespan extension mentioned above.

In humans, the same group found that higher serum taurine levels were associated with better metabolic health, less obesity, less inflammation, and better muscle mass in adults; this is not causal evidence yet, but it opened an active line of clinical research that is trying to confirm whether taurine supplementation can have effects similar to those of exercise or caloric restriction on human aging.

Cardiovascular health and blood pressure

Taurine has an older clinical history in cardiology: several randomized trials in people with mild to moderate hypertension have shown modest but significant reductions in systolic (3 to 8 mmHg) and diastolic (2 to 5 mmHg) blood pressure with doses of 1.5 to 6 grams daily for 8 to 12 weeks, an effect comparable to that of some mild antihypertensives used as monotherapy.

In heart failure, several studies have shown improvements in ejection fraction, in functional capacity measured by the 6-minute walk test, and in subjective markers such as fatigue, especially when taurine is combined with standard treatment; the most plausible mechanism combines better handling of intracellular calcium in the cardiomyocyte, modulation of the renin-angiotensin system, and a direct antioxidant effect on the myocardium.

Physical performance and recovery

In sports, taurine is present in almost all commercial energy drinks, but its effect independent of caffeine is modest: some studies suggest small improvements in aerobic capacity, submaximal strength, and post-exercise recovery with doses of 1 to 3 grams before training, without the stimulating, activating effect of the caffeine that usually accompanies it in commercial products.

Liver and metabolism

In chronic liver disease, especially toxic hepatitis and alcoholic liver disease, high doses (4 to 6 grams daily) for weeks have shown improvements in transaminases and in markers of liver function; in type 2 diabetes the data are more limited, but some trials suggest modest improvements in insulin sensitivity with prolonged supplementation.

Taurine and the stress axis (HPA): the preclinical evidence

A line of animal research suggests that taurine buffers the stress response by acting on the hypothalamic-pituitary-adrenal (HPA) axis. In a chronic unpredictable mild stress (CUMS) model in rats, administering taurine intraperitoneally (200 or 500 mg/kg/day) one week before and for 35 days prevented depressive behavior —loss of sucrose preference, spatial memory deficit, and anxiety— and curbed corticosterone hypersecretion in both serum and hippocampus (p<0.001), the central finding of the study; it also restored serotonin, dopamine, and norepinephrine, contained excess glutamate, and preserved the neurotrophic factors BDNF, FGF-2, and VEGF, associated with hippocampal neurogenesis.

In that same study, taurine did not significantly modify the inflammatory markers TNF-α and IL-1β, which indicates that the antidepressant effect observed is not explained by an anti-inflammatory pathway at those doses, but by regulation of the HPA axis and promotion of neuronal survival and growth.

The pattern repeats in other species: in Japanese flounder exposed to repeated acute stress, taurine reduced plasma epinephrine, norepinephrine, ACTH, and cortisol and lowered the expression of CRH and the urotensins UI and UII in the hypothalamus and in the caudal neurosecretory system, attenuating the stress response in both active-coping and passive-coping individuals. And a classic 1975 study had already shown that oral taurine prevents the stress-induced drop in adrenal adrenaline and inhibits its release from the granules of the medulla —probably by stabilizing its membrane—, an effect that L-isoleucine and DL-methionine did not reproduce; with one important nuance: in that study taurine acted on adrenaline but did not curb the rise in corticosterone, unlike the more recent CUMS model, a difference attributed to the dose, the duration, and the type of stress. Overall this is coherent preclinical evidence, still without clinical trials confirming an equivalent effect on human cortisol.

For practical use, it is worth remembering the safety margin: EFSA considers taurine safe up to about 3 g/day in healthy adults, with no adverse effects observed up to 1,000 mg/kg/day in toxicity studies, which makes it a low-risk candidate for investigating its role against chronic and mood-related stress.

How to take it and precautions

The doses studied range from 500 mg to 6 grams daily depending on the indication: 1 to 3 g/day for general use and physical performance, 4 to 6 g/day for heart failure or liver disease under supervision; ideally divided into two or three doses with meals, although it is also well absorbed on an empty stomach; clinical effects appear within weeks to months depending on the indication.

It is one of the supplemental amino acids with the best safety profile: practically no adverse effects at the doses studied over months, no relevant drug interactions described, and no specific contraindications beyond pregnancy (where the data are limited) and people with advanced kidney disease (where clearance may be impaired and it is advisable to consult before prolonged high doses).