6 min read

Alpha-Lipoic Acid: Function in the Body, Sources and Context

What alpha-lipoic acid does in the body, which foods contain it and how to put possible supplementation into realistic context.

Alpha-lipoic acid is a sulphur-containing substance made by the body itself and known mainly as an antioxidant. It appears again and again in sports nutrition and in the field of dietary supplements, often with big promises around cell protection and energy production that, on closer inspection, are not always backed by reliable studies.

In this guide you will learn what function alpha-lipoic acid actually has in the body, where it occurs in food and what research says about taking it additionally as a dietary supplement, including the usual questions about dosage and tolerability.

What alpha-lipoic acid does in the body

Alpha-lipoic acid, often abbreviated to ALA, is a sulphur-containing fatty acid that the body can produce itself. It occurs mainly in the mitochondria of cells, the power plants of the cell, where it is involved in energy production. In addition, alpha-lipoic acid acts as an antioxidant and can be active in both water-soluble and fat-soluble areas of the cell, which makes it quite versatile compared with many other antioxidants.

It is also interesting that alpha-lipoic acid can cross the blood-brain barrier, which means it may also play a role in nerve tissue. It is studied scientifically in connection with oxidative stress, that is, the burden on cells from free radicals, which can arise in greater numbers during intense physical exertion, for example.

Alpha-lipoic acid was discovered as early as the 1950s and was initially classed as a vitamin-like substance. Because the body can make it itself, strictly speaking it is not a vitamin in the true sense, even though some older texts still call it that. This ability to produce it internally distinguishes alpha-lipoic acid from true vitamins, which the body cannot form itself.

capsules on a wooden surface next to fresh spinach leaves, soft natural light

Natural sources in the diet

Alpha-lipoic acid occurs in both animal and plant foods, but usually only in small amounts. Organ meats such as liver and kidney as well as red meat are among the animal sources with a comparatively higher content. Among plant foods, mainly leafy green vegetables such as spinach and broccoli as well as tomatoes are considered useful sources.

Food	Classification of the content
Liver and kidney	comparatively high
Red meat	moderate
Spinach, broccoli	moderate, good plant source
Tomatoes	low to moderate
Peas, Brussels sprouts	low

Because the body also produces alpha-lipoic acid itself, an actual deficiency is described as very rare in healthy people with a balanced diet. This distinguishes alpha-lipoic acid from truly essential nutrients, which the body must take in through food.

Anyone who eats a varied diet overall, with regular vegetables and occasional lean meat or fish, already takes in a certain amount of alpha-lipoic acid through normal food, albeit in a much lower concentration than in a dietary supplement. For everyday supply, this combination of the body's own production and dietary intake is enough for most people.

Alpha-lipoic acid as a dietary supplement

Despite the body's own production, alpha-lipoic acid is offered as a dietary supplement, usually with the promise of improved energy supply or stronger cell protection during intensive training. The idea behind it is that a high training volume can go along with increased oxidative stress, which additional alpha-lipoic acid is supposed to intercept. This reasoning makes sense biochemically, but direct evidence of a corresponding benefit in real training routines is still lacking.

A clear performance advantage for healthy, well-trained athletes from additional intake, confirmed in controlled studies, has so far not been convincingly shown. The picture is different in some medical fields of application in which alpha-lipoic acid has been studied for some time, but there under medical supervision and in a completely different context from general sports nutrition.

Alpha-lipoic acid is often marketed together with other antioxidants such as vitamin C or vitamin E, with the argument that the individual antioxidants regenerate each other in the body and could therefore work more effectively. There are some laboratory studies on this interplay, but a clear effect on performance demonstrated in a sports context cannot be derived from them.

glass bowl with mixed vegetables including spinach and tomatoes on a kitchen counter

Dosage and tolerability

Products containing alpha-lipoic acid are offered with varying amounts, and there is no universally valid dosage recommendation for sport. Follow the information on the respective packaging and, if in doubt, start with the lower stated amount to gauge your own tolerability. Taking it with a meal is more comfortable for many people than taking it on an empty stomach.

In the usual supplement amounts, alpha-lipoic acid is generally considered well tolerated; with considerably higher amounts, stomach complaints or nausea are occasionally reported. If you have existing medical conditions, especially of the metabolism, are pregnant or breastfeeding, or take medication, planned use should first be discussed with a doctor. Supplements such as alpha-lipoic acid are no substitute for a balanced diet, but at most a targeted addition.

Capsules are generally considered a practical form of intake, as they deliver a consistent amount and are easy to fit into daily life. As with any dietary supplement, the amount actually contained per capsule or serving is most reliably found on the packaging of the respective product, not in general claims from advertising.

small amber glass bottle and loose capsules on a wooden table, soft light

What the research says

The role of alpha-lipoic acid as an antioxidant made by the body and as a cofactor in metabolic processes is well described in basic science. For the specific benefit of additional intake in healthy, physically active people, however, the evidence is much thinner and less consistent than for established sports nutrition products such as creatine or protein, among other reasons because there have so far been far fewer large-scale studies specifically on athletes.

Anyone interested in alpha-lipoic acid as a dietary supplement should therefore have realistic expectations: a noticeable, immediate boost in training performance is not to be expected on the basis of current data. A balanced diet rich in antioxidants with enough vegetables provides a solid foundation for most people, without targeted supplementation being strictly necessary, even with intensive, regular training.

The widespread assumption that more antioxidants are automatically better during intensive training is now also viewed in a more nuanced way in parts of sports science. Oxidative stress in training also has an adaptation-promoting function for the muscles, which is why a very high-dose, long-term intake of additional antioxidants is not necessarily beneficial in every case. Here too: balance is more important than the highest possible single dose of one individual product.

Frequently asked questions

Is alpha-lipoic acid an essential nutrient?

No. The body can make alpha-lipoic acid itself, so it is not one of the essential nutrients that must be taken in through food.

Does alpha-lipoic acid directly improve training performance?

A clear, immediate performance advantage has not been convincingly shown on the basis of current studies. Its role lies more in cell protection than in a direct increase in strength or endurance, which is why a noticeable effect in training generally does not appear.

Which foods contain a lot of alpha-lipoic acid?

Organ meats such as liver and kidney as well as red meat contain comparatively large amounts; among plant foods, spinach, broccoli and tomatoes are considered useful sources for a basic supply through normal diet.

Is supplementing with alpha-lipoic acid necessary?

In healthy people with a balanced diet, generally not strictly. Additional intake can be a personal decision, but a proven additional benefit in sport is limited, so it is worth looking at your basic diet first.

Can I combine alpha-lipoic acid with other dietary supplements?

In principle yes, and combining it with other antioxidants is common. When taking several products at the same time, it is worth checking for possible overlaps in composition so that individual ingredients are not unintentionally taken several times in high amounts, especially with other products with a similar antioxidant direction.

Are there side effects with alpha-lipoic acid?

In the usual amounts it is considered well tolerated. With very high amounts, stomach complaints are occasionally possible; if symptoms persist, talk to a doctor. Taking it with a meal can further reduce such complaints.

Explore