Alpha-lipoic acid

A sulphur compound the body makes itself, taken most often for nerve tingling.

People take it for

Tingling and numbness
Blood sugar
Weight
Cholesterol and blood fats
Inflammation markers
Sperm quality

A plain-English overview, not advice. Written from published reviews and trials and from what people say in public forums.

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What is alpha-lipoic acid?

Alpha-lipoic acid is a short-chain fatty acid containing sulphur, made by plants, by animals and by our own cells. It sits inside the mitochondria, where cells turn food into energy, and joins in those reactions. Reviews call it unusual among antioxidants: it dissolves in water and in fat alike, grips metal ions, and helps put glutathione and vitamins C and E back to work. Supplements come as capsules, in the ordinary mixed form or as R-lipoic acid.

Why do people take alpha-lipoic acid?

Tingling and numbness

The thinking. Pins and needles, numbness and burning in the feet and hands send most people to alpha-lipoic acid, and reviews note it is widely prescribed for that. The thinking is oxidative strain: reviews describe nerves in long-standing diabetes as sitting under it, with the small vessels feeding them working poorly.

What research has found. Trials in adults with nerve damage from diabetes measured symptom scores and found tingling, numbness and burning lower on 600 mg a day than on a dummy capsule; nerve conduction and vibration-sense tests mostly did not shift. One trial found a prescription medicine did better, and one run during chemotherapy found no clear difference. A fair body of trials has looked at this, and most point the same way.

Blood sugar

The thinking. Blood sugar is the other reason alpha-lipoic acid has a following, and the one the chemistry reviews dwell on: they describe it as behaving a little like insulin inside the cell, and as changing how readily tissues respond to it.

What research has found. Reviews pooling dozens of randomised trials, mostly in adults with diabetes or a metabolic condition, measured fasting glucose and HbA1c and found both a little lower on average than on a dummy capsule, at doses from 300 mg to 1,200 mg a day. Measures of insulin resistance moved in some reviews and not in others. Research here is still young: a few studies so far, mostly pointing the same way.

Weight

The thinking. Alpha-lipoic acid has long had a place in the slimming aisle, and several reviews were written to settle whether it belongs there. The idea comes from the same chemistry: reviews describe it working inside the mitochondria, where cells burn fuel.

What research has found. Pooled analyses of randomised, placebo-controlled trials measured weight and BMI and found small average falls, from under a kilogram in one review to a little over two in another. Waist measurements generally did not move, though one review found they did among women and in longer trials. Only a few studies have measured this so far, though they mostly agree.

Cholesterol and blood fats

The thinking. Cholesterol and triglycerides are a common reason people pick up an antioxidant, and alpha-lipoic acid gets measured for them in almost every metabolic trial it appears in. The thinking is indirect: reviews describe it as an antioxidant that also damps inflammation.

What research has found. Two reviews pooling trials in adults found triglycerides, total cholesterol and LDL cholesterol lower than on a dummy capsule, the largest difference around 30 mg/dL of triglycerides, with HDL cholesterol unchanged. A newer review limited to overweight and obese adults found no clear difference. Larger falls came at higher doses and in longer trials. A reasonable number of trials have measured this, and most of them agree.

Inflammation markers

The thinking. Some take alpha-lipoic acid simply as an antioxidant, for the general idea of inflammation rather than any one symptom. Reviews give that a mechanism: the molecule and its reduced partner quench free radicals and damp the signals behind inflammation.

What research has found. Trials here measure a few blood proteins, chiefly C-reactive protein and interleukin-6. Reviews pooling those trials found the proteins lower than on a dummy capsule, most clearly where the starting level was already raised and where trials ran beyond eight weeks. Many of the adults studied had a long-term kidney or liver condition. There is a decent body of trial evidence behind this, mostly pointing one way.

Sperm quality

The thinking. Men hoping to start a family are the newest group to reach for alpha-lipoic acid, usually alongside other antioxidants. The thinking is that sperm are unusually exposed to oxidative strain, and that this molecule gets inside cells and their mitochondria.

What research has found. A review pooling five randomised trials in 250 men measured semen samples after about three months and found more sperm moving, and moving forwards, and fewer oddly shaped ones, than on a dummy capsule; pregnancy rates did not differ. Two single trials pointed the same way on movement. This is early work, a small number of studies, mostly pointing the same way.

What does alpha-lipoic acid do in the body?

Alpha-lipoic acid works by moving between two shapes. Swallowed, it is absorbed quickly, carried into cells and turned by enzymes into its reduced partner, dihydrolipoic acid; the pair then flips back and forth. Both shapes soak up the reactive molecules thrown off when cells burn fuel, which is why one review nicknames it the antioxidant of antioxidants.

Because it dissolves in water and in fat alike, it travels where most antioxidants cannot, including into the mitochondria, where it also works in the reactions that release energy from food. It grips metal ions, and hands electrons back to glutathione and to vitamins C and E, putting those to work again. Reviews add two practical notes: the body makes less of it as we age, and only about a third of what is swallowed in the plain form reaches the blood.

What do people say about taking alpha-lipoic acid?

These are anecdotes people have shared, not evidence.

What people like

Very commonly, tingling, burning and numbness in the feet and toes easing off, sometimes until posters stopped noticing them at all.
Often the change arrives slowly: within days for some, two to six weeks for most, and far longer for a few.
Several say the proof was going without: symptoms crept back when they stopped or cut the dose, and settled again afterwards.
A good number report needing less insulin or better glucose readings, though most add that they changed how they ate at the same time.

Common complaints

Cost is far and away the commonest complaint: monthly supplies are called dear, and several buy in bursts or stop altogether.
Availability comes next: many say UK shops rarely stock it, so they order online, and a few have met customs charges.
Some report no change at all, even after a year or more, and a few doubt a capsule does what a hospital drip does.
Side effects come up rarely, and mildly: headaches when it was taken on an empty stomach, and early tiredness that later passed.
A recurring worry is what it might do to blood sugar alongside insulin, and that GPs often have not heard of it.

How people take it

600 mg a day is the dose named most often, with 300 mg common, and some splitting the total into smaller doses.
The R form is strongly preferred by many, who say a smaller dose of it does the job of a larger plain one.
Timing splits the threads: some take it with meals to head off headaches, others on an empty stomach or last thing at night.
Almost nobody takes it alone; B vitamins and vitamin D run alongside, which posters admit makes any single effect hard to judge.

Read from these public discussions:

Alpha Lipoic Acid (Diabetes Forum, 2016)
Alpha Lipoic Acid (Diabetes Forum, 2017)
Alpha lipoic acid - how much do you take? (Diabetes Forum, 2017)
ALA for neuropathy - any experiences or recommendations? (Diabetes Forum, 2018)
Alpha lipoic acid works (Diabetes Forum, 2018)
Diabetic neuropathy and r-alpha lipoic acid in the UK (Diabetes Forum, 2025)

What forms of alpha-lipoic acid are there?

Form	What’s different	Per serving, on products we list
Alpha-lipoic acid	An even mix of the molecule’s two mirror images, R and S, and the usual form on labels.	300 mg to 750 mg
R-lipoic acid	Only the R mirror image, sold on its own or as its sodium salt.	not in our price tables yet

What else is worth knowing about alpha-lipoic acid?

Labels give the amount per serving, which may be more than one capsule, and a plain alpha-lipoic acid figure is not the same as an R-lipoic acid one.
Trials used 300 mg to 1,200 mg a day, most often 600 mg, and one review described daily amounts up to 1,200 mg as safe.
Side effects were uncommon in the trials, though one review notes a small number of reported cases of insulin autoimmune syndrome. Most trials were in adults with diabetes, raised weight or a long-term condition, so there is less to go on for healthy younger adults.

If you take medication, are pregnant, or have a health condition, check with a pharmacist or GP first.

The research behind this page (29 studies)

How much does alpha-lipoic acid cost?

That depends on the form and the pack, so we work out the price of the same dose of every alpha-lipoic acid product we can find and rank them.

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