Alpha-lipoic acid on a cut: does it help

On forums alpha-lipoic acid (ALA) is often listed among "fat burners" or "carb blockers" for cutting. The editorial team checked what these notions rest on, what clinical weight-loss studies actually showed, and whether it makes sense to add ALA to the diet during a calorie deficit.

Where the "fat burner" reputation came from

ALA's history in fitness began not with fat burning but with diabetology. ALA was studied as a treatment for diabetic neuropathy and it was noticed that it could moderately improve glucose utilization by tissues. From this an idea was born: if the supplement helps muscles "take up" glucose, then carbohydrates will go into the muscles rather than into fat.

A second impulse came from a study in rodents (Kim et al., 2004, Nature Medicine), in which ALA suppressed the activity of the enzyme AMPK in the hypothalamus, which reduced food intake and increased energy expenditure in the animals. After this, ALA began to be widely added to weight-loss complexes with wordings like "suppresses appetite" and "revs up the metabolism".

The problem is that the doses the animals received, adjusted for body weight, were very high, and the mechanisms of appetite regulation in rodents and humans differ. Conclusions from such work are hypotheses that need to be tested in humans, not a ready-made argument for a label.

A third factor is the general "antioxidant" reputation. During dieting and training oxidative stress rises, so ALA was positioned as a means of "protecting muscles on a cut". There is no direct evidence of muscle mass preservation in a calorie deficit thanks specifically to ALA.

What weight-loss studies showed

The best-known randomized study is the work of Koh and colleagues (2011). Over 20 weeks adults with obesity followed a moderate diet and took 1200 mg, 1800 mg of ALA or placebo. In the 1800 mg group the reduction in body weight was slightly greater than in the placebo group; the 1200 mg dose gave no significant difference.

A meta-analysis by Kucukgoncu and colleagues (2017), which combined randomized studies, estimated the additional weight loss with ALA compared with placebo at about 1.3 kg. Another meta-analysis (Namazi et al., 2018) also found a statistically significant but small reduction in body weight and body mass index, without a convincing effect on waist circumference.

It matters who took part in these studies. For the most part these were people with obesity, often with disturbances of carbohydrate metabolism, who did not train intensely. There are essentially no studies specifically on athletes "cutting" before a competition with a low body fat percentage. The effect in a lean, trained person may be even smaller or unnoticeable altogether.

Also, weight-loss studies more often used high doses — 1200–1800 mg per day, that is, much higher than the 300–600 mg in a typical sports capsule. Along with the dose, the frequency of gastrointestinal side effects rose.

Appetite, glucose and "nutrient partitioning"

Does ALA reduce appetite in humans? In some studies participants reported somewhat less hunger, but these data are subjective and inconsistent. A systematic, reproducible effect on appetite in humans, comparable to what was observed in rodents, has not been recorded.

The idea of "nutrient partitioning" — that ALA directs carbohydrates into muscles instead of fat tissue — is popular in bodybuilding. It rests on ALA's ability to moderately enhance glucose uptake by muscles, shown mainly in people with insulin resistance (Jacob et al., 1999). But under a calorie deficit on a cut there is essentially no excess of carbohydrates to "redistribute".

Fat on a cut is lost when energy expenditure exceeds intake. No supplement substantially changes this equation. ALA does not increase energy expenditure in humans enough to be noticeable on the scale or in the mirror.

For people with prediabetes or insulin resistance who are losing weight, a small effect on glucose could theoretically matter. But for this group there are much more effective and better-studied approaches, and the decision here should be made by a doctor.

How ALA fits into a cutting plan

If we rank the priorities of a cut by their contribution to the result, the picture is as follows: a moderate calorie deficit, high protein intake to preserve muscle, strength training, sufficient sleep and stress control, everyday activity (steps). Supplements take last place, and among them ALA is not the most promising.

The IOC consensus on dietary supplements (Maughan et al., 2018) and the ISSN review (Kerksick et al., 2018) do not include ALA among agents with proven effectiveness for reducing fat mass in athletes. Caffeine, for example, has a much stronger evidence base for improving performance under a deficit.

• If ALA is already in the diet, it is reasonable to limit it to the doses studied and not to consider it the basis of a program.
• Take on an empty stomach or 30–60 minutes before a meal: food reduces absorption (Gleiter et al., 1996), but people with a sensitive stomach had better check tolerance.
• Do not combine it with a large number of other "fat-burning" components at the same time — that makes it harder to identify the cause of side effects.
• Assess the result by the dynamics of weight, waist and well-being over a few weeks, not by the sensations of the first day.

A separate question is why pay for ALA if the effect in a lean person is minimal. The editorial team believes that on a cut it is more sensible to spend the budget on quality protein, creatine (to preserve strength) and products for a complete diet.

Risks and limitations

At usual doses ALA is well tolerated, but on a cut some risks increase. Low carbohydrate intake together with ALA, which slightly enhances glucose utilization, theoretically increases the likelihood of episodes of low blood sugar, especially in people on glucose-lowering medications.

A rare but serious complication is insulin autoimmune syndrome (Hirata's disease), described in people who took ALA. It manifests as attacks of hypoglycemia: trembling, sweating, palpitations, confusion. On a cut such symptoms are easily confused with "normal" fatigue from dieting, so it is important to pay attention to them.

Gastrointestinal complaints — nausea, heartburn, discomfort — more often occur when taken on an empty stomach and at high doses. Against the background of a strict diet the stomach is often more sensitive as it is.

Finally, ALA is often part of multi-component "fat burners", where high-dose stimulants and sometimes undeclared substances may be alongside it. Safety problems with such products are usually linked not to ALA but to other components. Check the composition and choose products with independent certification.

Editorial conclusions

ALA is not a full-fledged fat burner. In people with obesity it produces a small additional weight loss — about a kilogram over a few months on top of the effect of the diet.

For a trained person with a low body fat percentage there is essentially no evidence of benefit, and the mechanisms of "appetite suppression" and "nutrient partitioning" have been convincingly shown only in animal models or in people with insulin resistance.

On a cut, the decisive factors are the calorie deficit, protein, strength training and sleep. ALA is an optional and non-essential element.

We also recommend reading "CLA on a cut: does it help", "Alpha-lipoic acid on a bulk: is there any point" and "How to choose quality Alpha-lipoic acid: what to look for on the label".

References

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3. Namazi N, Larijani B, Azadbakht L. Alpha-lipoic acid supplement in obesity treatment: a systematic review and meta-analysis of clinical trials. Clin Nutr. 2018;37(2):419–428.
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7. Maughan RJ, Burke LM, Dvorak J, et al. IOC consensus statement: dietary supplements and the high-performance athlete. Br J Sports Med. 2018;52(7):439–455.
8. Kerksick CM, Wilborn CD, Roberts MD, et al. ISSN exercise & sports nutrition review update: research & recommendations. J Int Soc Sports Nutr. 2018;15(1):38.