A Complete Guide to Acetyl-L-Carnitine (ALCAR)

ALCAR is becoming a popular dietary supplement due to its promising beneficial effects of reducing fatigue and improving brain function. 

In this guide, we’ll break down the research behind what makes acetyl-L-carnitine an exciting product for supporting your mental and physical wellness. We’ve scoured the studies to help you understand the substance’s benefits, safety, and frequently asked questions about this product.

What is Acetyl-L-Carnitine?

Acetyl-L-carnitine, also known as ALCAR or ALC, is a naturally occurring amino acid that is produced in the body. Its purpose is to help transport fat into your cells' mitochondria to produce energy (1).

Carnitine is essential for many of the body’s processes, and acetyl-L-carnitine is one of several different types of carnitine that are found in the body (2). L-carnitine is produced in the brain and is the biologically active form of carnitine. The body then converts L-carnitine into acetyl-L-carnitine.

Explained simply, carnitine plays an important role in the burning of fat for energy.

What is it used for?

One of the primary uses of acetyl-L-carnitine is to treat neurodegenerative diseases such as Alzheimer's, and there is evidence to suggest it can also be used to treat symptoms of depression, improve brain function, and reduce fatigue (3).

Carnitine’s responsibility for turning fat into energy suggests that it may be beneficial for weight loss.

Carnitine Deficiency

It is possible to have a deficiency of carnitine in your body through a genetic disorder or through not eating enough foods rich in carnitine. It is understood that a deficiency of acetyl-L-carnitine could play a role in developing depressive symptoms (4). 

Vegan diets are likely to get less carnitine as they do not consume animal-based products.

Foods rich in carnitine

Animal products are the best sources of carnitine, so meats and fish like beef or cod, and animal products such as milk.

Acetyl-L-Carnitine Benefits

Treat Neurodegenerative Disease

Several studies have shown that acetyl-L-carnitine can have beneficial effects on neurodegenerative disorders like Alzheimer's (5).

A longer-term study of 3, 6, and 12 months also showed that taking ALCAR to treat mild cognitive impairment and early Alzheimer’s disease was effective and increased its benefits over time.

Research has shown that Alzheimer's patients taking acetyl-L-carnitine showed significantly less mental deterioration (6). 

Antidepressant Effects

Studies using ALCAR supplements suggest that it can regulate neurotransmitters and help the brain adapt and reorganise itself, also known as neuroplasticity. A review of treating adults with depressive symptoms found that acetyl-L-carnitine significantly reduced depressive symptoms versus placebos, and showed similar effectiveness compared to established antidepressants (7). 

It was noted that the antidepressant benefits of taking ALCAR were long-lasting and quicker to act than other classic treatments (8).

Acetylcarnitine was also shown to have a quick-acting and long-lasting antidepressant effect in rats and mice (9).

These findings show that ALCAR could be a new way to treat symptoms of depression. 

Enhances Exercise Recovery

Thanks to carnitine’s role in energy metabolism, researchers have theorised that acetyl-L-carnitine could aid in reduced physical fatigue and increased athletic performance. Much of the research is based on L-carnitine, however, the body can convert L-carnitine to acetyl-L-carnitine.

Several studies show that taking L-carnitine enhances high-intensity exercise (10, 11), however other studies found contradictory results (12).

Overall, a review of the studies has concluded that L-carnitine supplements are beneficial for recovering from exercise (13).

Increase Muscle Mass

When combined with creatine and leucine, L-Carnitine has been shown to increase muscle mass and strength.

One study measuring skeletal muscle mass in older adults (aged 55 - 70) showed that taking a supplement containing L-Carnitine (1500 mg), L-leucine (2000 mg), creatine (3000 mg), and Vitamin D3 (10 μg) for 8 weeks showed a 1.0 kg increase in total lean muscle mass (14).

Reduces Fatigue

Extreme tiredness becomes more prevalent with age, and one study has shown that acetyl L-carnitine supplementation aged 70+ reduced both mental and physical fatigue (15).

Side Effects

Several studies have shown that ALCAR is highly tolerated and is free from side effects (16).

A study specifically measuring ALCAR’s safety for elderly patients also found that it can be taken without significant side effects (17).

A review comparing acetyl-L-carnitine to common antidepressants found that ALCAR actually has fewer adverse effects (18).

Recommended Dosage

Many of the studies on acetyl-L-carnitine have shown that health benefits are seen using doses between 1 - 3g per day, so we recommend taking 1,500mg per day. ALCAR supplements are safe for adults to take every day as they have shown no adverse side effects over a long time period.

How fast does ALCAR work?

Studies measuring how taking ALCAR can treat depression showed that it can start working within 2-3 days (19). 


Does acetyl-L-carnitine affect sleep?

Several studies have been conducted to evaluate how L-carnitine affects people with sleep disorders or poor sleep quality. One study showed that taking L-carnitine supplements can improve sleep quality for patients using a dialysis machine (20).

Another study measured how sleep deprivation negatively impacts memory due to oxidative stress and if taking L-carnitine helped the brain combat memory impairment. It found that L-carnitine protected against short and long-term memory impairment (21). 

Is Acetyl-L-carnitine a Nootropic?

A nootropic is a substance that helps boost your brain’s performance, and as ALCAR can improve your memory, mood and brain function, it can be classed as a nootropic.

Which is better, L-carnitine or Acetyl-L-carnitine?

A study comparing the effects of L-carnitine and acetyl-L-carnitine found that ALCAR was more effective at decreasing oxidative damage, and therefore it may be a better dietary supplement than L-carnitine (22).

Does acetyl-L-carnitine help with ED?

In one study comparing the difference between carnitine and androgen therapies for male ageing symptoms, the carnitine supplement was more effective at treating erectile dysfunction (23).

What is the difference between L-carnitine and acetyl-L-carnitine?

The main difference between L-carnitine and acetyl-L-carnitine is that acetyl-carnitine is more easily absorbed from the gut, which makes it a much more effective supplement to take (24).

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