Supplement Detective

By Curtis Alexander, Pharm.D.

Summary: Supplement manufacturers claim that acetyl l-carnitine’s benefits range from helping stroke victims to quickly improving mental focus to improving sperm motility. I did find that acetyl l-carnitine can benefit you in certain instances, but evidence supporting it’s use in many disease states is lacking or based on small, animal-based studies and unreliable at this point.

Q: How come you’ve never written about acetyl l-carnitine benefits?  Most of the natural health newsletters and guru’s I come across claim I should be taking it whether I’m healthy or not. What do you think?

A: Hopefully, this doesn’t turn into too long of an answer for you because all you have to do is take a quick look around the internet and some of the most popular websites about acetyl l-carnitine and look at the claimed benefits. Here’s what a two minute search of mine came up with:

Claimed Benefits of Acetyl L-Carnitine:

• Quickly Improves mental Focus and Energy
• Enhances Short-and Long-Term Memory
• Relieves Depression
• Slow Progression of Alzheimer’s Disease
• Protects the Brain from Stress
• Helps Repair Physically Damaged Nerves
• Helps Stroke Victims
• Helps Prevent Age-Related Memory Deterioration
• Increases Learning Capacity
• Helps Sperm Fertility
• Enhances Immune Function

In my opinion, listing this many benefits for one supplement in so many different areas without direct references to the exact studies is, at the least, misleading and maybe even irresponsible.

Moreover, remember, the sole purpose of these websites is to sell you supplements.

Please don’t misunderstand, there’s nothing wrong with making money. I’m all for it. But you can only go to that well so many times before you start to question that person motives.

Motives aside, let’s get back to the claimed benefits of acetyl l-carnitine (ALCAR).

Improved Memory

Your body’s levels of l-carnitine does drop as you age. So it’s theorized that supplementing with acetyl l-carnitine (ALCAR) can help stave off some of the ravages of aging. Including memory loss.

While the early studies have been promising you need to remember that the studies were performed in rats, at very high doses (100-300mg/kg of body weight/day) and for very short periods (only one month).

Human studies are set to be performed in the future. But, until they do and until they show a definite benefit in humans at reasonable doses I don’t think ALCAR is anything more than promising at this point.

SIDENOTE: In the animal studies it’s important to note that even better results were seen when ALCAR was given together with alpha-lipoic acid.

Slows Progression of Alzheimers Disease

There were some early human studies to support that ALCAR may slow the progression of Alzhimers Disease at a dose of 3-6 grams/day for twelve months. However, shortly after this promising study a larger, multi-center study came out in over 400 Alzheimer patients and showed no improvement versus a sugar (placebo) pill.

Proponents for ALCAR argued that early onset Alzheimer patients (under 65 years old) show a more rapid decline in cognitive function and that ALCAR was statistically helpful in that regard. After looking at over 160 early onset Alzheimer patients there was no statistically significant difference in slowing cognitive decline while using ALCAR.

There WAS a reduction in attention related decline with ALCAR but it was not statistically significant.

The bottom line: ALCAR has shown early promise in Alzheimers only to be shown to be ineffective. I do think that for someone newly diagnosed it wouldn’t hurt to give it a shot though as there were some improvement even though they weren’t statistically significant.

Enhanced Immune Function

Most of the evidence surrounding improved immune function with acetyl l-carnitine comes from HIV patients.

Quickly, HIV patients experience CD4 apoptosis. Which is a programmed cell death of their ‘fighter’ cells. When these cell numbers get too low patients can’t fight the disease on their own. In addition, some HIV drugs (nucleoside analogues) appear to lower l-carnitine concentrations in the body – leading to higher than normal cell death in CD4 cells.

In short, supplementing with acetyl l-carnitine has shown to slow down the cell death that occurs in HIV patients as well as increase CD4 counts in the blood (although it didn’t have any noticeable effect on actual HIV viral loads in the blood).

What does this mean for you? It appears that ALCAR increases CD4 counts which may lead to an improved immune response. However, these were not large scale trials and they were specifically focused on HIV patients who generally have underperforming immune systems to start with. So, until results are seen in non-HIV infected patients it’s only a promising option at this point.

The doses used in the studies was higher…2,000mg a day and more.

Improved Sperm Motility

More and more men appear to be suffering from fertility issues in recent years. In many cases, it’s a lack of motility in the sperm itself.

The evidence for ALCAR, while on a relatively small scale, is promising. In almost every trial I saw men showed an improvement in motility when taking ALCAR. It should be noted though that while motility is improved some clinicians argue that ALCAR use doesn’t equate to being more fertile.

Before using ALCAR for sperm motility you need to verify that motility is an issue for you. If it is, I wouldn’t hesitate to supplement with ALCAR. A reasonable dose would be 3,000mg daily.

In the End

I found no reliable studies or evidence to support the claim that acetyl l-carnitine benefits stroke victims, protects the brain from stress or quickly improves mental focus or energy.

However, there is good evidence to support it’s use as an adjunct in hemodialysis patients as the hemodialysis process pulls l-carnitine from the blood possibly leading to l-carnitine deficiency.

I suspect this wasn’t mentioned on many websites because the patient population would be so small and unprofitable.

I also think acetyl l-carnitine would be helpful to strengthen the immune system and for men who have low sperm motility. I think using acetyl l-carnitine for a long term memory aid or in Alzheimer’s disease may have some benefit but more human studies need to be performed at this point.

I’d appreciate any well-thought out critique’s or feedback.