Amino acid Acetyl-L-carnitine may reduce fatigue in the elderly and people with chronic fatigue.
Acetyl-L-carnitine (ALCAR) is a form of the naturally-occurring amino acid L-carnitine that is believed to have stimulating properties due to its role in:
- Facilitating energy production. ALCAR plays a key role in energy metabolism, and has been shown to reduce fatigue in the elderly and people with fatigue-related conditions.
Naturally produced in the body, Acetyl-L-carnitine, or ALCAR for short, is a special form of the amino acid carnitine that can pass through the blood-brain barrier. ALCAR has long been understood to have a pivotal role in the generation of energy (ATP) within mitochondria.
Similar to normal L-carnitine, one of the primary functions of ALCAR is to transport free fatty acids into mitochondria where they facilitate energy production. Helping convert fat into energy has led to the belief that ALCAR can burn fat and even help boost testosterone. ALCAR is additionally purported to have antioxidant and nootropic effects. The understanding that ALCAR is an essential piece in energy creation has also led some to suggest it might work as an energy supplement.
Carnitine and its various forms. The amino acid carnitine has four main varieties, each with a distinct structure and yet similar roles:
How Acetyl-L-Carnitine Might Help With Energy
ALCAR is purported to enhance such cognitive processes as attention and alertness due in no small part to its ability to reduce oxidative stress in the brain.3 Its anti-oxidative effects have been found to slow the degeneration of neurons (particularly prevalent in aging) and help in regenerating and repairing them.4
Acetyl-L-Carnitine Benefits & Uses for Energy
In terms of energy, acetyl-L-carnitine is frequently taken by older adults seeking to increase their energy levels, and individuals with fatigue-related conditions such as chronic fatigue syndrome. These uses are backed by clinical trials, suggesting that ALCAR is a good way to provide energy in cases of chronic fatigue. It is also sometimes used by younger adults for increasing energy during exercise, but this use is not currently backed by research.
Studies done in rodents indicate that Acetyl-L-Carnitine may:
- Increase physical activity. Old rats fed ALCAR were reported to have significantly increased ambulatory activity, or total walking distance traveled.6
Acetyl-L-carnitine has been reported to decrease fatigue in the elderly and individuals with chronic fatigue syndrome.
In this controlled study, 96 elderly patients with chronic fatigue syndrome (CFS) who took Acetyl-L-Carnitine (ALCAR) were found to have a decrease in physical fatigue, mental fatigue, and fatigue severity. Significant differences between the ALCAR and control groups were noted: muscle pain (-27% versus -3%), prolonged fatigue after exercising (-51% versus -4%), and fatigue severity scale (-22.5 versus 1.2).
- The study concluded that “administering ALC may reduce both physical and mental fatigue in elderly and improves both the cognitive status and physical functions.”7
In this placebo-controlled, randomized, double-blind investigation, 66 participants over the age of 100 were given either a placebo or 2 grams of L-Carnitine daily. Significant decreases were found in physical fatigue (-4.10) compared to the placebo (-1.10) and mental fatigue (-2.70) compared to the placebo (0.3).
- The study concluded that “oral administration of levocarnitine produces a reduction of total fat mass, increases total muscular mass, and facilitates an increased capacity for physical and cognitive activity by reducing fatigue and improving cognitive functions.”8
In this randomized investigation, 90 patients with CFS were given 2 grams of Acetyl-L-Carnitine, 2 grams of Propionyl-L-Carnitine, or a combination of both every day for 24 weeks. ALCAR was found to significantly improve mental fatigue and attention.
- The study concluded that “Acetylcarnitine and propionylcarnitine showed beneficial effect on fatigue and attention concentration.”9
In this randomized, double-blind, placebo-controlled investigation, 30 celiacs received either a placebo or 2 grams of L-carnitine daily for 180 days. Fatigue was shown to be significantly reduced in the L-carnitine group compared to the placebo group.
- The study concluded that “L-Carnitine therapy is safe and effective in ameliorating fatigue in celiac disease.”10
In this randomized, double-blind investigation, 18 men were given 60 grams of a carbohydrate control or 2 grams of L-carnitine 2 times a day for 24 weeks. Compared to the control, the L-carnitine group demonstrated a higher percentage of fat burning and better energy production while exercising at 80% intensity.
- The study concluded that “the Carnitine group increased work output 11% from baseline in the performance trial…[and] these changes were associated with an improvement in exercise performance.”11
In this placebo-controlled, randomized, double-blind investigation, 84 seniors were given either a placebo or 2 grams of L-Carnitine twice daily for 30 days. L-carnitine significantly decreased physical fatigue (by 40%) and mental fatigue (by 45%) compared to the placebo.
- The study concluded that “administration of levocarnitine to healthy elderly subjects resulted in a reduction of total fat mass, an increase of total muscle mass, and appeared to exert a favourable effect on fatigue and serum lipids.”12
Dosage for Energy
- Research studies use 2000 – 4000 of L-carnitine mg daily
- Typical supplement capsules contain 500 mg, taken 2 – 3 times daily
Supplements in Review Says
- Acetyl-L-carnitine 1500 – 2000 mg for energy.
Acetyl-L-carnitine may increase energy levels in the elderly or people with chronic fatigue. We recommend ALCAR for increasing energy in older adults and people with conditions marked by chronic fatigue, such as CFS.
Start with a 1500 mg dosage. Most supplements tend to recommend a total dosage of 1500 mg daily. But given that successful studies use doses of at least 2000 mg, moving up to this dose may be more effective.
- Evans AM, Fornasini G. Pharmacokinetics of L-carnitine. Clin Pharmacokinet 2003;42:941-67. ↩
- Stanley CA. Carnitine deficiency disorders in children. Ann N Y Acad Sci 2004;1033:42-51. ↩
- Kano M, Kawakami T, et al. Effects of ALCAR on the fast axoplasmic transport in cultured sensory neurons of streptozotocin-induced diabetic rats. Neurosci Res 1999;33:207-13. ↩
- Sima AAF, Calvani M, et al. Acetyl-L-carnitine improves pain, nerve regeneration, and vibratory perception in patients with chronic diabetic neuropathy: An analysis of two randomized, placebo-controlled trials. Diabetes Care 2005;28:89-94. ↩
- Zeiler FA, Sader N, et al. Levocarnitine induced seizures in patients on valproic acid: A negative systematic review. Seizure. 2016;36:36-9. ↩
- Hagen TM, Ingersoll RT, et al. Acetyl-L-carnitine fed to old rats partially restores mitochondrial function and ambulatory activity. Proc Natl Acad Sci U S A. 1998 Aug 4;95(16):9562-6. ↩
- Malaguarnera M, Gargante MP, et al. Acetyl L-carnitine (ALC) treatment in elderly patients with fatigue. Arch Gerontol Geriatr. 2008 Mar-Apr;46(2):181-90. ↩
- Malaguarnera M, Cammalleri L, et al. L-Carnitine treatment reduces severity of physical and mental fatigue and increases cognitive functions in centenarians: a randomized and controlled clinical trial. Am J Clin Nutr. 2007 Dec;86(6):1738-44. ↩
- Vermeulen RC, Scholte HR. Exploratory open label, randomized study of acetyl- and propionylcarnitine in chronic fatigue syndrome. Psychosom Med. 2004 Mar-Apr;66(2):276-82. ↩
- Ciacci C, Pelusi G, et al. L-Carnitine in the treatment of fatigue in adult celiac disease patients: a pilot study. Dig Liver Dis. 2007 Oct;39(10):922-8. ↩
- Wall BT, Stephens FB, et al. Chronic oral ingestion of L-carnitine and carbohydrate increases muscle carnitine content and alters muscle fuel metabolism during exercise in humans. J Physiol. 2011 Feb 15;589(Pt 4):963-73. ↩
- Pistone G, Marino A, et al. Levocarnitine administration in elderly subjects with rapid muscle fatigue: effect on body composition, lipid profile and fatigue. Drugs Aging. 2003;20(10):761-7. ↩