5/23/2025
Last update
5/23/2025
Reviewed By
Overview
SCIENTIFIC SCORE
Possibly Effective
Based on 8 Researches
7.8
USERS' SCORE
Good
Based on 6 Reviews
8.4
Supplement Facts
Serving Size: 1 Capsule
Amount Per Serving
%DV
L-Carnitine (as L-Carnitine Tartrate)
500 mg
†
Top Medical Research Studies
9
We investigated the effects of acetyl L-carnitine (ALC) on elderly patients experiencing chronic fatigue. In our study of 96 participants aged 70 and above, we found that ALC significantly reduced both physical and mental fatigue.
After treatment, improvements were noted in functional abilities and cognitive performance, with patients experiencing less muscle pain and fewer sleep disorders. Overall, our findings indicate that ALC can be an effective option for alleviating fatigue and enhancing quality of life in older individuals.
After treatment, improvements were noted in functional abilities and cognitive performance, with patients experiencing less muscle pain and fewer sleep disorders. Overall, our findings indicate that ALC can be an effective option for alleviating fatigue and enhancing quality of life in older individuals.
Read More
7
We analyzed the clinical features of 82 patients with chronic fatigue syndrome (CFS) to explore potential treatment options like L-carnitine. Most patients exhibited common symptoms, including fatigue and memory issues, alongside psychological abnormalities. Notably, we found that L-carnitine levels were significantly lower among CFS patients compared to healthy controls.
After two weeks of supplementation, L-carnitine levels rose and symptoms showed improvement. While further research is necessary, these initial findings suggest that L-carnitine might play a positive role in managing CFS symptoms.
After two weeks of supplementation, L-carnitine levels rose and symptoms showed improvement. While further research is necessary, these initial findings suggest that L-carnitine might play a positive role in managing CFS symptoms.
Read More
9
We aimed to explore how L-carnitine supplementation affects individuals suffering from chronic fatigue syndrome (CFS) by analyzing their serotonin levels and fatigue symptoms. Our study focused on a group of 12 individuals with CFS and compared their serotonin and fatigue levels before and after 7 weeks of L-carnitine treatment.
Remarkably, we observed that after the supplementation, serotonin levels in those with CFS increased drastically—by eight times! Alongside this boost in serotonin, participants reported a significant two-fold reduction in fatigue symptoms, which was noteworthy given the persistent fatigue commonly experienced in CFS.
These findings also revealed a strong negative correlation between serotonin levels and fatigue, suggesting that higher serotonin is associated with lower fatigue levels. This paints a promising picture of L-carnitine as a potential treatment for managing fatigue in CFS, contributing to a better quality of life for those affected.
Remarkably, we observed that after the supplementation, serotonin levels in those with CFS increased drastically—by eight times! Alongside this boost in serotonin, participants reported a significant two-fold reduction in fatigue symptoms, which was noteworthy given the persistent fatigue commonly experienced in CFS.
These findings also revealed a strong negative correlation between serotonin levels and fatigue, suggesting that higher serotonin is associated with lower fatigue levels. This paints a promising picture of L-carnitine as a potential treatment for managing fatigue in CFS, contributing to a better quality of life for those affected.
Read More
Most Useful Reviews
9
Increased energy levels
23 people found this helpful
This works! I put my wife on this for energy and weight loss. She has seen a noticeable increase in energy and has lost 5 lbs in 2 weeks without exercise, which is impressive as she does not lose weight easily. My daughter, aged 18, was extremely fatigued and experienced racing heart multiple times daily. Since taking this product, her energy has improved, and her instances of a lowered heart rate have diminished. P.S. Don't take it late at night, as it may keep you awake.
Read More
8
Enhanced energy levels
My experience with L-Carnitine has been positive. I've noticed a clear improvement in my energy levels and focus, particularly after long workdays. Since including L-Carnitine in my routine, I've felt more energised and have improved my endurance during workouts. I can push myself harder without feeling as fatigued. Overall, I am very satisfied with its effects on my health regimen.
Read More
7.5
Improved endurance significantly
I've been taking L-Carnitine from Jarrow Formulas for a few weeks, and the results are remarkable. It has significantly increased my endurance during training, making cardio easier. I also feel a light energy boost without excessive excitement. It aids in fat burning, especially when combined with regular workouts and a healthy diet. This product is high quality, pleasant to take, and an excellent investment for anyone trying to enhance their fitness.
Read More
Medical Researches
SCIENTIFIC SCORE
Possibly Effective
Based on 8 Researches
7.8
- All Researches
9
We aimed to explore how L-carnitine supplementation affects individuals suffering from chronic fatigue syndrome (CFS) by analyzing their serotonin levels and fatigue symptoms. Our study focused on a group of 12 individuals with CFS and compared their serotonin and fatigue levels before and after 7 weeks of L-carnitine treatment.
Remarkably, we observed that after the supplementation, serotonin levels in those with CFS increased drastically—by eight times! Alongside this boost in serotonin, participants reported a significant two-fold reduction in fatigue symptoms, which was noteworthy given the persistent fatigue commonly experienced in CFS.
These findings also revealed a strong negative correlation between serotonin levels and fatigue, suggesting that higher serotonin is associated with lower fatigue levels. This paints a promising picture of L-carnitine as a potential treatment for managing fatigue in CFS, contributing to a better quality of life for those affected.
Remarkably, we observed that after the supplementation, serotonin levels in those with CFS increased drastically—by eight times! Alongside this boost in serotonin, participants reported a significant two-fold reduction in fatigue symptoms, which was noteworthy given the persistent fatigue commonly experienced in CFS.
These findings also revealed a strong negative correlation between serotonin levels and fatigue, suggesting that higher serotonin is associated with lower fatigue levels. This paints a promising picture of L-carnitine as a potential treatment for managing fatigue in CFS, contributing to a better quality of life for those affected.
Read More
9
We investigated the effects of acetyl L-carnitine (ALC) on elderly patients experiencing chronic fatigue. In our study of 96 participants aged 70 and above, we found that ALC significantly reduced both physical and mental fatigue.
After treatment, improvements were noted in functional abilities and cognitive performance, with patients experiencing less muscle pain and fewer sleep disorders. Overall, our findings indicate that ALC can be an effective option for alleviating fatigue and enhancing quality of life in older individuals.
After treatment, improvements were noted in functional abilities and cognitive performance, with patients experiencing less muscle pain and fewer sleep disorders. Overall, our findings indicate that ALC can be an effective option for alleviating fatigue and enhancing quality of life in older individuals.
Read More
8
ACCAR surpasses amantadine for fatigue
We explored the effectiveness of acetyl L-carnitine (ALCAR) in treating fatigue among patients with multiple sclerosis, comparing it to amantadine. In a robust randomized, double-blind, crossover trial involving 36 participants, ALCAR showed a significant improvement in fatigue levels on the Fatigue Severity Scale after three months compared to amantadine. However, when looking at secondary outcomes, like depression and social experiences, no significant differences were noted. Overall, ALCAR proved to be better tolerated and more effective for managing fatigue in this population.
Read More
8
We evaluated how L-carnitine impacts fatigue in patients undergoing treatment for chronic hepatitis C. The study involved 50 patients split into two groups: one received just interferon-alpha, while the other received interferon alongside L-carnitine.
We discovered that those taking L-carnitine reported a significant reduction in fatigue levels, particularly noticed early on in treatment. By contrasting these observations, we suggested that L-carnitine may enhance energy levels, effectively helping alleviate treatment-induced fatigue in these patients.
We discovered that those taking L-carnitine reported a significant reduction in fatigue levels, particularly noticed early on in treatment. By contrasting these observations, we suggested that L-carnitine may enhance energy levels, effectively helping alleviate treatment-induced fatigue in these patients.
Read More
7
We set out to explore how l-carnitine, a common dietary supplement, affects individuals suffering from chronic fatigue syndrome (CFS). By conducting a systematic review of fourteen studies involving 809 participants, we aimed to gather reliable evidence about the effectiveness of l-carnitine in alleviating fatigue, one of the primary symptoms of this complex disorder.
Many patients turn to dietary supplements like l-carnitine to find relief from their fatigue and its accompanying symptoms. Our review found that while some studies reported a significant reduction in fatigue from interventions that included l-carnitine, we also noticed methodological challenges that limit these findings. Issues such as small sample sizes and missing data led to a high risk of bias, which makes it hard to draw clear conclusions about the supplement's effectiveness on its own.
Additionally, our review highlighted mixed results when it came to secondary outcomes, such as cognitive function and biomarkers of inflammation. Some participants did report adverse effects, like nausea and insomnia, which adds another layer of complexity in assessing the use of l-carnitine for CFS. Overall, while l-carnitine shows potential benefits for reducing fatigue, the limitations of the current studies make us cautious about confirming its isolated effectiveness.
Many patients turn to dietary supplements like l-carnitine to find relief from their fatigue and its accompanying symptoms. Our review found that while some studies reported a significant reduction in fatigue from interventions that included l-carnitine, we also noticed methodological challenges that limit these findings. Issues such as small sample sizes and missing data led to a high risk of bias, which makes it hard to draw clear conclusions about the supplement's effectiveness on its own.
Additionally, our review highlighted mixed results when it came to secondary outcomes, such as cognitive function and biomarkers of inflammation. Some participants did report adverse effects, like nausea and insomnia, which adds another layer of complexity in assessing the use of l-carnitine for CFS. Overall, while l-carnitine shows potential benefits for reducing fatigue, the limitations of the current studies make us cautious about confirming its isolated effectiveness.
Read More
User Reviews
USERS' SCORE
Good
Based on 6 Reviews
8.4
- All Reviews
- Positive Reviews
- Negative Reviews
9
Increased energy levels
23 people found this helpful
This works! I put my wife on this for energy and weight loss. She has seen a noticeable increase in energy and has lost 5 lbs in 2 weeks without exercise, which is impressive as she does not lose weight easily. My daughter, aged 18, was extremely fatigued and experienced racing heart multiple times daily. Since taking this product, her energy has improved, and her instances of a lowered heart rate have diminished. P.S. Don't take it late at night, as it may keep you awake.
Read More
8
Enhanced energy levels
My experience with L-Carnitine has been positive. I've noticed a clear improvement in my energy levels and focus, particularly after long workdays. Since including L-Carnitine in my routine, I've felt more energised and have improved my endurance during workouts. I can push myself harder without feeling as fatigued. Overall, I am very satisfied with its effects on my health regimen.
Read More
7.5
Improved endurance significantly
I've been taking L-Carnitine from Jarrow Formulas for a few weeks, and the results are remarkable. It has significantly increased my endurance during training, making cardio easier. I also feel a light energy boost without excessive excitement. It aids in fat burning, especially when combined with regular workouts and a healthy diet. This product is high quality, pleasant to take, and an excellent investment for anyone trying to enhance their fitness.
Read More
7.5
Significant improvement noted
This supplement is incredibly valuable for those experiencing fatigue and muscle weakness. Its key role is to create carnitine, which helps transport fatty acids into mitochondria for energy. I absolutely love this product; I've noticed an improvement within just a few days of use.
Read More
7
Helped post-Covid fatigue
I found good quality L-Carnitine helpful for battling fatigue after Covid; it worked effectively. It’s also beneficial for stamina during workouts and muscle building.
Read More
Frequently Asked Questions
7.5
Significant improvement noted
This supplement is incredibly valuable for those experiencing fatigue and muscle weakness. Its key role is to create carnitine, which helps transport fatty acids into mitochondria for energy. I absolutely love this product; I've noticed an improvement within just a few days of use.
9
Increased energy levels
23 people found this helpful
This works! I put my wife on this for energy and weight loss. She has seen a noticeable increase in energy and has lost 5 lbs in 2 weeks without exercise, which is impressive as she does not lose weight easily. My daughter, aged 18, was extremely fatigued and experienced racing heart multiple times daily. Since taking this product, her energy has improved, and her instances of a lowered heart rate have diminished. P.S. Don't take it late at night, as it may keep you awake.
7.5
Improved endurance significantly
I've been taking L-Carnitine from Jarrow Formulas for a few weeks, and the results are remarkable. It has significantly increased my endurance during training, making cardio easier. I also feel a light energy boost without excessive excitement. It aids in fat burning, especially when combined with regular workouts and a healthy diet. This product is high quality, pleasant to take, and an excellent investment for anyone trying to enhance their fitness.
8
Enhanced energy levels
My experience with L-Carnitine has been positive. I've noticed a clear improvement in my energy levels and focus, particularly after long workdays. Since including L-Carnitine in my routine, I've felt more energised and have improved my endurance during workouts. I can push myself harder without feeling as fatigued. Overall, I am very satisfied with its effects on my health regimen.
7
Helped post-Covid fatigue
I found good quality L-Carnitine helpful for battling fatigue after Covid; it worked effectively. It’s also beneficial for stamina during workouts and muscle building.
7.5
Consistent energy boost
10 people found this helpful
Absolutely fantastic! In the morning, I drink it on an empty stomach, and throughout the day, I feel energetic, with only slight fatigue arriving in the evening. For those keen on losing weight, this is essential! Finally, I lost 2 kg that I've struggled with for the last five years! It boosts metabolism and fat burning. Highly recommend it!
7
We set out to explore how l-carnitine, a common dietary supplement, affects individuals suffering from chronic fatigue syndrome (CFS). By conducting a systematic review of fourteen studies involving 809 participants, we aimed to gather reliable evidence about the effectiveness of l-carnitine in alleviating fatigue, one of the primary symptoms of this complex disorder.
Many patients turn to dietary supplements like l-carnitine to find relief from their fatigue and its accompanying symptoms. Our review found that while some studies reported a significant reduction in fatigue from interventions that included l-carnitine, we also noticed methodological challenges that limit these findings. Issues such as small sample sizes and missing data led to a high risk of bias, which makes it hard to draw clear conclusions about the supplement's effectiveness on its own.
Additionally, our review highlighted mixed results when it came to secondary outcomes, such as cognitive function and biomarkers of inflammation. Some participants did report adverse effects, like nausea and insomnia, which adds another layer of complexity in assessing the use of l-carnitine for CFS. Overall, while l-carnitine shows potential benefits for reducing fatigue, the limitations of the current studies make us cautious about confirming its isolated effectiveness.
Many patients turn to dietary supplements like l-carnitine to find relief from their fatigue and its accompanying symptoms. Our review found that while some studies reported a significant reduction in fatigue from interventions that included l-carnitine, we also noticed methodological challenges that limit these findings. Issues such as small sample sizes and missing data led to a high risk of bias, which makes it hard to draw clear conclusions about the supplement's effectiveness on its own.
Additionally, our review highlighted mixed results when it came to secondary outcomes, such as cognitive function and biomarkers of inflammation. Some participants did report adverse effects, like nausea and insomnia, which adds another layer of complexity in assessing the use of l-carnitine for CFS. Overall, while l-carnitine shows potential benefits for reducing fatigue, the limitations of the current studies make us cautious about confirming its isolated effectiveness.
9
We aimed to explore how L-carnitine supplementation affects individuals suffering from chronic fatigue syndrome (CFS) by analyzing their serotonin levels and fatigue symptoms. Our study focused on a group of 12 individuals with CFS and compared their serotonin and fatigue levels before and after 7 weeks of L-carnitine treatment.
Remarkably, we observed that after the supplementation, serotonin levels in those with CFS increased drastically—by eight times! Alongside this boost in serotonin, participants reported a significant two-fold reduction in fatigue symptoms, which was noteworthy given the persistent fatigue commonly experienced in CFS.
These findings also revealed a strong negative correlation between serotonin levels and fatigue, suggesting that higher serotonin is associated with lower fatigue levels. This paints a promising picture of L-carnitine as a potential treatment for managing fatigue in CFS, contributing to a better quality of life for those affected.
Remarkably, we observed that after the supplementation, serotonin levels in those with CFS increased drastically—by eight times! Alongside this boost in serotonin, participants reported a significant two-fold reduction in fatigue symptoms, which was noteworthy given the persistent fatigue commonly experienced in CFS.
These findings also revealed a strong negative correlation between serotonin levels and fatigue, suggesting that higher serotonin is associated with lower fatigue levels. This paints a promising picture of L-carnitine as a potential treatment for managing fatigue in CFS, contributing to a better quality of life for those affected.
7
We explored the effects of acetyl-L-carnitine and propionyl-L-carnitine on chronic fatigue syndrome (CFS) through a randomized study involving 90 patients. Over 24 weeks, improvements were notable for both types of carnitine, enhancing mental fatigue and overall fatigue levels.
However, the combined treatment didn’t show as much benefit. Despite initial gains, many participants experienced fatigue worsening two weeks after treatment ended. Ultimately, while acetylcarnitine and propionylcarnitine appear helpful, results on long-term effectiveness remain mixed.
However, the combined treatment didn’t show as much benefit. Despite initial gains, many participants experienced fatigue worsening two weeks after treatment ended. Ultimately, while acetylcarnitine and propionylcarnitine appear helpful, results on long-term effectiveness remain mixed.
References
- Dorczok MC, Mittmann G, Mossaheb N, Schrank B, Bartova L, et al. Dietary Supplementation for Fatigue Symptoms in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)-A Systematic Review. Nutrients. 2025;17. 10.3390/nu17030475
- Raij T, Raij K. Association between fatigue, peripheral serotonin, and L-carnitine in hypothyroidism and in chronic fatigue syndrome. Front Endocrinol (Lausanne). 2024;15:1358404. 10.3389/fendo.2024.1358404
- Leombruni P, Miniotti M, Colonna F, Sica C, Castelli L, et al. A randomised controlled trial comparing duloxetine and acetyl L-carnitine in fibromyalgic patients: preliminary data. Clin Exp Rheumatol. 2015;33:S82.
- Malaguarnera M, Gargante MP, Cristaldi E, Colonna V, Messano M, et al. Acetyl L-carnitine (ALC) treatment in elderly patients with fatigue. Arch Gerontol Geriatr. 2008;46:181.
- Li YJ, Wang DX, Bai XL, Chen J, Liu ZD, et al. [Clinical characteristics of patients with chronic fatigue syndrome: analysis of 82 cases]. Zhonghua Yi Xue Za Zhi. 2005;85:701.
- Vermeulen RC, Scholte HR. Exploratory open label, randomized study of acetyl- and propionylcarnitine in chronic fatigue syndrome. Psychosom Med. 2004;66:276.
- Tomassini V, Pozzilli C, Onesti E, Pasqualetti P, Marinelli F, et al. Comparison of the effects of acetyl L-carnitine and amantadine for the treatment of fatigue in multiple sclerosis: results of a pilot, randomised, double-blind, crossover trial. J Neurol Sci. 2004;218:103.
- Neri S, Pistone G, Saraceno B, Pennisi G, Luca S, et al. L-carnitine decreases severity and type of fatigue induced by interferon-alpha in the treatment of patients with hepatitis C. Neuropsychobiology. 2003;47:94.
