Thorne Acetyl-L-Carnitine 500 mg Review
THORNE Acetyl-L-Carnitine, 500 mg per Capsule, 60 Capsules is listed on Amazon as a supplement from the brand THORNE, with the item form given as capsule and the flavor as unflavored. The product is classified under Vitamins, Minerals and Supplements, in the Amino Acids category, and its primary supplement type is Acetyl-L-Carnitine. The page lists 60 count, a single bottle, and a total of 60 servings per container. The item weighs 0.07 kg and measures 2.09 x 2.09 x 3.72 inches. The diet type is given as gluten free, and the item highlight reads: Supports Cognitive Function, Positive Mood and Nerve Health in Hands and Feet, Gluten, Dairy and Soy-Free, NSF Contents Certified. The product benefits are listed as Cognitive Health, Cellular Health and Longevity. The special ingredient is listed as Antioxidant. The About this item section makes several points. It says the product promotes cognitive function and supports healthy cortisol levels to help maintain a positive mood. It says the product supports the function and comfort of the nerves in the upper and lower limbs. It says the product promotes healthy sperm count and sperm motility, under a men's health heading. It also states that the product has been third-party tested and certified to verify that what is in the package matches what is on the label. Finally, it says Thorne is trusted by 100 plus professional sports teams and is described as the number one most recommended clinical brand by consumers and health-care practitioners, based on a 2026 independent survey of US supplement consumers and health-care practitioners. The page notes the product is sold by Pattern. and ships from Amazon, with a one-time purchase price of $32.00 and a Subscribe and Save option at $27.20 with 15 percent savings. The item is non-returnable due to food safety reasons, though damaged or defective items may be refunded or replaced. The page lists the manufacturer as Thorne Research, model number SA520, and ASIN B005P0UYGA. The Best Sellers Rank shows number 8,265 in Health and Household and number 4 in Acetyl-L-Carnitine Nutritional Supplements. The page also links to the THORNE store and shows related items, including other THORNE products such as Alpha-Lipoic Acid and Magnesium Glycinate, along with competing acetyl-L-carnitine and L-carnitine products from other brands. Shoppers see a rating of 4.7 out of 5 stars from 1,180 ratings on this page.
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Study, Trial or Testing Result Summary
Members Only44 human studies · 28 improved
Acetyl-L-carnitine is taken here at 1500 mg a day, the dose that worked in studies. A pooled analysis of placebo-controlled trials in people with mild memory problems or early Alzheimer's disease, using 1.5 to 3 grams daily for 3 to 12 months, found a clear benefit over placebo starting at 3 months [1]. In 92 frail older adults, 3 grams daily for 3 months improved memory and thinking scores and lowered a marker of inflammation [2]. In 481 older people with mild decline, 1.5 grams daily for 90 days improved overall thinking, memory and mood, and the memory gains lasted after stopping [3]. The picture is different in established Alzheimer's disease. Two one-year trials at 3 grams daily did not slow decline [4][5], and a review of 11 trials found better clinician ratings but no benefit on thinking tests [6]. In short, the support is strongest for older adults with mild decline. It has not been shown to help people with Alzheimer's disease, and it was not tested in healthy younger adults seeking mental clarity. Animal and cell studies are never counted.
See all 44 studies →Hide the studies
- Across 48 studies of 3,650 children with attention problems testing 12 antioxidants including acetyl-L-carnitine, other antioxidants ranked best for attention, and the abstract reports no specific result for acetyl-L-carnitine.Safety and efficacy of antioxidant therapy in children and adolescents with attention deficit hyperactivity disorder: A …
- Two small trials in healthy young adults found no effect of L-carnitine on reaction time, vigilance or memory after three days, and the evidence was very low quality.L-carnitine for cognitive enhancement in people without cognitive impairment.
- In two small trials of 83 boys with fragile X syndrome given L-acetylcarnitine or placebo for one year, intellectual functioning and hyperactivity did not clearly improve, with low-quality evidence.L-acetylcarnitine for treating fragile X syndrome.
- Pooled placebo-controlled trials of 3 to 12 months in people with mild cognitive impairment or mild Alzheimer's disease using 1.5 to 3 grams daily showed a significant advantage over placebo on clinical and memory-thinking tests, beginning at 3 months.Meta-analysis of double blind randomized controlled clinical trials of acetyl-L-carnitine versus placebo in the treatmen…
- One study of 40 adults with Down syndrome tested acetyl-L-carnitine, but data were too limited to draw conclusions about its effect on cognitive decline.Pharmacological interventions for cognitive decline in people with Down syndrome.
- Across 11 placebo-controlled trials in people with Alzheimer's disease, acetyl-L-carnitine improved overall clinician-rated impression at 12 and 24 weeks but showed no benefit on cognition tests, and the reviewers said this may be due to chance.Acetyl-L-carnitine for dementia.
- Two studies of L-acetylcarnitine in people with fragile X syndrome and attention-deficit hyperactivity disorder reported positive effects with no side effects, but the review found no robust evidence overall.Systematic review of pharmacological treatments in fragile X syndrome.
- A review of 122 studies of mitochondria-targeting supplements in psychiatric disorders, including acetyl-L-carnitine, found heterogeneous results and high risk of bias, with no specific acetyl-L-carnitine result given.Clinical outcomes of mitochondrial-enhancing nutraceutical supplementation in psychiatric disorders: A systematic review…
- In 431 people with mild to moderate Alzheimer's disease, 3 g a day of acetyl-L-carnitine for one year did not slow decline overall compared with placebo, though a later subgroup look hinted at slower decline in those aged 65 or younger.A 1-year multicenter placebo-controlled study of acetyl-L-carnitine in patients with Alzheimer's disease.
- In a reanalysis of 334 people with Alzheimer's disease, acetyl-L-carnitine for one year gave the same average decline as placebo, but younger patients (about 61 or under) declined more slowly on the drug.Acetyl L-carnitine slows decline in younger patients with Alzheimer's disease: a reanalysis of a double-blind, placebo-c…
- In 229 people aged 45 to 65 with early-onset Alzheimer's disease, 3 g a day of acetyl-L-carnitine for one year did not slow decline on the main measures versus placebo, with less decline on a memory test only among those who completed the study.A 1-year controlled trial of acetyl-l-carnitine in early-onset AD.
- In 130 people with Alzheimer's disease, one year of oral acetyl-L-carnitine slowed decline compared with placebo on 13 of 14 measures, with significant benefits for attention, memory and logical thinking.Long-term acetyl-L-carnitine treatment in Alzheimer's disease.
- In 125 cirrhotic people with minimal hepatic encephalopathy, acetyl-L-carnitine over 90 days lowered blood ammonia and improved memory, attention and thinking test scores more than placebo did.Acetyl-L-carnitine treatment in minimal hepatic encephalopathy.
- In 119 people with cognitive decline taking donepezil, adding acetyl-L-carnitine together with ginkgo biloba extract was followed by a drop in mini-mental state scores at 12 and 24 weeks, while adding choline alfoscerate instead gave better results, so the acetyl-L-carnitine effect cannot be separated from ginkgo.Comparative study of choline alfoscerate as a combination therapy with donepezil: A mixed double-blind randomized contro…
- In 112 children aged 5 to 12 with ADHD taking 500 to 1500 mg twice daily for 16 weeks, the main test showed no benefit over placebo, though a subgroup with inattentive symptoms showed a possible improvement.Acetyl-L-carnitine (ALC) in attention-deficit/hyperactivity disorder: a multi-site, placebo-controlled pilot trial.
- In a double-blind placebo-controlled trial of 106 people with Alzheimer's disease, a multi-ingredient supplement containing acetyl-L-carnitine improved cognitive test scores within 3 months compared with placebo.A Phase II Randomized Clinical Trial of a Nutritional Formulation for Cognition and Mood in Alzheimer's Disease.
- In 96 elderly people with fatigue taking acetyl-L-carnitine, physical and mental fatigue decreased, and memory and thinking scores improved more than in the comparison group.Acetyl L-carnitine (ALC) treatment in elderly patients with fatigue.
- In 92 prefrail older adults, taking 1.5 g of acetyl-L-carnitine twice daily for 3 months improved memory and thinking scores and lowered C-reactive protein compared with placebo.Acetyl-L-carnitine Slows the Progression from Prefrailty to Frailty in Older Subjects: A Randomized Interventional Clini…
- In an 80-person double-blind trial of older adults with dysthymic disorder, L-acetylcarnitine improved depression and anxiety scores over 7 weeks and worked about as well as a med.Read the study on PubMed (23428336) →
- In 67 people with minimal hepatic encephalopathy, taking 2 grams of acetyl-L-carnitine twice daily for 90 days improved energy, daily functioning, well-being, depression scores and trail-making test times compared with placebo.Acetyl-L-carnitine reduces depression and improves quality of life in patients with minimal hepatic encephalopathy.
- In a placebo-controlled trial of 61 people with severe hepatic encephalopathy, 2 g twice daily of acetyl-L-carnitine for 90 days improved memory, attention and thinking test scores compared with placebo and lowered blood ammonia.Acetyl-L-carnitine improves cognitive functions in severe hepatic encephalopathy: a randomized and controlled clinical t…
- In a 3-month double-blind placebo-controlled trial of 60 elderly people with mild mental impairment, 2 g per day of acetyl-L-carnitine produced significant improvements in behavior scales, memory tests, attention and verbal fluency compared with placebo.Acetyl-L-carnitine in the treatment of mildly demented elderly patients.
- In 55 alcoholics with mild thinking deficits taking 2 g per day for 90 days, memory and drawing test scores improved more than with placebo.Role of acetyl-L-carnitine in the treatment of cognitive deficit in chronic alcoholism.
- In 51 boys with fragile X syndrome and ADHD analysed, acetyl-L-carnitine at 20-50 mg per kg a day for one year reduced hyperactivity and improved social behaviour more than placebo.A double-blind, parallel, multicenter comparison of L-acetylcarnitine with placebo on the attention deficit hyperactivit…
- In 40 adults with Down syndrome taking acetyl-L-carnitine for six months, brain function and thinking tests did not improve compared with controls.The effect of acetyl-L-carnitine administration on persons with Down syndrome.
- In a 6-week placebo-controlled trial of 40 children and adolescents with ADHD, adding acetyl-L-carnitine to methylphenidate produced no difference in parent or teacher ratings compared with placebo added to methylphenidate.Acetyl-L-carnitine as an adjunctive therapy in the treatment of attention-deficit/hyperactivity disorder in children and…
- In 36 people with Alzheimer's dementia taking 2 g per day for 24 weeks, short-term memory tests showed a trend toward benefit, but differences from placebo were not statistically significant.Double-blind, placebo controlled study of acetyl-l-carnitine in patients with Alzheimer's dementia.
- In a 6-month placebo-controlled trial of 34 people with mild cognitive impairment, a multi-ingredient nutrient formula that includes acetyl-L-carnitine improved dementia rating scores compared with placebo, and the placebo group improved after switching to the formula.A Nutritional Formulation for Cognitive Performance in Mild Cognitive Impairment: A Placebo-Controlled Trial with an Ope…
- In 30 adults over 65 with mild mental impairment, 2 grams a day of acetyl-L-carnitine for three months did not differ significantly from placebo overall, though treated patients improved on some memory, attention and behaviour tests.Mental impairment in aging: selection of patients, methods of evaluation and therapeutic possibilities of acetyl-L-carni…
- In a placebo-controlled pilot of 12 institutionalized people with moderate to late-stage Alzheimer's disease, a multi-ingredient nutrient formula that includes acetyl-L-carnitine delayed decline in dementia rating and clock-drawing scores compared with placebo.Efficacy of a vitamin/nutriceutical formulation for moderate-stage to later-stage Alzheimer's disease: a placebo-control…
- A multi-ingredient supplement containing acetyl-L-carnitine improved memory and attention test scores in community-dwelling adults without dementia compared with placebo, though adults 74 and older often did not improve.A vitamin/nutriceutical formulation improves memory and cognitive performance in community-dwelling adults without demen…
- In two placebo-controlled trials of elderly outpatients with mild to moderate cognitive decline, acetyl-L-carnitine produced significant EEG changes after 8 weeks and better clinical global impression and daily activity ratings after 12 weeks, with generally minor side effects.Pharmaco-electroencephalographic and clinical effects of the cholinergic substance--acetyl-L-carnitine--in patients with…
- In a single-blind study of 481 elderly people with mild mental decline, 1.5 g per day of L-acetylcarnitine for 90 days significantly improved overall cognitive scores, memory, and mood, with memory benefits persisting after stopping.L-acetylcarnitine treatment of mental decline in the elderly.
- In 236 mildly impaired elderly people taking 1500 mg per day in alternating 45-day phases with placebo, cognitive and mood scores improved more than with placebo.[Effects of L-acetylcarnitine on mental deterioration in the aged: initial results].
- In 17 healthy young adults, 1.5 grams a day of acetyl-L-carnitine for one month sped reflexes and reduced errors and time on a maze test compared with an untreated control group.[Psycho-functional changes in attention and learning under the action of L-acetylcarnitine in 17 young subjects. A pilot…
- In a double-blind crossover trial of 12 elderly people recovering from acute cerebral circulatory insufficiency, acetyl-L-carnitine outperformed placebo on memory, word and number tests, and simple reaction tasks, with no side effects reported.Effects of acetyl-L-carnitine on reaction times in patients with cerebrovascular insufficiency.
- In a 12-week double-blind placebo-controlled trial of people with early Alzheimer's disease or vascular dementia taking 2250 to 3000 mg of acetyl-L-carnitine per day, the drug's treatment effect was 2.8 times higher than placebo, and it was well tolerated.[Acetyl-L-carnitine (carnicetine) in the treatment of early stages of Alzheimer's disease and vascular dementia].
- In people with Down syndrome, 90 days of acetyl-L-carnitine improved visual memory and attention compared with untreated groups, while people with other intellectual disabilities did not improve.[Effect of the chronic treatment with L-acetylcarnitine in Down's syndrome].
- In an open-label randomized study of 90 people with chronic fatigue syndrome, 2 g per day of acetyl-L-carnitine for 24 weeks led to considerable improvement in 59% of patients, mainly in mental fatigue, and attention improved, though no placebo group was included.Exploratory open label, randomized study of acetyl- and propionylcarnitine in chronic fatigue syndrome.
- In an open-label one-year study of 24 people with Alzheimer's disease, a multi-ingredient supplement containing acetyl-L-carnitine kept cognitive performance and behavior at baseline levels, unlike the decline usually seen with placebo.Maintenance of Cognitive Performance and Mood for Individuals with Alzheimer's Disease Following Consumption of a Nutrac…
- In 23 people with mild Alzheimer's disease already on cholinesterase inhibitors, adding 2 g per day of acetyl-L-carnitine for 3 months raised the response rate from 38% to 50% in an open study without a control group.Effects of acetyl-L-carnitine in Alzheimer's disease patients unresponsive to acetylcholinesterase inhibitors.
- In 9 schizophrenia patients who completed 12 weeks of 1 g daily acetyl-L-carnitine added to clozapine, cognitive test scores did not significantly change and symptom improvement was limited to one symptom domain.Acetyl-L-Carnitine Augmentation of Clozapine in Partial-Responder Schizophrenia: A 12-Week, Open-Label Uncontrolled Prel…
- In a pilot study of 17 boys with fragile X syndrome, L-acetylcarnitine taken for one year significantly reduced hyperactivity as rated on a parent-teacher questionnaire.[L-acetylcarnitine treatment on fragile X patients hyperactive behaviour].
- A review of four published trials with over 100 patients each found that acetyl-L-carnitine over 3 months improved dementia-related rating scales beyond baseline variability, and placebo changes depended on how severe the disease was at the start.Efficacy and clinical relevance of cognition enhancers.
Review Totals and Summary
Members Only1,180 reviews · 94% positive
Customer feedback on Thorne's Acetyl-L-Carnitine is mostly positive, and brand trust runs through much of it. Reviewers on iHerb, which draws a global audience, often describe a clean lift in energy, focus and mental clarity. Many say they notice it before workouts or during a long workday, and that it feels noticeable without jitters or a crash. Some reviewers say it helped with weight management. They mention better metabolism and fewer cravings. A smaller group says they took it for fertility or general health reasons and saw benefits. Many buyers say they chose Thorne because they trust its reputation for purity, quality ingredients and third-party testing. They often prefer it to cheaper brands they see as less reliable. They also appreciate that the capsules are easy to swallow and that the packaging is well made. That contrasts with the common complaint about large pills in other supplements. The criticism is milder and falls into a few groups. Some customers report no noticeable effect yet. Several of them say they are still waiting for results but keep taking it because they trust Thorne. Others point to price. Editorial reviewers call it pricey compared with other ALCAR products. Some buyers also say they feel mild stimulation, restlessness or trouble sleeping, particularly if they take it late in the day. Independent reviewers also list nausea or stomach upset for some users. The general safety literature adds a fishy body odor and digestive upset as known carnitine effects. I did not see these as dominant themes in Thorne reviews. Overall, customers who take it for cognition, energy or nerve support are largely satisfied. Those who are disappointed mostly say they saw no obvious benefit or found the cost high. Note on sources: this summary rests mainly on iHerb's aggregated customer feedback, plus editorial reviews and listings from Vitacost, Carewell and SuppCo. I could not read individual reviews on every retailer page. The themes are therefore directional and not a full count of all reviews.
Biohacker Summary
Members Only6 of 10 recommend it
Most of the panel recommends or uses carnitine, and several of them name acetyl-L-carnitine specifically. They mainly take it for energy, because it carries fatty acids into the mitochondria, and for fat loss, exercise, male and female fertility, heart health, and thinking. Doses vary: 500 to 750 milligrams a day for fertility, 500 to 2000 milligrams a day for general energy (often 500 once or twice a day), and 1 to 4 grams a day in other cases, with one person pairing it with carbohydrates and another with alpha-lipoic acid. Cautions come from one panelist who warns against injecting it because of contamination, one who has moved to a low-dose injectable over concerns about a heart-risk compound from oral use, and one who stopped taking it over that same concern and because he saw little benefit. Two others point out that red meat is already high in carnitine, so some people may need less of it.
See all 9 biohackers →Hide the biohackers
Ben Greenfield · L-Carnitine · recommends
- Recommends L-carnitine for male fertility, explaining that it helps shuttle fatty acids into mitochondria, assisting with beta-oxidation, and its concentration in sperm correlates with sperm motility.
- He mentions L-carnitine as a supplement with real human data behind it for male fertility.
- Recommends L-carnitine at 1-3 grams per day for at least 30 days pre-conception to improve mitochondrial function tied to sperm quality.
- Recommends MitoQ +Heart, a Mitoquinol-enhanced blend with L-Carnitine, Magnesium, and Vitamin D3 for cardiovascular and energy support.
- States that acetyl L-carnitine is very important as a transport molecule that facilitates the entry of fatty acids into the mitochondrial chain, which can produce 100 ATP per molecule.
- Mentions L-carnitine as a supplement that is "not bad" but less of a priority than creatine, protein, vitamin D, fish oil, and essential amino acids.
- Recommends L-carnitine at 500 to 1,000 milligrams for male fertility, noting it can be found in capsules or as an intramuscular injection.
- Ben mentions that L-carnitine ranks pretty high in a database ranking of anti-aging drugs and compounds by effectiveness.
- States that he does not use L-carnitine, but many people in the exercise industry are reporting using it efficaciously for muscle gain as an injectable compound.
- Mentions L-Carnitine as an ingredient that helps existing functioning mitochondria make more energy.
Dr. Rhonda Patrick · L-Carnitine · neutral
- Discusses L-carnitine's role as a transporter for fatty acids into mitochondria for energy, its role in detoxifying metabolites, and its involvement in stabilizing cell membranes and ketone production. They mention studies showing it helps increase muscle mass and improve cognitive function in women, and meta-analyses showing reductions in body weight, waist size, and body fat in overweight and obese individuals.
- Takes acetyl-L-carnitine in the morning, believing it is beneficial with the ketogenic diet and can help boost ketosis, as people on a ketogenic diet can be deficient in carnitine.
- L-carnitine is important for transporting fatty acids into the mitochondria for energy and plays a role in detoxifying potentially toxic metabolites. Supplementation in the range of 1 to 4 g a day along with carbohydrates has shown benefits in muscle mass, cognitive function, and reductions in body weight and waist size in overweight and/or obese individuals.
- She thinks it would be useful to add acetyl-L-carnitine to her alpha-lipoic acid for mitochondrial benefits, but it's not high on her list because she eats a lot of meat, which is high in carnitine.
- Dr. Rhonda Patrick reviews how L-carnitine affects mitochondrial energy metabolism.
Andrew Huberman · L-Carnitine · recommends
- Andrew Huberman, based on discussions with fertility doctors, recommends L-carnitine for patients trying to increase fertility, egg quality, or sperm quality, noting it can be taken orally in higher dosages like 500 or 750 milligrams a day, or via injectable form.
- He shares science-based tools for modulating aggression, including supplementation with acetyl-L-carnitine.
- Discusses a study showing that acetyl-L-carnitine supplementation significantly improved symptoms of ADHD, including reductions in aggressive behavior, attentional problems, and delinquency.
- Recommends L-carnitine for sperm health.
- Has started experimenting with L-carnitine in an injectable form, taking a much lower milligram count than oral doses, to avoid absorption issues and concerns about increased TMAO from oral intake. They acknowledge its benefits for mitochondrial health.
- Mentions Acetyl-L-carnitine in the context of whole body pain.
- Recommends 1 gram of L-carnitine with 1 gram of vitamin C for male patients with any abnormal sperm parameter as part of a sperm enhancement protocol.
- Discusses L-Carnitine as a fertility supplement.
- Recommends L-carnitine in capsule form, 1 to 3 grams per day for 30 to 60 days, to significantly improve egg quality by supporting mitochondrial function, which is vital for chromosomal organization and egg fusion.
- Recommends L-Carnitine for hormone health.
Dave Asprey · L-Carnitine · recommends
- States that L-Carnitine shows changes happening in fertility.
- Mentions that Acetyl-L-Carnitine is usually a good mitochondrial enhancer, but not everyone needs it.
- Uses Acetyl-L-Carnitine on a regular basis as a well-known enhancer of mitochondrial fatty acid oxidation.
- Has included L-carnitine or acetyl-L-carnitine in his cognitive enhancement and longevity stack since his mid-20s, and finds its use for joints to be innovative.
- Dave Asprey mentions acetyl-L-carnitine as a mitochondrial stimulator that is widely available and can be felt right away.
- Notes that people in longevity have been taking acetyl-L-carnitine for 30 years for cognitive function and fat burning, and combining it with fatty 15 might produce PDC.
- Includes Acetyl-L-Carnitine as a helpful addition to a med protocol.
- Has been on acetyl-L-carnitine most of the time since [18:46] but found that taking too much caused jaw tension, so he had to dial back on it. He notes it is a mitochondrial enhancer.
- Used to take acetyl L-carnitine at a dose of about 500 milligrams, but stopped because it raised his acetylcholine levels too much, causing jaw tension.
- Dave found that if he takes too much acetyl-L-carnitine, he gets a headache and jaw tension, indicating he has enough in his system and it raises his acetylcholine levels more than he needs.
Dr. Mark Hyman · L-Carnitine · neutral
- Mentions that supplementing with L-carnitine can make mitochondria more efficient.
- Recommends Acetyl L-Carnitine as it is critical in fat metabolism and supports the transport of fatty acids into the mitochondria for energy.
- Recommends L-carnitine as critical for producing sperm and increasing antioxidant status in men.
- States that making energy in mitochondria requires carnitine and recommends acetylol carnitine or L-Carnitine at 500 to 2000 milligrams a day, usually 500 once or twice a day, as it is important in metabolizing fats.
- Mentions that L-carnitine was part of the mitochondrial therapy that helped a child with autism improve.
- Used L-carnitine as one of the first things with a 55-year-old woman with Graves' disease, as it can act as a thyroid peroxidase inhibitor, and she began to have relief from her symptoms.
- Used L-carnitine as one of the first interventions for a woman with Graves' disease, noting its ability to act as a thyroid peroxidase inhibitor, which provided symptom relief.
- Dr. Hyman discusses L-carnitine as an important nutrient for metabolic flexibility, helping the body use fat and carbohydrates for energy. He notes that people with diabetes, insulin resistance, pre-diabetes, and gestational diabetes are often low in this nutrient and that good prenatal vitamins often include it.
- Lists Acetyl-L-Carnitine 500mg as a product available, noting its regular price and capsule count.
- Acetyl-L-Carnitine 500mg is listed for sale on Dr. Mark Hyman's website.
Thomas DeLauer · L-Carnitine · recommends
- Recommends L-carnitine, especially if working out, to help shuttle fat into the cell better and improve fat oxidation, particularly in a fasted state before a workout.
- Takes L-carnitine.
- Takes supplements like Acetyl-L-Carnitine to enhance mitochondrial function.
- Discusses the mixed opinions on L-Carnitine for fat loss but concludes that it is beneficial, citing a meta-analysis showing an average of 1.33 kg of fat lost. He suggests that many people may be more deficient than they think, especially those who exercise intensely, and that it is an inexpensive supplement worth trying.
- Discusses the benefits of L-Carnitine for fat loss, citing a meta-analysis showing an average of 1.33 kg of fat lost, and suggests it's worth exploring as it's inexpensive and critical for fat oxidation.
- Recommends Acetyl L-Carnitine during a fast, especially for active individuals who deplete carnitine, as it's critical for fat burning, can cross the blood-brain barrier, and may have antioxidant effects and improve brain fat utilization.
- Discusses Acetyl L-Carnitine, noting its potential for cognitive improvement in dementia patients by stimulating mitochondrial function, acting as an antioxidant, and promoting neuronal growth and membrane stabilization.
- Recommends 1500 milligrams (1.5 grams) of L-Carnitine to help mobilize fat, suggesting it be taken earlier in the day, possibly during a fast.
- Recommends acetyl-L-carnitine, especially for active individuals or those fasting/low-carb, as it crosses the blood-brain barrier to provide fat-based fuel to the brain, promoting sharpness and alertness.
- Takes 2-4 grams of Acetyl-L-Carnitine, noting its importance for fat transport into mitochondria, especially for those on a ketogenic diet and athletes, and its mood-boosting effects for depression.
Dr. Eric Berg · L-Carnitine · neutral
- Mentions L-carnitine as another nutrient that can be depleted, similar to co-enzyme Q10.
- Explains that L-Carnitine helps burn fat during exercise, preserves muscle protein, and aids in recovery from exercise, noting it is very high in red meat.
- States that the best way to use L-Carnitine is for cardiovascular health, as the heart needs it to transport fatty acids for energy.
- Recommends L-carnitine for people with congestive heart failure, arrhythmia, or any type of heart damage, stating it is dynamite for the heart.
Peter Attia · L-Carnitine · warns
- Discusses L-carnitine, noting that people inject it for fat loss and to get more out of testosterone input, but warns against injecting it due to potential contamination from homebrewing or even compounding pharmacies, which have had issues leading to deaths.
- Warns that injecting L-carnitine, especially if home-brewed, is a bad idea due to sterilization concerns and potential for contamination, which can lead to serious health issues.
- Derek explores L-carnitine as a fat loss supplement.
Siim Land · L-Carnitine · stopped
- Stopped taking L-Carnitine because it converts to TMAO, a cardiovascular disease risk factor, and he hasn't noticed significant benefits for muscle growth or fat oxidation, preferring not to gamble with the risk given his family history of cardiovascular disease.
- States that L-Carnitine is great and can help with androgen receptor density for muscle growth, and he takes it before resistance training for this purpose, but not daily.
- Experimented with acetyl-L-carnitine to improve his performance on the soccer field, specifically his ability to read the play.
- Mentions L-carnitine as an ingredient in Kapex that helps transport fatty acids into the mitochondria and liver.
RAL Summary
Members OnlyTier 4 for Focus and Memory
The ineffective tier misreads the evidence: 28 of 44 human studies improved, and placebo-controlled trials in older adults with mild mental decline showed better memory and thinking; only trials in established Alzheimer's disease found no benefit. So it is graded Tier 4, as the studies disagree.
- Emerging: not enough evidence to rank higher yet.
Where the evidence disagrees: 9 of the 44 human studies found no effect.
More Details
Members OnlyBody systems · Combine with · Possible side effects
Body systems: Nervous system
Combine with: For cognitive and mitochondrial support, ALCAR pairs well with Alpha-Lipoic Acid (often used together in research on mitochondrial and nerve health), Omega-3 fish oil (DHA/EPA) for neuronal membrane health, and B vitamins (methylated B12, folate, B6) for neurotransmitter and methylation support. Citicoline or Alpha-GPC can complement it for acetylcholine support and focus, and CoQ10 or PQQ can add mitochondrial support. If the user still wants weight management support, consider combining with protein-rich nutrition, green tea extract (EGCG), and berberine or chromium for glucose metabolism, along with diet and exercise. Take ALCAR earlier in the day on an empty stomach, since it can be stimulating for some people. Consult a healthcare provider if on meds, meds, or anticonvulsants.
Possible side effects: No side effects were reported in the study findings given. Reviews could not be read individually, so nothing specific is known about side effects users report.
Supplement Facts
Acetyl-L-Carnitine 500 mg
| Acetyl-L-Carnitine | 500 mg | † |
Other ingredients: Hypromellose, Microcrystalline Cellulose, Leucine, Silicon Dioxide.
Directions: Suggested use: Take 1 capsule two to three times daily or as recommended by your health-care practitioner.
Barcode (UPC) 693749520023 · Label source: NIH label database · Report a label change
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Graded November 5, 2026 by the Reverse Age Lab evidence engine, from human studies, real reviews and our biohacker panel. How we grade. Is this medical advice? No. Rala organizes the published evidence; go over any change with your doctor, especially if you take meds.
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