BulkSupplements.com L-Carnitine 1000mg Capsules - 240 Count (Pack of 1) Review

BulkSupplements.com L-Carnitine 1000mg Capsules - 240 Count (Pack of 1) is an unflavored amino acid dietary supplement designed to support adult energy management, strength, and performance goals. Packaged in a single bottle weighing 4.8 ounces with dimensions of 3 x 3 x 4 inches, this individual supplement formulation provides a total of 240 capsules, which equals 120 total servings per container at a substantial 1000mg dose per serving. The product is tailored to maximize your potential and enhance an active lifestyle, catering to fitness enthusiasts looking to push their limits. It offers versatility for all lifestyles, whether you are an athlete, a sprinter, or someone simply looking to stay active, fitting seamlessly into your daily regimen and adapting to a wide range of dietary needs and preferences. These L-Carnitine 1000mg capsules provide gluten-free and transparent nutrition, made with quality ingredients and featuring clear nutritional content per serving so consumers know exactly what they are taking. Furthermore, the supplement is produced in a cGMP-compliant facility that follows current Good Manufacturing Practices (cGMP), ensuring a consistent and reliable product that reflects the manufacturer BULKSUPPLEMENTS.COM's commitment to quality and care in every step of the process. All supplements from the brand are made with quality and integrity, produced with a focus on clarity, consistency, and high standards, where every batch is tested to help ensure quality and peace of mind for wellness-focused consumers. The item carries model number and manufacturer part number LCARNB, UPC 849720041128, and ASIN B0C3SFJRQD.

Product Focus: Weight and Metabolism for MenAlso covers:Digestion
Tier ⓘ
Tier 4 · Rank 11
Tier 4 · Emerging. A promising mechanism or animal data, with thin human evidence so far. Rank 11 within Tier 4 for Weight and Metabolism for Men; 21 of 26 overall. Tiers run from 1, the strongest evidence, to 5. How we grade →
Evidence ⓘ
27 /100
How strongly the evidence says this product works: human studies count most, then real reviews, then our biohacker panel.
Positive Reviews
0% of 438
Biohacker Mentions
6 of 10
Cost per month
$3

Study, Trial or Testing Result Summary

Members Only30 human studies · 16 improved

2 of these 30 human studies gave l-carnitine by drip, not by mouth.

30 human studies16 improved10 no effect83,113 people studied

L-carnitine is in this product at 1000 mg a day, a dose used in studies. Most pooled analyses find it gives a small extra weight loss. A 2025 review of eight pooled analyses covering 16,352 people found lower body weight, body mass index and waist size at 150 to 4000 mg a day for 8 to 30 weeks [1]. Across 43 trials in overweight adults, weight fell about 1.1 kg and fat mass about 1.2 kg, but body fat percent and waist size did not change [2]. In 37 trials with 2,292 people, weight fell about 1.2 kg, with the biggest effect near 2000 mg a day, twice this dose [3]. In nine trials with 911 adults, users lost about 1.3 kg more than controls, though the effect shrank the longer it was taken [4]. A one-year trial in 258 obese people with diabetes found 2 grams daily added to meds improved weight loss [5]. However, a large 2022 pooled analysis of 143 trials with 49,810 adults found it did not lower weight compared with lifestyle changes alone [6]. Overall, any benefit appears small. Animal and cell studies are never counted.

See all 30 studies →Hide the studies

Review Totals and Summary

Members Only438 reviews · 0% positive
438 reviews · Amazon 390 · Walmart 47 · BulkSupplements 1
0% positive0% neutral100% negative

This L-Carnitine supplement from BulkSupplements.com has garnered approximately 438 ratings across various stores. Overall, customers express a generally positive sentiment, often highlighting the product's effectiveness and value. **What it did for buyers** Many customers report positive effects from taking these L-Carnitine capsules. Some users experienced an increase in energy, with one noting, "my aunt says it's giving her a bit more energy." Others found the product simply "served its purpose" or was an "amazing supplement." For some, it aligned with specific health recommendations, with one reviewer stating it "has just what our doctor ordered." One customer mentioned using it to help with hyperthyroidism and alcohol cravings, noting it "has many benefits." **Complaints** Despite the positive feedback, several significant concerns were raised. Quality control issues were a recurring theme, with reports of "several capsules were damaged" upon arrival. Some customers found foreign objects, such as "aluminum shreds kind of glued to the capsules." There were also serious concerns about product integrity, including a report of "Fake brown capsules hidden below" at the bottom of a bottle, leading to questions about authenticity. A direct side effect mentioned was that "pills immediately cause heartburn" for one user. **Taste, Smell, Pill Size, Form** The most prominent feedback regarding sensory attributes was about the smell. One reviewer explicitly stated, "the smell is terrible." There was no specific feedback provided in the reviews or store summaries regarding the taste or the size of the capsules. The product reviewed is specifically the 1000mg capsules, and feedback on other forms like gummies or powder was not included. **Value for Money** Many buyers consider this L-Carnitine product to be an excellent value. Customers frequently praised the pricing for the quantity and dosage provided. One reviewer highlighted it as the "Best price for the amount as well as amount of mg," further adding it was the "best price for the amount for 1.000 mg." This suggests that for those seeking a cost-effective L-Carnitine supplement, this product stands out. **Who it suits and who it did not** This supplement appears to suit individuals looking for an L-Carnitine product that offers good value and a high dosage, particularly those seeking an energy boost or using it under a doctor's recommendation, as one buyer noted it was "just what our doctor ordered." It may also appeal to those who appreciate a large quantity per bottle. However, it did not suit customers who experienced quality control issues, such as damaged or questionable capsules, or those sensitive to strong smells. Individuals prone to heartburn might also find it unsuitable, as one user reported that "pills immediately cause heartburn."

Biohacker Summary

Members Only6 of 10 recommend it
6 of 10 biohackers on our panel recommend it

Most of the panel recommends or uses L-carnitine, with five of ten giving a latest position of recommends and three neutral, while one warns and one stopped. The main reasons are moving fat into the cell's energy centers for fat burning and exercise, male and female fertility and sperm quality, heart support, and mental or mitochondrial energy. Doses mentioned range from 500 to 750 milligrams a day up to 1 to 4 grams a day, with one panelist suggesting 500 milligrams once or twice a day and another taking it before a fasted workout, and several prefer the acetyl form. One panelist takes it with carbohydrates for best results, and another thinks it is less needed if you eat a lot of meat. On the caution side, one panelist stopped because it converts to TMAO, a heart disease risk marker, and saw no real benefit, while another warns against injecting it because of contamination risks.

See all 9 biohackers →Hide the biohackers
  • Ben Greenfield · L-Carnitine · recommends
    • 19 Sep 2026 · recommends · YouTube ↗
      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.
    • 19 Sep 2026 · neutral · Podcast ↗
      He mentions L-carnitine as a supplement with real human data behind it for male fertility.
    • 8 Sep 2026 · recommends · X ↗
      Recommends L-carnitine at 1-3 grams per day for at least 30 days pre-conception to improve mitochondrial function tied to sperm quality.
    • 20 Nov 2025 · recommends · Facebook ↗
      Recommends MitoQ +Heart, a Mitoquinol-enhanced blend with L-Carnitine, Magnesium, and Vitamin D3 for cardiovascular and energy support.
    • 13 Nov 2025 · recommends · YouTube ↗
      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.
    • 25 Nov 2023 · neutral · YouTube ↗
      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.
    • 24 Aug 2023 · recommends · YouTube ↗
      Recommends L-carnitine at 500 to 1,000 milligrams for male fertility, noting it can be found in capsules or as an intramuscular injection.
    • 10 Aug 2023 · neutral · Podcast ↗
      Ben mentions that L-carnitine ranks pretty high in a database ranking of anti-aging drugs and compounds by effectiveness.
    • 10 Aug 2023 · stopped · YouTube ↗
      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.
    • 20 Jul 2023 · neutral · YouTube ↗
      Mentions L-Carnitine as an ingredient that helps existing functioning mitochondria make more energy.
  • Dr. Rhonda Patrick · L-Carnitine · neutral
    • 7 Sep 2026 · neutral · YouTube ↗
      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.
    • 28 Apr 2022 · uses · YouTube ↗
      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.
    • Date not recorded · neutral · Website ↗
      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.
    • Date not recorded · neutral · Website ↗
      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.
    • Date not recorded · neutral · Website ↗
      Dr. Rhonda Patrick reviews how L-carnitine affects mitochondrial energy metabolism.
  • Andrew Huberman · L-Carnitine · recommends
    • 27 Jul 2026 · recommends · YouTube ↗
      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.
    • 14 May 2026 · recommends · Podcast ↗
      He shares science-based tools for modulating aggression, including supplementation with acetyl-L-carnitine.
    • 14 May 2026 · neutral · YouTube ↗
      Discusses a study showing that acetyl-L-carnitine supplementation significantly improved symptoms of ADHD, including reductions in aggressive behavior, attentional problems, and delinquency.
    • 13 Apr 2026 · recommends · YouTube ↗
      Recommends L-carnitine for sperm health.
    • 23 Mar 2026 · uses · YouTube ↗
      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.
    • 19 Jun 2025 · neutral · Podcast ↗
      Mentions Acetyl-L-carnitine in the context of whole body pain.
    • 13 Nov 2023 · recommends · YouTube ↗
      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.
    • 23 Jan 2023 · neutral · Podcast ↗
      Discusses L-Carnitine as a fertility supplement.
    • 23 Jan 2023 · recommends · YouTube ↗
      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.
    • 9 Jan 2023 · recommends · Podcast ↗
      Recommends L-Carnitine for hormone health.
  • Dave Asprey · L-Carnitine · recommends
    • 16 Dec 2025 · recommends · YouTube ↗
      States that L-Carnitine shows changes happening in fertility.
    • 10 Oct 2025 · neutral · YouTube ↗
      Mentions that Acetyl-L-Carnitine is usually a good mitochondrial enhancer, but not everyone needs it.
    • 5 Aug 2025 · uses · YouTube ↗
      Uses Acetyl-L-Carnitine on a regular basis as a well-known enhancer of mitochondrial fatty acid oxidation.
    • 27 Jun 2025 · uses · YouTube ↗
      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.
    • 6 May 2025 · neutral · YouTube ↗
      Dave Asprey mentions acetyl-L-carnitine as a mitochondrial stimulator that is widely available and can be felt right away.
    • 27 Mar 2025 · neutral · YouTube ↗
      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.
    • 2 May 2024 · recommends · YouTube ↗
      Includes Acetyl-L-Carnitine as a helpful addition to a med protocol.
    • 18 Apr 2023 · uses · YouTube ↗
      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.
    • 15 Dec 2020 · stopped · YouTube ↗
      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.
    • 25 Sep 2020 · warns · YouTube ↗
      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
    • 25 Jun 2025 · neutral · YouTube ↗
      Mentions that supplementing with L-carnitine can make mitochondria more efficient.
    • 23 Aug 2024 · recommends · YouTube ↗
      Recommends Acetyl L-Carnitine as it is critical in fat metabolism and supports the transport of fatty acids into the mitochondria for energy.
    • 28 Feb 2024 · recommends · YouTube ↗
      Recommends L-carnitine as critical for producing sperm and increasing antioxidant status in men.
    • 29 Sep 2023 · recommends · YouTube ↗
      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.
    • 25 May 2022 · uses · YouTube ↗
      Mentions that L-carnitine was part of the mitochondrial therapy that helped a child with autism improve.
    • 22 Sep 2021 · uses · YouTube ↗
      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.
    • 26 Jul 2021 · uses · YouTube ↗
      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.
    • 8 Mar 2021 · recommends · YouTube ↗
      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.
    • Date not recorded · neutral · Website ↗
      Lists Acetyl-L-Carnitine 500mg as a product available, noting its regular price and capsule count.
    • Date not recorded · neutral · Website ↗
      Acetyl-L-Carnitine 500mg is listed for sale on Dr. Mark Hyman's website.
  • Thomas DeLauer · L-Carnitine · recommends
    • 6 Jun 2025 · recommends · YouTube ↗
      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.
    • 18 Mar 2025 · uses · YouTube ↗
      Takes L-carnitine.
    • 17 Dec 2024 · uses · YouTube ↗
      Takes supplements like Acetyl-L-Carnitine to enhance mitochondrial function.
    • 2 Dec 2024 · recommends · YouTube ↗
      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.
    • 24 Jun 2024 · recommends · YouTube ↗
      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.
    • 1 Nov 2023 · recommends · YouTube ↗
      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.
    • 19 Oct 2023 · recommends · YouTube ↗
      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.
    • 8 Jun 2023 · recommends · YouTube ↗
      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.
    • 11 Feb 2023 · recommends · YouTube ↗
      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.
    • 29 Jul 2022 · uses · YouTube ↗
      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
    • 31 May 2024 · neutral · YouTube ↗
      Mentions L-carnitine as another nutrient that can be depleted, similar to co-enzyme Q10.
    • 24 Feb 2024 · recommends · YouTube ↗
      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.
    • 18 Mar 2020 · recommends · Podcast ↗
      States that the best way to use L-Carnitine is for cardiovascular health, as the heart needs it to transport fatty acids for energy.
    • 6 Oct 2019 · recommends · YouTube ↗
      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
    • 3 Mar 2024 · warns · YouTube ↗
      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.
    • 26 Feb 2024 · warns · YouTube ↗
      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.
    • 26 Feb 2024 · neutral · Podcast ↗
      Derek explores L-carnitine as a fat loss supplement.
  • Siim Land · L-Carnitine · stopped
    • 12 Apr 2023 · stopped · YouTube ↗
      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.
    • 5 Dec 2022 · uses · YouTube ↗
      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.
    • 16 Jun 2021 · uses · YouTube ↗
      Experimented with acetyl-L-carnitine to improve his performance on the soccer field, specifically his ability to read the play.
    • 11 Jul 2019 · neutral · YouTube ↗
      Mentions L-carnitine as an ingredient in Kapex that helps transport fatty acids into the mitochondria and liver.

RAL Summary

Members OnlyTier 4 for Weight and Metabolism for Men

The review counts say 98% of 448 reviews are negative, but our own summary of about 438 ratings for these same capsules describes mostly positive buyers, so the counts cannot be trusted as a measure of this product. Its reviews are set aside, so it is graded on its studies alone. Human studies support L-Carnitine (16 of 30 human studies showed an improvement), but there are not yet enough reviews to confirm it (0).

  • Emerging: not enough evidence to rank higher yet.

Where the evidence disagrees: 10 of the 30 human studies found no effect.

More Details

Members OnlyBody systems · Combine with · Possible side effects

Body systems: Metabolic system, Digestive system

Combine with: To enhance the effects of L-Carnitine for weight management, consider combining it with supplements that further support metabolism and fat oxidation. Green Tea Extract (EGCG) can boost metabolic rate and fat burning. Conjugated Linoleic Acid (CLA) may help reduce body fat and improve body composition. Alpha-Lipoic Acid (ALA) works synergistically with L-Carnitine to improve glucose utilization and energy production. Additionally, a high-quality protein powder can support muscle mass maintenance during weight loss, which is crucial for a healthy metabolism. Fiber supplements can also aid satiety and digestive health, complementing a weight management regimen.

Possible side effects: One buyer reported heartburn right after taking the pills, and some noted a bad smell; other complaints were about damaged or questionable capsules rather than side effects.

Supplement Facts

L-Carnitine 1000 mg
Supplement Facts
Serving Size 2 Capsules
Servings Per Container 120
Amount Per Serving% Daily Value
L-Carnitine1,000 mg†
† Daily Value not established.

Other ingredients: Rice Flour, Bovine Gelatin Capsules.

Directions: Suggested Use: As a dietary supplement, take 2 capsules with 8-12 oz of water or as directed by your healthcare professional.

Label source: Bulksupplements · Report a label change

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The BulkSupplements.com L-Carnitine 1000mg Capsules - 240 Count (Pack of 1) label
L-Carnitine 1000mg Capsules - 240 Count (Pack of 1)

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Our articles on this subject

Graded October 28, 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.