Bain MA, Faull R, Fornasini G, Milne RW, Evans AM. Accumulation of trimethylamine and trimethylamine-N-oxide in end-stage renal disease patients undergoing haemodialysis. Nephrol Dial Transplant. 2006;21(5):1300–4. https://doi.org/10.1093/ndt/gfk056. For this reason, L-carnitine levels are often lower in vegetarians and vegans since they restrict or avoid animal products ( 37). Wall BT, Stephens FB, Constantin-Teodosiu D, Marimuthu K, Macdonald IA, Greenhaff PL. Chronic oral ingestion of L-carnitine and carbohydrate increases muscle carnitine content and alters muscle fuel metabolism during exercise in humans. J Physiol. 2011;589(Pt 4):963–73. https://doi.org/10.1113/jphysiol.2010.201343.

Doses of 0.25 mg subcutaneously once a week and 3 mg orally once a day are intended for treatment initiation and are not effective doses for glycemic control. Since red meat is particularly rich in LC [ 69], dietary intervention in healthy adults, indicated a significant increase in plasma and urine TMAO levels following 4 weeks of the red meat-enriched diet [ 70]. The rise of plasma TMAO was on average three-fold compared with white meat and non-meat diets [ 70]. Conversely, habitual consumption of red, processed or white meat did not affect plasma TMAO in German adult population [ 71]. Similarly, a minor increase in plasma TMAO was observed following red meat and processed meat consumption in European multi-center study [ 72]. Farah replied: “Definitely not telling the truth, 100%. I’ve never taken L‑carnitine injections at all.” Keller J, Ringseis R, Koc A, Lukas I, Kluge H, Eder K. Supplementation with l-carnitine downregulates genes of the ubiquitin proteasome system in the skeletal muscle and liver of piglets. Animal. 2012;6(1):70–8. https://doi.org/10.1017/S1751731111001327.In a pharmacokinetic study where five normal adult male volunteers received an oral dose of [ 3H-methyl]-L-carnitine following 15 days of a high carnitine diet and additional carnitine supplement, 58 to 65% of the administered radioactive dose was recovered in the urine and feces in 5 to 11 days. Maximum concentration of [ 3H-methyl]-L-carnitine in serum occurred from 2 to 4.5 hr after drug administration. Major metabolites found were trimethylamine N-oxide, primarily in urine (8% to 49% of the administered dose) and [ 3H]-y-butyrobetaine, primarily in feces (0.44% to 45% of the administered dose). Urinary excretion of levocarnitine was about 4 to 8% of the dose. Fecal excretion of total carnitine was less than 1% of the administered dose. 10

Volpato S, Bianchi L, Cherubini A, Landi F, Maggio M, Savino E, Bandinelli S, Ceda GP, Guralnik JM, Zuliani G, et al. Prevalence and clinical correlates of sarcopenia in community-dwelling older people: application of the EWGSOP definition and diagnostic algorithm. J Gerontol A Biol Sci Med Sci. 2014;69(4):438–46. https://doi.org/10.1093/gerona/glt149. Koeth RA, Wang Z, Levison BS, Buffa JA, Org E, Sheehy BT, Britt EB, Fu X, Wu Y, Li L, et al. Intestinal microbiota metabolism of L-carnitine, a nutrient in red meat, promotes atherosclerosis. Nat Med. 2013;19(5):576–85. https://doi.org/10.1038/nm.3145. Prefilled dial-a-dose pen: Use Novofine(R) and Novofine(R) Plus disposable needles up to 8 mm length; use a new needle for each injection According to one older study, 57–84% of L-carnitine is absorbed when it’s consumed from food, compared to only 14–18% when taken as a supplement ( 36). Pan A, Sun Q, Bernstein AM, Schulze MB, Manson JE, Stampfer MJ, Willett WC, Hu FB. Red meat consumption and mortality: results from 2 prospective cohort studies. Arch Intern Med. 2012;172(7):555–63. https://doi.org/10.1001/archinternmed.2011.2287.

What Is Levocarnitine?

Rebouche CJ. Quantitative estimation of absorption and degradation of a carnitine supplement by human adults. Metabolism. 1991;40(12):1305–10. Furthermore, while it may aid in weight loss for some people, you may wish to consult with a dietician to develop a thorough diet and exercise regimen first. Summary Concomitant use of an insulin secretagogue (e.g., sulfonylurea) or insulin increases the risk of hypoglycemia, including severe hypoglycemia Stephens FB, Constantin-Teodosiu D, Laithwaite D, Simpson EJ, Greenhaff PL. An acute increase in skeletal muscle carnitine content alters fuel metabolism in resting human skeletal muscle. J Clin Endocrinol Metab. 2006;91(12):5013–8. https://doi.org/10.1210/jc.2006-1584.

Initial dose: 0.25 mg subcutaneously once a week for 4 weeks, then 0.5 mg subcutaneously once a weekThe evidence is mixed when it comes to the effects of L-carnitine on sports performance, but it may offer some benefits. Chakraverty also seemed concerned about possible “side‑effects”, also writing: “I understand [Salazar] is keen but we should be asking him to follow this advice.” If a dose is missed, administer as soon as possible within 5 days after the missed dose; if more than 5 days have passed, skip the missed dose and administer the next dose on the regularly scheduled day, resume regular once a week dosing Heianza Y, Ma W, Manson JE, Rexrode KM, Qi L. Gut Microbiota Metabolites and Risk of Major Adverse Cardiovascular Disease Events and Death: A Systematic Review and Meta-Analysis of Prospective Studies. J Am Heart Assoc. 2017;6(7). https://doi.org/10.1161/JAHA.116.004947. Severe renal dysfunction—administration of high doses of oral levocarnitine for long periods of time may build up in the body of patients with severe kidney disease