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Dr. Grey AI

Condition

Fragile X Syndrome

Fragile X syndrome is the most common inherited cause of intellectual disability and autism, arising when a change in the FMR1 gene on the X chromosome stops the body from making FMRP, a protein the developing brain needs. Little research on supplements for it has been reviewed here so far, so there are no trial findings to report yet. Omega-3 fatty acids and melatonin have the most support in related areas, but that is not the same as evidence in people with Fragile X.

Supplements studied
1
Graded outcomes
0
Trials
1
People studied
56

Evidence by supplement

  • Strong
  • Moderate
  • Limited
  • Very limited

1 supplement

L-Carnitine: outcomes studied for Fragile X Syndrome
GradeOutcomeEffectSizeStudiesPeopleStudies list
ADHD SymptomsImproves (the measure goes down)4 studies56 people

The Fragile X Syndrome Supportive Care protocol

2 primary supplements · 7 supporting supplements

  • Omega-3 Fatty Acids1–2 g EPA+DHA daily (adjust for age/weight in children)
  • Vitamin D1,000–2,000 IU daily (children); 2,000–4,000 IU daily (adults)

See the full protocol

Studies cited

100 studies from PubMed

  1. L-carnitine ameliorated fasting-induced fatigue, hunger, and metabolic abnormalities in patients with metabolic syndrome: a randomized controlled studyNutr J · PMID 25424121
  2. L-Carnitine's Effect on the Biomarkers of Metabolic Syndrome: A Systematic Review and Meta-Analysis of Randomized Controlled TrialsNutrients · PMID 32932644
  3. Ameliorating hypertension and insulin resistance in subjects at increased cardiovascular risk: effects of acetyl-L-carnitine therapyHypertension · PMID 19620516
  4. Comparative study to evaluate the effect of l-carnitine plus glimepiride versus glimepiride alone on insulin resistance in type 2 diabetic patientsDiabetes Metab Syndr · PMID 30641691
  5. Effects of simvastatin and carnitine versus simvastatin on lipoprotein(a) and apoprotein(a) in type 2 diabetes mellitusExpert Opin Pharmacother · PMID 19618992
  6. Comparison between orlistat plus l-carnitine and orlistat alone on inflammation parameters in obese diabetic patientsFundam Clin Pharmacol · PMID 21077943
  7. Effects of combination of sibutramine and L-carnitine compared with sibutramine monotherapy on inflammatory parameters in diabetic patientsMetabolism · PMID 20423740
  8. L-Carnitine supplementation reduces oxidized LDL cholesterol in patients with diabetesAm J Clin Nutr · PMID 19056606
  9. Effect of L-carnitine on plasma glycemic and lipidemic profile in patients with type II diabetes mellitusEur J Clin Nutr · PMID 15741989
  10. Effect of carnitine-orotate complex on glucose metabolism and fatty liver: a double-blind, placebo-controlled studyJ Gastroenterol Hepatol · PMID 24611967
  11. Efficacy and tolerability of combined treatment with L-carnitine and simvastatin in lowering lipoprotein(a) serum levels in patients with type 2 diabetes mellitusAtherosclerosis · PMID 16384561
  12. Blood Pressure and Metabolic Effects of Acetyl-l-Carnitine in Type 2 Diabetes: DIABASI Randomized Controlled TrialJ Endocr Soc · PMID 29696241
  13. The effects of oral L-carnitine treatment on blood lipid metabolism and the body fat content in the diabetic patientAsia Pac J Clin Nutr · PMID 24393648
  14. The effect of L-carnitine on plasma lipoprotein(a) levels in hypercholesterolemic patients with type 2 diabetes mellitusClin Ther · PMID 12867219
  15. The effects of L-carnitine supplementation on cardiovascular risk factors in participants with impaired glucose tolerance and diabetes: a systematic review and dose-response meta-analysis.Diabetol Metab Syndr · PMID 39085907
  16. Effects of acetyl-L-carnitine and methylcobalamin for diabetic peripheral neuropathy: A multicenter, randomized, double-blind, controlled trialJ Diabetes Investig · PMID 27180954
  17. Effect of oral L-carnitine administration on insulin sensitivity and lipid profile in type 2 diabetes mellitus patientsAnn Nutr Metab · PMID 18714152
  18. The effects of L-carnitine supplementation on glycemic markers in adults: A systematic review and dose-response meta-analysis.Front Nutr · PMID 36704801
  19. L-carnitine improves glucose disposal in type 2 diabetic patientsJ Am Coll Nutr · PMID 10067662
  20. Caloric restriction and L-carnitine administration improves insulin sensitivity in patients with impaired glucose metabolismJPEN J Parenter Enteral Nutr · PMID 20467011
  21. Preliminary observations on the use of propionyl-L-carnitine in combination with sildenafil in patients with erectile dysfunction and diabetesCurr Med Res Opin · PMID 15383186
  22. Acetyl-l-carnitine versus placebo for migraine prophylaxis: A randomized, triple-blind, crossover studyCephalalgia · PMID 25601916
  23. The effects of magnesium, L-carnitine, and concurrent magnesium-L-carnitine supplementation in migraine prophylaxisBiol Trace Elem Res · PMID 22895810
  24. Effects of carnitine on glucose and lipid metabolic profiles and fertility outcomes in women with polycystic ovary syndrome: A systematic review and meta-analysis.Clin Endocrinol · PMID 36746677
  25. Oral carnitine supplementation reduces body weight and insulin resistance in women with polycystic ovary syndrome: a randomized, double-blind, placebo-controlled trialClin Endocrinol · PMID 26666519
  26. Effects of Carnitine Administration on Carotid Intima-media Thickness and Inflammatory Factors in Patients with Polycystic Ovary Syndrome: A Randomized, Double-blind, Placebo-controlled TrialInt J Prev Med · PMID 31360336
  27. Effects of L-carnitine supplementation for women with polycystic ovary syndrome: a systematic review and meta-analysisPeerJ · PMID 36132218
  28. Effect of glycine propionyl-L-carnitine on aerobic and anaerobic exercise performanceInt J Sport Nutr Exerc Metab · PMID 18272931
  29. Influence of L-carnitine administration on maximal physical exerciseEur J Appl Physiol Occup Physiol · PMID 2127744
  30. Effects of nine weeks L-Carnitine supplementation on exercise performance, anaerobic power, and exercise-induced oxidative stress in resistance-trained malesJ Exerc Nutrition Biochem · PMID 30661327
  31. l-Carnitine l-tartrate supplementation favorably affects biochemical markers of recovery from physical exertion in middle-aged men and womenMetabolism · PMID 20045157
  32. Glycine propionyl-L-carnitine produces enhanced anaerobic work capacity with reduced lactate accumulation in resistance trained malesJ Int Soc Sports Nutr · PMID 19341458
  33. Chronic oral ingestion of L-carnitine and carbohydrate increases muscle carnitine content and alters muscle fuel metabolism during exercise in humansJ Physiol · PMID 21224234
  34. The effect of oral supplementation with L-carnitine on maximum and submaximum exercise capacityEur J Appl Physiol Occup Physiol · PMID 3305002
  35. Effect of intravenous L-carnitine on carnitine homeostasis and fuel metabolism during exercise in humansClin Pharmacol Ther · PMID 8004884
  36. Effects of prolonged L-carnitine administration on delayed muscle pain and CK release after eccentric effortInt J Sports Med · PMID 8858401
  37. l-Carnitine Supplementation in Older Women. A Pilot Study on Aging Skeletal Muscle Mass and FunctionNutrients · PMID 29473908
  38. Effects of L-carnitine L-tartrate supplementation on muscle oxygenation responses to resistance exerciseJ Strength Cond Res · PMID 18545197
  39. The effects of L-carnitine L-tartrate supplementation on hormonal responses to resistance exercise and recoveryJ Strength Cond Res · PMID 12930169
  40. Levocarnitine administration in elderly subjects with rapid muscle fatigue: effect on body composition, lipid profile and fatigueDrugs Aging · PMID 12875611
  41. Oxidative stress in response to aerobic and anaerobic power testing: influence of exercise training and carnitine supplementationRes Sports Med · PMID 19266389
  42. Effect of L-carnitine on submaximal exercise metabolism after depletion of muscle glycogenMed Sci Sports Exerc · PMID 8321112
  43. Androgenic responses to resistance exercise: effects of feeding and L-carnitineMed Sci Sports Exerc · PMID 16826026
  44. Carbohydrate, protein, and fat metabolism during exercise after oral carnitine supplementation in humansInt J Sport Nutr Exerc Metab · PMID 19164828
  45. Effects of four weeks L-carnitine L-tartrate ingestion on substrate utilization during prolonged exerciseInt J Sport Nutr Exerc Metab · PMID 16521850
  46. L -Carnitine and the recovery from exhaustive endurance exercise: a randomised, double-blind, placebo-controlled trialEur J Appl Physiol · PMID 16193341
  47. Effects of carnitine coingested caffeine on carnitine metabolism and endurance capacity in athletesJ Nutr Sci Vitaminol · PMID 11922111
  48. Effects of L-carnitine supplementation on physical performance and energy metabolism of endurance-trained athletes: a double-blind crossover field studyEur J Appl Physiol Occup Physiol · PMID 8803503
  49. Clinical Effects of L-Carnitine Supplementation on Physical Performance in Healthy Subjects, the Key to Success in Rehabilitation: A Systematic Review and Meta-Analysis from the Rehabilitation Point of View.J Funct Morphol Kinesiol · PMID 34842765
  50. L-Carnitine/Simvastatin Reduces Lipoprotein (a) Levels Compared with Simvastatin Monotherapy: A Randomized Double-Blind Placebo-Controlled StudyLipids · PMID 27914033
  51. Effect of lysine, vitamin B(6), and carnitine supplementation on the lipid profile of male patients with hypertriglyceridemia: a 12-week, open-label, randomized, placebo-controlled trialClin Ther · PMID 22818869
  52. L-carnitine infusion does not alleviate lipid-induced insulin resistance and metabolic inflexibilityPLoS One · PMID 32976523
  53. Effects of acute versus chronic L-carnitine L-tartrate supplementation on metabolic responses to steady state exercise in males and femalesInt J Sport Nutr Exerc Metab · PMID 16286670
  54. Liver-Oriented Acute Metabolic Effects of A Low Dose of L-Carnitine under Fat-Mobilizing Conditions: Pilot Human Clinical TrialJ Nutr Sci Vitaminol · PMID 32350175
  55. The effects of L-carnitine supplementation on glycemic control: a systematic review and meta-analysis of randomized controlled trialsEXCLI J · PMID 31611746
  56. The effect of L-carnitine on inflammatory mediators: a systematic review and meta-analysis of randomized clinical trialsEur J Clin Pharmacol · PMID 30915521
  57. Single dose administration of L-carnitine improves antioxidant activities in healthy subjectsTohoku J Exp Med · PMID 21701126
  58. Comparison of pre-workout nitric oxide stimulating dietary supplements on skeletal muscle oxygen saturation, blood nitrate/nitrite, lipid peroxidation, and upper body exercise performance in resistance trained menJ Int Soc Sports Nutr · PMID 20459623
  59. Glycine propionyl-L-carnitine modulates lipid peroxidation and nitric oxide in human subjectsInt J Vitam Nutr Res · PMID 20209464
  60. L-carnitine supplementation to diet: a new tool in treatment of nonalcoholic steatohepatitis--a randomized and controlled clinical trialAm J Gastroenterol · PMID 20068559
  61. Effects of carnitine supplementation on flow-mediated dilation and vascular inflammatory responses to a high-fat meal in healthy young adultsAm J Cardiol · PMID 18993165
  62. The effect of l-carnitine on fat oxidation, protein turnover, and body composition in slightly overweight subjectsMetabolism · PMID 15281008
  63. Effects of exercise intensity and altered substrate availability on cardiovascular and metabolic responses to exercise after oral carnitine supplementation in athletesInt J Sport Nutr Exerc Metab · PMID 21813919
  64. Safety measures of L-carnitine L-tartrate supplementation in healthy menJ Strength Cond Res · PMID 11726261
  65. Effects of oral L-carnitine supplementation on insulin sensitivity indices in response to glucose feeding in lean and overweight/obese malesAmino Acids · PMID 20963457
  66. Glycine propionyl-L-carnitine increases plasma nitrate/nitrite in resistance trained menJ Int Soc Sports Nutr · PMID 18053183
  67. Effects of L-carnitine on oxidative stress responses in patients with renal diseaseMed Sci Sports Exerc · PMID 20216464
  68. Effects of L-carnitine supplementation on blood pressure: a systematic review and meta-analysis of randomized controlled trials.J Hum Hypertens · PMID 31481697
  69. Effects of combined treatment with simvastatin and L-carnitine on triglyceride levels in diabetic patients with hyperlipidaemiaClin Drug Investig · PMID 23315432
  70. Effects of L-carnitine supplementation on lipid profiles in patients with coronary artery diseaseLipids Health Dis · PMID 27317162
  71. Effects of carnitine on thyroid hormone actionAnn N Y Acad Sci · PMID 15591013
  72. L-carnitine improves the asthma control in children with moderate persistent asthmaJ Allergy · PMID 22162707
  73. Carnitine supplementation improves metabolic flexibility and skeletal muscle acetylcarnitine formation in volunteers with impaired glucose tolerance: A randomised controlled trialEBioMedicine · PMID 31676389
  74. The effects of L-carnitine supplementation on performance during interval swimmingInt J Sports Med · PMID 8063466
  75. Carnitine versus androgen administration in the treatment of sexual dysfunction, depressed mood, and fatigue associated with male agingUrology · PMID 15072869
  76. Acetyl-L-carnitine plus propionyl-L-carnitine improve efficacy of sildenafil in treatment of erectile dysfunction after bilateral nerve-sparing radical retropubic prostatectomyUrology · PMID 16286128
  77. l-carnitine and l-acetylcarnitine supplementation for idiopathic male infertility.Reprod Fertil · PMID 35128424
  78. Effects of L-carnitine administration on VO2max and the aerobic-anaerobic threshold in normoxia and acute hypoxiaEur J Appl Physiol Occup Physiol · PMID 2311588
  79. The effects of acute L-carnitine supplementation on endurance performance of athletesJ Strength Cond Res · PMID 24263659
  80. Acetyl-L-carnitine (ALC) in attention-deficit/hyperactivity disorder: a multi-site, placebo-controlled pilot trialJ Child Adolesc Psychopharmacol · PMID 18315451
  81. Acetyl-L-carnitine as an adjunctive therapy in the treatment of attention-deficit/hyperactivity disorder in children and adolescents: a placebo-controlled trialChild Psychiatry Hum Dev · PMID 21336630
  82. Efficacy of carnitine in the treatment of children with attention-deficit hyperactivity disorderProstaglandins Leukot Essent Fatty Acids · PMID 12213433
  83. A double-blind, parallel, multicenter comparison of L-acetylcarnitine with placebo on the attention deficit hyperactivity disorder in fragile X syndrome boysAm J Med Genet A · PMID 18286595
  84. L-Carnitine supplementation combined with aerobic training does not promote weight loss in moderately obese womenInt J Sport Nutr Exerc Metab · PMID 10861338
  85. Acetyl-L-carnitine treatment in minimal hepatic encephalopathyDig Dis Sci · PMID 18357530
  86. Acetyl-L-carnitine improves cognitive functions in severe hepatic encephalopathy: a randomized and controlled clinical trialMetab Brain Dis · PMID 21870121
  87. Acetyl-L-carnitine reduces depression and improves quality of life in patients with minimal hepatic encephalopathyScand J Gastroenterol · PMID 21443422
  88. Oral acetyl-L-carnitine therapy reduces fatigue in overt hepatic encephalopathy: a randomized, double-blind, placebo-controlled studyAm J Clin Nutr · PMID 21310833
  89. L-Carnitine in the treatment of mild or moderate hepatic encephalopathyDig Dis · PMID 14571103
  90. Acetyl-L-carnitine for patients with hepatic encephalopathyCochrane Database Syst Rev · PMID 30610762
  91. L-Carnitine for the Treatment of Overt Hepatic Encephalopathy in Patients with Advanced Liver CirrhosisJ Nutr Sci Vitaminol · PMID 30381621
  92. Effects of L-carnitine in patients with hepatic encephalopathyWorld J Gastroenterol · PMID 16437672
  93. Cinnoxicam and L-carnitine/acetyl-L-carnitine treatment for idiopathic and varicocele-associated oligoasthenospermiaJ Androl · PMID 15292108
  94. Does L-carnitine therapy add any extra benefit to standard inguinal varicocelectomy in terms of deoxyribonucleic acid damage or sperm quality factor indices: a randomized studyUrology · PMID 25260444
  95. Use of carnitine therapy in selected cases of male factor infertility: a double-blind crossover trialFertil Steril · PMID 12568837
  96. Placebo-controlled double-blind randomized trial on the use of L-carnitine, L-acetylcarnitine, or combined L-carnitine and L-acetylcarnitine in men with idiopathic asthenozoospermiaFertil Steril · PMID 16169400
  97. Use of carnitine therapy in selected cases of male factor infertility: a double-blind crossover trialJ Urol · PMID 14601569
  98. Oral carnitine supplementation increases sperm motility in asthenozoospermic men with normal sperm phospholipid hydroperoxide glutathione peroxidase levelsFertil Steril · PMID 15705374
  99. Safety and efficacy of clomiphene citrate and L-carnitine in idiopathic male infertility: a comparative studyUrol J · PMID 20845296
  100. Carnitine for the treatment of idiopathic asthenospermia: a randomized, double-blind, placebo-controlled trialFertil Steril · PMID 16600222