CholineVitamin

• Liver and muscle integrityLikely helps

  The established, non-negotiable function. Human depletion studies reliably reproduce fatty liver and raised muscle enzymes when choline runs short [1].
  
  The Adequate Intake was set at the level where serum ALT stayed in the normal range [1].
  
  Everything below this line is considerably less settled. ^[1]

• Cognition in healthy adultsPossibly helps

  The observational and trial evidence pull apart here, and NIH ODS reports both.
  
  In the Hordaland study, adults with plasma free choline below 8.4 micromol/L scored worse on sensorimotor speed, perceptual speed, executive function and global cognition [1].
  
  But a 2015 systematic review of 13 human studies found choline supplements produced no clear cognitive improvement in healthy adults [1].
  
  A 2003 Cochrane review of 12 lecithin trials found no clear clinical benefit in Alzheimer's disease or Parkinsonian dementia either [1]. ^[1]

• Alpha-GPC on acute cognitive and strength testsPossibly helps

  Newer, smaller studies of alpha-GPC specifically — not choline salts — report acute effects the broader reviews did not find [10].
  
  A randomized controlled trial in healthy young men found acute alpha-GPC supplementation significantly improved Stroop test performance [10].
  
  Others report better explosive strength and rate of force development during fatiguing tasks [16]. Sample sizes are small and replication is thin. ^[10]

• Citicoline in elderly people with chronic cerebral disordersPossibly helps

  A Cochrane review of CDP-choline (citicoline) reported improvements in memory and behaviour scores in this group [1].
  
  Most of the included trials ran 3 months or less, so nothing there speaks to longer-term use [1]. ^[1]

• Nonalcoholic fatty liver diseasePossibly helps

  Choline deficiency is an established cause of fat accumulating in the liver, which makes the supplementation question a reasonable one to ask [1].
  
  A cross-sectional study of 56,195 Chinese adults found the highest intake quintile (412 mg/day) carried 32% lower NAFLD risk than the lowest (179 mg/day) [1].
  
  That association held only in normal-weight women — not men, not people with overweight or obesity [1].
  
  Direct intervention data is one pilot study: in 15 adults on long-term IV nutrition, adding 2 g of choline resolved NAFLD, while none of those without it did [1]. ^[1]

• Endurance performanceNot shown to help

  Controlled studies in marathon runners, cyclists and load-carrying soldiers found no significant effect of choline supplementation on endurance outcomes [15].
  
  In one run-to-exhaustion test, a choline-supplemented beverage raised plasma choline 128% with no performance difference at all [15].
  
  Prolonged hard exercise does lower blood choline — a marathon can cut it about 40%, from roughly 14.1 to 8.4 micromolar [14].
  
  A 2008 review's conclusion: oral choline might only matter where it keeps free choline from dropping below normal, which is not a general ergogenic case [14]. ^[15]

• Fatty liver (hepatosteatosis) — the first clinical sign, from too little phosphatidylcholine to package and export VLDL out of the liver
• Raised serum aminotransferases such as ALT, the marker the Adequate Intake itself was benchmarked against
• Raised serum creatine phosphokinase, reflecting damage to muscle-cell membranes and enzyme leakage into blood
• Higher plasma homocysteine after a methionine load, because choline feeds the betaine methyl-donor pathway
• In a controlled feeding study, 37 of 57 adults fed under 50 mg per 70 kg body weight daily for up to 42 days developed liver dysfunction
• Frank deficiency is rare outside intravenous nutrition, since the body synthesises some choline itself
• Most US adults still fall short of the Adequate Intake — NHANES 2013-2014 averages were 402 mg/day in men and 278 mg/day in women
• 90-95% of pregnant women consume less than the pregnancy Adequate Intake, per NIH ODS
• Higher-risk groups: people on long-term IV nutrition without added choline, people with PEMT gene variants that limit their own synthesis, and postmenopausal women who lose the estrogen-driven lift to endogenous production
• For reference, fasting plasma choline in healthy adults runs 7-20 micromol/L^[1]

• Choline bitartrateTopping up general intake. It is not the form the brain-effect studies used

  Elemental content

  About 41% elemental choline by weight

  Absorption

  The default in multivitamins and standalone products, and the cheapest.
  
  NIH ODS lists it, phosphatidylcholine and lecithin as the main US supplement forms, with products typically supplying 10-250 mg [1].

  Best for

  Topping up general intake. It is not the form the brain-effect studies used [1]

• Alpha-GPC (L-alpha-glycerylphosphorylcholine)Where the cognition and acute-performance studies went.

  Elemental content

  About 40% choline by weight, phospholipid-derived

  Absorption

  Converted straight into free choline, and crosses the blood-brain barrier efficiently.
  
  One comparative study found intramuscular alpha-GPC reached 25.8 micromol/L plasma choline against 13.1 for citicoline — an injected comparison, not an oral one [8].

  Best for

  Where the cognition and acute-performance studies went. NIH ODS still says no studies have compared bioavailability across the standard supplement forms, so the commercial ranking outruns the government evidence [1]

• Citicoline (CDP-choline)The Cochrane memory-and-behaviour finding in elderly people with chronic cerebral disorders rests on this form

  Elemental content

  About 18% choline by weight, delivered alongside cytidine

  Absorption

  Takes more metabolic steps than alpha-GPC to release free choline.
  
  It splits into choline and cytidine, which are absorbed separately and reassembled in the brain [8].

  Best for

  The Cochrane memory-and-behaviour finding in elderly people with chronic cerebral disorders rests on this form [1]

• Phosphatidylcholine and lecithinGeneral intake. Lecithin is a legitimate source, just less concentrated per gram than bitartrate or citicoline

  Elemental content

  Choline bound into a phospholipid; lecithin is a mixture in which phosphatidylcholine is a major component

  Absorption

  Pancreatic and mucosal enzymes have to digest it before the choline is absorbed.
  
  Well absorbed for general and liver purposes, but generally considered weaker than alpha-GPC at raising brain choline [1].

  Best for

  General intake. Lecithin is a legitimate source, just less concentrated per gram than bitartrate or citicoline [1]

• High-dose effects behind the upper limit

  NIH ODS lists vomiting, excessive sweating and salivation, low blood pressure and liver toxicity at high intakes [1].
  
  These are the findings the 3,500 mg/day adult upper limit was built from [1]. ^[1]

• Fishy body odour

  The best-documented effect of excess choline, and it has a clean mechanism.
  
  Gut bacteria convert choline into trimethylamine (TMA), which the liver enzyme FMO3 normally oxidises into something odourless [12].
  
  Push intake high enough and TMA accumulates, leaving via sweat, urine and breath [12]. Case reports describe it resolving once the supplements stop [13]. ^[12]

• Trimethylaminuria (FMO3 deficiency)

  People with this rare genetic condition have reduced FMO3 activity, so the odour appears at intakes others tolerate [12].
  
  In one case report, TMAO fell to 5.3 micromol/L two months after the patient stopped L-carnitine supplements and restricted choline- and carnitine-rich foods [13]. ^[13]

• TMAO and cardiovascular risk

  Choline is a precursor for TMAO, a gut-microbiome product some observational research links to higher cardiovascular disease risk [1].
  
  NIH ODS notes several large observational studies found no association between choline intake and cardiovascular or peripheral artery disease [1].
  
  One more recent large analysis did find higher mortality at higher choline intake, an association its own authors could not fully explain [1].
  
  Unresolved, and we are leaving it that way rather than picking a side. ^[1]

• Bipolar disorder

  Here the government and hospital sources part ways.
  
  Hospital patient-education pages caution that choline may worsen mood in some people, and advise against use in bipolar disorder over a theoretical risk of triggering mania [19].
  
  The NIH fact sheets that call the interaction profile clean do not mention it at all [1].
  
  This reads as a precautionary clinical note rather than a finding from the primary literature. Worth knowing, not settled. ^[19]

• Prescription medications

  NIH ODS states choline is not known to have any clinically relevant interactions with medications [1].
  
  Johns Hopkins' health library reports the same — no known food or medication interactions at typical doses [19]. ^[1]

Choline is spread across a lot of foods but concentrated in animal products, per NIH ODS's table built on USDA FoodData Central [1].

Top of the list: beef liver, pan-fried, 3 oz — 356 mg, or 65% of the 550 mg Daily Value [1].

One large hard-boiled egg gives 147 mg (27% DV); 3 oz of braised lean beef top round gives 117 mg (21%); half a cup of roasted soybeans gives 107 mg (19%) [1].

The middle tier lands around 13% DV: chicken breast and 93%-lean ground beef at about 72 mg per 3 oz, Atlantic cod at 71 mg [1].

Plant sources are real but smaller — a large baked red potato 57 mg, an ounce of toasted wheat germ 51 mg, a cup of cooked quinoa 43 mg [1].

Half a cup of boiled broccoli or Brussels sprouts adds 31-32 mg, about 6% DV [1].

Cooking does not wreck it. USDA's Table of Nutrient Retention Factors puts true retention at 70-100% across most methods [20].

Cooked eggs keep roughly 75-95% of their raw choline; roasted chicken and pan-fried liver sit lowest, at about 68-74%, mostly through fat and moisture loss [21].

Under the US labelling rule, a food needs 55 mg per serving (10% DV) to be called a good source, and 20% DV to be called high [1]. Choline is not required on Nutrition Facts labels unless such a claim is made.

There is no government or clinical-guideline recommendation on time of day. NIH ODS's fact sheets do not address supplement timing at all [1].

GoodRx, which does address it, says plainly that choline needs no particular time of day and that consistency is what counts [18].

Wellness sources commonly say to take it with a meal, reasoning that food aids absorption and blunts the mild nausea or diarrhoea choline salts can cause at higher doses [18].

That food-absorption claim is not something the government or academic sources here confirmed for choline specifically. Read it as general supplement convention [18].

No source found evidence that morning versus evening dosing changes effectiveness or side effects [1].