What is inside
“Lipo-C with B12” is a sales name for the most common form of the “lipotropic” injection. It holds the MIC trio, methionine, inositol and choline, plus L-carnitine and B-vitamins, as in the Lipo-C Fat Blaster, and adds vitamin B12. B12 is the vitamin that keeps blood cells and nerves healthy. It comes in two forms in these products: cyanocobalamin, the stable form in approved shots, or methylcobalamin, a form made only by compounding pharmacies in the United States. None of the ingredients is a peptide.
There is no official recipe. Each pharmacy or seller decides which B-vitamins go in, which form of B12, and how much of everything. Nothing is standardised. FDA inspection letters describe such products as “Lipo-B” or “LIPO (MIC) + B”. The label is the only description of what is inside. L-carnitine and vitamin B12 have their own pages on this site; the Lipo-C page covers the core four ingredients in more detail.
The product is an aqueous mixture of the MIC lipotrope triad, L-methionine, myo-inositol (C6H12O6, 180.16 g/mol, NF monograph) and choline (usually as the chloride), with levocarnitine (C7H15NO3, 161.20 g/mol), a seller-chosen subset of water-soluble B-vitamins, and vitamin B12 as cyanocobalamin (C63H88CoN14O14P, 1355.4 g/mol) or methylcobalamin. FDA warning letters describe representative products as a “Lipo-B/Methionine/Choline Chloride/Cyanocobalamin” injection solution and as “LIPO (MIC) + B”. Cyanocobalamin is the active ingredient of approved injections; methylcobalamin has no US approval and sits in 503A Category 1.
No reference standard exists for the mixture. The cyanocobalamin injection label states that B12 coenzymes are very unstable in light and specifies light protection; riboflavin is likewise photolabile, and no compatibility or stability data for cobalamin stored with the other components were found. Pharmacokinetics after intramuscular cyanocobalamin are documented on its label (plasma peak within an hour; 50-98% of a 100 or 1,000 mcg dose in urine within 48 hours), and the Carnitor label gives a 17.4-hour terminal half-life for intravenous levocarnitine; the kinetics of the remaining components given as an intramuscular bolus are unpublished.
Who made it and when
No one invented this blend. It has no inventor or date. It combines two older ideas: the “lipotropic” injection, from twentieth-century animal research on nutrients that clear fat from the liver, and the B12 shot, one of the oldest injectable vitamins. B12 was isolated in 1948, and cyanocobalamin injections have been FDA-approved for decades for B12 deficiency, including pernicious anemia. Adding B12 to a lipotropic shot borrows its reputation for fighting the tiredness of deficiency.
The other regulated ancestors are separate. Levocarnitine was approved as Carnitor for carnitine deficiency. Methionine is part of amino acid drips. B-vitamin injections such as Infuvite Adult are approved for people fed through a vein. No company has developed the combination as a medicine, and no regulator has reviewed it. Compounding pharmacies and outsourcing facilities make it to order.
No originator, patent or investigational programme exists for the combination. Its scientific lineage is the lipotrope literature reviewed by Fardet and Chardigny (2013), which names choline, betaine, myo-inositol, methionine and carnitine as the main lipotropes and niacin, pantothenate and folate as indirect supporters in animal studies, and notes that human intervention studies are practically non-existent. Vitamin B12 has no place in that literature; its inclusion reflects the established use of parenteral cyanocobalamin for deficiency states and the fatigue that accompanies them.
Component regulatory histories: cyanocobalamin injection is indicated for vitamin B12 deficiency due to malabsorption, including pernicious anemia; levocarnitine is the active ingredient of Carnitor; L-methionine is a component of parenteral amino acid products such as Travasol 10%; thiamine, riboflavin, niacinamide, dexpanthenol, folic acid, biotin and cyanocobalamin are components of Infuvite Adult (initial approval 2003); myo-inositol has an NF monograph; choline chloride and methylcobalamin were nominated for the 503A bulks list and sit in Category 1. The injectable combination is a compounding-market product without a development history in the regulatory sense.
What the data say
No study has tested this mixture. The Lipo-C page sets out the evidence for the core four ingredients: the one good L-carnitine weight trial was negative (36 overweight women, 2 g twice a day for 8 weeks, no change in weight or fat), inositol by mouth lowered body mass index by about 0.4 units across 15 trials, choline corrects fatty liver caused by choline shortage, and methionine has no human weight trial. The Fat Blaster page covers the B-vitamins, which have no weight-loss trials.
B12 does not change this picture. For true B12 deficiency, shots are a proven, decades-old treatment; the label says people with pernicious anemia need them for life. But that is deficiency. The NIH fact sheet lists the areas where B12 has been studied as cancer, heart disease, dementia and energy and endurance, not weight loss. No trial of B12 for weight loss in people with normal B12 levels was found. B12 deficiency does cause fatigue, so correcting it can make a deficient person feel better; that is not a fat-loss effect.
No trial of the combination, and no trial of any B12-supplemented lipotropic injection, was identified. Core-ingredient evidence is detailed on the Lipo-C page: Villani et al. (2000) found no effect of L-carnitine 2 g twice daily for 8 weeks with aerobic training on body mass or fat mass in overweight women; Zarezadeh et al. (2022) pooled 15 oral inositol trials for a weighted mean BMI reduction of 0.41 kg/m2; NIH ODS summarises choline’s evidence as correction of deficiency-induced steatosis with limited data for treating NAFLD; no human methionine trial for adiposity exists; and the NIH fact sheets for the B-vitamins record no weight-loss outcome.
For vitamin B12, the evidence base is deficiency treatment. The cyanocobalamin injection label covers deficiency due to malabsorption, including pernicious anemia, gastrointestinal pathology or surgery, fish tapeworm infestation and pancreatic or bowel malignancy, and states that pernicious anemia requires lifelong parenteral therapy. NIH ODS identifies the health areas in which B12 has been investigated as cancer, cardiovascular disease, dementia and cognitive function, and energy and endurance; adiposity is not among them, and no randomised trial of B12 for weight loss in replete individuals was identified. Deficiency symptoms listed by ODS include fatigue, neurological changes, megaloblastic anemia, glossitis, palpitations and low blood counts, with older adults, people with pernicious anemia or gastrointestinal disorders or surgery, vegetarians and infants of vegan mothers at risk; metformin and gastric acid inhibitors can lower B12 levels. Any symptomatic benefit from the B12 component is therefore predicted only in deficient recipients.
Ingredient: Methionine, inositol and choline (MIC)
These three are the “lipotropic” core, described in full on the Lipo-C page. Methionine is an essential amino acid that supplies “methyl groups”, chemical tags the liver uses to build phosphatidylcholine, the fat that packages other fats for export. Choline is a direct building block of the same molecule. Inositol sits in the same membrane chemistry and is studied for insulin signalling. In animals, a diet short of methionine and choline causes fatty liver, and adding them back clears it.
That is deficiency science. No human trial shows that extra methionine or choline burns body fat. Inositol by mouth has a small effect on body mass index, mostly in women with polycystic ovary syndrome. Too much choline causes a fishy body odour and low blood pressure. Methionine’s approved injectable use is as one of 15 amino acids in nutrition drips; choline and inositol have no approved injection.
L-methionine is the precursor of S-adenosylmethionine, the methyl donor for phosphatidylcholine synthesis via phosphatidylethanolamine N-methyltransferase; choline is the direct precursor of phosphatidylcholine and, via betaine, an alternative methyl donor; myo-inositol is a phosphoinositide constituent. Phosphatidylcholine is required for hepatic VLDL assembly, the mechanistic basis of the lipotrope concept and of the methionine- and choline-deficient rodent steatohepatitis model (Fardet and Chardigny 2013). Vitamin B12 is the cofactor of methionine synthase, which regenerates methionine from homocysteine, the one biochemical link between the B12 and MIC components; whether that link has any consequence in replete individuals is untested.
Human data are confined to deficiency correction and oral inositol: NIH ODS reports liver dysfunction in 37 of 57 adults on a near-choline-free diet and resolution of NAFLD in a 15-patient TPN pilot with 2 g supplemental choline, while noting limited data for treatment; Zarezadeh et al. (2022) report a 0.41 kg/m2 BMI reduction with oral inositol. Choline’s tolerable upper intake levels were set on hypotension and fishy body odour, and choline raises TMAO dose-dependently. Regulatory: L-methionine is a component of approved parenteral amino acid products (Travasol 10%, 400 mg per 100 mL); myo-inositol has an NF monograph; choline chloride is in 503A Category 1 and choline bitartrate in Category 3 on FDA’s list updated 2026-05-14.
Ingredient: L-carnitine
L-carnitine carries long fat chains into mitochondria, the parts of the cell that burn fat for energy. The body makes it, and red meat supplies more. As the drug levocarnitine (Carnitor) it is FDA-approved for people who cannot make or keep carnitine and for people on dialysis. It is also sold as a supplement, often for fat loss.
The fat-loss evidence is negative. In the 2000 trial, 36 overweight women took 2 g twice a day or placebo for 8 weeks while walking four days a week. Weight and fat did not change, and five women on carnitine dropped out with nausea or diarrhoea. The Carnitor injection label warns of severe allergic reactions, mostly in dialysis patients, of seizures, and of a possible rise in INR (a clotting test) in people on warfarin. Pharmacies may use levocarnitine in compounding but may not copy Carnitor while it is on the market.
Levocarnitine mediates the carnitine palmitoyltransferase shuttle for mitochondrial long-chain fatty-acid beta-oxidation. Carnitor injection is indicated for secondary carnitine deficiency from inborn errors of metabolism and for prevention and treatment of carnitine deficiency in dialysis patients; the label gives a 17.4-hour terminal half-life after intravenous dosing. Villani et al. (2000): no significant change in total body mass, fat mass or resting lipid utilisation with 2 g twice daily for 8 weeks plus supervised walking, versus lactose placebo, in 36 overweight premenopausal women, with 5 gastrointestinal withdrawals in the carnitine group.
Label safety: no known contraindications; warnings for serious hypersensitivity reactions including anaphylaxis, laryngeal edema and bronchospasm (mostly dialysis patients), post-marketing seizures, and TMA/TMAO accumulation with high oral doses in severely compromised renal function; adverse reactions include injection-site reactions, headache, pain, gastrointestinal symptoms and transient nausea and vomiting; INR monitoring with warfarin. Regulatory: an approved drug substance, eligible for compounding subject to the essentially-copies prohibition, and absent from FDA’s category lists.
Ingredient: B-vitamins
The B-vitamins in these products are helpers (cofactors) for the enzymes that release energy from food: thiamine (B1) for carbohydrate, riboflavin (B2) and niacin (B3) for electron transfer, pantothenic acid (B5) for coenzyme A, which handles fats, and sometimes folic acid (B9) for making DNA. They do not contain energy and do not burn fat. The Fat Blaster page covers them in detail.
Most Americans get enough from food, and the body excretes the extra. Nicotinic acid, one form of niacin, causes flushing, burning and itching at 30 to 50 mg or more; most injectables use niacinamide, which does not. Thiamine into a vein has caused hives, wheezing and swelling, so the approved B-vitamin injection carries an anaphylaxis warning. Folic acid deserves a special note in a B12 product: it can hide the blood signs of B12 deficiency while nerve damage goes on, a warning that appears on both the cyanocobalamin and the Infuvite labels.
Thiamine, riboflavin, niacin, pantothenic acid and folate serve as precursors of thiamine pyrophosphate, FAD/FMN, NAD/NADP, coenzyme A and tetrahydrofolate coenzymes respectively. NIH ODS documents saturable absorption and urinary excretion of excess, no tolerable upper intake level for thiamine, riboflavin or pantothenic acid, nicotinic acid flushing at 30-50 mg with hypotension, glucose intolerance and hepatotoxicity at 1,000-3,000 mg/day, and 1% of US adults below the niacin EAR in NHANES 2009-2012. None of the fact sheets records weight loss as a studied outcome.
Parenteral safety comes from the Infuvite Adult label: allergic reactions after intravenous thiamine, anaphylaxis and anaphylactoid reactions, rash, headache and dizziness, aluminium content, and masking of folate and B12 deficiency in megaloblastic anemia. The folate-B12 interaction is doubly relevant here: the cyanocobalamin injection label warns that folic acid above 0.1 mg per day may produce a haematological response that masks B12 deficiency while neurological damage progresses. Regulatory: thiamine, riboflavin, niacinamide, dexpanthenol and folic acid are components of Infuvite Adult; pantothenic acid is in 503A Category 3 on FDA’s list updated 2026-05-14; FDA’s 2026 warning letter to GenoGenix found an injectable B-complex at 43.1% of labelled dexpanthenol.
Ingredient: Vitamin B12
Vitamin B12 is a large red molecule with a cobalt atom at its centre. The body cannot make it; only certain bacteria can, and people get it from animal foods. Cells need it to make DNA in new blood cells and to keep nerves healthy. Without enough, people develop anemia with oversized red cells, and nerve damage that can become permanent. Cyanocobalamin shots have been FDA-approved for decades for B12 deficiency caused by poor absorption, including pernicious anemia. Methylcobalamin shots are made by compounding pharmacies and are not approved.
B12 is not a weight-loss drug. The NIH lists its studied uses as cancer, heart disease, dementia and energy and endurance. Deficiency causes fatigue, so a shot can help a deficient person feel better. The shots have serious warnings: severe allergic reactions and deaths have been reported, and people sensitive to cobalt or B12 should not have them. Early in treatment of severe anemia, some people got fluid in the lungs, heart failure or dangerously low potassium. Metformin and stomach-acid drugs can lower B12 levels.
Cobalamins share a corrin ring coordinating cobalt; methylcobalamin is the cofactor of cytosolic methionine synthase and adenosylcobalamin of mitochondrial methylmalonyl-CoA mutase, so deficiency traps folate, impairs DNA synthesis and raises methylmalonic acid, the most sensitive status marker per NIH ODS. Cyanocobalamin injection is indicated for B12 deficiency due to malabsorption, including pernicious anemia, and its label states that pernicious anemia requires parenteral B12 for life and that deficiency progressing beyond 3 months may produce permanent spinal cord lesions.
Label safety: anaphylactic shock and death after parenteral B12; pulmonary edema and congestive heart failure early in treatment; peripheral vascular thrombosis; hypokalemia and sudden death in severe megaloblastic anemia treated intensively; severe, swift optic atrophy in early Leber’s disease; polycythemia vera, transient diarrhea, itching and rash; contraindicated in sensitivity to cobalt or B12; benzyl alcohol and aluminium warnings; storage at 20-25 °C protected from light. Interactions: most antibiotics, methotrexate and pyrimethamine invalidate B12 and folate assays; colchicine, para-aminosalicylic acid and heavy alcohol intake may cause malabsorption; folic acid above 0.1 mg/day may mask deficiency. NIH ODS sets no tolerable upper intake level and names metformin and gastric acid inhibitors as agents that lower B12 levels, and its investigated health areas are cancer, cardiovascular disease, dementia and cognition, and energy and endurance. Regulatory: cyanocobalamin is a component of approved drugs; methylcobalamin is in 503A Category 1 (under evaluation) on FDA’s list updated 2026-05-14 and is not on the bulks list.
Why researchers might study these together
The idea is to add the best-known “energy” vitamin to a “fat-moving” injection. The MIC trio and carnitine are meant to help the liver package fat and carry it into cells to be burned; the B-vitamins are the helpers those reactions need; and B12 is the vitamin whose shortage most famously causes tiredness. There is one real chemical link: B12 helps recycle methionine from homocysteine, so it sits in the same “methyl group” pathway as methionine and choline. Whether that matters in a person who is not deficient has never been tested.
No study has tested the combination. The parts with human trials point the wrong way: carnitine did not cause weight loss, and B12 has never been tested for it. B12 shots make a deficient person feel less tired; they are not known to do anything for someone with normal levels. And no study has compared this injection with the same nutrients by mouth, or with placebo.
The rationale combines the lipotrope hypothesis (methyl-donor and phosphatidylcholine supply for hepatic VLDL export, plus carnitine-dependent beta-oxidation), cofactor support from the B-vitamins, and the reputation of parenteral B12 for reversing deficiency-associated fatigue. The only mechanistic connection between B12 and the MIC components is methionine synthase, the B12-dependent enzyme that remethylates homocysteine to methionine using 5-methyltetrahydrofolate, placing B12, folate, methionine and choline (via betaine) in one methyl-group economy; no study has examined whether supplementing all of them parenterally alters hepatic lipid handling in replete individuals.
No preclinical or clinical study of the combination, or of B12 as an adjunct to any lipotropic regimen, was identified. Component data are negative for adiposity (Villani et al. 2000), modest and oral-only (Zarezadeh et al. 2022), limited to deficiency correction (choline, NIH ODS), or absent (methionine, B-vitamins, B12 for weight). The B12 evidence base is confined to deficiency treatment, and NIH ODS does not list adiposity among B12’s investigated health areas. Whether intramuscular administration alters exposure relative to dietary intake for any component other than B12 in malabsorption is unstudied.
Regulatory picture
Approval: no regulator has approved this mixture. Most of its parts are in approved medicines for other uses: cyanocobalamin shots for B12 deficiency, levocarnitine (Carnitor) for carnitine deficiency, methionine in nutrition drips, and B-vitamins in the multivitamin injection Infuvite Adult. Choline and inositol have no approved injection, and methylcobalamin shots are not approved.
Compounding (pharmacies mixing their own drugs): the FDA judges each ingredient on its own. Most qualify because they are parts of approved drugs, and inositol has an official monograph. Choline chloride and methylcobalamin are “under evaluation” (Category 1). Pantothenic acid was nominated without enough support (Category 3). The mixture itself has no status. Products of this kind are widely compounded: FDA letters in 2020, 2025 and 2026 mention “Lipo-B”, lipotropic and “LIPO (MIC) + B” injections, citing missing prescriptions, contamination-control failures, incomplete labels, and a methylcobalamin injection at about two-thirds of its labelled strength. Those letters are about how the products were made and sold, not about whether the formula works.
Approval: none for the combination. Cyanocobalamin injection, Carnitor, parenteral amino acid formulations containing L-methionine, and Infuvite Adult are approved products for unrelated indications; no approved parenteral choline, inositol or methylcobalamin product was identified.
Compounding: under section 503A(b)(1)(A)(i), each bulk substance must have an applicable USP or NF monograph, be a component of an approved drug, or appear on the 503A bulks list (21 CFR 216.23). Cyanocobalamin, levocarnitine, L-methionine and the B-vitamins present in Infuvite Adult qualify as components of approved drugs (cyanocobalamin and levocarnitine subject to the essentially-copies prohibition); myo-inositol qualifies through its NF monograph; choline chloride and methylcobalamin are in 503A Category 1 (under evaluation, with interim-policy enforcement discretion) and choline bitartrate and pantothenic acid in Category 3 on FDA’s list updated 2026-05-14. A blend has no status of its own and rests on its least-established component; this article records compounding as unknown.
Enforcement: FDA’s 2025-04-02 warning letter to Empower Pharma, a 503B outsourcing facility, cited a “Lipo-B/Methionine/Choline Chloride/Cyanocobalamin” injection solution in findings on an inadequate investigation of fungal contamination on an operator’s fingertips and on personnel monitoring; its 2026-01-20 letter to GenoGenix LLC listed a “LIPO (MIC) + B” product with a deficient label, an injectable methylcobalamin product at 65.3% of labelled strength and an “Injectable B12 Complex” whose strength differed from its label; and its 2020-09-17 letter to Randol Mill Pharmacy cited a lipotropic injection made without valid prescriptions. None evaluates the formula’s safety or efficacy.
