L-Carnitine Fumarate
Compiled from published pharmacological and botanical literature. Not independently verified by Herbuno. Spotted an error or have a correction? Flag it below →
| Compound | L-Carnitine fumarate |
|---|---|
| Chemical class | Fumarate salt of L-carnitine, conventionally 1:1 |
| CAS | 90471-79-7 (L-carnitine fumarate) · 541-15-1 (L-carnitine) |
| Component MW | L-carnitine 161.20 · fumaric acid 116.07 |
| Carnitine equivalence | Approx. 58.1% L-carnitine at the 1:1 ratio |
| Counter-ion rationale | Fumarate is a tricarboxylic acid cycle intermediate |
| Claim strength | High for non-hygroscopic handling; Emerging for the fumarate contribution |
| Buy from Herbuno | L-Carnitine Fumarate Powder |
| Origin | Processed / Sourced from India |
| MOQ | R&D 100 g / 250 g (subject to stock) · Pilot batch 1–5 kg · Bulk 10 kg, 25 kg and above |
| Lead Time | Dispatch within 72 hrs from stock · fresh-batch production (typically 50 kg+): 10 working days |
| Documentation | CoA & MSDS standard with every lot |
Name origin: The salt of L-carnitine with fumaric acid, the unsaturated dicarboxylic acid first obtained from Fumaria officinalis, common fumitory, from which it takes its name. Fumarate is one of the eight intermediates of the tricarboxylic acid cycle, sitting between succinate and malate, which is the basis of the rationale for choosing it as a carnitine counter-ion rather than a nutritionally inert one.
Why the salt exists: As with the tartrate, the immediate reason is hygroscopicity. Free-base L-carnitine is a permanently charged quaternary ammonium zwitterion that deliquesces in ambient humidity, making dry formats impractical. The fumarate is a stable, non-hygroscopic, free-flowing crystalline powder. Its distinguishing feature against the tartrate is the counter-ion's metabolic identity: where tartrate is largely a handling convenience, fumarate is a substrate the mitochondrion uses.
Research trajectory: There is no substantial clinical literature specific to L-carnitine fumarate as distinct from L-carnitine. The salt appears in cardiovascular and fatigue-related formulations, generally on the combined rationale that carnitine supports long-chain fatty acid oxidation while fumarate supports tricarboxylic acid cycle flux, so the pair addresses mitochondrial energy production from two directions. The rationale is biochemically coherent and has not been isolated in a controlled comparison against carnitine with an inert counter-ion.
Commercial source: The carnitine component is produced by chemoenzymatic synthesis or fermentation and combined with fumaric acid, which is manufactured industrially from maleic anhydride or by fermentation using Rhizopus species. Fumaric acid is achiral, which simplifies the specification relative to the tartrate — only the carnitine's configuration requires confirmation. Fumaric acid is also not a wine by-product, which removes the tartrate's kosher and halal assessment question.
Evidence for L-Carnitine Fumarate Applications
The non-hygroscopic handling advantage applies equally to the fumarate and is the primary unqualified benefit. Free-base carnitine deliquesces in ambient humidity, which rules out tablets, capsules, dry blends and bars without specialised packaging and humidity control. L-carnitine fumarate is a free-flowing crystalline powder with ordinary handling characteristics, stable in standard foil-lined packaging and compatible with direct compression and automated capsule filling. For dry carnitine formats some non-hygroscopic salt is required, and this is one of the two standard choices. Claim strength: High.
The carnitine fraction is materially lower than the tartrate's and that is the trade-off being made. At the conventional 1:1 ratio, carnitine is 161.20 parts in 277.27 total, or approximately 58.1%. The tartrate at 2:1 delivers approximately 68.2% and the hydrochloride approximately 81.6%. A formulator choosing the fumarate is therefore accepting roughly 15% lower carnitine density per gram than the tartrate for the same handling benefit, and the justification has to come from the fumarate itself rather than from the carnitine. Claim strength: High.
The fumarate rationale is biochemically coherent but has not been isolated experimentally. Fumarate is a genuine tricarboxylic acid cycle intermediate, so supplying it alongside carnitine addresses mitochondrial energy production at two points: carnitine enabling long-chain fatty acid entry for β-oxidation, fumarate feeding the cycle that oxidises the resulting acetyl-CoA. The difficulty is that no controlled trial has compared carnitine fumarate against an equivalent carnitine dose from an inert-counter-ion salt, which is the only design that could attribute an effect to the fumarate. Anaplerotic contribution from a dietary dose of fumarate is also unquantified. Claim strength: Emerging.
The fumarate simplifies the specification relative to the tartrate in two useful ways. Fumaric acid is achiral, so only the carnitine's configuration requires chiral confirmation, where the tartrate requires attention to both ions. And fumaric acid is manufactured from maleic anhydride or by fungal fermentation rather than recovered from wine by-products, which removes the grape-derived material question that complicates kosher and halal assessment of wine-derived tartaric acid. For a product carrying those certifications this is a practical advantage worth weighing against the lower carnitine density. Claim strength: High.
Carnitine's own constraints are unchanged by the salt and should be stated clearly. Oral carnitine bioavailability is approximately 14 to 18% against 54 to 87% for dietary carnitine; muscle uptake via OCTN2 is insulin-dependent and difficult to achieve without substantial carbohydrate co-ingestion over weeks; carnitine is not rate-limiting for fat oxidation in replete muscle, so fat-loss positioning remains weakly supported; and the carnitine-to-TMAO microbial pathway and its observational cardiovascular association apply here as elsewhere. Claim strength: High.
Chirality specification remains critical for the carnitine component and is a safety rather than a potency matter. D-carnitine competes with L-carnitine for the OCTN2 transporter and for carnitine acyltransferases, so its presence actively opposes the L-form rather than merely diluting it, and historical clinical problems with racemic carnitine arose from exactly this mechanism. Require optical rotation or chiral chromatography on every certificate. An unexplained price advantage in this category warrants testing rather than ordering. Claim strength: High.
Sourcing L-carnitine fumarate from Herbuno. We supply the fumarate and the L-tartrate, so the choice can be made on specification rather than availability.
Our view on selection: take the tartrate where carnitine density per unit dose is the binding constraint, and the fumarate where the fumarate itself is wanted, where the tartrate's acid profile is unhelpful, or where kosher and halal assessment makes a non-wine-derived counter-ion preferable. We will not claim the fumarate is better absorbed, because no controlled comparison establishes it. All lots ship with CoA and MSDS; request a quotation for pilot or bulk volumes.
Dosage & Formulator Specification
Dose on carnitine content. At the conventional 1:1 ratio, L-carnitine fumarate is approximately 58.1% carnitine, so 1 gram delivers about 581 milligrams of carnitine and a 1 gram carnitine target requires about 1.72 grams of the fumarate. Against the tartrate's 1.47 grams for the same carnitine delivery, that is a 17% larger fill weight, which matters for capsule sizing and for tablet weight. Where general carnitine doses of 500 milligrams to 2 grams apply, the corresponding fumarate quantities are roughly 860 milligrams to 3.4 grams.
Ratio and assay basis belong on the specification. The 1:1 stoichiometry is conventional but should be stated rather than assumed, and a certificate reading "L-carnitine fumarate 99%" establishes salt purity and nothing about carnitine content. Require the mole ratio, the carnitine assay as a percentage of total mass, and the fumaric acid content, with the three internally consistent. This is the same discipline the tartrate and citrulline malate require.
Handling is comparable to the tartrate with one meaningful difference. L-carnitine fumarate is a free-flowing crystalline powder, non-hygroscopic in normal conditions, stable in standard packaging and compatible with direct compression and capsule filling. Its aqueous solubility is lower than the tartrate's, because fumaric acid is itself poorly soluble — around 0.6 grams per 100 millilitres at room temperature — which constrains high-concentration liquid applications and can produce haze or sediment in a beverage where the tartrate would give a clear solution. For dry formats this is irrelevant; for liquids it is decisive.
Co-formulation considerations follow from that solubility and from the acid contribution. In a reconstituted powder the fumarate contributes to acidity and has a distinctive sour, slightly astringent profile that integrates with fruit flavour systems but can be difficult in neutral or dairy matrices. Where the objective is muscle carnitine, the insulin requirement applies as it does to any carnitine form: substantial carbohydrate co-ingestion over weeks, or a claim written so it does not depend on muscle saturation. The fumarate's TCA rationale is best presented as a mechanistic design choice rather than a demonstrated outcome.
For analytical control, specify L-carnitine identity and assay with basis stated, optical rotation or chiral chromatography confirming L-configuration, fumaric acid content, the mole ratio, and water content. Maleic acid is the relevant process-related impurity where the fumaric acid is manufactured from maleic anhydride, and it should be specified as a limit test; it is not captured by a carnitine assay. Standard coverage includes heavy metals, residual solvents, microbiological limits, loss on drying and sulphated ash, with the carnitine production route named for certification purposes.
On selecting between the two salts, the honest framing separates the three variables. Carnitine density favours the tartrate decisively, at 68.2% against 58.1%, which translates directly into capsule size and tablet weight. Solubility favours the tartrate for liquid formats, since fumaric acid's own low solubility limits the fumarate there. Certification simplicity favours the fumarate, because fumaric acid is achiral and is not a wine by-product, removing both the second chirality specification and the kosher and halal assessment question that wine-derived tartaric acid raises. The fumarate's metabolic rationale is real biochemistry and a legitimate reason to prefer it, provided it is presented as a design rationale rather than as an established clinical advantage, since the comparative trial has not been run.
Frequently Asked Questions — L-Carnitine Fumarate
How much carnitine does the fumarate deliver?
Approximately 58.1% at the conventional 1:1 ratio — 161.20 parts carnitine in 277.27 total. A 1 gram carnitine target needs about 1.72 grams of fumarate, against 1.47 grams of tartrate for the same delivery. That 17% larger fill weight matters for capsule sizing and tablet weight.
Why accept lower carnitine density than the tartrate?
Three possible reasons. Fumarate is a tricarboxylic acid cycle intermediate, so the counter-ion is a metabolic substrate rather than a handling convenience. Fumaric acid is achiral, simplifying the specification. And it is not a wine by-product, which removes the kosher and halal assessment question that wine-derived tartaric acid raises.
Does the fumarate actually contribute anything?
Biochemically coherent, experimentally unestablished. Fumarate feeds the TCA cycle that oxidises the acetyl-CoA carnitine helps generate, so addressing both points has a rationale. But no controlled trial has compared carnitine fumarate against an equivalent carnitine dose from an inert-counter-ion salt, and the anaplerotic contribution of a dietary fumarate dose is unquantified.
Can I use it in a beverage?
With caution. Fumaric acid is itself poorly soluble — around 0.6 g per 100 ml at room temperature — so the fumarate constrains high-concentration liquids and can give haze or sediment where the tartrate would give a clear solution. For dry formats the difference is irrelevant; for liquids the tartrate is the better choice.
What impurity should I specify?
Maleic acid, where the fumaric acid is manufactured from maleic anhydride. It is the relevant process-related impurity and a carnitine assay will not catch it. Also require optical rotation on the carnitine, the mole ratio, the fumaric acid content, and the carnitine assay as a percentage of total mass.
Is racemic carnitine acceptable at a lower price?
No. D-carnitine competes with L-carnitine for the OCTN2 transporter and for carnitine acyltransferases, so it opposes the L-form rather than diluting it, and historical clinical problems with racemic carnitine arose from exactly that. This is a safety specification, not a potency one. An unexplained price advantage here warrants testing.