L-Ornithine HCl
Compiled from published pharmacological and botanical literature. Not independently verified by Herbuno. Spotted an error or have a correction? Flag it below →
| Compound | L-Ornithine monohydrochloride |
|---|---|
| Chemical class | Hydrochloride salt of a non-proteinogenic basic amino acid |
| CAS | 3184-13-2 (L-ornithine HCl) · 70-26-8 (L-ornithine free base) |
| Molecular weight | 168.62 g/mol (free base 132.16) |
| Free base equivalence | 78.4% L-ornithine by weight · chloride ~21.0% |
| Solution pH | Approx. 5.0–6.5 at 10% (free base is strongly alkaline) |
| Claim strength | High for the salt chemistry; ornithine's own evidence is unchanged by salt form |
| Buy from Herbuno | L-Ornithine HCl Powder · L-Ornithine L-Aspartate 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 hydrochloride of L-ornithine, formed by adding one equivalent of hydrochloric acid across the side-chain amino group. Ornithine takes its name from the Greek ornis, bird, after the ornithuric acid Jaffé isolated from hen excreta in 1877. The hydrochloride is not a variant but the default commercial article, and free-base ornithine is the specialty item.
Why the salt exists: Free-base L-ornithine is a diamino compound, strongly basic, and very hygroscopic — it absorbs atmospheric moisture to the point of deliquescence under ordinary storage, caking and then liquefying in the container. It also gives strongly alkaline solutions, which is incompatible with flavoured liquids and harsh on mucosa. The hydrochloride crystallises cleanly, is only mildly hygroscopic, flows well, and gives solutions near pH 5 to 6.5. For any dry or flavoured format the salt is effectively mandatory.
Research position: There is no clinical literature specific to L-ornithine hydrochloride as distinct from L-ornithine. Once dissociated in solution or in the stomach the ornithine cation is identical whatever salt delivered it, so the salt form has no independent pharmacology. Ornithine's own research — the growth hormone response to intravenous dosing, the modest oral fatigue and ammonia findings, the polyamine pathway — was largely generated using the hydrochloride, because that is the available material.
Commercial source: Produced by fermentation using engineered Corynebacterium glutamicum or by enzymatic conversion from L-arginine using arginase, then acidified and crystallised as the hydrochloride. The enzymatic route leaves arginine and citrulline as the characteristic process-related impurities. Substrate and organism determine vegan, non-GMO, kosher and halal eligibility.
Evidence for L-Ornithine HCl Applications
The hygroscopicity of the free base is the salt's entire justification and it is a severe rather than marginal problem. Free-base ornithine deliquesces in ambient humidity, which rules out tablets, capsules, powder blends and bars without specialised packaging and tight humidity control, and causes weight-variation and flow failures in automated filling. L-ornithine hydrochloride is only mildly hygroscopic, flows as a normal crystalline powder, and is stable in standard foil-lined packaging. For dry formats this is decisive. Claim strength: High.
The conversion factor is 78.4% and should be stated on every specification. L-ornithine HCl is 168.62 g/mol against the free base's 132.16, so 1 gram of salt delivers 784 milligrams of ornithine and 210 milligrams of chloride. A product declaring 1,000 milligrams of ornithine and filled with 1,000 milligrams of hydrochloride is 22% under label. Write the purchase specification as a stated ornithine quantity supplied as the hydrochloride, and the ambiguity disappears. Claim strength: High.
Chloride content is high relative to most amino acid hydrochlorides because ornithine is a small molecule. At 210 milligrams of chloride per gram of salt, ornithine HCl carries a higher chloride fraction than arginine HCl at 168 or lysine HCl at 194, simply because the cation is lighter. A 5 gram dose of the salt contributes slightly over 1 gram of chloride. Stacked with other hydrochlorides in a pre-workout or clinical formula, the cumulative anion and acid load becomes a design constraint rather than a rounding error. Claim strength: Moderate.
pH behaviour favours the hydrochloride for anything flavoured. Free-base ornithine gives strongly alkaline solutions, which destabilises co-formulated actives, accelerates Maillard browning with reducing sugars, is harsh on oral mucosa and is very difficult to flavour. The hydrochloride at 10% sits near pH 5 to 6.5, a workable range. Attempting to use the free base in a flavoured liquid and correcting with acid simply generates a salt in situ with less control over which counter-ion results. Claim strength: High.
Ornithine's own evidence is unchanged by the salt and should be presented at its actual strength. Ornithine is non-proteinogenic and catalytic rather than consumed in the urea cycle, so it is neither a protein building block nor straightforwardly a urea cycle fuel. Oral growth hormone effects are inconsistent and modest where present, unlike the intravenous response. The fatigue, sleep and serum ammonia findings come from small trials with subjective endpoints and limited replication. None of this changes with the counter-ion. Claim strength: Emerging for the supplementation claims.
Selection against the aspartate turns on chloride and on whether the counter-ion should be functional. The hydrochloride delivers 78.4% ornithine against the 1:1 aspartate's 49.8%, so it is substantially denser and gives smaller capsules and lower fill weights. The aspartate carries less ornithine but supplies aspartate, which supports skeletal muscle glutamine synthetase and is itself a urea cycle participant, and it avoids the chloride entirely. For ammonia-handling rationales the aspartate has the stronger story; for ornithine density the hydrochloride wins. Claim strength: High.
Sourcing L-ornithine HCl from Herbuno. We supply the hydrochloride and the L-aspartate salt.
Take the hydrochloride where ornithine density per unit dose is the binding constraint — it delivers 78.4% against the aspartate's 49.8%. Take the aspartate where chloride is unwanted or where the ammonia-handling rationale matters, since aspartate supports muscle glutamine synthetase rather than sitting inert. Note the chloride fraction here is higher than for arginine or lysine HCl, because the cation is lighter. All lots ship with CoA and MSDS; request a quotation for pilot or bulk volumes.
Dosage & Formulator Specification
Dose on ornithine content: multiply salt weight by 0.784, or divide the ornithine target by 0.784. A 2 gram ornithine target requires about 2.55 grams of L-ornithine HCl; a 3 gram scoop of the salt delivers about 2.35 grams of ornithine. Doses in the oral fatigue and sleep literature range from a few hundred milligrams to around 6 grams of ornithine daily, which corresponds to roughly 0.4 to 7.7 grams of the hydrochloride. Divided dosing mitigates the gastrointestinal threshold, which is reached around 10 grams of ornithine in a single dose.
Assay basis belongs on the specification. L-ornithine HCl is assayed against the salt, so a certificate reading 99.0% refers to the hydrochloride, not to ornithine content, and ornithine is that figure times 0.784. A chloride determination should accompany the assay to confirm salt stoichiometry, because an under-chlorided lot behaves as partial free base on both pH and hygroscopicity — and with ornithine the hygroscopicity consequence is more severe than for most hydrochlorides.
Handling is good and is the whole point of the form. L-ornithine HCl dissolves readily in water, well above 40 grams per 100 millilitres, giving clear mildly acidic solutions. It is only mildly hygroscopic, flows acceptably as a crystalline powder, blends uniformly and is compatible with direct compression and automated capsule filling. Taste is mildly bitter with a saline note from the chloride, considerably easier to mask than the free base's alkaline bite. Store sealed; the material is manageable rather than indifferent to humidity.
Co-formulation requires counting the chloride and thinking about pathway redundancy. The chloride fraction here is the highest of the common amino acid hydrochlorides at 21%, so in a formula stacking arginine HCl, lysine HCl, creatine HCl and choline chloride the total anion and acid load needs calculating across the formula. On pathway logic, combining ornithine with arginine is partly redundant, since arginase converts arginine to ornithine in vivo; combining ornithine with citrulline is more coherent if arginine elevation is the objective, since citrulline bypasses intestinal arginase.
For analytical control, specify identity and assay with the basis stated, optical rotation confirming L-configuration, chloride confirming stoichiometry, and water content. Specify L-arginine and L-citrulline as process-related impurities where the enzymatic arginase route is used, and L-lysine as a limit given the close structural similarity — ornithine is lysine minus one methylene, and the two are not always cleanly separated by a basic amino acid method. Standard coverage includes heavy metals, residual solvents, microbiological limits, loss on drying and sulphated ash, with the fermentation organism and substrate named.
Two positioning points worth building into customer documentation, because they come up repeatedly. First, ornithine is non-proteinogenic: there is no codon for it, it is never incorporated into protein, and claims framed around muscle protein substrate are simply the wrong mechanism for this molecule. Second, the urea cycle regenerates ornithine via arginase rather than consuming it, so the "fuels the urea cycle" framing needs qualifying — ammonia disposal is normally limited by carbamoyl phosphate synthetase activity or hepatic capacity rather than by ornithine supply, and supplemental ornithine raising cycle flux is a claim about compromised states rather than healthy ones. Both corrections are easier to make at specification stage than after artwork is approved.
Frequently Asked Questions — L-Ornithine HCl
How much ornithine does the hydrochloride deliver?
78.4% by weight — 168.62 g/mol salt against 132.16 free base, with 210 mg chloride per gram. A 2 gram ornithine target needs about 2.55 grams of salt. A capsule declaring 1,000 mg ornithine and filled with 1,000 mg of hydrochloride is 22% under label.
Why is the chloride fraction higher than for arginine or lysine HCl?
Because the cation is lighter. Ornithine is 132.16 g/mol against arginine's 174.20 and lysine's 146.19, so the same single chloride is a larger share of the total mass — 21% here against 16.8% and 19.4%. A 5 gram dose contributes slightly over 1 gram of chloride, which matters in a formula stacking several hydrochlorides.
Why not use free-base ornithine?
It deliquesces. Free-base ornithine is a strongly basic diamino compound that absorbs atmospheric moisture until it liquefies in the container, which rules out tablets, capsules and dry blends without specialised packaging and humidity control. It also gives strongly alkaline solutions that are harsh and unflavourable. The hydrochloride solves both.
Hydrochloride or aspartate?
Hydrochloride for ornithine density — 78.4% against the 1:1 aspartate's 49.8%, meaning smaller capsules and lower fill weights. Aspartate where chloride is unwanted, or where the ammonia-handling rationale matters, since aspartate supports skeletal muscle glutamine synthetase and is itself a urea cycle participant rather than an inert counter-ion.
Is ornithine a protein building block?
No. It is non-proteinogenic — no codon, no tRNA, never incorporated into a polypeptide. It is purely a metabolic intermediate. Claims framed around muscle protein substrate are the wrong mechanism for this molecule, and it is worth correcting at specification stage rather than after artwork.
What impurities should I specify?
L-arginine and L-citrulline where the enzymatic arginase route is used — they are the characteristic process-related impurities. Also L-lysine as a limit: ornithine is lysine minus one methylene group, and a basic amino acid method does not always separate them cleanly. Plus chloride to confirm stoichiometry and water content.