L-Norvaline
Compiled from published pharmacological and botanical literature. Not independently verified by Herbuno. Spotted an error or have a correction? Flag it below →
| Compound | L-Norvaline (2-aminopentanoic acid) |
|---|---|
| Chemical class | Non-proteinogenic amino acid — straight-chain isomer of L-valine |
| CAS | 6600-40-4 (L-norvaline) · 760-78-1 (DL-norvaline) |
| Molecular weight | 117.15 g/mol |
| Proposed mechanism | Arginase inhibition — demonstrated in vitro, not in human outcomes |
| Safety signal | In vitro cytotoxicity reported at supplement-relevant concentrations |
| Claim strength | Emerging for the mechanism; no human efficacy evidence; safety unresolved |
| Buy from Herbuno | L-Norvaline Powder · L-Citrulline 99% 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: "Nor-" denotes the unbranched analogue, so norvaline is the straight-chain isomer of valine — 2-aminopentanoic acid, carrying an n-propyl side chain where valine carries an isopropyl. The two share a molecular formula and differ only in that branching, which is enough to exclude norvaline from protein synthesis in higher organisms.
Biochemical position: Norvaline is non-proteinogenic in humans: there is no codon for it and no transfer RNA carries it. It occurs in some bacterial systems as a by-product of branched-chain amino acid biosynthesis, and in recombinant protein manufacture it is a recognised nuisance precisely because bacterial leucyl-tRNA synthetase can mischarge it, leading to norvaline misincorporation in place of leucine in expressed proteins under certain fermentation conditions.
Why it is marketed: Norvaline inhibits arginase in vitro. Arginase cleaves arginine to urea and ornithine and competes with nitric oxide synthase for arginine, so inhibiting it should in principle preserve arginine for nitric oxide production. That reasoning placed norvaline in pre-workout formulations marketed for "sustained" vasodilation. The in vitro inhibition is a documented pharmacological property; what has never been demonstrated is a human outcome.
Safety position: In vitro work has reported cytotoxicity in human cell lines at concentrations described as relevant to supplemental intake, alongside the known potential for misincorporation into protein in place of leucine. Neither finding establishes harm in humans at dietary doses, and neither has been resolved by human study. Together they place norvaline in a different category from the arginine salts it is sold alongside, and we state that rather than leave it out.
Evidence for L-Norvaline Applications
The in vitro cytotoxicity report is the finding a formulator most needs to see, so it belongs first rather than last. Cell-based work has reported reduced viability in human cell lines exposed to norvaline at concentrations characterised as achievable through supplemental intake. This is in vitro evidence and does not establish harm in humans at dietary doses, and no human safety study has been conducted to resolve it. But for an ingredient whose human efficacy evidence is absent, an unresolved toxicity signal shifts the risk-benefit assessment materially, and a customer specifying norvaline should be told it exists. Claim strength: Emerging, and unresolved.
There is no human efficacy evidence for norvaline on any endpoint. Despite its presence in pre-workout products for over a decade, no controlled human trial has demonstrated that norvaline supplementation improves vasodilation, nitric oxide markers, blood flow, strength, power, endurance or any performance outcome. This is not a thin literature but an absent one. The ingredient's commercial position rests entirely on a mechanistic inference from in vitro pharmacology. Claim strength: Absent.
The arginase inhibition itself is real in vitro, and that is the one solid technical point. Arginase hydrolyses arginine to urea and ornithine and competes with nitric oxide synthase for the same substrate, and norvaline inhibits the enzyme in cell-free and cell-based systems. The inference that this should preserve arginine for nitric oxide synthesis is biochemically coherent. What is missing is any demonstration that oral norvaline reaches arginase-relevant concentrations in vivo, or that arginase activity is a limiting factor for nitric oxide production in healthy people. Claim strength: Moderate for the in vitro pharmacology.
The misincorporation question is a second theoretical concern with a solid factual basis. Bacterial leucyl-tRNA synthetase can mischarge norvaline, and norvaline misincorporation in place of leucine is a documented and commercially relevant problem in recombinant protein manufacture under certain fermentation conditions. Whether this occurs meaningfully in human protein synthesis at supplemental intakes is not established, mammalian aminoacyl-tRNA synthetases having different specificity and proofreading. It is a theoretical concern rather than a demonstrated one, and it is worth knowing alongside the cytotoxicity signal rather than instead of it. Claim strength: Emerging.
If the formulation objective is nitric oxide substrate, citrulline is the better-evidenced route and the honest recommendation. Oral arginine is extensively degraded by intestinal and hepatic arginase before reaching circulation, which is the actual bottleneck norvaline is meant to address; citrulline bypasses that pathway entirely, is converted to arginine in the kidney, and raises plasma arginine more effectively per gram than arginine itself. That is an established pharmacokinetic result rather than an inference, and it addresses the same problem without an unresolved safety question. Claim strength: High.
Norvaline's defensible applications are analytical and research rather than nutritional. It serves as a reference standard in amino acid analysis, where it is commonly used as an internal standard precisely because it is non-proteinogenic and therefore absent from protein hydrolysates, and it appears in biochemical research on arginase and on translational fidelity. These are legitimate uses with genuine demand and no claim attached, and they are a better basis for supplying the material than a pre-workout positioning the evidence does not support. Claim strength: High.
Sourcing L-norvaline from Herbuno. We supply L-norvaline and L-citrulline.
We state the position plainly rather than in a footnote. Norvaline inhibits arginase in vitro; no human trial has shown it improves vasodilation, nitric oxide markers or any performance outcome; and in vitro work has reported cytotoxicity in human cell lines at concentrations described as relevant to supplemental intake, which no human study has resolved. We will supply it for analytical and research use, and for a customer formula that specifies it, and we will not support a performance claim. If the objective is nitric oxide substrate, citrulline is the better-evidenced route. All lots ship with CoA and MSDS; request a quotation for pilot or bulk volumes.
Dosage & Formulator Specification
There is no established effective dose for L-norvaline, because no human trial has established an effect. Pre-workout products have commonly used 100 to 300 milligrams per serving, a range derived from marketing convention rather than from dose-ranging data. Because the in vitro cytotoxicity report describes concentrations characterised as achievable through supplemental intake, and because that signal is unresolved, we do not recommend a dose and would not characterise any dose as established as safe for extended use.
Application selection is where the useful guidance sits. Norvaline's defensible uses are analytical and research: it is a standard internal standard in amino acid analysis, chosen because being non-proteinogenic it is absent from protein hydrolysates and therefore does not interfere with the analytes, and it is used in biochemical work on arginase and on translational fidelity. Those applications have real demand, no claim attached, and no safety question at the quantities involved. For an oral nutritional product, the evidence does not support it and the safety signal is unresolved.
Handling is straightforward. L-norvaline is freely soluble in water, stable to heat and across a broad pH range, and only mildly hygroscopic. It is a free-flowing crystalline powder with a mildly bitter taste, and blends uniformly at the low inclusion rates used in formulations. None of the handling characteristics are limiting, which is worth noting because it means ease of formulation is not a reason to prefer it and has never been the argument for it.
Isomeric form should be specified. L-norvaline at CAS 6600-40-4 and DL-norvaline at CAS 760-78-1 are separate articles, the racemate being cheaper, and a standard assay will not distinguish them. Require optical rotation or a chiral method. Specify L-valine as a limit test: norvaline and valine share a molecular formula and differ only in side-chain branching, so they are not always cleanly separated by a general amino acid method, and valine is both a plausible process impurity and a far cheaper material.
Beyond that, standard coverage applies: identity and assay by HPLC or ion-exchange chromatography, heavy metals, residual solvents, microbiological limits, loss on drying and sulphated ash, with the production route named. Where the material is fermentation-derived, specify residual host-cell protein and endotoxin and name the organism and substrate; where it is synthetic, name the route-specific process impurities. For research and analytical grades, the relevant specification is usually tighter on related substances and looser on microbiological limits than a nutritional grade, so state the intended use when requesting a quotation.
On claim construction, the boundaries here are narrower than for any other ingredient in this catalogue, and documenting them protects the customer as much as us. Defensible: norvaline is a non-proteinogenic straight-chain isomer of valine that inhibits arginase in vitro, and it is a standard internal standard in amino acid analysis. Not defensible: any statement about vasodilation, nitric oxide, blood flow, pump, endurance or strength, none of which has been tested in humans. Not resolved: the cytotoxicity signal and the misincorporation potential, neither of which has been addressed by human study. A customer proposing a consumer pre-workout built on norvaline should see all three categories before committing to artwork, and should know that citrulline addresses the same mechanistic objective with established pharmacokinetics and no open safety question.
Frequently Asked Questions — L-Norvaline
Does norvaline work?
No human trial has shown that it does. Despite over a decade in pre-workout products, no controlled human study has demonstrated improved vasodilation, nitric oxide markers, blood flow, strength, power or endurance. That is an absent literature rather than a thin one. Its commercial position rests entirely on an inference from in vitro pharmacology.
What is the safety concern?
In vitro work has reported reduced viability in human cell lines at norvaline concentrations characterised as achievable through supplemental intake. That is cell-based evidence and does not establish harm in humans at dietary doses — but no human safety study has resolved it, and for an ingredient with no efficacy evidence, an unresolved toxicity signal changes the risk-benefit assessment.
Is the arginase inhibition real?
In vitro, yes — norvaline inhibits arginase in cell-free and cell-based systems, and the inference that this should preserve arginine for nitric oxide synthesis is biochemically coherent. What is missing is any demonstration that oral norvaline reaches arginase-relevant concentrations in vivo, or that arginase activity limits nitric oxide production in healthy people.
What should I use instead?
Citrulline, if nitric oxide substrate is the objective. Oral arginine's real bottleneck is extensive intestinal and hepatic arginase first-pass metabolism — the problem norvaline is meant to address. Citrulline bypasses that pathway entirely and raises plasma arginine more effectively per gram than arginine itself. Established pharmacokinetics, no open safety question.
What is the misincorporation issue?
Bacterial leucyl-tRNA synthetase can mischarge norvaline, and norvaline misincorporation in place of leucine is a documented problem in recombinant protein manufacture under certain fermentation conditions. Whether it occurs meaningfully in human protein synthesis at supplemental intakes is not established — mammalian synthetases differ in specificity and proofreading. Theoretical, but worth knowing.
What is it genuinely good for?
Analytical work. Norvaline is a standard internal standard in amino acid analysis, chosen precisely because being non-proteinogenic it is absent from protein hydrolysates and does not interfere with the analytes. It also appears in biochemical research on arginase and on translational fidelity. Real demand, no claim attached, no safety question at those quantities.