N-Acetyl-L-Tyrosine
Compiled from published pharmacological and botanical literature. Not independently verified by Herbuno. Spotted an error or have a correction? Flag it below →
| Compound | N-Acetyl-L-tyrosine (NALT) |
|---|---|
| Chemical class | N-acetylated derivative of L-tyrosine |
| CAS | 537-55-3 (N-acetyl-L-tyrosine) · 60-18-4 (L-tyrosine) |
| Molecular weight | 223.23 g/mol — 81.2% tyrosine equivalent by weight |
| Solubility advantage | Freely soluble, against tyrosine's ~0.045 g/100 ml — real and large |
| The catch | Human deacetylation is poor; much is excreted intact in urine |
| Claim strength | High for solubility; High that it raises plasma tyrosine less than tyrosine |
| Buy from Herbuno | N-Acetyl-L-Tyrosine Powder · L-Tyrosine 98% 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 N-acetylated derivative of L-tyrosine, with an acetyl group on the α-amino nitrogen. Tyrosine itself takes its name from the Greek tyros, cheese, from which Liebig isolated it in 1846. N-acetylation is a general strategy for improving the solubility and stability of poorly soluble amino acids, and tyrosine is the archetypal case because it is the least soluble of the proteinogenic amino acids.
Why it was developed: For parenteral nutrition, not for supplements. L-tyrosine dissolves at roughly 0.045 grams per 100 millilitres of water at room temperature, which is far too low to formulate an adequate tyrosine content into an intravenous amino acid solution. N-acetyl-L-tyrosine is freely soluble, which solved that formulation problem, and it was adopted in parenteral amino acid preparations on that basis. The subsequent oral supplement positioning borrowed the solubility argument and attached a bioavailability claim to it.
What the clinical pharmacology showed: The parenteral experience is the most informative evidence available, and it was not encouraging. Studies of intravenous N-acetyl-L-tyrosine found that a large proportion was excreted intact in the urine rather than deacetylated to tyrosine, indicating that human aminoacylase activity toward this substrate is limited. The practical conclusion drawn in the clinical nutrition literature was that N-acetyl-L-tyrosine is an inefficient tyrosine source, which is the opposite of the oral supplement claim.
Commercial source: N-acetyl-L-tyrosine is produced by acetylation of fermentation-derived L-tyrosine, typically with acetic anhydride, then crystallised. Free tyrosine is the characteristic process and degradation impurity, and chirality must be confirmed on the tyrosine centre.
Evidence for N-Acetyl-L-Tyrosine Applications
The solubility advantage is real, large and not in dispute. L-tyrosine is the least soluble proteinogenic amino acid at roughly 0.045 grams per 100 millilitres of water at room temperature, which makes any liquid tyrosine format effectively impossible and limits even powder reconstitution. N-acetyl-L-tyrosine is freely soluble and gives clear solutions at practical concentrations. For intravenous amino acid preparations, clear beverages, shots or any liquid format, that difference is decisive and is why the compound exists. Claim strength: High.
Deacetylation in humans is poor, and this is the finding that undoes the bioavailability claim. Studies of intravenous N-acetyl-L-tyrosine found a large proportion excreted intact in the urine rather than hydrolysed to free tyrosine, indicating limited human aminoacylase activity toward this particular substrate. The clinical nutrition literature concluded that it is an inefficient tyrosine source. Because the acetyl group must be removed for the molecule to act as tyrosine, poor deacetylation means poor delivery regardless of how well the material dissolves. Claim strength: High.
The net consequence is that N-acetyl-L-tyrosine raises plasma tyrosine less effectively per gram than tyrosine does, despite the solubility. This is the inverse of the usual marketing position, which argues that superior solubility implies superior absorption and therefore a lower effective dose. Solubility and bioavailability are distinct properties: tyrosine's absorption from the gut is adequate despite its poor solubility, whereas NALT dissolves readily and then largely fails to be converted. A formulator choosing NALT for bioavailability has the relationship backwards. Claim strength: High.
The weight conversion compounds the problem rather than offsetting it. N-acetyl-L-tyrosine is 223.23 g/mol against tyrosine's 181.19, so 1 gram delivers at most 812 milligrams of tyrosine-equivalent even assuming complete deacetylation, which does not occur. A product declaring tyrosine content from a NALT input should state the basis, and should not imply equivalence to free tyrosine at the same weight. In practice the delivered tyrosine is substantially below the 81.2% stoichiometric figure. Claim strength: High.
Tyrosine's own evidence, which NALT is sold to deliver, is narrower than generally presented and does not improve with the acetylated form. Tyrosine supplementation shows reasonably consistent effects on cognitive performance under acute stressors — cold, noise, sleep deprivation, multitasking load — where catecholamine turnover is elevated, and little to no effect in rested, unstressed subjects, because catecholamine synthesis is not substrate-limited at baseline. Any tyrosine product's defensible claim is the acute-stressor one, and NALT delivers it less well. Claim strength: Moderate for tyrosine under acute stress.
The legitimate application is parenteral and liquid formulation, which is a real and defensible use. Where an aqueous formulation must carry tyrosine and free tyrosine's solubility makes that impossible, NALT is the article that works, and the parenteral nutrition industry uses it for exactly that reason while acknowledging its conversion inefficiency. For oral solid formats, where tyrosine's solubility is not the binding constraint, free tyrosine is both cheaper and more effective, and that is the honest recommendation. Claim strength: High.
Sourcing N-acetyl-L-tyrosine from Herbuno. We supply NALT and L-tyrosine.
Our position is specific and runs against the category. The solubility advantage is real and large — tyrosine dissolves at about 0.045 g per 100 ml, NALT freely — so for liquids and parenteral-style formulations NALT is the article that works. But human deacetylation is poor, with much excreted intact, so NALT raises plasma tyrosine less effectively per gram than tyrosine itself. For capsules and tablets, specify free tyrosine: cheaper and more effective. All lots ship with CoA and MSDS; request a quotation for pilot or bulk volumes.
Dosage & Formulator Specification
The honest answer on dosing is that no conversion factor can be given with confidence. Stoichiometrically NALT is 81.2% tyrosine-equivalent, so 1 gram would deliver 812 milligrams of tyrosine on complete deacetylation — but deacetylation is incomplete and variable, with a large proportion excreted intact, so the delivered tyrosine is substantially below that figure and has not been reliably quantified for oral administration. Tyrosine's own acute-stressor literature has used roughly 100 to 150 milligrams per kilogram, and reproducing those doses through NALT cannot be done by arithmetic.
Form selection therefore follows the format rather than the claim. For any aqueous formulation — intravenous preparations, clear beverages, shots, concentrated liquids — NALT is the only workable article, because free tyrosine's solubility of around 0.045 grams per 100 millilitres makes a meaningful tyrosine content impossible. For capsules, tablets and dry powders, where solubility is not the binding constraint, free L-tyrosine is cheaper, delivers more tyrosine per gram, and is better supported. Accept the conversion inefficiency as the price of solubility rather than presenting it as a benefit.
Handling is good and is the compound's strength. NALT is freely soluble in water, giving clear solutions at practical concentrations, stable to heat and across a reasonable pH range, and only mildly hygroscopic. It flows acceptably as a crystalline powder and blends uniformly. Taste is mildly bitter with a faint acidic note. Strongly alkaline conditions will hydrolyse the acetyl group, liberating free tyrosine which will then precipitate out of solution — a failure mode worth checking in any formulation that drifts alkaline on storage.
That hydrolysis behaviour deserves a specific stability note, because it fails visibly. If the acetyl group is cleaved in a finished liquid, the liberated tyrosine exceeds its own solubility almost immediately and precipitates, producing haze or sediment in a product that was clear at manufacture. Accelerated stability testing on any aqueous NALT formulation should therefore include a free tyrosine determination alongside visual inspection, and the formulation pH should be held comfortably away from the alkaline range.
For analytical control, specify identity and assay with optical rotation confirming L-configuration on the tyrosine centre, and specify free L-tyrosine as a limit test — it is both the characteristic process impurity from incomplete acetylation and the hydrolysis product from storage, making it the direct indicator of material quality and handling history. Specify residual acetic acid and acetic anhydride-related impurities for the synthetic route. Standard coverage includes heavy metals, residual solvents, microbiological limits, loss on drying and sulphated ash, with the tyrosine production route and fermentation organism named.
On claim construction, the boundaries are unusually clear-cut here. Defensible: NALT is freely soluble where L-tyrosine is the least soluble proteinogenic amino acid, which makes aqueous and parenteral tyrosine formulation possible; it is the article the parenteral nutrition industry uses for that reason. Not defensible: superior bioavailability, superior absorption, or equivalent effect at a lower dose, all of which invert the actual pharmacology — the parenteral studies found a large proportion excreted intact and the clinical nutrition literature concluded it is an inefficient tyrosine source. A customer specifying NALT for a capsule on bioavailability grounds should be redirected to free tyrosine, and will get a cheaper and more effective product for doing so.
Frequently Asked Questions — N-Acetyl-L-Tyrosine
Is NALT better absorbed than tyrosine?
No — the relationship is inverted. The solubility advantage is real and large: tyrosine dissolves at about 0.045 g per 100 ml, NALT freely. But human deacetylation is poor. Parenteral studies found a large proportion excreted intact in urine, and the clinical nutrition literature concluded NALT is an inefficient tyrosine source. It raises plasma tyrosine less per gram.
Then why does it exist?
Parenteral nutrition. Free tyrosine's solubility is far too low to formulate an adequate tyrosine content into an intravenous amino acid solution, and NALT solved that. The oral supplement positioning borrowed the solubility argument and attached a bioavailability claim that the pharmacology does not support.
What conversion factor should I use?
None can be given with confidence, which is itself the answer. Stoichiometrically NALT is 81.2% tyrosine-equivalent, but deacetylation is incomplete and variable, so delivered tyrosine is substantially below that and has not been reliably quantified for oral use. Tyrosine's acute-stressor trials used 100 to 150 mg/kg, and that cannot be reproduced through NALT by arithmetic.
When should I specify NALT?
When the format is aqueous — intravenous preparations, clear beverages, shots, concentrated liquids — where free tyrosine simply cannot be dissolved at a meaningful content. For capsules, tablets and dry powders, free L-tyrosine is cheaper, delivers more tyrosine per gram, and is better supported.
Any stability failure mode to watch?
Yes, and it fails visibly. Alkaline conditions hydrolyse the acetyl group, and the liberated tyrosine immediately exceeds its own solubility and precipitates — haze or sediment in a product that was clear at manufacture. Include a free tyrosine determination in accelerated stability on any aqueous NALT formulation, and hold pH away from alkaline.
What should I specify beyond assay?
Free L-tyrosine as a limit test — it is both the process impurity from incomplete acetylation and the hydrolysis product from storage, so it is the direct indicator of quality and handling history. Plus residual acetic acid and acetic-anhydride-related impurities for the synthetic route, and optical rotation on the tyrosine centre.