L-Lysine 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-Lysine monohydrochloride |
|---|---|
| Chemical class | Hydrochloride salt of an essential basic (diamino) amino acid |
| CAS | 657-27-2 (L-lysine HCl) · 56-87-1 (L-lysine free base) |
| Molecular weight | 182.65 g/mol (free base 146.19) |
| Free base equivalence | 80.0% L-lysine by weight · chloride ~19.4% |
| Solution pH | Approx. 5.0–6.0 at 10% (free base gives ~10.5) |
| Claim strength | High for the salt chemistry; lysine's own evidence is unchanged by salt form |
| Buy from Herbuno | L-Lysine HCl 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: From the Greek lysis, loosening, reflecting its isolation by Edmund Drechsel in 1889 from casein hydrolysate. Lysine carries two amino groups, which makes it strongly basic and is the reason the hydrochloride is the dominant commercial form. The salt is formed by adding one equivalent of hydrochloric acid, typically across the ε-amino group on the side chain.
Why the salt exists: L-lysine HCl is not a specialty variant but the default commercial article. Free-base lysine is strongly alkaline, giving a 10% solution at around pH 10.5, and is markedly hygroscopic — it picks up atmospheric moisture, cakes, and is awkward to handle and store at scale. The hydrochloride crystallises cleanly, is only mildly hygroscopic, flows well, and gives solutions near pH 5 to 6. Essentially the entire global lysine trade, which is dominated by swine and poultry feed where lysine is the first limiting amino acid, moves as the hydrochloride.
The declaration convention: This is where most specification errors in the category originate. In animal feed, lysine is conventionally declared on a free-base basis even when supplied as the hydrochloride, so a feed formula calling for 0.3% lysine means 0.375% of L-lysine HCl. In human supplements the convention is inconsistent: some labels declare the salt, some the free base, and a minority declare the salt while implying the free base. Because the difference is exactly 20%, the ambiguity is material rather than academic.
Commercial source: L-lysine HCl is produced by fermentation using Corynebacterium glutamicum on a carbohydrate substrate, typically molasses, sucrose or glucose from starch, then acidified and crystallised. It is covered by USP, EP and JP monographs and by feed-grade standards, and the specification gap between feed and supplement grade is meaningful. Substrate and organism determine vegan, non-GMO, kosher and halal eligibility.
Evidence for L-Lysine HCl Applications
The 80% conversion factor is the single most consequential fact about this material. L-lysine HCl is 182.65 g/mol against the free base's 146.19, so 1 gram of salt delivers exactly 800 milligrams of lysine and 194 milligrams of chloride. The round number is convenient and also a trap, because it is close enough to 100% that a careless reading passes unnoticed until an analytical dispute or a label review. A product declaring 1,000 milligrams of lysine per capsule and filling with 1,000 milligrams of the hydrochloride is 20% under label. Claim strength: High.
The feed-versus-supplement declaration divergence is a real commercial hazard rather than a technicality. Feed formulation universally declares lysine on a free-base basis, which is unambiguous within that industry. Human supplement labelling has no settled convention, and buyers moving between the two sectors, or sourcing from suppliers whose primary market is feed, routinely encounter a 20% mismatch between what was specified and what was understood. The remedy is to state the basis explicitly in the purchase specification — "1,000 mg lysine as free base, supplied as L-lysine HCl" leaves nothing to interpret. Claim strength: High.
Lysine's Maillard reactivity is the highest of the common amino acids, and the salt does not mitigate it. The free ε-amino group on lysine's side chain is the most reactive primary amine in the proteinogenic set, which is why lysine is the first amino acid lost during thermal processing of protein foods and why added lysine browns readily in the presence of reducing sugars. In the hydrochloride the side-chain amine is protonated, which reduces reactivity at low pH, but in a neutral or alkaline matrix, or on heating, browning and lysine loss proceed. For any thermally processed format containing reducing sugars this needs active management. Claim strength: High.
The cereal fortification application is the strongest and most defensible use, and it is specified on the free-base basis. Lysine is the first limiting amino acid in wheat, rice, maize and most cereal proteins, so adding it raises the amino acid score of a cereal-based protein substantially — the mirror image of methionine's role in legume proteins. The inclusion is calculated against the base protein's measured profile, and because the calculation is in lysine terms, the salt quantity is that figure divided by 0.80. This is routine protein formulation rather than a health claim. Claim strength: High.
Lysine's own clinical evidence, which the salt inherits, is strongest for herpes simplex and weaker elsewhere. Several controlled trials have examined lysine supplementation for recurrent herpes labialis, with some reporting reduced recurrence frequency or severity and others finding no effect; the mechanistic rationale is lysine's antagonism of arginine, which the virus requires. The evidence is suggestive rather than settled. Claims around calcium absorption, collagen synthesis and anxiety rest on thinner ground, generally mechanistic or small-trial. Claim strength: Emerging to Moderate depending on the endpoint.
Safety and tolerability are good, with chloride and gastrointestinal threshold as the practical limits. Lysine at supplemental doses is well tolerated; high single doses can cause gastrointestinal upset. The chloride contribution at 194 milligrams per gram of salt is modest at typical supplement doses but becomes relevant at the multi-gram doses used in fortification or in products stacking several hydrochloride salts. Lysine should be used cautiously in renal impairment, where both the amino acid and the chloride load warrant attention. Claim strength: Moderate.
Sourcing L-lysine HCl from Herbuno. We supply fermentation-derived L-lysine HCl to supplement-grade specification.
Two points worth settling on the purchase specification before order. First, the declaration basis — write it as "X mg lysine as free base, supplied as L-lysine HCl" and the 20% ambiguity disappears. Second, because the global lysine trade is dominated by feed-grade volume, confirm microbiological limits, residual host-cell protein and endotoxin explicitly rather than assuming them. All lots ship with CoA and MSDS; request a quotation for pilot or bulk volumes.
Dosage & Formulator Specification
The conversion is clean: multiply salt weight by 0.80 for lysine, or divide lysine target by 0.80 for salt weight. A 1,000 milligram lysine claim requires 1,250 milligrams of L-lysine HCl. Supplemental doses in the herpes literature run 1 to 3 grams of lysine daily, requiring 1.25 to 3.75 grams of the salt. Adult requirement is around 30 milligrams per kilogram daily, met by adequate protein. For cereal protein fortification, inclusion is calculated against the isolate's measured amino acid profile and typically falls in the range of 2 to 4% of protein weight for a wheat or rice base.
Assay basis should be stated on every specification. L-lysine HCl is assayed against the salt — typically 98.5 to 101.5% on the dried basis per USP — so a certificate reading 99.0% refers to the hydrochloride. Lysine content is that figure times 0.80. A chloride determination should accompany the assay to confirm salt stoichiometry, since an under-chlorided lot behaves as a partial free base on pH and hygroscopicity.
Handling is straightforward and better than the free base in every respect that matters. L-lysine HCl dissolves readily in water at above 50 grams per 100 millilitres, gives clear near-neutral-to-mildly-acidic solutions, is only mildly hygroscopic, flows well as a crystalline or granular powder, and blends uniformly. Taste is mildly bitter with a saline note, markedly easier to handle than the free base's alkaline character. Granular grades are available where direct compression or dust control is a concern.
Thermal processing requires an explicit Maillard strategy. Lysine's side-chain amine is the most reactive in the proteinogenic set, so in any format heated in the presence of reducing sugars — bars, baked goods, retorted liquids, spray-dried blends with lactose or glucose — expect browning and measurable lysine loss. Mitigation options are keeping pH low, using non-reducing sugars such as sucrose or isomalt, minimising thermal load, encapsulating the lysine, or over-formulating to compensate. Decide which before the process is locked, and validate lysine content on finished goods rather than on the premix.
For analytical control, specify identity and assay per USP, EP or JP with optical rotation confirming L-configuration, chloride content confirming stoichiometry, and standard coverage of heavy metals, residual solvents, microbiological limits, loss on drying and sulphated ash. Given the feed-dominated market structure, specify microbiological limits, residual host-cell protein and endotoxin explicitly rather than relying on a generic amino acid specification, and require the fermentation organism and substrate to be named for vegan, non-GMO, kosher and halal documentation.
On form selection, the free base has narrow but real applications. Where chloride must be minimised, where lysine density per capsule is the binding constraint, or where a high-pH matrix makes the alkalinity useful rather than problematic, free-base lysine delivers 25% more lysine per gram. Against that it is markedly hygroscopic, harder to handle, and less widely available to monograph specification. For most supplement and fortification work the hydrochloride is the correct default, and the acetate is the form specified where chloride is genuinely contraindicated and the lower lysine fraction is acceptable.
Frequently Asked Questions — L-Lysine HCl
How much lysine does L-lysine HCl deliver?
Exactly 80% by weight — 182.65 g/mol salt against 146.19 free base. One gram of salt gives 800 mg lysine and 194 mg chloride. The round number is convenient and also a trap: a capsule declaring 1,000 mg lysine and filled with 1,000 mg of hydrochloride is 20% under label. A 1,000 mg lysine claim needs 1,250 mg of salt.
Why do feed and supplement specifications disagree?
Feed formulation universally declares lysine on a free-base basis even when supplied as the hydrochloride. Human supplement labelling has no settled convention. Because the gap is exactly 20%, buyers moving between sectors routinely get a mismatch. Write the specification as "X mg lysine as free base, supplied as L-lysine HCl" and it disappears.
Will lysine brown in my product?
Very likely, if there is heat and a reducing sugar. Lysine's side-chain amine is the most reactive primary amine in the proteinogenic set, which is why lysine is the first amino acid lost in thermal processing. Options: low pH, non-reducing sugars, lower thermal load, encapsulation, or over-formulating. Validate on finished goods, not the premix.
When would I use the free base or the acetate?
Free base where chloride must be minimised or lysine density per capsule is binding — it gives 25% more lysine per gram, but is markedly hygroscopic and harder to source to monograph. The acetate where chloride is genuinely contraindicated and the lower lysine fraction is acceptable. For most supplement and fortification work the hydrochloride is correct.
Is the herpes evidence solid?
Suggestive rather than settled. Several controlled trials on recurrent herpes labialis report reduced recurrence or severity; others find no effect. The rationale is lysine's antagonism of arginine, which the virus requires. It is the strongest of lysine's clinical claims, which is not the same as a strong claim.
Why source L-lysine HCl from India?
Around 80% of raw nutraceutical ingredients originate in China and amino acids are among the most concentrated categories, so a second qualified origin is a continuity measure. For lysine specifically, the market is dominated by feed-grade volume, so the ability to supply reliably to supplement specification is the distinction that matters.