Two products, the same amino acid, and a price difference that makes the purchasing decision look obvious – until you do the arithmetic on delivered lysine. L-Lysine sulphate (CAS 60343-69-3) at 55% on a dry basis versus L-lysine HCl at 98.5% salt strength: the concentrations differ by a factor of about 1.4, and so does the freight, the storage space and the handling behaviour.
This guide is the comparison a formulator or buyer actually needs: how to convert between the two, what the real cost per kilogram of lysine is, where each one fits, and the specification details that decide whether a switch saves money or quietly costs performance.
The two products side by side
| Item | L-Lysine sulphate | L-Lysine HCl |
|---|---|---|
| CAS | 60343-69-3 | 657-27-2 (hydrochloride) |
| Production | Fermentation broth concentrated and dried | Fermented, purified by ion exchange, crystallised as HCl salt |
| Lysine content | 55% min on dry matter basis | 78.5-78.8% lysine (98.5% as HCl salt) |
| Moisture | Max 4.0% | Typically under 1% |
| Appearance | Light brown granular powder | White to off-white crystalline powder |
| Other nutrients | Other amino acids and fermentation solids | None of significance |
| Sulphur contribution | Yes – sulphate | Chloride instead |
| Handling | Granular, low dust, less hygroscopic | Fine crystalline, hygroscopic, prone to caking |
The conversion everyone gets wrong
You cannot compare prices per tonne. You have to compare cost per kilogram of lysine, and that means three corrections:
| Step | L-Lysine sulphate | L-Lysine HCl |
|---|---|---|
| Nominal assay | 55% on dry matter | 98.5% as HCl salt |
| Correct for moisture | 55 x (1 – moisture) e.g. 55 x 0.97 = 53.4% | 98.5% x 0.8 = 78.8% lysine (the HCl salt carries ~20% HCl by mass) |
| Delivered lysine per tonne | ~534 kg | ~788 kg |
| Product needed for 1 tonne of lysine | ~1,873 kg | ~1,269 kg |
The HCl correction is the one that surprises people: the 98.5% figure is the salt assay, not the lysine assay. Lysine hydrochloride is roughly 80% lysine and 20% hydrogen chloride by mass, so 98.5% salt strength delivers about 78.8% lysine. Comparing “55%” against “98.5%” overstates the HCl advantage by a quarter.
Cost per kilogram of lysine: the only valid comparison
| Line item | Sulphate | HCl |
|---|---|---|
| Product price (illustrative) | Base | Higher per tonne |
| Lysine per tonne of product | ~534 kg | ~788 kg |
| Freight per tonne of lysine | ~1.87 tonnes shipped per tonne of lysine | ~1.27 tonnes shipped per tonne of lysine |
| Storage space per tonne of lysine | Higher | Lower |
| Handling cost | Lower – granular, less caking, less dust | Higher – hygroscopic, needs dry storage |
In most markets the sulphate form wins on landed cost per kilogram of lysine for compound feed, and the hydrochloride wins where storage space, premix volume or a tight sulphur budget dominate. The calculation must be done with real freight, because the two products differ by 47% in shipping volume per unit of lysine.
Where each one fits
| Application | Better choice | Why |
|---|---|---|
| Swine grow-finish compound feed | Sulphate | Inclusion 0.2-0.8%; cost per kg lysine dominates; granular handling |
| Broiler feed (mash or pellet) | Sulphate | High inclusion, cost-sensitive |
| Aquatic feed | Sulphate | Very high inclusion; cost per kg lysine is the whole decision |
| Vitamin-mineral premix | HCl | Premix volume must stay small; high concentration matters |
| Diets with a strict sulphur limit | HCl | Avoids adding sulphate |
| Humid or tropical storage | Sulphate | Less hygroscopic, better flow, less caking |
| Low-inclusion precision diets | HCl | Easier to weigh accurately at small doses |
Specification details that decide the switch
When you move a formulation from one source to the other, four numbers need to be re-checked – not just the price:
- Moisture – the sulphate form is specified at max 4.0% loss on drying, and delivered lysine depends on it. Request the figure per lot.
- Assay basis – sulphate is quoted on dry matter, HCl on salt. Both must be converted to delivered lysine before comparison.
- Sulphur budget – the sulphate form contributes sulphur to the diet. In most formulations this is not limiting, but it must be checked against the formulation’s total sulphur constraint.
- Physical form – granular versus fine crystalline changes the mill’s dosing, dust control and caking experience. A switch can require different handling equipment.
Quality control for either source
| Check | Sulphate | HCl |
|---|---|---|
| Lysine assay | Dry matter basis, min 55% | Salt basis, typically 98.5% |
| Moisture | Max 4.0% loss on drying | Typically under 1% |
| Appearance / flow | Granular, brown, free-flowing | White crystalline, check for caking |
| Heavy metals and microbiology | Per feed safety rules | Per feed safety rules |
| Registration | Check national feed additive catalogue | Check national feed additive catalogue |
Frequently asked questions
Is 98.5% HCl twice as strong as 55% sulphate? No. The 98.5% is the salt assay; lysine is about 78.8% of the salt. The real ratio of lysine content is roughly 1.4 to 1, not 1.8 to 1.
Can I substitute one for the other kilo for kilo? No – convert by delivered lysine. Replacing 1 kg of HCl needs about 1.48 kg of sulphate at 53.4% delivered lysine.
Which is cheaper? Almost always the sulphate per kilogram of lysine, but freight changes the answer: the sulphate form ships 47% more mass per tonne of lysine.
Does the sulphate form affect feed colour or smell? It is light brown and carries a fermentation odour; usually irrelevant in compound feed, but worth checking in premium or white-feed applications.
Is the HCl form purer? Yes by definition – it is a purified salt. That purity matters in premixes and where the sulphate’s other components are undesirable; in compound feed it usually does not.
Contact PolyBlueChem for samples of both grades and a cost comparison for your freight lane.