AMINO ACID

Lysine Hcl

amino acid

A salt form of the amino acid lysine, used in conditioning blends.

60products in our library

0.9%of researched products

usually #9on the label, in our shampoos

Shampoomost common in

Water-solublein water

products in our library: 60
of researched products: 0.9%
on the label, in our shampoos: usually #9
most common in: Shampoo
in water: Water-soluble

At a glance

Four things worth knowing about how this ingredient behaves on hair.

Buildup risk Low

How much of it is left on hair between washes.

Rinse-out behaviour Rinses clean

What it takes to get it off the hair again.

Fragment size Smallest

Smaller fragments travel further into the strand.

Stiffening potential in our shampoos Slight

Read from where it sits on the labels we have, not from the molecule.

The same figures as a table. The at-a-glance levels for Lysine Hcl.
Property	Level	Out of
Buildup risk	Low	1 of 5
Rinse-out behaviour	Rinses clean	5 of 5
Fragment size	Smallest	1 of 5
Stiffening potential	Slight	2 of 5

What it does for a formula

What Lysine Hcl does

The general function first, then how the role changes by product type where we have researched it.

The smallest protein fragment

Small enough to travel further into the strand than a whole protein can.

Rinses away easily

Water alone removes it, so it does not accumulate between washes.

Charge

Not recorded not recorded for this entry

Charge is not recorded for this ingredient.

Solubility

Water-solubleOil-solubleWater-dispersibleInsolubleVolatile

Rinses out with water alone, so it does not build up on hair between washes.

Where it appears

One row per product category in our library: how many products list it, what share of that category that is, and where it typically sits on the label.

Product type	How common	Typical position on label ?
Shampoo 20 products	1%	secondary · #9
Conditioner 13 products	1%	supporting · #8
Leave-in 12 products	2%	secondary · #19
Mask / treatment 5 products	1%	secondary · #18
Finisher: serum 2 products	1%	secondary · #14
Heat protectant 2 products	1%	secondary · #24
Styler: curl cream 2 products	1%	secondary · #31
Co-wash 1 product	1%	secondary · #18
Styler: lotion 1 product	3%	secondary · #17
Styler: mousse 1 product	0%	secondary · #16

Leading 1–3Supporting 4–8Secondary 9–15Lower 16–25Trace 26+

1 more product type

Product type	How common	Typical position on label ?
Styler: volumizer 1 product	1%	secondary · #15

The same figures as a table. Where Lysine Hcl sits on the ingredient list, by product type.
Product type	Products	Share of category	Median position	Earliest position	Band
Shampoo	20	1%	9	6	secondary
Conditioner	13	1%	8	7	supporting
Leave-in	12	2%	19	4	secondary
Mask / treatment	5	1%	18	12	secondary
Finisher: serum	2	1%	14	10	secondary
Heat protectant	2	1%	24	22	secondary
Styler: curl cream	2	1%	31	24	secondary
Co-wash	1	1%	18	18	secondary
Styler: lotion	1	3%	17	17	secondary
Styler: mousse	1	0%	16	16	secondary
Styler: volumizer	1	1%	15	15	secondary

We have not researched differences by product type yet. The reading below comes from where it sits on the labels in our library.

Position footprint

Leading 0Supporting 19Secondary 7Lower 27Trace 7

Every listing in our library, by position on the label.

Every listing of Lysine Hcl in our library, grouped by its position on the label.
Positions	Zone	Listings
1-3	Leading	0
4-8	Supporting	19
9-15	Secondary	7
16-25	Lower	27
26+	Trace	7

How to read this

US labelling rules put ingredients above 1% in descending order of amount; below 1% they may be listed in any order.

So position tells you about relative amount only above that line, and we never convert a position into a percentage.

Who should pay attention

Formulation guidance for specific hair conditions, limited to the label positions where it applies. It is not a conclusion about any finished product, or about you.

May suitVery dry or highly damaged hair

Amino acids are the smallest protein fraction and bind water as well, so they add far less stiffness than a hydrolysed protein does.

DependsProtein-sensitive hair

The lightest option in the protein family, but still protein — worth watching if protein reliably stiffens your hair.

Read from this ingredient’s chemical class. Where we have researched the ingredient itself, that reading replaces the class one.

Why it matters to shoppers

What seeing this ingredient tells you, what it does not, and the limits of our own method.

A good sign if you want

the lightest protein option
a light protein
a rinse-clean feel
help on very dry or damaged hair

Less relevant if you want to know

an exact safety score (we do not publish one for any ingredient)
how a finished product performs, which depends on the whole formula, not one line of it
the exact percentage in a bottle, because label position never converts into a number

Seeing it usually means

a secondary amino acid, listed below the main ingredients in our shampoos
it was on the printed ingredient list of every product we counted (we read labels, not marketing copy)

It does not automatically mean

that a product is right or wrong for you

We do not publish safety scores or hazard grades. Where a regulator has published a restriction or a use condition, we state it and cite it; otherwise we describe what the ingredient does and stop.

Commonly paired with

The ingredients that most often appear alongside this one in our library. We leave out the near-universal ones, because they pair with everything and tell you nothing.

The number beside a name is how many products in our library list both.

These ingredients tend to appear together to carry the formula and let it dry, firm up damaged areas, and keep the formula stable.

Found in these products

The most prominent placements first. The badge is the position on that product’s own ingredient list.

Pantene · Leave-in Gold Series Leave-on Detangling Milk #4 on the label · $4.60/oz

TRESemme · Shampoo Keratin Smooth Shampoo for Transforming Unruly Hair #6 on the label · $0.21/oz

Rusk · Shampoo Elevate Weightless Volume Shampoo #7 on the label · $2.40/oz

TRESemme · Conditioner Anti-Breakage Conditioner for Brittle or Weak Hair #7 on the label · $0.70/oz TRESemme · Shampoo Anti-Breakage Shampoo for Brittle or Weak Hair #7 on the label

TRESemme · Conditioner Bouncy Curls Conditioner for Curly Hair #7 on the label · $0.21/oz

TRESemme · Conditioner Cruelty-Free Keratin Smooth Color Conditioner for Color-Treated Hair #7 on the label · $0.33/oz

TRESemme · Shampoo Flawless Curls Shampoo #7 on the label · $0.21/oz

TRESemme · Conditioner Keratin Smooth Conditioner for Frizzy Hair #7 on the label · $0.21/oz

TRESemme · Conditioner Moisture Rich Conditioner #7 on the label · $0.21/oz

TRESemme · Shampoo Moisture Rich Shampoo with Vitamin E #7 on the label · $0.21/oz

TRESemme · Conditioner Silky & Smooth Anti-Frizz Conditioner #7 on the label · $0.21/oz

See all 60 products in the library that list Lysine Hcl

Identity

What this entry is, and what our references call it.

Canonical name

Lysine Hcl

Identifiers

CAS 657-27-2
PubChem 69568

Most-listed rank

#33 of 127 proteins and amino acids in our library, by how many products list it

Also listed as

lysine hcl

For your hair?

Whether Lysine Hcl matters for your hair depends on your hair.

60 products in our library list it

What this page is

What this ingredient does, and where it sits on the labels we have researched.

What it is not

A verdict on any product that contains it, and never a safety grade.

Next

Build your hair profile and let the whole library sort itself

Use products with this ingredient? Get free recall alerts for them.

We do not physically test your hair. Everything above comes from the ingredient lists in our library and from published references. The consultation is what turns it into a plan.

References

Sourced Backed by a manufacturer or regulatory source.

This ingredient

Manufacturer or regulatory PubChem : Compound identity: CID 69568, CAS 657-27-2, C6H15ClN2O2 · accessed 2026-08-28

How this page was made

Every number above is counted from the ingredient lists in our own product library: 60 of 6816 researched products list this ingredient. Nothing on this page is written per ingredient.
The dots are levels, not scores. Each one comes from what kind of ingredient it is (its chemical class, charge and solubility) or from where it sits on the labels we have.
US labelling rules put ingredients above 1% in descending order of amount; below 1% they may be listed in any order. Position tells you about relative amount only above that line, and we never convert a position into a percentage.
The prominence bands (leading, supporting, secondary) are the same ones the product pages use to read a single label, applied here to the median position across a category.
We do not publish safety scores or hazard grades. Where a regulator has published a restriction or a use condition, we state it and cite it; otherwise we describe what the ingredient does and stop.
Identifiers and references appear only when a published source is attached to this entry. Without one, we leave the row out rather than fill it in.
This is cosmetic information, not medical advice, and nothing here diagnoses or treats a health condition.
Entry last updated 2026-09-22. Product-page methodology: the product library.

Lysine Hcl

What Lysine Hcl does

Where it appears

Position footprint

Whether Lysine Hcl matters for your hair depends on your hair.

References

This ingredient

How this page was made

Hair Care Consultation