Made in Korea
Silk Protein Peptide
The protein behind how silk feels, in both the shampoo and the conditioner. Smoother hair, more shine, less snagging — and it builds every wash.
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The actives
What's in it, and what the research says
Five actives do the work here. Below is what each one is, what it has actually been shown to do — and, where the evidence is thin, we say so.
Silk protein peptide
Conditioning · humectant · antistatic
Silk protein, hydrolyzed into short peptide chains. Hair carries a slight negative charge and these peptides carry positive sites along their length, so they are drawn to the strand and stay there through the rinse rather than washing away.
Roughly a third of silk protein is serine, an amino acid carrying a hydroxyl group — the chemical handle that grabs water and holds it. On hair that means a smoother surface, less friction in the comb, and more light reflected rather than scattered.
Copper peptide
GHK-Cu · scalp conditioning
A copper-binding peptide the body produces on its own. Levels peak in your twenties and fall steadily with age, which is much of why it became interesting to researchers in the first place.
Work on the scalp points to anti-inflammatory activity in scalp tissue, improved blood-vessel formation around follicles, and activation of follicle stem cells. A 2015 randomised trial in postmenopausal women reported increases in hair count and diameter over 90 days, and a 2018 study reported improvements in density and diameter comparable to minoxidil, with fewer side effects.
Straight answer: these are small studies. Copper peptide is not an approved hair-loss treatment, and it does not block DHT, the hormone behind pattern baldness. It is a scalp-condition ingredient with promising but early evidence — not a substitute for a medicine.
Panthenol
Provitamin B5 · humectant
One of the best-established conditioning agents in cosmetics, and one of the few where the effect is straightforwardly measurable. It is a humectant: it draws water in and holds onto it.
In hair that shows up as higher moisture content, better elasticity, and measurably easier combing. It also calms the irritation other ingredients can cause, which is why it turns up in so many formulas for sensitive skin. Typically used somewhere between 3% and 10%.
Heartleaf extract
Houttuynia cordata · soothing
The Korean skincare staple for calm skin, from a heart-shaped-leaf plant long used in East Asian medicine and cooking. It carries flavonoids and polyphenols, and is used to settle redness and irritation and to help balance oil production.
On a scalp, that is the difference between comfortable and tight by the end of the day.
Salicylic acid
Beta-hydroxy acid · clarifying
A beta-hydroxy acid, and unusually among exfoliants it is oil-soluble — so it works its way into the follicle rather than sitting on the surface.
That is what lifts the mix of product residue, oil and dead skin that leaves a scalp feeling congested and flaky, and it is why the shampoo rinses out feeling genuinely clean rather than coated.
The problem
Your hair's surface takes a beating
A strand of hair isn't smooth. Its outer layer — the cuticle — is built from overlapping scales, laid down like roof tiles, six to ten deep on healthy hair. When those scales lie flat, hair does what you want: it slides past itself instead of tangling, and it reflects light in one direction, which is what shine actually is.
Then everyday life gets at it. Heat tools lift and crack the scales. Bleach and colour chemically erode them. Brushing, towel-drying and sleeping on cotton wear them down. Hard water leaves mineral deposits wedged between them.
Rough up that layer and everything changes at once. Strands catch on each other, so hair tangles and breaks when you comb it. Light scatters in every direction instead of reflecting, so hair looks dull. And the gaps let moisture escape faster, so it dries out between washes.
Almost everything people dislike about their hair is a surface problem.
What it is
The protein that makes silk feel like silk
Silk fibre is two proteins. Fibroin is the structural core. Wrapped around it is sericin — a gummy protein coating that makes up roughly a quarter of the raw fibre, and it's the one responsible for how raw silk feels in the hand.
Sericin's makeup is unusual. About a third of it is serine, an amino acid carrying a hydroxyl group — the chemical handle that grabs onto water molecules and holds them. That's why silk feels the way it does rather than dry and papery.
In its natural state the protein is far too large to do anything useful on hair; it would sit on the surface and rinse straight off. So it's hydrolyzed — broken down into short peptide chains. Small enough to cling. That's the ingredient in both of these bottles, and it's why the label says silk protein peptide.
How it works on the strand
Four things happen every wash
It clings
Hair carries a slight negative charge, and silk peptides carry positive sites along their chains. They are drawn to the strand and stay there through the rinse instead of washing away.
It fills and flattens
The peptides settle into the microscopic gaps where cuticle scales have lifted or chipped, and lie down across the surface as a fine film.
Friction drops
A smoother surface means less drag, so the comb pulls through instead of catching. Catching is where a great deal of everyday breakage actually begins.
Light behaves
A flat surface reflects light in one direction rather than scattering it. That is shine. It is not added to hair; it is what an intact surface does.
Why the duo
Most routines undo step one with step two
The usual pattern is a shampoo that strips the surface, followed by a conditioner trying to put back what the shampoo just took. You end up roughly where you started, every wash.
Silk protein peptides are in both bottles here. The shampoo carries them down the strand while it cleans, so the wash itself isn't purely subtractive. The conditioner then lays down a heavier pass and seals it. Two steps, same direction.
Shop the Duo$39.98 for both — $20.00 off, free shipping.
What to expect
It builds
Wash one
You will feel the slip first. The comb moves differently — that is immediate, and it is the easiest thing to notice.
Week one to two
Shine starts showing up as the cuticle stays consistently smoother instead of being roughed up and patched each wash.
Week three onward
The difference in how hair behaves as it dries — less frizz lifting, ends sitting better. This is the part people tend to comment on.
Straight answers
What it doesn't do
This is not a bond builder. Bleach and high heat break disulfide bonds deep inside the strand. Reconnecting those takes specific chemistry, and no protein does it — not silk, not keratin, not collagen.
The effect is on the surface, and it builds with use. That's how the category works — it's why you keep using it, the same way you keep moisturising.
What silk protein does do is make hair smoother, shinier, easier to comb and better at holding moisture. That's a real result, it's noticeable, and it's enough.
Common questions
What does the silk protein peptide actually do?
It is a conditioning agent. Silk protein is hydrolyzed into peptides small enough to cling to the outside of the hair, where it smooths the cuticle, cuts friction and helps the fibre hold onto water. That is why hair combs easier and catches more light.
Where is it made?
Made in Korea.
How does it smell?
Herbal rosemary and peach on the opening, florals through the heart, and a musk-and-wood base that stays with the hair after it dries.
Is it sulfate-free?
No. It is a traditional lathering shampoo built on sodium laureth sulfate.
Is it safe for colour-treated hair?
Yes. It will not lift colour or leave a fresh dye job looking dull.
How big are the bottles?
100 ml (3.38 fl oz) each — roughly 4 to 5 weeks of washing for short-to-medium hair.
How long does shipping take?
Shipping is free on every order. Orders are processed within 1 to 3 business days, then delivery typically takes 7 to 10 days, with tracking emailed when it ships.
What if it does not work for my hair?
Return it within 30 days for a full refund. Email support@shoplenix.com to start a return.