You'll see "keratin" on the label of all sorts of hair products, and "keratin treatment" on most salon menus. But what is it actually doing — and is it genuinely good for your hair, or just a buzzword?
Here's a clear, no-hype explanation of what keratin is, what it does, and how to keep your hair's own keratin strong.
What is keratin?
Keratin is a protein — and it's the main thing your hair is made of. Around 90% of each strand is keratin, the structural protein that also forms your nails and the outer layer of your skin. It's tough, fibrous and water-resistant, which is exactly why it makes such good building material for hair.
In other words, keratin isn't an added extra. It's the scaffolding your hair is built on.
What does keratin do for your hair?
Keratin is responsible for most of the qualities we associate with healthy hair:
- Strength — it gives each strand its tensile strength, so hair resists snapping and breakage.
- Elasticity — healthy keratin lets hair stretch slightly and spring back rather than breaking.
- A smooth cuticle — the outer layer of overlapping "scales" lies flat when the keratin structure is intact, which is what reflects light and gives shine.
- Protection — that smooth, sealed cuticle helps lock in moisture and shields the inner hair from damage.
When hair is bleached, coloured, heat-styled or simply weathered over time, the keratin structure gets disrupted and the cuticle lifts. That's when hair starts to feel dry, rough, dull and prone to breakage — the classic signs of damage.
Is keratin good for your hair?
In the sense that keratin is your hair, yes — keeping that protein structure healthy is the whole game. But there's some nuance worth knowing, because "keratin" gets used to mean a few different things:
- Protein in your everyday care (shampoos, conditioners and masks that help support the hair's structure) is generally beneficial, especially for damaged hair that's lost some of its integrity.
- Salon "keratin treatments" usually refers to smoothing or straightening services. These can leave hair sleek and frizz-free for months, but they're not all equal — some formulas have historically used formaldehyde or formaldehyde-releasing ingredients. If you're considering one, choose a reputable salon and ask exactly what's in the treatment and how it's applied.
- Protein overload is a real thing. Too much protein, without enough moisture to balance it, can actually leave hair stiff and brittle. Healthy hair needs both.
So keratin is good for your hair — with the caveat that balance matters, and not every product or service labelled "keratin" is the same.
How to support your hair's keratin at home
You can't literally glue new keratin onto your hair, but you can protect the structure you have and support weakened, damaged hair with the right care:
- Strengthen and replenish with a repair-focused routine. Insight's premium vegan Rebuild Replenishing Shampooand Rebuild Replenishing Conditioner are designed to support and rebuild hair that's been weakened — a treatment that starts in the salon and continues at home.
- Reconstruct damaged lengths with the Restructurizing Hair Mask, formulated with organic wheat extract, olive butter and argan oil to nourish and rebuild the fibre of stressed hair.
- Balance protein with moisture. If your hair starts to feel stiff or straw-like, ease off protein-heavy products and lean into hydration. The goal is supple, elastic hair — not rigid hair.
- Reduce the damage in the first place. Lower your heat-styling temperatures, protect before hot tools, and avoid over-processing. Prevention protects keratin better than any treatment can repair it.
Explore the full vegan Damaged Hair range if your hair needs rebuilding from the inside out.
Frequently asked questions
Does keratin repair damaged hair? Protein-based care can help reinforce and smooth damaged hair, improving how it looks and feels. But no product permanently "repairs" hair the way skin heals — the most lasting results come from supporting the hair you have and preventing further damage.
Is keratin good for curly or afro hair? Curly and textured hair is naturally drier and more fragile, so it benefits from protein support — but it especially needs moisture alongside it. Balance is key to avoid stiffness.
How is keratin different from a bond builder? Protein/keratin care reinforces the hair's structure broadly, while bond builders target specific chemical bonds disrupted by bleaching and colouring. Many routines use both.
How often should I use protein or keratin products? For most people, once or twice a week is enough, balanced with regular moisturising care. Watch how your hair responds and adjust.
Your hair's strength comes down to its protein structure — so look after it. Rebuild weakened, damaged hair with Insight's vegan Damaged Hair range and Rebuild Home Care.