Quick answer: hair that feels dry, rough, brittle and snaps easily usually needs moisture. Hair that feels limp, gummy or overly stretchy when wet and won't hold a style usually needs protein to strengthen it. A simple stretch test on a wet strand tells you a lot. Most hair needs both in balance: moisture for softness, protein for strength.
What protein and moisture do for hair
- Protein helps strengthen the hair fibre and fill in weak, damaged areas, so hair is more resilient and holds its shape. Look for plant proteins, amino acids and phyto-keratin.
- Moisture keeps hair soft, flexible and smooth, so it bends rather than snaps. Look for humectants, butters and oils.
Signs your hair needs moisture
- Feels dry, rough or straw-like
- Looks dull, with frizz
- Snaps quickly with very little stretch
- Tangles easily
Signs your hair needs protein
- Feels limp, mushy or gummy when wet
- Stretches a long way when wet and doesn't spring back
- Won't hold a curl or style
- Has been bleached, chemically straightened or heavily heat-styled
The stretch test
Take a single shed strand of wet hair and gently stretch it.
- It stretches a little and springs back: balanced.
- It snaps straight away with little stretch: it probably needs moisture.
- It stretches a long way, feels gummy and doesn't spring back (or breaks after stretching): it probably needs protein.
It's a guide, not a precise measurement, so use it alongside how your hair looks and feels.
What is protein overload?
Too much protein, too often, can leave hair stiff, rough and brittle, which looks a lot like dryness. If your hair feels straw-like after a run of strengthening treatments, switch to moisturising care for a while.
Products for each
For strength (protein):
- Rebuild, with phyto-keratin, for weakened hair. In a cyclic fatigue test on bleached hair, the Rebuild routine helped hair withstand more breakage cycles than untreated hair.
- Restructurizing Hair Mask and Restructurizing Hair Spray, with plant proteins.
For moisture:
- Nourishing Hair Mask, with organic oat extract, illipé butter and organic coconut oil, for dry hair.
- Hydrating Hair Mask for dry, frizzy hair.
If your hair needs both, alternate: a strengthening mask one week and a moisturising mask the next. See how to choose a hair mask.
Frequently asked questions
How often should I use a protein treatment?
It depends on how damaged your hair is. Heavily bleached hair may need it weekly; healthy hair, much less often. Watch for stiffness as a sign to cut back.
Does curly hair need protein or moisture?
Usually more moisture, but curls that won't hold their shape can benefit from protein. See curl types explained.
Is protein the same as keratin?
Keratin is the protein hair is made of. Many strengthening products use plant proteins or phyto-keratin. Read what does keratin do for your hair?
Does porosity affect protein needs?
Often, yes: high porosity hair is usually damaged and benefits from strengthening. See hair porosity explained.
About the author
Charlotte Read has spent six years in the hair industry with Insight Professional and holds a First Class BSc in Business Management and Marketing. She writes with reference to real salons across social media and the wider Insight community, and draws on the Insight office team, who between them bring over 100 years of combined experience on salon floors.
Where technical expertise is needed, Charlotte consults Lorraine Matic, Head of Insight UK Education, who brings over 38 years of global experience in colour, technique and hair science.