Almost every mystery breakage problem comes down to this balance. Hair needs both water and structure. Too much of one without the other, and the hair either snaps or goes limp.
How to tell which one you need
Take a single strand, wet it, and stretch it gently.
- Stretches a long way, then snaps and does not return: too much moisture, not enough protein.
- Snaps almost immediately with no stretch: too much protein, not enough moisture.
- Stretches slightly and springs back: balanced. Leave it alone.
What each one does
Moisture comes from water and the humectants that help hair hold it. It gives softness, elasticity and movement. Protein comes from hydrolysed keratin, wheat, silk or rice, and temporarily patches gaps in the cuticle, giving structure and strength.
Protein is a scaffold, not a cure. It washes out, which is why it needs reapplying, and why overdoing it leaves hair stiff and brittle.
A practical rhythm
For most textures: moisture at every wash, protein every third or fourth. Colour-treated or heat-styled hair usually needs protein more often. Fine hair usually needs it less. Adjust based on the stretch test, not the calendar.