WH contributors with stressed hair trialled products which claim to nurse a mangled mane back to health. Here, their verdicts.

Breakage

The cause The friction of brush bristles rubbing against the cuticle - the overlapping cells along the outer layer of your hair - tears the surface.
The remedy Keep the cuticle smooth and intact by dabbing a pea-size amount of serum containing silicone (or any ingredient ending in "ethicone") on damp or dry hair from the mid-shaft to the ends. Our tester tried Schwarzkopf Liquid Silk Gloss Leave In Treatment, $7.29, using it twice a week after washing.
Our verdict We vote this bargain of the year - a huge, easy-to-dispense pump bottle that will last ages. It gave instant gratification - super shiny hair.

Split ends

The cause When the protective cuticle at the end of the hair shaft wears away, the tip frays; that crack then travels up the hair shaft.
The remedy Sorry, there's no magic glue to paste split ends together (yet), so the only way to get rid of them is with a trim every six to eight weeks. For a temporary fix, apply a styling product to only the tips. Find one with glycerin or hyaluronic acid - both temporarily bond the ends together. Try VO5 Mega Hold Styling Gel, $3.90.
Our verdict For our unruly-haired tester, this product gave great control, made her locks feel healthier and the ends look less frazzled. This product isn't a long-term solution, but a very cost-effective way to buy time between the inevitable haircut.

Fried hair

The cause If styling tools top 230˚C, the water inside each hair starts to boil. As the moisture tries to escape, hair blisters then breaks.
The remedy Set styling tools to low, and use shampoos and conditioners that hydrate fragile spots such as Clairol Herbal Essences Hello Hydration Moisturising Shampoo and Conditioner, $6.59 each. Use stylers with protective oils such as glycerin. Spritz on the top layers of hair before using high-temp tools.
Our verdict Both smelled amazing - they'll invoke daydreams of lying on a daybed in Bali. But because of the fragrances, these products irritated one of our tester's scalp. So we wouldn't recommend them for sensitive types.

Over processing

The cause Bleaching and dyeing strip natural pigments and cause tears that make hair porous and weak.
The remedy Once a week, use a deep-conditioning protein fix such as Redken Real Control Overnight Treat, $38, to coat the cuticle and fill hollow areas. Apply it evenly over freshly shampooed hair, then twist your hair into a bun and sleep with a towel on your pillow. Rinse hair in the morning.
Our verdict Our intrepid volunteer slathered her parched ends, popped a shower cap over her head and hit the sack. After washing her hair in the morning she immediately noticed the difference, saying her locks felt stronger than Conan the Barbarian, and looked sleek and polished.

Chemical chaos

The cause Professional straightening, toners, even some semi-permanent dyes can change the structure of hair, making it weak and brittle. Parched strands soak up moisture from the air, causing frizz.
The remedy Look for styling products that contain stearyl alcohol, a fatty alcohol that strengthens and softens hair. One that does: L'Oréal Professionnel Serie Expert Liss Ultimate Smoothing Treatment, $29. Run a 10-cent size blob through damp hair, then blow-dry, or use it on dry hair to tame and style.
Our verdict If you have fine hair, only use a Tic Tac-size amount - if you go overboard you'll get greasy hair. This one's better for those with thick hair, and should only be applied to the ends.

Toxic locks

Your hair acts like a paper towel - it's absorbent. And it also has a mild electrical charge - particularly in low humidity - and this can attract charged pollutant particles like cigarette smoke. So lather up, as the toxins in pollutants like smoke are harmful to your hair.