Like love, the pursuit of beauty has its risks. Whether you’re going for the perfect high-society wave, the most glamorous shade of blond, the sleekest bob or just a few earthy lowlights, the very acts of adding heat and chemicals to your hair can permanently alter its moisture balance, making it vulnerable to everything from frizz to fly-aways and split ends.

We’re going in
Moisture doesn’t move freely inside the hair like water running through a straw. Rather, water molecules — which account for about 10 to 15 percent of the weight of healthy hair and only five percent of damaged hair — attach themselves to protein chains within the cortex of each strand. (The cortex is the inner part of the hair, responsible for giving it its elasticity.) Hair that has never come into contact with a curling iron or a highlighting wand is nearly waterproof because these protein chains and water bonds are stronger, weight for weight, than steel.

Natural disasters — from droughts to floods
Dyes, relaxers and styling tools can corrode the cuticle, or protective outer covering, of healthy hair and disrupt the inner cortex by breaking up the protein chains and dislodging their attached water molecules. Free to escape through the damaged cuticle, these molecules evaporate into thin air, which is how you get dry, fly-away hair. But the reverse holds true as well. Because colour-treated and heat-damaged hair is so porous, moisture from the air can enter the hair, making it heavy, limp and unmanageable, especially on damp days. (Freshly permed hair, for example, holds 200 percent its normal water content.)

Relief workers
Conditioning treatments used regularly can help repair dry, porous hair by giving it back the ability to regulate its own moisture content. They artificially raise the water content of the hair back up to 15 percent of its weight. They do this through a combination of dimethicones (these protect the outside of the hair by filling in the holes of damaged cuticles); amino acids that bond onto the hair protein; and humectants, which pair up these added proteins with just the right number of water molecules to prevent moisture overload.

Need to know how to defend your hair from damage? Read about it here!

What really works

• Adipic acid A conditioning polymer that protects against breakage when you lather up. It works with glycerine, silk amino acids and borage-seed oils to stabilize the internal structure of colour-treated hair, making strands more pliable and smooth.

• Amodimethicone A form of silicone found in serums, conditioning creams and sprays that adds high gloss to damaged hair. It also improves the spreadability of conditioning treatments on wet hair, ensuring that every hair is coated and protected.

• Cationic surfactants Positively charged molecules that condition hair by seeking out negatively charged areas of severe damage, such as dry, ragged ends or strands weakened by colour treatments. They appear in shampoos and conditioners and have names like behenyltrimethylammonium chloride and stearamidopropyl dimethylamine.

• Cetyl alcohol and stearyl alcohol These fatty emollients — found mostly in moisturizing products like serums and leave-in sprays — offer superior moisturization, soaking into the hair and trapping water inside the cuticle. They work best when followed by products that lock in moisture with ingredients like dimethicone.

• Pluronic silicones These waterproofing conditioners seal the hair, fill in gaps and lock in moisture. They are especially good for dry, colour-treated hair. Colouring removes hair’s outer lipid (protein) layer, but silicones artificially mimic the cuticle, making hair feel softer and be more light reflective. They also protect hair against future damage.

• Quaterniums “Quats” are lightweight, positively charged polymers that deposit an invisible film on hair without creating buildup. They are great for combatting static. Fly-away hair happens when negatively charged strands repel each other due to friction caused by combs and wool hats. The more damaged the hair, the more negative the charge. Replacing a negative electrical charge with a positive charge allows strands to work together instead of flying in every direction.

Finding your match
Depending on how you treat your hair, at some point it may cross the threshold of needing only a light conditioner to craving a more intense hit of moisture.

• Regular moisturizing shampoos Ideal for normal, unprocessed hair or hair with slight symptoms of dryness, such as fly-aways, split ends or frizzies. These shampoos clean without stripping the natural sebum.

• Regular conditioners Add softness and shine to normal, untreated hair but also strengthen hair that is slightly damaged by styling tools.

• Leave-in mists Hair damaged by dyes and heat can swell right after being washed, leading to matting and tangles. Leave-in mists used on wet hair smooth out the snags, making it easier to comb and style. Use on dry hair to reduce frizz and fly-aways.

• Deep moisturizing shampoos and conditioners These conditioning products will help to reduce breakage in hair that is showing severe symptoms of damage and dryness due to colouring and excessive heat.

• Masks Ideal for repeatedly flatironed, permed and colour-treated hair. Gum extracts and dimethicones fill in holes, temporarily smoothing out rough hair and boosting shine. Use once or twice a week, depending on the level of damage.

• Colour-care moisturizing shampoos and conditioners These cleansing and conditioning formulas for lightened hair strengthen the internal structure of the hair by temporarily adding protein back to bleached strands. Formulas for hair that is dyed darker, or closer to its natural shade, target external damage by smoothing down the scales of rough cuticles so that the hair looks shinier and the colour lasts longer.

• Anti-frizz sprays and creams On humid days, these tame curly hair and prevent frizz in over-processed ‘dos by coating the hair with silicone.

What are your favourite hair products?