Shiny, bouncy, healthy hair -- it’s every woman’s best beauty asset. But as much as we treasure our tresses, we put them through a lot of torture. Blow-dryers, flat irons, hair dyeing or bleaching, chemical straightening and tight ponytails can leave our hair dry, fried and unable to hold a style. Hair expert John Gray, author of The World of Hair, explains all this rough handling strips away your mane’s outer protective layer -- the “F” layer -- leading to a degradation of the cortex, the central core of the hair shaft. Ouch!

Dire as that sounds, with just a few tweaks to your hair care routine, your damaged hair will act, look and feel healthy while you prevent future harm. “Hair care technology has come a long way,” says Pantene senior scientist Jeni Thomas. “You can still color your hair, use styling tools or spend time out in the sun and have great hair -- as long as you are taking the right steps to protect it.”

Here’s how to mend your damaged hair from the four main types of assault.

Over-processing
If you dye or lighten your hair, staying within two shades of your natural color will be far less damaging than going from dark brown to blond -- or the other way around. When you touch up your hair at home with permanent or semipermanent color, focus on the roots so you’re not processing your porous ends again.

Be cautious about exposing your color-processed hair to chemical straightening or permanent waves. If you love the results you get with chemical straightening, talk to your stylist about switching to a gentler process that improves the texture of your hair -- leaving it soft, glossy and manageable rather than pin-straight.

Use a shampoo and conditioner formulated for colored hair. Chemical treatments alter the structure of the hair and these products contain ingredients, such as certain polymers, that enhance this new structure.

Heat Damage
The highest setting of your flat iron, curling iron and blow-dryer may actually exceed the boiling point of water. Instead of poaching your tresses, apply a heat-protecting spray and use the lowest setting that will allow you to get the results you want and maintain your healthy hair. Don’t blow-dry your hair when it’s sopping wet; wait until it’s two-thirds dry, or blot with a towel to absorb extra moisture. When you use your flat iron, keep it moving: Try to go through each section of hair only once.

Look for hair care products that contain the words “moisturizing” or “hydrating” on the label; these will provide your thirsty locks with the restorative drink they need.

Rough Handling
Use only a wide-tooth comb to detangle wet hair. Cut down on how frequently and aggressively you brush your hair. Forget the 100 nightly strokes maxim and use the minimum number of brush strokes that are needed to achieve or refresh your style. If you wear a ponytail, be sure to use seamless elastics and take care when you remove them; carelessly ripping out your pony holder can lead to breakage. If you already have signs of breakage, such as flyways around the crown, use a smoothing cream. Rub a dime-size amount between your palms, then lightly apply to your flyaway zones.

Sun Exposure
Just as UV rays damage your skin, they also wreak havoc on your locks, weakening the protein structure that keeps hair strong and healthy. The best way to protect your healthy hair from damage on a sunny day is to wear a hat; choose one with a wide brim and you’ll protect your skin too. If your tresses have already seen more sunny days than you can count, choose a shampoo and conditioner that are designed to strengthen your hair, and pick the formula that’s right for your texture (fine/fragile or medium/thick).

As fall sets in, you notice that your skin and hair have gone from sun-kissed to sun-stressed. “When a patient comes to me in September, the most common complaints are brown spots, broken capillaries and fine lines,” says Rebecca Fitzgerald, M.D., a Los Angeles dermatologist. And while a season of sun, sea and chlorine has left your skin dehydrated and blotchy, your hair is likely to look fried and lifeless. “Hair needs extra TLC at the end of summer,” says Los Angeles hairstylist Rebecca DuMoulin, “especially if it’s color treated.”

Here are the top fixes for summer’s beauty blunders; some you can do on your own and others with a little help from the pros.

How to Get Your Glow Back
Your dermatologist can help erase sun damage by literally shining a light on the problem. Intense pulsed light treatments (also known as IPL, Fotofacial or Photofacial) deliver high-intensity bursts of light to areas of pigment that don’t match your regular skin tone, such as red, tan and brown spots as well as tiny broken capillaries. The melanin in those areas absorbs the light, and over the next few days, the spots darken and then flake off, replaced by new even-toned skin tissue. (IPL, however, may be less effective on skin that already contains a lot of pigment, so women with darker skin tones should discuss with their dermatologist whether the treatment is right for them.)

Another option your doctor may suggest is a light chemical peel that uses salicylic or glycolic acid to exfoliate the top layers of skin, helping to slough away discoloration, fine wrinkles and coarse texture. Your doctor may also write a prescription for a topical retinoid -- a vitamin A derivative -- that smoothes the skin and evens out discoloration by speeding cell turnover. “The only caveat with retinoids is that the gain is long haul and not overnight. Give them a few months,” advises Fitzgerald.

Skin Fixes From the Drugstore
Over-the-counter retinoids are lower in strength than their prescription sisters, but still highly effective. Look for the word “retinol” on the product’s label. And while nonprescription retinoids are less likely than prescription formulas to irritate your skin, they can still cause dryness, so start by using your new cream every other night.

Other great drugstore ingredients to look for are AHA’s (alpha hydroxy acids, commonly listed as glycolic or salicylic on the ingredients list). Like the chemical peels you’d receive in a doctor’s office, these products work to exfoliate the top damaged layers of skin.

Moisture and Shine Repair for Hair
“End-of-summer hair looks dry because the cuticle on the hair shaft isn’t lying flat, causing strands to lose moisture and gloss,” says DuMoulin. A trim at a salon is the only way to get rid of split or ragged ends, but there are also deep-conditioning treatments available that help the scalp and flood your hair with moisturizers. These deep-conditioning treatments smooth the scale-like cells of the cuticle, instantly boosting shine. At home, switch to moisturizing conditioners and fake shine with a silicone spray. Silicone gives hair an instant gloss and tames flyaways while you are babying your hair back from summer damage.

Reversing Hair’s Brassiness and Blahs
After months of sun exposure, hair that has been colored often looks brassy and dull. “Women who color their hair dark brown or red suffer the most because these colors really fade in the sun,” says DuMoulin. A toner can help add some extra depth to your hue. While blondes don’t suffer from fading in the summer, too much sun “and their hair looks one-dimensional,” says DuMoulin. One solution is to add some lowlights to give your light tresses more depth.

You’re itching to get out of your hair rut -- same color, same cut for years -- and into a dramatic new do. Before committing to an extreme hair makeover, most experts agree you should start with small, well-considered steps rather than all at once, and leave yourself open to some unexpected discoveries.

“I love when women are open to experimenting,” says Jon Patrick, a Beverly Hills colorist and stylist, “but I want the risks to be well-calculated.”

Here’s advice from the pros on how to achieve a hair makeover that will turn heads without leaving your own head spinning.

Growing out Hair
If you’ve decided to go from chin length to shoulder grazing, don’t kiss your stylist goodbye for the next year. Remember, hair grows from the scalp -- not the ends -- says Michael Shaun Corby, a hair guru who primps runway models for New York’s Fashion Week. “Left on its own, short hair will grow into something resembling a mullet in the back and unwieldy feathers in the front,” he says. 

The most graceful way to grow your hair out is to establish what Corby calls “a clean perimeter,” with a one-length bob that falls somewhere between the jawline and the middle of the neck. See your stylist every six weeks to trim and maintain that line while the underneath layers catch up. If you’re growing out bangs, keep one quarter as fringe, while your stylist begins incorporating the remaining bangs into the bob.

Cutting Hair
Ask yourself what look you’re really going for. “Sometimes women don’t really want short hair,” says Patrick. “What they want is the appearance, at least now and then, of short hair. If you think that may be the case, have your stylist show you how to put your hair up in a chignon or into a looped bun.” If you’re going short for the sake of convenience, keep in mind that a short do might actually require more upkeep since you won’t have the option of pulling your hair back into a ponytail or bun. You’ll also need trims every four to six weeks to maintain the shape. 

Bring photos to show your stylist what you mean by “short-ish” or “a few inches.” And before you commit to a new style, “ask your hairdresser what it’s going to take for you to duplicate the salon results on your own,” say Damien Miano of the Miano Viel Salon in New York City. If you have thick, wavy hair, for example, you’ll need to log a long session with your hair dryer and flatiron to get it to bend into a Victoria Beckham bob.

Transform Your Color With No Regrets
Remember when Cameron Diaz, Reese Witherspoon and Gwyneth Paltrow all became brunettes a few years ago? “Suddenly I had all these blondes who said they wanted to go dark,” says colorist Andrea Sher of Anagen Salon in New York City. “I’d say, ‘No, what you really want is a change.’”

An all-at-once change doesn’t allow for incremental and dazzling shifts. A blonde who thought she wanted to go mink brown may feel reinvented with a few caramel streaks, while a brunette dreaming of Gwen Stefani platinum may discover she looks fabulous in Debra Messing auburn. “When women say they want a dramatic color change, it’s usually because they want to brighten their look,” explains Viel. “Sometimes the solution can be as simple as adding lowlights to hair that has been over-highlighted.”

Schedule a consultation with your colorist to discuss flattering shades for your skin tone. If you want to go lighter, ask how many shades your hair can be lifted or bleached without causing damage and how many visits it will take. Finally, be sure to talk about upkeep. “Any change that takes you more than two or three shades lighter or darker is going to require a lot of maintenance,” warns Viel. “And straight hair will need more frequent touchups than curly hair because when roots grow in, the line of demarcation is much more obvious.”

One of the best ways to stretch your getting-gorgeous dollars is by coloring your hair at home. If that sounds scary, relax: Today’s drugstore hair coloring products are gentler than ever and loaded with botanicals and conditioners. Following a few easy steps, you can use them to get natural-looking color as well as body and shine. 

Here are five secrets to foolproof at-home color.

At-home Coloring Secret No. 1: Stay within your color range.
Go only one or two shades lighter or darker than your starting hair color (the color your hair is at the moment). You don’t want to make extreme color changes on your own, because hidden beneath the shade that’s apparent to the naked eye are underlying pigments -- from pale yellow to dark red-brown. When hair is dyed, those pigments take center stage. “I can put the exact same color on seven medium brunettes, and they’ll each end up with different results because every woman's hair takes the color in its own way” says Philip Pelusi, who owns salons in Pittsburgh and Manhattan. That's called individuality, and it's something we all want to celebrate.

However, when you’re going from brunette to Lady Gaga platinum or vice versa, you first need to prep the hair by filling in the pigments that are being removed, or by removing pigments before depositing a darker color. This is what’s known as a “double process,” and it’s something you want to leave to the pros to avoid ending up with an orange or green hue.

At-home Coloring Secret No. 2: Choose the right formula.
Start out with a clear understanding of what you want to achieve, and that will lead you to the appropriate type of product.

• Glosses and glazes work in just three to five minutes to boost color by adding tone, shine and vibrancy. They last up to six shampoos. If your hair is highlighted, opt for a clear gloss that will add shine without depositing a hint of color that can affect the tone of those finely calibrated streaks.
• Semipermanent color contains pigments that coat the outside of the hair fiber and fade after six to 12 shampoos. Semipermanent color will only darken the tone of your hair and cover a sprinkling of gray.
• Permanent color contains ingredients that open the hair’s cuticle, allowing the color to penetrate the shaft. It can lighten or darken hair and will provide full gray coverage. After four to six weeks, you’ll need a touch-up to cover showing roots.

At-home Coloring Secret No. 3: Select the right shade.
Josh Wood, a celebrated London hair colorist who looks after some of the most pampered locks in the world, has done many corrections on at-home dye jobs gone wrong. “Typically, women have simply chosen the wrong color because they haven’t identified their skin tone, and skin tone and hair color go hand in hand,” he says. “The right hair color will bring your skin to life, lending it that beautiful luminescent glow.”

You want to balance warm skin tones with cool hair color (look for champagne, ash and beige shades) and cool skin tones with warm hair color (look for cocoa, pecan, caramel, bronze, honey and chestnut shades). “The foundation you wear will give you a good indication of whether you’re cool or warm skin tone,” says Wood. “If you’re still not sure, ask for a color consultation at a cosmetics counter.”

At-home Coloring Secret No. 4: Read the hair color box.
The product box is crammed with information to help you make the right buying decision. Pay attention to the language: Words such as “bold” and “brilliant” indicate you’ll get more dramatic results than a natural “true-to-you” color. Study the color chart on the back of the box as a guide to the results you can expect, and read the ingredients list for things such as botanicals to nourish the hair.

At-home Coloring Secret No. 5: Don’t skip the strand test
Snipping and dyeing a few strands will give you a precise preview of how the color will look on your locks and how long you need to keep the product in your hair if you’re covering resistant grays. Remember, don’t start the timer until you’ve finished applying the color to your hair, and keep the product on for the entire suggested time.