After spending 10 hours on research and interviews and more than five hours on testing the grip, heat, and performance of 11 hair straighteners on four different people with different hair textures, the GVP Digital stood out from the competition with its adjustable temperature in 10-degree increments, and an easy-to-read digital display that updates in real time so you know when it’s ready, unlike like the rest of the straighteners we tested.
The GVP Digital’s temperature range is as wide as the rest, and its plates are big enough to grab a strand of hair without being too big to maneuver. It heats up as quickly and is about as light as the rest of the straighteners, and the casing never snagged our hair. The 9-foot-long cord means you won’t have to lurk near a power outlet, and its auto shutoff keeps your home and belongings safe. The casing is solid black, and the design is simple and straightforward, but it doesn’t look cheap.
If our pick is unavailable, we recommend the Rusk W8less. It was the third-lightest hair straightener we tested at 0.50 pound, but the slim plates get just as hot as the GVP’s, and the cord is the same length. The smaller design of this straightener makes it great for curling or flipping hair. It also fits nicely in a suitcase.
If you find yourself going through new hair straighteners on a semi-regular basis, Conair Infiniti Pro offers the longest warranty—five years—among the hair straighteners we tested. The 1-inch-wide model is lightweight at 0.51 pound and comfortable to hold. The plates are also an inch and a half longer than our pick, at about 5 inches, which can make it cumbersome to flip or curl hair but is useful if you want to work with thicker sections of hair at once.
We spoke with Trefor Evans, the director of research at TRI Princeton, a hair testing and consulting firm; cosmetic chemist Perry Romanowski; and stylist Tippi Shorter, Aveda’s global artistic director for textured hair. We read research papers on heat damage, blog posts about hair destroyed by hair straighteners, hundreds of Amazon reviews of various products, and a dozen published lists of the best tools (most of which we threw out).
We tested the straighteners on Tiffany’s hair, which isn’t thick or curly, so she doesn’t have the same priorities as someone who wants a tool that makes their hair super straight. Because of that, she also gathered the opinions of friends with thicker or curlier hair when researching and writing this guide.
Anyone can use a hair straightener, but how well a straightener will work on your hair—how straight it will get, how long it will stay that way, and how much damage it will endure from the heat—depends on a combination of genes, climate, and practice. The curlier or more textured your hair, the more heat, time, or styling products you’ll need to invest to get the style you want; the finer your hair, the more easily it will be damaged by high temperatures. If you live in a humid climate, your hair will reabsorb water more quickly, which restores its natural (less straight) shape. With practice, you can figure out the ideal temperature for your hair and how to best maneuver the tool to create the style you want, but it’s best to take things low and slow at first.
The downside is that a straightener can damage hair if used incorrectly—or even correctly. (See the How we picked section where we address the heat-hair conundrum.) If you can straighten your hair to your liking with a less direct heat method, like a hair dryer, you should probably stick with that.
If you dye your hair lighter colors, like blondes or reds, you probably want to stay away from straighteners. Cosmetic chemist Perry Romanowski has tested straighteners on hair dyed in a range of colors and found that high heat from straightening can change color noticeably for blondes or redheads. “A brown color won’t be as noticeable if there’s a change typically,” he said.
If you already own a hair straightener you like—one that you can hold and maneuver easily, and that heats to the temperature you want and stays there—you’re probably set.
If you find the device clumsy to use, you’re damaging your hair unnecessarily. If it’s hard to hold and move around, you’re probably clamping your hair too tightly, unevenly, or for too much time. If hair regularly gets snagged or otherwise caught on the device, you’re forced to apply more heat on those areas to fix them. “Any time there’s friction, there’s tugging and snagging and fatiguing of the hair,” said researcher Evers. “You’re spending more time at that one particular portion of the hair and potentially causing more damage.” If it’s set at the right temperature but the plates tend to cool between passes, you’re probably forced to redo the same sections more than two times and damage it in the long term (and spend excessive time on your hairstyle). If your current straightener doesn’t have granular temperature settings, or if it takes many passes even at its highest settings to get your hair straight, replacing it with a straightener that gets a bit hotter and lets you find that sweet spot for your own hair may not only save you time, but also may save your hair some breakage or split ends.
We can’t promise that you’ll never damage your hair again; it’s a risk you take whenever you use a flat iron. But by using a quality device and using it correctly, you can reduce your chances for heat damage and keep your hair looking healthy (and straight).
Temperature range is the biggest factor when it comes to choosing a straightener. Hair straighteners, or flat irons, are essentially two hot metal plates, held like tongs, that you slide over sections of hair to dispel water from individual strands, leaving them sleek and smooth. Hair researcher Trefor Evans compares the process to manipulating a strand of cooked spaghetti: When it’s wet, it’s soft and pliable, but if you wrap the spaghetti around a pencil and let it dry, it holds its shape. “Hair does the same thing,” he said. “Once you dry it out, it locks itself into a shape—at least until the hair reabsorbs water again.” Do you notice how your hair goes flat in the dry climates or in an airplane, but curls or frizzes up in humidity? Same concept—hair straighteners work in part by steaming the moisture out of your hair.
Everyone who uses a hair straightener wants to avoid frizz, split ends, and hair breakage. There is no straightener you can use to avoid this entirely, because heat damage is an inevitable consequence of applying heat to hair, especially if you have thin, curly, or textured hair.
Straighteners get really hot: Some go up to 450 °F, which is twice as hot as blow dryers, and that high heat is pressed directly onto your locks. Hair theoretically decomposes at a little hotter than 460 °F, said Evers, although he’s seen decomposition at lower temperatures, too. When hair decomposes, the inside breaks down, leaving only the external cuticle behind. “If you look at it under high magnification, it’s almost like looking down a toilet paper roll: The outside is there and the inside is all gone,” he said. Less severe damage—like bits of the outer cuticle flaking off, which we observe as “frizz”—can occur even at lower temperatures if your hair is pressed to the hot plates for too long.
That is bad, obviously, and largely irreversible—frizzy and crunchy went out of style in the ’80s. The problem is that the maximum temperatures that hair can endure before developing damage varies by hair type and, really, by individual. “It really just depends on your particular hair and the way that you use the flat iron,” said cosmetic chemist Perry Romanowski. There are some general temperature guidelines by hair type, but even those vary by head.
Here’s the rule to live by, according to Romanowski: Generally, it’s less damaging to apply higher heat for less time than to apply lower heat for a long time. “The time and the amount of heat exposure will be more of a factor in the damage than the temperature,” he said. Evers agrees: “To get the efficacy, you crank up the temperature, and if you crank up the temperature, there’s going to be damage. It’s just a consequence of those kinds of temperatures.” Romanowski still warned, “Once you’re getting up over 400 °F, the temperature starts to be crucial.” Therefore, an ideal straightener gets quite hot, but not hotter than 460 ºF, with clear and granular controls that will help you figure out what temperature your hair responds to without getting destroyed by heat.
Stylist Tippi Shorter has seen women with curly hair straighten their curls into oblivion, leaving behind permanently straight frizzy hair. “Once it has been straightened from too much heat, it’s hard to bring it back,” she said. Even before it gets that bad, accumulated damage can cause frizz, split ends, rough-feeling hair, and breakage.
Romanowski advises to go up to at least 300 degrees to get the job done. We suggest experimenting carefully with temperatures between 300 and 400 degrees. Only try temperatures above 400 degrees if you find that you have to do multiple passes on strands of hair. Again, the goal is to limit the amount of time that you use a straightener on your hair. One quick pass at a high temperature is better than multiple slightly cooler passes.
When it comes to plate size, stylist Tippi Shorter said that a 1-inch-wide plate is the best option for most people. Wider plates are bulkier and increase the chances of accidentally clamping the same sections of hair multiple times, and the chance of warping, such that the plates don’t meet evenly across the whole surface. Plus, they’re not great for people with curly or textured hair, who need to focus on small sections of hair at a time, or people with short hair. Likewise, we aimed for straighteners with plates on the long side, but not so long the straightener wouldn’t be maneuverable.
We knew weight and cord length would be important, as they are with hair dryers, but this information is never listed on the box, so we had to wait until testing to sort that out. We also preferred products with warranties (since sometimes the electronics simply burn out) and automatic shutoff features, as it’s dangerous to leave hot plates lying around.
Price can vary, with straighteners that cost from as little as $20 to more than $200. After hearing consistent reports from our experts, we decided to exclude most straighteners that cost less than $50, except for one or two of the highest-rated ones to be certain. The basic technology is the same in all the devices, said Romanowski; the difference is that the more expensive ones (which he defines as $50 and up) have higher quality electronics that last longer. “You can get a $20 flat iron, and maybe it works for a couple of months, and then it breaks, and that’s because they’re using cheap electronics,” he said. “If you put in better quality parts and it’s put together in better quality, you can actually make a more durable, longer-lasting product that uses less electricity.” Tippi Shorter has noticed that strands of hair get stuck on decorative jewels or between gaps in the plastic on poorly constructed devices. She’s also learned to distrust the temperature settings on inexpensive devices. “They get hot so quickly that they must be hotter than the guide is telling me they are,” she said.
The following features are less important:
A number of straighteners claim to emit negative ions, often thanks to tourmaline-infused plates, which supposedly straighten hair faster and reduce frizz. This claim has some scientific backing, Evers said . We discuss this in our guide to hair dryers, but basically, ions would theoretically help kill static. In practice, Evers says he’s found that some hair dryers are able to do this. However, normal conditioners (like ones you use in the shower after shampoo) “do a wonderful job of killing static flyaway,” Evers said. “If you use a conditioner, you barely get any static buildup anyway,” he added. If you’re straightening your hair, you’d better be using a conditioner in the shower.
Some straighteners claim that their negative ion technology “locks in moisture.” This is false. “What you’re trying to do with heat styling is drive off the water,” Evers said. “The last thing you want to do is lock it in.”
Many straighteners claims to have a special coating on their plates, such as silicone, argan oil, or microconditioners. It’s not hard to understand the marketing story here, said Romanowski: There’s some layer of oil on the plates and, when they’re heated, the conditions rub off your hair to protect it. “The amount that comes off would be so low that it wouldn’t be noticeable,” he said. “In practice, you’ve already used a conditioner so you shouldn’t notice it.”
Infrared heat or energy theoretically breaks up water clusters for faster straightening, but it won’t do it “any differently than the heat does,” Romanowski said. “It’s not going to dry your hair more quickly.”
Some claim that titanium plates hold heat better than the standard ceramic plates. Three of the models we tested—the CHI Pro G2 Digital, the BabylissPro Nano, and the TS-2 Millennium—featured titanium plates. We found that straighteners with ceramic plates held heat just as well as the models with titanium plates.
Finally, nearly all high-temperature straighteners—those reaching 450 °F—advertise this fact as if it’s a good thing. All three of our experts (stylist, cosmetic chemist, and research consultant) agree that going above 400 °F will damage hair, it’s just a matter of degree depending on your hair thickness and texture. Still, as we noted above, using a slightly hotter temperature in favor of being able to work quickly may help minimize damage, versus applying lower amounts of heat for more time.
We whittled down our list of products by combining those featured on lists from websites like Top Ten Reviews, Good Housekeeping, Hair Straightener Judge, and TotalBeauty.com with the top reviewed products on Amazon. We were somewhat surprised to find the same brands, and in some cases the same models, listed over and over again, which made our job easier.
Of the models we looked at, we decided to test 11 devices and, if more than one came recommended and fit our criteria, we chose the one that had more user reviews on Amazon.
We took some vital stats for each straightener: We weighed each straightener on a postal scale, measured the length of the cords, and used a stopwatch to time how long it took to heat up. Then we turned on each straightener and compared the button placement, temperature ranges, and temperature dials. Next, we tested the straighteners on many, many strands of 1-inch-wide dry hair. Some pieces we straightened; other pieces we flipped up or curled under.
After the first round of tests, it was easy to disqualify several of the straighteners. One model, the OnePass, had plates coated with silicone strips that smelled weird when it heated up and fell off shortly after testing. Others were hard to grip, and a couple left dents in the hair when trying to curl it. The top straighteners were easy to hold, easy to grip, and passed over strands of hair seamlessly. How the plates closed was also a factor; on a few straighteners, the plates didn’t line up well or required heavy gripping to make them completely touch.
Once we picked out our favorites, we tested the straighteners over a couple of weeks. We noted the time it took to straighten or style hair with each straightener and if any snagged pieces of hair. We tested the straighteners on strands of three friends’ hair to see how they worked on different hair textures.
We tried dropping each of the straighteners a few times on a bathroom floor and then turned them on to see if they still worked (they did). We also left the straighteners on for an extended period of time to test out automatic shutoff features and see if any of the models started smoking or acting irregularly when plugged in and turned on for a long time (they didn’t). Finally, we compared their warranties.
We tested all the straighteners before looking up the current retail prices for each one, so we wouldn’t be swayed by expensive models. After the initial round of testing, our favorite models were the priciest ones. This was probably because the most expensive straighteners featured easy-to-hold casings and high-quality hinges that allowed for easy gripping. In flat straighteners, price does correlate pretty well with quality. Except for our budget pick, the models we tested that cost less than $60 were not worth buying.
All flat irons straighten and curl hair about the same, but the GVP Digital stands out because it heats up quickly and is well-constructed enough to style hair without causing snags or dents. The GVP also includes features that are usually found on higher-end models, like a real-time digital display and accurate temperature, at a midrange price.
Most of the straighteners we tested were equipped with a dial to change the temperature instead of a digital display. GVP’s digital display shows the temperature of the straightener in 10-degree increments from 160 to 450 degrees Fahrenheit (Celsius is available in a separate setting), and it tracks the temperature in real time, so you know when the straightener is heated up. Per all our experts’ advice, figuring out the right temperature to get your hair straight in as close to a single fluid pass is crucial to helping it maintain its health. The GVP’s display will best allow you to figure out the right temperature and use it consistently. People with fine or thick hair especially need to see how hot the straightener is before clamping it down on their hair. The GVP takes 40 seconds to bring its 3.5-inch-long plates to 360 °F, and 1 minute to get to 450 °F, which was about as fast as the rest of the straighteners.
All of the straighteners we tested weighed less than a pound, and the difference between the lightest and heaviest straighteners was minimal (1 to 2 ounces). The GVP weighs 0.56 pound—it was one of the heaviest straighteners we tested, but it weighed only 0.12 pound more than the lightest straightener we tested. The GVP is still light enough to hold on a daily basis, and the straightener’s other features, such as quality plates and a digital display, compensate for the added weight. The cord is 9 feet long, giving you plenty of space to plug it into an outlet that is located far away from a mirror. The straightener is 13 inches long, which we found to be the perfect length to wield while styling hair—and the plates are around 3.5 inches long, plenty sufficient to capture a good-size section of hair.
The auto shutoff time on the GVP is adjustable, and ranges from 0 to 90 minutes. Its soft rubberized exterior feels nice, without any rough edges or fancy patterns.
The buttons are color-coded and are located on the outside of the plates. This placement seems logical, but some brands put their buttons on the inside of the straightener, making it easier to accidentally burn a finger.
The GVP is marketed as a cheaper alternative to the popular CHI brand, and it really glided over pieces of hair just as well as the CHI Pro G2 Digital that we tested (the design is also very similar, and both straighteners are the same weight). I preferred the feel of the glossy finish on the casing of the CHI to the matte finish of the GVP, and it was only slightly bulkier than other straighteners we tested. Neither of these issues would discourage me from buying the GVP.
The hinge at the bottom of the GVP is curved and a bit wide. If you place your hand at the bottom of the straightener while the plates are closed, you risk getting some skin caught in the hinge. But if you watch your hand placement, you should be fine. The hinge on the CHI straightener we tested is similarly designed—with the plates closed, there’s enough space at the bottom of the device to trap a finger. On most of the other straighteners we tested, however, the hinge placement and width was unnoticeable.
The one-year warranty is shorter than most of the warranties on the 10 other flat straighteners we tested; the average warranty was around three years.
The Rusk W8less is around the same price as the GVP, but it offers a lighter and more compact design. At 0.50 pound, it was among the lightest straighteners we tested (the lightest was Rusk’s Deepshine, at 0.44 pound). Rusk W8less was one of the easiest to hold for long periods of time.
The Rusk W8less has a manual dial that goes to 450 degrees Fahrenheit, the same max temperature as the GVP. However, it lacks some of the features of our main pick. Besides the temperature dial and the on/off switch, there are no other buttons on this straightener. The temperature dial goes from 1 to 50, which correspond to 10-degree increments between 240 °F and 450 °F. If you want more settings, such as auto shutoff or a display that shows the digital temperature of the straightener in real time in Fahrenheit or Celsius, you may be happier with the GVP. It’s also our pick for those who need a straightener that can easily fit in a suitcase.
The straightener is the same length as the GVP, but the casing is slimmer in width by about half an inch and the plates are slightly shorter (around 3.25 inches). The smaller plates are ideal for flipping or curling hair.
The Rusk W8less also looks nice, with a glossy white casing. The ceramic plates felt durable and left hair smooth.
The Rusk has a 9-foot-long cord and comes with a two-year limited warranty.
Our pick is in the middle range for straighteners, but we liked another one that costs around one-third of the price. The Conair Infiniti Pro is very lightweight—0.51 pound—and clamping the plates together doesn’t require a lot of muscle. We tested the 1-inch-wide model with a purple casing, but Conair makes this straightener in three sizes and seven colors, so it’s easy to find one that suits your needs.
Like the Rusk, this straightener has a temperature dial, which goes from 165 °F up to 455 °F in 10-degree increments. It is slightly longer than our pick, at 14 inches, which made it a little unwieldy when styling. However, one advantage to a longer straightener is that it can straighten wider sections of hair at once, which can save time. The plates on the Conair are nearly 5 inches long.
On cheaper straighteners, the cord tends to be shorter, and this model is no exception, with a 6-foot cord. Yes, it gets slightly hotter than our pick, but those five extra degrees are unnecessary.
This straightener comes with a five-year warranty—ideal if you need to replace flat straighteners often.
The CHI Pro G2 Digital gets up to 425 degrees. Most other models we tested, including our pick, get up to 450 degrees or higher. We decided on a straightener that reaches higher temperatures because it’s compatible with more hair types.
Another high-end straightener we tested, the BabylissPro Nano, is very narrow and overall good, but we didn’t find anything to justify the cost. The size and design is very similar to the Conair model that we tested, except the Nano has a longer cord.
The Rusk Deepshine is actually slightly lighter—0.44 pound—than our runner-up pick, the Rusk W8less, which weighs half a pound. The Deepshine straightener was the lightest model out of all the flat straighteners we tested, but didn’t feel sturdy enough like the rest did.
The straighteners I tested that I wouldn’t buy:
The Bio Ionic OnePass is reviewed well on Amazon, but it smelled weird. The silicone “speed strips”—which are stuck on the plates and are intended to cut down on the time it takes to straighten hair—also peeled off after one test, and the plates do not seem securely fastened to the housing.
One side of the TS-2 Millennium was thicker than the others, which made it feel unbalanced. The plates also came to an odd point at the top and the plates were hard to clamp together.
The HSI Professional Ceramic Tourmaline felt bulky and uncomfortable to hold. All of the dials and buttons are also located inside the straightener, dangerously close to the plates. Not worth risking a burn.
The casing on the Remington S5500 Digital Anti Static Ceramic felt cheap (probably because the straightener is cheap), and it was hard to really clamp the plates together.
The plates on the Babyliss Pro Porcelain Ceramic straightener didn’t touch, making it hard to actually straighten hair. The plates also felt a little loose.
(Photos by Michael Hession.)
Originally published: December 21, 2016