Hair breakage is an all too common problem, and even the most seasoned of hair stylists can slip up from time to time. That’s why LumaBella’s Keratin Duel Touch Hair Straightener features a unique smart heat sensor. This nifty little gadget can actually tell when there is too much heat for your hair, and will automatically adjust to a safer styling temperature!
By-and-large, most people with natural hair have some variation of type 3 or type 4 – which is exactly why low-end hair straighteners can be so dangerous. More curly natural black hair has a tendency to be more porous than other hair types. As a result, it can lose moisture easily and become damaged. With the wrong flat iron, this can lead to split ends and breakage after just a single use.
Heat protectants contain ingredients that coat hair and slow down heat induction. Janine Jarman says, “Blow dry your hair properly; use a heat protectant product; and with the right iron, you should not have to make a bunch of passes to get the results you want.” We used TRESemmé Expert Selection Heat Protection Spray, Keratin Smooth. Most of our testers liked how it worked on their hair and felt a noticeable difference when using it. Our tester with kinky hair didn’t use the product because she knew it wouldn’t work on her hair. Instead, she recommends using an oil (like an Argan oil) or a hair grease to add moisture to the hair, which makes it easier to straighten.
The question is, does it live up to all the hype? There are more than 30,000 reviews on Amazon, 70% of these reviews give a 5-star rating, and 14% give a 4-star rating. According to the numbers, the HSI Professional truly is a high-quality product that is well-deserving of the attention it's been given. Buyers love how quickly the HSI Professional heats up, what it does for their hair, and how easy it is to use— even on short hair.
Straightening irons, straighteners, or flat irons work by breaking down the positive hydrogen bonds found in the hair's cortex, which cause hair to open, bend and become curly. Once the bonds are broken, hair is prevented from holding its original, natural form, though the hydrogen bonds can re-form if exposed to moisture.[2] Straightening irons use mainly ceramic material for their plates. Low-end straighteners use a single layer of ceramic coating on the plates, whereas high-end straighteners use multiple layers or even 100% ceramic material. Some straightening irons are fitted with an automatic shut off feature to prevent fire accidents.

We started with six flat irons but ultimately dropped two because they didn’t work well on any of our testers’ hair. The inexpensive, but highly rated HSI Professional Glider Ceramic Tourmaline Ionic Flat Iron was bulky and awkward. Testers said it felt like two pieces of plastic passing through their hair. We thought the NuMe Megastar Hair Straightener, a popular and more high-end tool, would be a clear contender for our list. However, testers said it snagged hard against their hair to the point of hurting. It was also difficult to hold closed when styling. Because both of these flat irons received such low ratings among our testers, we didn’t include them in our top picks.
Eight embedded sensors regulate and evenly distribute the heat on this ceramic iron, minimizing damage and increasing shine and smoothness. With adjustable temperature settings that go as low as 140 degrees (the coolest we've ever seen), it's ideal for anyone with super fine hair, or to smooth out the tiny frizzies around your hairline. It also comes with a lifetime warranty, which is never a bad thing.
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