For the better part of last calendar year, two hair irons (the HSI professional and the Sedu Revolution) have been the two main competitors in the category of best hair straighteners for thick hair in shoulder-length.

That all changed when the HSI dropped the price from $200 to $39.99.

Suddenly, we had two high-quality products, both of them a very good suit for this hair type and length, but one of them was 3 times less expensive.

It doesn’t come as a surprise that the HSI has been dominating this category ever since (last 3 updates) both in the reviews of users and my fellow hair stylists.

What you should keep in mind is that, since the HSI is on discount, it goes out of stock almost daily and we never know when (and if) it’s coming back.

I contacted the company to get an explanation. They were vague about why it goes out of stock so often, but the rumor I heard from my peers is that the HSI Professional is being discontinued and they’re selling the remaining stock.

Anyway, let’s get to the list of the top rated hair straighteners in the category, their ratings and their reviews. Here we go:

ModelRead moreOverall Quality RatingPicture
Professional Ionic Hair Straightener By HSI PROFESSIONALSee_ratings_button4.9 / 5HSI_voted_best_for_thick_hair
Revolution Styling Iron By SeduSee_ratings_button4.6 / 5sedu-revolution_second_best_rated_iron_for_coarse_hair
Ceramic Flat Iron By ChiSee_ratings_button4.6 / 5chi_professional_multicolor_thick_hair


Professional Ionic Hair Straightener

HSI_best_price_and_quality_hair_straightenerBy HSI PROFESSIONAL

Let’s go over some basic manufacturer’s info:

  • Flip, curl, and straighten your hair
  • Adjustable different intensity temperature (240-410F)
  • Ion ceramic and tourmaline plates offer a silkier and shinier finish in much less time
  • 1†wide plates suit any hair type
  • The width of the plates is also great for bangs

Check out what users are saying about it on Amazon >>

No high praise needed if the product is good. Nevertheless, we’ll move on and gather as much information about it as possible. Here is what our fellow customers and featured testers shared:

The PROs:

  • I love the traveling bag that came with it! When we start talking about the actual product, I have only one thing to say, best hair straightener for thick hair ever!
  • The instructions are very comprehensive; the iron’s ease of use is amazing, so even a tech ignoramus like me can find her way around!
  • I have a real nightmare on my head, and it requires really intense temperatures to straighten it out. Luckily, I have a new hairstyling gem that dishes out just the right amount of heat, without me ever losing the sense of being in full control of it. Best flat iron for the kind of frizzy hair I walk around with!
  • These ceramic plates are unlike anything I’ve used so far. They’re incredibly smooth and glide effortlessly through my hair, so there is no tugging or pulling at all throughout my straightening routine. It’s a real blessing after all these years of merciless pulling on my strands and the pain that goes with it!
  • Super hot super fast is the name of the game, and I can’t believe how much less time I have to spend straightening my hair! The greatest thing is that it keeps my hair straight until I wash it, which eliminates the need for constant touch ups on the fly during the day
  • The power cord is very long and can reach every single part of wherever I decide to do a quick straightening. The circuit breaker installed within the cord really amplifies the overall sense of safety for me. It’s a piece of cake to use, and the job is done way faster than any other hair iron I’ve ever used
  • I really enjoy the extra stuff coming with a product I buy, and there’s absolutely no shortage of that here. Besides this one being the best hair straightener for thick hair ever, I really enjoy using the heat-resistant glove I got from the deal. It’s not mandatory since the iron doesn’t heat up near the holding area, but I still use it anyway
  • This swivel cord is one amazing thing! If you tend to twist the cord as much as I do, it’s bound to be wrecked sooner or later, but this really puts such problems out of the picture
  • Imagine my shock when I took a closer look at these plates after I was done. There wasn’t a single piece of my hair on them! I guess there’s a first time for everything
  • I use my hair straightener on a daily basis, and it’s a true breath of fresh air that there is no smell like something is on fire every time I go about doing my thing

Here are some of the negative sides users reported:

  • The reset button was somewhat hard to press right off the bat, but that was just the first time. It loosened up after that, so I guess I don’t have any real con to report now
  • I had to return mine since it couldn’t be turned on when I got it. The user support was great, though, and I cleared it all with them very fast. They were very patient, and you can see they aim to please, which is a nice change. I’m still waiting for the new one to arrive as I’m writing this


At the moment, this HSI provides by far the biggest bang for your buck. This especially goes if your hair is thick and coarse.

Overall Quality Rating of 4.9/5.

HSI review rating

Based on what the users reported, I would characterize this model as a Jack-of-all-trades. It does everything, and it does it well. It straightens, curls, flips…the customers love the smooth ceramic plates, ease of use, and the speed. They report to be amazed by the aftereffects – the shiny finish and the longevity of the straight look of their hair.

The CONs I’ve found couldn’t really be construed as such, most of the time it’s subjective objections or a matter of taste. Lastly, dozens of 4 and 5-star reviews on Amazon seal the deal.

Revolution Styling Iron

sedu-revolution_second_best_rated_iron_for_coarse_hairBy Sedu

Let’s see what Sedu has to say about their product:

  • Unique plates with curved edges for any look you might think of
  • Polished, ultra-smooth plates eliminate snagging, friction, pulling or stretching of your hair
  • Ceramic nano tourmaline technology produces far-infrared heat and a large negative ions mass
  • Heats up quickly! Delivers constant temperature for a healthier and quicker styling process
  • Variable temperature (180 – 450F)
  • 2-year warranty

There’s a lot of extra info found on Amazon:

Click here for extra reviews, ratings, and prices >>

If this Sedu was half as good as the fact sheet promises, it’s place on this list would be well-deserved. Let’s check what the users and my colleagues had to say:

Some of the things they liked and shared:

  • This is the best hair straightener for thick hair ever! It heats up incredibly fast, and my hair is completely done in a matter of minutes, regardless of its thick nightmarish bulk
  • Excellent product! The handling is out of this world, which especially shows once you start doing your curling. It’s very easy to use, and the body doesn’t get hot, so I don’t have to worry about my fingers getting scorched
  • The plates are simply amazing! There is no pulling on my hair at all, as they simply glide through it with such ease. Not to mention there is no heat damage whatsoever. My hair is very thick but also somewhat fragile, so heat damage is a very likely possibility if I let my guard down
  • There are no cold spots on the plates, which is really a breath of fresh air. And I only have to go through my hair once, unlike with my previous attempts at hairstyling. It’s the best flat iron for thick hair, and I think Sedu just got a customer for life!
  • It is a very well made and thought out product. It also looks very sharp, featuring some pretty fancy lines. Looks pretty durable so far, and I like the way it feels when I hold it or straighten my hair with it
  • The results it gives me are completely different level from everything I’ve ever experienced so far! It straightens my hair perfectly, but also leaves it very shiny and soooo smooth and silky. I can’t stop going through my hair with my fingers since the softness stuns me every time
  • This is the best hair straightener for thick hair, in my opinion! I’ve previously owned Sedu Pro, and I think Revolution beats it to the punch. Never was my hair so sleek and soft, not to mention the incredible shine
  • This flat iron saves me a ton of time, but also money. I have a lot of hair, and I mean A LOT! That’s why it costs more for a hairstylist to straighten it, simply because there’s so much of it, and it takes extra time. This would be the best flat iron for thick hair I’ve owned so far since it literally cuts the time it takes me to get my hair perfectly straight in half!

Let’s take a peek at the other side of the coin by going over some of the CONs:

  • Great product! But ouch, that price! My home budget really felt it this time, but my overly thick hair is more than grateful for this investment. So, the price is a bit stingy, but it’s definitely worth it!
  • There’s something off with the temperature settings. I think it’s not accurate because I burned my hair with this thing using the same settings I always used with my old CHI…
  • It damaged my ends…
  • The one I got had some sort if internal wiring issue. It started out working perfectly fine but died on me a couple of uses later. I’ve returned it immediately, and now I am waiting for the replacement to arrive. The customer support guys were more than forthcoming and patient, so kudos to them.

Conclusions and ratings

Speed and efficiency are the main selling point of this model as far as Sedu is concerned.

What I am concerned about is seeing one too many people reporting hair burns. I have a gut feeling that they changed something in the electronics of the temperature controls. I’m saying it because I’ve seen it happen before.

Final Quality Rating 4.6 / 5 – one star deducted for price and hair protect.

Sedu Revolution Styling Iron

There aren’t many hair irons out there that’ll straighten large chunks of thick hair as fast as this Sedu will. It doesn’t lack in features, but you’ll primarily want it if you’re feeling like you’re wasting ages on getting your bulks of hair straight.

Do be careful until you get to know it, it “behaves” a bit differently than any other iron I know (heat-wise).

Ceramic Flat Iron

chi_professional_multicolor_thick_hairBy Chi

The fact-sheet:

  • 1 inch tourmaline ceramic plates
  • Perfect for all hairstyles due to far infra-red heating, negative ions and even temperature distribution
  • Unparalleled shine with silky smooth feel to your hair
  • Great for smoothing, straightening, waving, curling, flipping, spiraling and bending
  • Reduces frizz and eliminates static
  • Heats up very quickly and features a convenient swivel cord
  • 2-year guarantee

Its dedicated Amazon page holds a lot more juicy things to read:

Click here to proceed to the website >>

The PROs customers shared:

  • This Chi is the best hair straightener for thick hair ever! My first Chi model broke after serving me perfectly for more than ten years! This new one also looks very durable and gets the job done as I would from expect my favorite brand of hair-styling tools
  • My hair is simply impossible! It’s very thick, and there’s a lot of it, but also very curly and coarse, which is a combo from hell for me! I struggled through it constantly grinding my teeth until I got this little Chi gem and tried it for the first time. It’s that feeling when you turn your horrendous hair into a silky smooth and straight thing of beauty
  • I’ve stopped counting how much money this little guy has saved me. I’m by no means an expert in doing my hair, but going to the salon simply isn’t a viable daily plan. This Chi really helps me out, as it is really easy to use. The results speak for themselves every single day when I leave my house, and I think my husband also has a positive thing or two to add
  • This is the best hair straightener I’ve ever owned! It heats up lightning fast, so a bit of time saved right there. I can do my entire hair with it in a matter of minutes, and it used to take me a full hour before; a lot of time saved! It’s overall just a big time saver and don’t even get me started on the results. My thick, impossible hair was never so straight and smooth to the touch. I especially like how shiny it gets every time I use this little magic tool
  • Very practical and easy to use. I have a very long and thick hair, and constant pulling and tugging was a real problem with every other hair iron I ever had. These plates are just amazing! They glide perfectly, leaving my hair bone straight in just one pass
  • The most important thing about this flat iron for me, besides doing what it’s supposed to do is that there is no heat damage at all! No burnt smell either

What the users didn’t like:

  • The only thing I can really complain about is the price, but I guess it should be expected for the product of this caliber
  • It’s actually too powerful for my fine hair to handle

Ratings and thoughts

Chi has been around for as long as I can remember. Some people from the hair-styling community just don’t like the brand (never heard of a reason that would make sense to me, though). On the other hand, you have the raving CHI fans and most of them praise the unique design of the brand.

But with this particular eye candy, time saving and versatility is the name of the game. You can do all kinds of stuff with your hair, in much less time, and you’ll always get a perfectly straight hair with a beautiful natural shine and that coveted silky smooth feel that gets heads turning on the street (or so they promise).

In reality, it’s not that simple, and it’s not “always” – hence the few stars deducted bringing this CHI to the Rating of 4.6/5.

Chi Ceramic Flat Iron

Still, it’s an excellent product, which certainly has a lot to offer in return for the money invested, but it’s never been the top rated iron in this category.

To sum up

The old-school approach of titanium being unsurpassed for thick hair is over. That’s evident. Not a single titanium iron has made it to the top 3 in this category for over a year now.

It used to be the case that only titanium could deal with the unruly coarse hair.

But as the technology changed and new products with increased negative ions output started hitting the market, titanium was becoming increasingly obsolete, and I was watching the process from the best seat in the house.

The reason is that you can now get the same results using tourmaline irons, but the risk of burning your hair is significantly lowered.

Please, feel free to comment, share your experiences or, if you want, contact me directly using the form on the contact page.

Stay smart and pretty,