BIO IONIC Onepass Straightening Flat Iron

Last updated date: June 25, 2020

DWYM Score

8.4

BIO IONIC Onepass Straightening Flat Iron

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We looked at the top Flat Irons and dug through the reviews from some of the most popular review sites. Through this analysis, we've determined the best Flat Iron you should buy.

Editor's Note October 7, 2020:
Checkout The Best Flat Iron for a detailed review of all the top flat irons.

Overall Take


In our analysis of 53 expert reviews, the BIO IONIC BIO IONIC Onepass Straightening Flat Iron placed 15th when we looked at the top 18 products in the category. For the full ranking, see below.

From The Manufacturer

The Fastest Straightening Iron Ever. The OnePass Iron represents a true break-through in straightening iron technology. The OnePass allows users to straighten hair in half the time compared to traditional irons. This is the professional's #1 choice in irons. With patented silicone speed strips in the plates, it allows users to straighten and style hair in half the time. BioCeramic heaters heat up OnePass to 400 Degrees Fahrenheit with instant recovery for smooth results, roots to ends. OnePass Iron plates emit natural negative ions and far infrared energy that break down water clusters on the hair surface into smaller molecules that penetrate deeper, hydrating hair, removing frizzies, and creating healthy-looking, shiny hair. It's Multi-level heat controller, and 9 ft Swivel Cord make it one the most preferred irons chosen by stylists.

Expert Reviews

Expert Summarized Score

8.0
3 expert reviews

User Summarized Score

9.3
186 user reviews

What experts liked

An attractive choice for fast yet gentle styling thanks to ceramic plates. Varied heat settings give users full control, regardless of hair type.
- BestReviews
Consumer testers thought the Bio Ionic One Pass flat iron did a better job of straightening long thick hair, so it may be worth the high price tag if you have hair that is harder to straighten.
- Good Housekeeping
The Bio Ionic OnePass heats up within seconds, not minutes, making it one of the more efficient straighteners out there today. It also straightens hair in half the time of similar models, for speedy, high-quality ironing.
- ratingle

What experts didn't like

Lacks an automatic shut-off switch.
- BestReviews
This iron excelled in most of our lab tests, straightening hair quickly and making it smooth and shiny, but faltered slightly in its ability to keep hair frizz free after straightening.
- Good Housekeeping
Silicon tends to attract more residue and dirt from your hair than non-silicon plates, so you will want to make sure to clean this model after every use to keep it clean and sanitary.
- ratingle

An Overview On Flat Irons

Regardless of the hair type and texture they were born with, most people have attempted to alter the appearance of their locks at one time or another throughout their lives. Chemical perms and straighteners create results that last but can be quite harsh and damaging to hair shafts and ends. That’s why many people opt to use hair styling tools to achieve the looks they desire. The flat iron, also referred to as a straightening iron, is one of those tools that can drastically change the look and texture of naturally wavy or curly hair.

In a family of gadgets that includes hair dryers, curling irons and hot rollers, flat irons have an important place. That’s because they are great at what they are designed to do — giving all types of hair a straight, sleek appearance while smoothing out the shafts of individual hairs for a uniform, stylish look. Flat irons are heated styling tools constructed with two metal or ceramic plates that open and close around strands of hair. Pulling the tool down the strands smooths and straightens the hair. In other words, flat irons are necessary when it comes to creating many of today’s straight, flowing ‘dos.

Over the decades, stick-straight hairstyles have come in and out of fashion.  But as styles come and go, so does the desire to vary an individual hairstyle, from curly to straight whenever the feeling hits. The technology of flat irons makes it possible to sport your curls one day and have straight hair the next with minimal effort.

It’s the combination of electric-powered heat and the plates that make it possible for a flat iron to alter the appearance of hair that’s not naturally straight. However, it’s the plate material that helps protect hair from damage from the heat, as well as reduce frizz and flyaway strands. Many brands have plates that are either made entirely of ceramic or of ceramic-coated metal, like the HSI Professional Glider Ceramic Tourmaline Ionic Flat Iron. The advantage of the ceramic is that it produces powerful heat and negative ions that smooth hair while styling it, giving it a shiny finish. On the downside, plates that are made entirely of ceramic are prone to breakage, while ceramic-coated plates may peel over time. Additionally, they don’t do the best job straightening very curly hair.

Arguably the best type of flat iron for very thick, curly and frizzy hair is one that has plates that are coated with titanium. They too produce negative ions that help smooth and protect delicate hair shafts, but also heat up extremely fast to effectively straighten hair.

Titanium isn’t the only mineral that’s used in making flat iron plates that help reduce damage to the hair. Some plates are also coated in tiny crushed pieces of tourmaline that makes them smooth and durable. In turn, the addition of tourmaline, which can be found on ceramic and titanium plates, increases the output of negative ions and give hair even more shine.

Flat irons also come in a variety of sizes, from 1 inch to 2.5 inches in width. While thin plates work well on all hair lengths, those that are thicker are ideal for transforming long hair into sleek strands.

The Flat Iron Buying Guide

  • Do you plan to take your flat iron along when traveling? A model that has around 1- to 1.5-inch plates will work well for your needs without taking up too much space in your bag.
  • If you are new to using a flat iron, it can take a little practice to get used to it. Try practicing with your new hair styling tool while it’s turned off and cool first. This will give you a feel for how to use the flat iron and help prevent accidental burns.
  • Did you know that flat irons can also be used on straight hair to create waves and curls? Try twisting the tool in a back-and-forth motion down strands of hair for waves or wrapping strands around it like you would a curling iron to create soft curls.
  • The majority of flat irons have variable heat controls that allow you to select the best temperature for your hair type as well as the style you want to achieve. For hair that’s very curly or difficult to straighten, the highest temperature, usually around 450 degrees Fahrenheit, is the best choice.
  • For best results, don’t try to place very thick strands of hair between the plates of your flat iron at once. Typically, dividing strands into sections of about 1 to 2 inches works best.
  • Today’s flat irons do a decent job protecting hair from heat damage, thanks to ceramic, titanium and tourmaline technology. However, frequent use can still take a toll on hair, making it prone to breakage. Using a moisturizing shampoo and conditioner will help keep your hair looking its best.
  • Some flat irons are available at very low prices, but remember that you may not save money in the long run if you buy a cheap tool. That’s because inexpensive flat irons are more likely to have finishes that peel, may not produce effective heat and are more likely to damage hair.