A long-barrel curling iron: what the extra length is for, and what heat can and cannot do to hair

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Researched. We have not used this one long enough to give you a verdict, and we would rather say so than invent one. What follows is how it works, who it suits, and what it will not do. When we have used it properly, this page carries the verdict and the date.

Bio Ionic Long Barrel Curling Iron

Two measurements decide what a curling iron does. The width of the barrel decides the size of the curl. The length decides how much hair you can wrap in one go — and how easily you can reach the back of your own head.

The width: 1.25 inches

According to the listing, the barrel is 1.25 inches across, and it is meant for large, soft curls and waves. That is a middle-to-large size: big enough for loose, bouncy curls on shoulder-length hair and longer, which relax into waves over the day. On short hair it tends to give a bend rather than a curl.

The length: two inches more

The listing says the barrel is two inches longer than a standard curling iron. On long hair, a short barrel means wrapping a section over itself, which gives uneven curls and heats some of the hair twice. A longer barrel lets you spread each section out along the barrel in a single layer.

The listing also points out that the extra length makes the back of the head easier to reach, whatever length your hair is. Anyone who has tried to curl the back of their own head with a short iron will see why.

Choosing a temperature

The listing says the heat is adjustable up to 430°F. The rule is to use the lowest setting that holds a curl in your hair, not the highest the tool can reach. Fine, bleached or damaged hair needs much less heat than thick, coarse hair. Start low, and only turn it up if the curl does not hold.

A heat protectant goes on first, every time. We explained what the number on a protectant does and does not mean in what the temperature on a heat protectant actually means.

The claim about moisture

The listing describes its technology as locking in moisture and helping water penetrate the hair, to keep curls hydrated rather than dull. Heat styling works by removing water from the hair, and a hot barrel cannot add any. The most a tool can do is heat evenly and avoid hot spots, so the hair loses less.

So read the moisture language as a description of a smooth, even barrel rather than as conditioning. For moisture, use a leave-in conditioner or an oil — something like a styling oil with a heat rating — before and after, not the iron.

The safety features

The listing mentions an automatic shut-off after an hour and a cool-touch grip. The shut-off is the one that matters: it is the difference between a curling iron left on and a curling iron left on all day.

What it will not do

It will not give tight ringlets — the barrel is too wide. It will not add moisture to hair, whatever the technology is called. And it will not make heat styling harmless; lower temperatures, a protectant and fewer passes do more than any barrel.

The product

A 1.25-inch curling iron with a longer-than-usual barrel and adjustable heat, made for loose curls and waves on medium to long hair. The length is the reason to choose it.

The one people are searching for is the Bio Ionic Long Barrel Curling Iron, 1.25 inch.

Bio Ionic Long Barrel Curling Iron

We do not print prices here, because a price we typed last month is a price that is wrong today.

Written by CatieH, who covers nails and hair here.