Hairdryers: FAQs
What is an ionic function?
Normal hair under the electron microscope
If you like to blast your dry your hair quickly, we would recommend a hairdryer with an ionic function.
This technology generates negatively charged ions as you dry your hair, and is intended to protect hair, reduce frizz, improve shine and ban static.
It is a fairly standard feature of professional-style hairdryers, and manufacturers claim it will save your hair from the ravages of drying.
But their explanations for how the ionic functions work are so confusing that they sound overstated, which is why we've put them to the test.
Damage caused by drying on high heat and speed settings
We compared hair dried 100 times on maximum heat and speed, both with and without negatively charged ions, under an electron microscope.
These pictures show hair which has been magnified 750 times.
We found that the ionic function visibly reduced such microscopic signs of damage as hair-shaft blistering and lifting of the cuticles.
But we also found that drying hair on low power and speed has the same effect, so an ionic function is less vital if you prefer to dry your hair slowly and carefully.
Hair dried on high settings with the ionic function
Our testers weren’t always sure that using the ionic function saved them from frizz, but they often said it made their hair feel softer.
When you first buy a hairdryer with ionic function you might notice a strange smell when you use the dryer. But this soon disappears with further uses.
Can I use my hairdryer overseas?
The hairdryers we’ve tested are designed to operate at 230-240 volts, which is the mains voltage in the UK and Europe.
To use your dryer in the US, you’ll need a dual voltage dryer which will operate at 120 volts.
If you have a dual voltage hairdryer, remember to select the correct voltage before you plug it in, or you could blow the fuse or break they dryer altogether.
Which settings should I use?
Variable heat and speed settings give you more choice
As a general rule, manufacturers recommend higher settings for initial or rough hair drying, and for thicker hair.
Use lower settings for finer hair, to complete your style, or for more control over where the airflow is directed.
Set your hairstyle using the cool-shot function. It cools hair rapidly, preventing your style from losing its shape.
Professional hairdressers recommend drying down along the hair shaft to avoid lifting the hair cuticles, which can make it appear frizzy.
How can I use my hairdryer safely?
Clean the inlet often
Hairdryer dos:
- Dab hair dry with a towel to remove excess moisture
- Keep the air inlet grille and filter free of dust, fluff and styling product
- Ensure your hands are dry and your hair is free from excess water before handling the plug or switching the dryer on
- Allow to cool before putting it away
Hairdryer don'ts
- Use a diffuser on the highest heat settings
- Dry dripping wet hair
- Immerse a hairdryer in water to clean
- Use in a bathroom where it could come into contact with water
- Damage the cable by winding it around the dryer when you put it away
- Carry or lift the hairdryer by the mains cable
- Cover the hairdryer, or put it down on soft furnishing or bedding, against a wall or upright surface when it is hot