A styling oil with a heat rating: what No.7 does in two drops, and what the numbers compare

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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.

Olaplex No.7 Bonding Hair Oil

A styling oil is one of the few hair products that shows what it does the moment you use it. A couple of drops, and the hair looks smoother and shinier before you have put the bottle down. The interesting questions are about the claims that do not show straight away.

What an oil does on the outside of a strand

A hair strand is covered in overlapping scales. When they lie flat and smooth, light bounces off evenly and hair looks shiny. When they are lifted and roughened — by bleach, heat, brushing, weather — light scatters, the hair looks dull, and individual strands catch on each other and on the air and turn to frizz.

A thin film of oil smooths that surface. That is where the instant shine comes from, and it is also why frizz calms down: a coated strand takes on less moisture from humid air, which is what makes it swell and kink.

What is in it, according to the listing

The listing names a coconut-derived emollient, vitamin E and sunflower seed oil as the ingredients doing the conditioning, smoothing and shine. It describes the oil as weightless and concentrated, which is why the dose is so small.

The "bonding" in the name refers to the Olaplex bond-building range this belongs to. We have written separately about what a bond builder does, and what it cannot undo — worth reading before assuming an oil you use a few drops of is doing the same job as a dedicated treatment.

Reading the clinical numbers

The listing claims 125% more shine, 72-hour frizz control and humidity resistance, and a 77% reduction in breakage. The footnote matters: the shine figure is compared to bleached hair with no oil on it at all.

That is a fair test of whether the oil does something. It is not a comparison with other oils, and bleached hair with nothing on it is about as dull as hair gets, so a large percentage is expected. Read the numbers as "this works on damaged hair", not "this beats everything else on the shelf".

The heat rating

The listing says it protects up to 450°F (232°C). The temperature on a heat protectant tells you something narrower than people think, and we cover that in what the temperature on a heat protectant actually means. The practical point: a protectant slows the damage, it does not switch it off, and turning your tools down does more than any rating.

How to use it without greasy ends

Start with less than you think — the listing says two or three drops. Rub them between your palms first, then work from the mid-lengths to the ends, where hair is oldest and driest. Keep it off the roots unless your hair is very dry, because that is where it will look greasy first.

It can go on damp hair before drying and styling, or on dry hair to finish and tame flyaways. On fine hair, one drop on dry ends may be all you need.

What it will not do

It will not rebuild hair that is badly broken — it makes the surface behave better and look better, which is a real improvement and not the same thing as repair. It will not make heat styling safe; it makes it less damaging. And the shine and frizz control last until you wash it out, then it needs to go back on.

The product

A concentrated styling oil for shine, frizz and heat protection, at its best on dry, coloured or bleached hair. A bottle goes a long way, because the dose is a few drops.

The one people are searching for is the Olaplex No.7 Bonding Hair Oil.

Olaplex No.7 Bonding Hair Oil

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.