Does washing less help?

For oil, often. For volume, usually not — day-three hair is heavier at the root, not lighter. If flatness is the complaint rather than greasiness, washing less makes it worse.

Would a shorter cut fix it?

It genuinely can. Weight is the thing pulling the root down, so removing length removes the cause rather than fighting it. Layers do the same in a smaller way by taking weight out without taking length off.

Is mousse or root spray better?

A root spray goes where the problem is. Mousse tends to get distributed through the length, which adds the weight you are trying to lose. If mousse is what you have, apply it only at the roots and dry it in.

The answer

My hair goes flat by lunchtime

Hair falls flat because the weight of the length pulls the root down, and because a root that was only lifted with a brush has nothing holding it there. Mousse and dry shampoo work on the wrong part of the problem — one coats the length and adds weight, the other absorbs oil that has not appeared yet. What lasts is lifting the root while it is damp, setting that lift with heat, and only then dealing with texture. Product at the root, heat to fix it, texture at the ends: in that order it holds all day, and in any other order it does not.

What answers it

Color WowRaise the Root thicken and lift sprayThe direct answer, and the order matters: sprayed at the root on damp hair, then dried in. It is heat-activated, so applying it to dry hair at noon does almost nothing.Buy on Amazon
OribeDry Texturizing SprayFor the second half of the day. A texturising spray gives the root something to grip against itself, which holds lift that has already started to drop.Buy on Amazon
Color WowDream Coat anti-humidity sprayIf the collapse happens on humid days specifically, it is not weight — it is moisture pulling the style out. That is a different problem with a different answer.Buy on Amazon
MoroccanoilPerfect Defense heat protectantNone of the above survives if the heat that sets it is also damaging the hair. A dry mist protects to 450F without adding the weight a cream would.Buy on Amazon

Prices live on Amazon, where they change hourly — so we never quote one. Every product here is a brand we would name out loud.

Lift is set by heat, not by product

Product at the root only holds the shape that the drying puts there. Rough-dry the roots with your head upside down, or lift each section straight up and dry it at the base, then let it cool completely before touching it. The cooling is the part people skip and it is where the shape actually locks — a root brushed out while still warm falls immediately.

Conditioner belongs on the ends and nowhere near the root

Most flatness at the crown is conditioner residue. The scalp makes its own oil and the root needs nothing added to it, so conditioner from the ears down is not a rule of thumb, it is the whole fix for a lot of people. The same goes for masks and leave-ins: length only.

Dry shampoo is for oil, not for volume

It is sold for both and it is genuinely good at one. On clean hair it can add grit that reads as volume for an hour or two, and then it builds up and weighs the root down over a week. If the hair is flat and clean, that is a lift problem. If it is flat and oily, that is what dry shampoo is for.

Questions

Does washing less help?: For oil, often. For volume, usually not — day-three hair is heavier at the root, not lighter. If flatness is the complaint rather than greasiness, washing less makes it worse.
Would a shorter cut fix it?: It genuinely can. Weight is the thing pulling the root down, so removing length removes the cause rather than fighting it. Layers do the same in a smaller way by taking weight out without taking length off.
Is mousse or root spray better?: A root spray goes where the problem is. Mousse tends to get distributed through the length, which adds the weight you are trying to lose. If mousse is what you have, apply it only at the roots and dry it in.

Your turn

What should we dress next?

An occasion you cannot find anything for, or a product you want us to look at properly.