Do lemon, baking soda or turmeric work?

No, and the first two make it worse. Lemon juice is acidic enough to burn thin underarm skin and contains compounds that make skin react badly to sunlight; baking soda is strongly alkaline and strips the barrier. Both cause irritation, and irritation is what made the pigment in the first place. This is a case where the home remedies reliably run backwards.

Should I scrub my elbows?

Gently, if at all. A scrub takes off some of the dry surface layer and it is a blunt instrument on skin that is dark because it was traumatised. An acid does the same job without the friction, which is the thing you are trying to remove from the equation.

Is it the deodorant staining my skin?

Very rarely staining, and commonly the cause. Most antiperspirants do not deposit colour -- what they do is irritate, and the skin answers with pigment. So changing the product often helps, but not because it was leaving a mark.

Could it be something medical?

It can be. Dark, velvety, thickened skin in the folds -- underarms, neck, groin -- appearing fairly quickly is acanthosis nigricans, which is associated with insulin resistance and is worth a doctor's opinion rather than a body lotion. Gradual darkening in areas you shave or lean on is the ordinary kind.

The answer

How do I lighten dark underarms and elbows?

Skin makes pigment when it is irritated, and underarms and elbows are two of the places that get irritated most reliably -- one by shaving and deodorant and the friction of sleeves, the other by leaning on things. That is the commonest reason, though not the only one: colouring here also runs in families, changes with hormones, and can be a medical sign worth reading rather than treating (the last question below says which). Where it is irritation, the treatment follows from it -- take the friction away and let the pigment fade, rather than attacking the colour. Elbows have a second thing happening on top of it, which is that the skin there is thicker and drier, so part of what reads as dark is simply rough dead skin catching shadow. That part comes off with acid and moisture in a fortnight. The pigment underneath takes months.

What answers it

Paula's ChoiceSkin Revealing Body Lotion 10% AHAThe one for elbows. Glycolic acid works across the surface, and on an elbow a good part of the darkness is a thick dry layer sitting on top rather than pigment underneath. This is also the fastest visible result on this page.Buy on Amazon
AnuaAzelaic Acid 10 Hyaluron Redness Soothing SerumFor the pigment itself, and gentle enough for an underarm where a 10% glycolic would sting. Azelaic acid works on pigment made in response to irritation, which is exactly what this is.Buy on Amazon
CeraVeMoisturizing Cream, the daily tubUnglamorous and load-bearing. Dry skin is rougher, rougher skin catches more shadow, and an elbow that is simply well moisturised looks lighter before any acid has done anything.Buy on Amazon
La Roche-PosayAnthelios Melt-In Milk SPF 60Elbows are in the sun far more than people account for -- every short sleeve, every year. Pigment that is being treated and then lit daily does not move.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.

Change how you remove the hair

A blunt razor dragged over an underarm several times a week is a small injury repeated indefinitely, and pigment is the skin's answer to it. A fresh blade, shaving with the grain, and a gap of a day or two do more here than any brightening product does. If the darkness arrived after a period of frequent shaving, that is the cause, and the cause is still running.

Friction is the elbow's whole story

Leaning on a desk, a car door, an armrest -- the same square inch, compressed, every day. It is worth noticing where yours actually happens, because most people have one dominant elbow and have never registered why. Nothing on this page outruns a habit that continues.

Deodorant is worth changing before it is blamed

Alcohol and fragrance in an antiperspirant irritate thin underarm skin, and irritation is the pigment trigger. A fragrance-free formula is a cheap test and takes a fortnight to report. Worth doing before spending months on a brightening routine that is fighting something you reapply each morning.

Give it a season, not a week

Surface roughness improves in two weeks and looks like progress. Pigment sitting deeper in the skin takes two to three months of the irritation being gone, and it fades from the edges rather than all at once. Judge it against a photograph taken today, because day-to-day comparison in a bathroom mirror will tell you nothing.

Questions

Do lemon, baking soda or turmeric work?: No, and the first two make it worse. Lemon juice is acidic enough to burn thin underarm skin and contains compounds that make skin react badly to sunlight; baking soda is strongly alkaline and strips the barrier. Both cause irritation, and irritation is what made the pigment in the first place. This is a case where the home remedies reliably run backwards.
Should I scrub my elbows?: Gently, if at all. A scrub takes off some of the dry surface layer and it is a blunt instrument on skin that is dark because it was traumatised. An acid does the same job without the friction, which is the thing you are trying to remove from the equation.
Is it the deodorant staining my skin?: Very rarely staining, and commonly the cause. Most antiperspirants do not deposit colour -- what they do is irritate, and the skin answers with pigment. So changing the product often helps, but not because it was leaving a mark.
Could it be something medical?: It can be. Dark, velvety, thickened skin in the folds -- underarms, neck, groin -- appearing fairly quickly is acanthosis nigricans, which is associated with insulin resistance and is worth a doctor's opinion rather than a body lotion. Gradual darkening in areas you shave or lean on is the ordinary kind.

Your turn

What should we dress next?

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