Home teeth whitening kits. Any experience?

[Fordian]

DS (adult) has quite yellow teeth. He's a student so not much cash.

Has anyone has any experiences, good or bad, with home teeth whitening kits?

Thanks.

No whitening kit ,that you can legally buy , to use at home without a dentists prescription will contain enough active ingredient to whiten teeth.
At best they are acidic or abrasive and will remove surface stain (and enamel) .

some people have naturally yellower teeth that is not due to staining so stain removal will do nothing for them .

A dentist whitening will cost from £250 to £350 ish so with some saving up he can do it in a safe way that won't damage his teeth.