CWeak evidence, or evidence againstBotanical
The short answer
The spice in food is fine and pleasant. The concentrated extract is a different product with real reports of harm and no authorised claim behind it.
Who this is actually for
No group with an established need.
What it is legally allowed to claim
Nothing. There is no authorised EU health claim for this substance, so any packet promising a specific benefit is making a claim it is not entitled to make. That is worth knowing before you judge the price.
How much is too much
No EFSA upper level. High-dose extracts are not the same as the spice.
Cautions and interactions
No authorised EU health claims exist for turmeric or curcumin. Liver injury has been reported with concentrated extracts, particularly those enhanced for absorption. May increase bleeding risk with anticoagulants and interacts with some chemotherapy.
Ask a pharmacist before you start anything. Interactions with prescribed medicines are the most common way supplements cause harm, and they are easy to check. Bring the actual packet, or a photo of the ingredients panel, because doses and forms vary enormously between products. Nothing here is a substitute for advice about your own situation.