Looking around the web they are an unregulated product which means anyone can administer them and you never really know if the ingredients are what they say they are, also they can have side effects from minor bruising to more serious like affect the liver
The GPhC has issued a warning about “emerging issues” taking place in some community pharmacies including the supply of unlicensed ‘Lemon Bottle’ injections – which claim to dissolve fat – and “alternative therapy services” such as acupuncture and cupping.
www.chemistanddruggist.co.uk
I got the below from a commercial site so can’t post a link but copied this bit
Lemon bottle is typically considered safe for most people, but it may not be recommended in certain circumstances, such as
* Pregnant or breastfeeding;
* Under the age of 18.
* Undergoing IVF treatment
* Autoimmune disease
* Active skin conditions in the area, e.g. rashes
* Blood-thinning medication, e.g. warfarin
* Lipodystrophy or pathological conditions, e.g. liver or kidney disease – if you have diabetes, then treatment will only be carried out with the consent of a GP