B12 deficiency can cause mood changes, irritability, heightened anxiety, and depressive symptoms these are documented, clinically recognized consequences of insufficient B12
You can of course complain to you MP and ask for help, some will oblige, others will direct you to NICE or NHS England
Not intended to diagnose, treat, cure, mitigate, or prevent any disease
After all, hangovers are the result of alcohol metabolism, which leads to inflammation, dehydration, and acetaldehyde buildup that happens when our liver gets overwhelmed
Is the claimed purpose authorised in the UK
But, if you have a severe or chronic vitamin B12 deficiency, you may need repeated shots until the levels are replenished, followed by occasional maintenance shots