In a very practical sense, B12 and other water-soluble vitamins are the safest and easiest nutrients to supplement because your body takes what it needs and gets rid of what it doesnt
Vitamin D is fat-soluble and can be synthesised through UVB sunlight exposure, whilst vitamin B12 is water-soluble and must be obtained entirely from dietary sources NHS recommends 10 micrograms (400 IU) daily vitamin D supplementation during autumn and winter for all UK residents B12 deficiency can cause irreversible neurological damage including peripheral neuropathy and subacute combined degeneration of the spinal cord Testing for deficiency should be targeted rather than routine, based on symptoms, risk factors, or conditions affecting absorption Long-term metformin use requires B12 monitoring due to impaired absorption, as advised by the MHRA Table of Contents What Are Vitamin D and B12
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Timeline of effects: what youll notice If you are wondering what do B12 shots do in terms of a timeline, the results arent always instant, but they are often more noticeable than oral vitamins
Depending on the severity of your B12 deficiency and your bodys unique response to the treatment, improvements in your symptoms may be noticeable within hours or days of your injection