Difficulty concentrating or brain fog
In other words, you can have iron deficiency without being diagnosed with iron deficiency anemia
Good to know about b12, I always when available bought more than enough then disposed when out of date except on that one occasion

Topical GHK-Cu serum shelf life Pre-made commercial serums: Usually 6-12 months unopened 3-6 months after opening Check manufacturer recommendations Refrigerate after opening extends life DIY serums (mixing powder with carrier): Shorter shelf life than commercial 2-4 weeks typical (no preservatives) Must refrigerate Discard if color changes Factors affecting topical shelf life: Preservatives: Extend significantly pH: Neutral pH more stable Carrier: Some better than others (hyaluronic acid, glycerin good) Storage: Cool, dark, sealed Contamination: Sterile technique critical Best practices for topical GHK-Cu: Buy small bottles (use within 3-6 months) Refrigerate after opening Don't double-dip (pour into hand, don't touch dropper to skin) Watch for color changes (brown = oxidized) Replace every 6 months even if looks fine See our how to reconstitute peptides , bacteriostatic water for peptides , and how long reconstituted peptides last in fridge

however, there is hardly any talk about overdosing vitamin B12 and possible side effects
Her death led to her parents, both healthcare professionals, to investigate the effects of B12 deficiency, and what they saw as gaps in awareness, testing and treatment, particularly around its psychiatric symptoms