This means a lower and less predictable amount of the active compound might reach systemic circulation, potentially requiring higher doses and introducing variability into research findings
10.1002/macp.1964.020720110 298 JirgensonsB
This includes people who dont get enough sun, older people whose bodies are unable to produce as much Vitamin D, and people with darker complexions, whose skin is more resistant to the suns UV rays
doi:10.1128/AEM.60.5.1495-1499.1994
The GLP-1 agonist slowing gastric emptying can affect the glucose peak from meals, which in turn affects insulin timing
Nevertheless, studies utilizing more specific biomarkers of vitamin B 12 status, including measures of holo-transcobalamin and methylmalonic acid, have shown more consistent results and a trend towards associations between poor vitamin B 12 status and faster cognitive decline and increased risk of Alzheimers disease (82-86)