Average milk levels in mature milk are 200 to 700 pmol/L (270 to 950 ng/L) during the first 28 weeks postpartum in healthy, lactating women with known or presumed adequate vitamin B 12 status and not taking a supplement.[27,28,42-45] Levels are highest during the first 4 weeks postpartum and gradually decrease thereafter.[25,28,29,42-47] Hindmilk levels are 20% to 30% higher than foremilk.[29] In populations with a high prevalence of vitamin B 12 deficiency or insufficient dietary vitamin B 12 intake, reported median or average milk levels are 120 to 160 pmol/L (160 to 220 ng/L) at 6 months postpartum.[30,46] In one study of 210 lactating women from different regions of Cameroon, rates of maternal vitamin B 12 deficiency were 15% to 25% and median milk levels were between 47 and 236 pmol/L (64 and 320 ng/L)
For neurological applications, the evidence is more preliminary and the extrapolation from rodent to human more uncertain
Written by the Well Labs+ editorial team Last updated July 2026 Category Overview Some vitamins and nutrients are better delivered by injection than by supplement, bypassing digestion so your body can put them to use directly
Common mental and emotional symptoms of high cortisol include: Anxiety that feels constant or disproportionate to circumstances Irritability and mood swings Brain fog and difficulty concentrating Depression or a persistent flat feeling Racing thoughts especially at night Feeling wired but exhausted at the same time High Cortisol Symptoms in Women Symptoms of high cortisol in females often show up in the hormonal system first
