Science 336 , 12681273 (2012)
quality is always consistent and the team answered my questions quickly
Vitamin B 12 can also be absorbed by passive diffusion, but this process is very inefficient only about 1% to 2% of the oral vitamin B 12 dose is absorbed passively (2)
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The hair-growth interest comes from a line of animal research: T4 was shown to increase hair growth in rats and mice by activating hair-follicle stem cells in the bulge region, per PubMed (Philp et al., 2003, DOI), with follow-up work showing faster regrowth in T4-overexpressing mice and slower regrowth in knockout mice via VEGF and P38/ERK/AKT signalling (Gao et al., 2015, DOI)
5mg with 5mL = 1,000mcg/mL