Quote Originally Posted by basketballfan22 View Post
Okay, I understand. Oral B12 is as effective as injectable B12 within normal levels; but to exceed normal levels, injectable B12 is needed. My concern about intravenous injections is the same as intramuscular injections. If one is to inject only once per week, would it not be better to inject subcutaneously that way the B12 will slowly enter your system instead of running the risk of absorbing too much too quickly and excreting it out? The few articles I read compared the three methods and recommended subcutaneous injections, specifically in the buttocks because it contains even more fat.

The mindset I currently have (please correct me if I am wrong) is that all three methods (intravenous, intramuscular, and subcutaneous) have the same (or extremely close to) level of absorbability and only differ in the time it takes to absorb the dose.
Your first sentence is correct. Just as effective for normal-in-range levels.

B12 can be injected SubQ, but the absorption rate/speed is semi-negligible. It is oil-based compounds that are considerably slower. B12 is water. But like you said, the more fatty the area, the slower the absorption. But comparing oil and water into say... the buttocks, water is a clear winner as far as speed.

Excretion is different deal. Excretion is based on your B12 binding capacity. I'm not concerned with excretion because I know I am at max capacity. If you were to supplement with orals or whatever really, and you are concerned about excretion rate, you need to test your binding capacity and monitor your B12 levels and log your intake. Everyone is different in that area. If someone told me that I inject too much because I excrete most of it, I'd ask them for my blood work. There isn't a set percentage of excretion.

You can always supplement with Sialic Acid to increase binding capacity, but you really don't need to unless you're deficient. As for your last question re IM/SubQ absorbability, I would say yes, speed should be the only factor. I can't speak for IV yet.