RNY gastric bypass and Vitamin B-12 injections

Posted by breezy718 @breezy718, Nov 15, 2025

Curious, does anyone that had RNY gastric bypass do vitamin B-12 injections rather than B-12 pills? Do you feel it’s more effective? Do you do the 1000 mcg/ml? And how often do you inject? Once a month, twice a month, or weekly for best results? I had my surgery over 15 years ago in the United States, but am now retired and living full time in Costa Rica. The maintenance and vitamin protocol here is very different.

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Profile picture for dlc1953 @dlc1953

I had my surgery in 2005. I still get my B12 injections once a month. If I forget I feel horrible. Tired. Therefore if I forget, my body lets me know that it’s time. To keep it simple I take it the first day of the month.

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@dlc1953 thank you for your reply.

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A few members mentioned forgetting to take their injections on schedule. If you do once a month, I like @dlc1953's idea of doing it on the first of the month. I take every 21 days, so when I give myself an injection, I figure out when the next one is due and put it on my calendar.

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Profile picture for Laurie, Volunteer Mentor @roch

A few members mentioned forgetting to take their injections on schedule. If you do once a month, I like @dlc1953's idea of doing it on the first of the month. I take every 21 days, so when I give myself an injection, I figure out when the next one is due and put it on my calendar.

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@roch why the shot instead of supplements?

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Profile picture for cathjerry @cathjerry

@roch why the shot instead of supplements?

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@cathjerry
Good question, and I do not have an answer. When I had my surgery in 2012, they started me on B12 injections and have been doing them ever since. I tried Googling to see if there was any data, and most articles implied that B12 injections or supplements may yield the same results. B12 injections bypass the digestive system; maybe that is an advantage. I do not mind gining my self injections and only need to do it once every 21 days. If doing supplements, not sure of frequency.

Good question for your provider.

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Profile picture for Laurie, Volunteer Mentor @roch

@cathjerry
Good question, and I do not have an answer. When I had my surgery in 2012, they started me on B12 injections and have been doing them ever since. I tried Googling to see if there was any data, and most articles implied that B12 injections or supplements may yield the same results. B12 injections bypass the digestive system; maybe that is an advantage. I do not mind gining my self injections and only need to do it once every 21 days. If doing supplements, not sure of frequency.

Good question for your provider.

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@roch I am now giving myself B-12 injections twice a month now and feeling better.

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