What the 7 percent / 29-week line is
Controlled Glucophage trials lasting 29 weeks saw about 7 percent of people fall to subnormal B12 after a normal baseline. Many of those falls did not show clinical anemia in that window. It is a trial frequency, not a promise you will be in that group.
Longer real-world years are why the label also writes hematologic checks yearly and vitamin B12 at 2- to 3-year intervals. The 29-week percent is the signal that a screen exists.
Whether anemia had to appear in those 29 weeks
The trial line describes a laboratory fall, often without clinical manifestations in that stretch. Waiting for a textbook tongue or a crashing hemoglobin misses the point of a periodic level.
Numb feet still get blamed on 'just diabetes.' Draw B12 when neuropathy or anemia shows, even if the 2- to 3-year interval has not arrived.
Why the diarrhea scan must not carry this 7 percent
First-week stool is a different reader job. Repeating 7 percent at 29 weeks on that URL smears two scenes. The split is explained on the keep-the-percent scan without restating the number there as a diarrhea fact.
Board-check: 7 percent, 29 weeks, intrinsic factor, yearly CBC, 2- to 3-year B12. Then stop. Yuki Tanaka wants the figure on this card only.
What the intrinsic-factor sentence adds
Interference with B12 absorption from the B12-intrinsic factor complex is the mechanism the label names. People with poor B12 or calcium intake sit at higher risk of a subnormal level.
That sentence is why a low level is treated as a vitamin problem, not as proof the 850 mg tablet 'failed glucose.' Glucose and B12 are two levers.
What yearly CBC and 2- to 3-year B12 are for
Measure hematologic parameters annually on Glucophage or Glucophage XR. Measure vitamin B12 at 2- to 3-year intervals and manage what you find. Those intervals are the labelled screen, not a forum guess.
The short card for who to screen and how deficiency hides is the B12 flag signal. This scan keeps the 7 percent so other URLs do not repeat it.
Whether a low B12 forces the 850 to stop
Supplementation or stopping metformin can reverse the fall. Many people replace B12 and stay on Glucophage 850 mg if glucose still needs it. That fork is a clinician's, not a kitchen stop.
Stopping 850 only to 'treat B12' without a glucose plan can bounce A1C. The panel still locks the 850 GI story separately.