Hi Madeleine, I didn't try to test the drops for absorption. It would be interesting to see how long a 50mg dose or series of doses in rapid succession, need to be held in order to duplicate the amount of cobalamin in the urine from a 7.5-12.5mg SC injection or 50mg of the Jarrow. Logically I would expect to see a similar absorption curve. There used to be doubt whether b12 could be absorbed in that way at all because of the large size of the molecule. My inclination was always to test out theories and opinions to find out what actually worked. You could perform the tests and let us know.