I have been experimenting with some alternative methods of absorbing high doses of vitamin B12 transdermally across the skin, and thought I might list these methods for everyone's benefit. Below is a list of various skin areas on your body that you can consider using experimentally to absorb vitamin B12 transdermally with high efficiency. Some methods involve body parts that you don't normally talk about in polite company, but hey, we are all friends here. I was experimenting with 3 different physical formulations of vitamin B12 in these transdermal skin absorption experiments: B12 tablets 5 mg B12 powder (simply made from one or two of the above 5 mg B12 tablets crushed under a tablespoon) B12 liquid drops, containing 1,000 mcg B12 per liquid drop. Note Some skin areas are a little experimental, and naturally you should do your own research and/or consult with your doctor before going ahead. In other words, make sure you know that no harm will come from using any of the suggestions below. It is possible that certain ingredients in a B12 formulation, or the B12 itself, may cause skin irritation or other problems in these skin areas. For example: B12 scavenges nitric oxide, and since nitric oxide is an antibacterial naturally secreted by mucous membranes, excessive 24 hour application of B12 to a mucous membrane may reduce nitric oxide levels enough to allow bacteria to flourish more, or cause some temporary imbalance in mucous membrane flora. Note also that citric acid-containing B12 formulations used orally can erode tooth enamel. B12 Administration Techniques: on Mucous Membranes Intranasal. Placing some liquid B12 into your mucous membrane-lined nasal cavity, using a dropper pipette. You need to place the tip of the pipette inside the openings to the nasal cavity; these openings are found at the end of each nostril. Lying down on your back and tilting your head backwards while administering allows the B12 drops to better enter the nasal cavity. Note: test any B12 liquid on your tongue first, and if there is any harshness or acidic sharpness to the taste, it may sting once in the nasal cavity. If it passes the tongue sharpness test, then next test a small amount in the nose, to ensure it does not sting, before taking a larger dose. Intranasal. Snorting up powder from a finely crushed B12 tablet via a drinking straw. (Best not performed outside a police department). Again, if the powder tastes acidic, it may sting the nose. Test a small amount of powder in the nose first, to ensure it does not sting. On upper gums, using either a B12 tablet, B12 powder, or B12 drops. There is a reasonably large area of mucous membranes on the upper gums and inner cheeks that can absorb the B12. Try to let the B12 slowly absorb in this area over an hour or so. The advantage of this upper gums/cheeks area is that the B12 will not be washed away by saliva. This method I learnt from Freddd. Note that B12 formulations containing citric acid (and/or other acids) can erode tooth enamel. Sublingual, using either B12 powder or B12 drops. Saliva may wash away the B12 before it has a chance to absorb through the sublingual mucous membranes. However, it is possible to gently massage in the B12 into the mucous membranes using your finger tip for a few minutes, to mechanically aid absorption. Intraurethral using liquid B12 drops from a dropper pipette. An unusual but probably viable method. B12 is seemingly very quickly absorbed in the urethra (in that no red color from the B12 is seen during urination a few hours later). The skin lining the urethra is a mucous membrane. The male urethra is around 18 cm long; the female urethra is around 4 cm long. B12 drops may sting if the formulation is too acidic, but the urethral mucous membranes are not quite as sensitive as the nasal mucous membranes. The glans is also a mucous membrane. Intravaginal pessary. Such pessaries are a well-known and highly effective means of absorbing drugs or supplements. Rectal suppository. A B12 tablet can be placed in the rectum as a suppository, just using some hand cream, say, for lubrication. The rectum is lined with mucous membranes, and will absorb B12 well. You may be able to get your pharmacy to compound up some purpose-made B12 suppositories. Intrasinus administration. Vitamin B12 powder or B12 drops dissolved in mildly saline water, and administered into nasal and sinus cavities via nasal irrigation (yoga neti). Both the nasal and sinus cavities are lined with mucous membranes. Very wasteful, as much of the administered liquid tends to drip out of the nose. B12 Administration Techniques: Other Skin Areas Transscrotal absorption. Whilst the scrotum is not a mucous membrane, it is much more absorbent than other skin sites. Transscrotal absorption is employed by some transdermal testosterone patches, and scrotal skin permits 5 to 40 times greater absorption of testosterone than other skin sites. Hopefully, similar figures apply to B12 absorption across the scrotum. This method is suited to liquid B12 drops, and possibly fine B12 powder applied like talcum powder. Under armpits and underside of arms. Skin here is thinner and more absorbent than other areas of body skin. This method is suited to liquid B12 drops, and possibly fine B12 powder. A shaved armpit is useful here. UPDATE: some of the above methods may not work, because the molecular weight of B12 methylcobalamin is 1344 daltons, and B12 hydroxocobalamin is 1346 daltons. Now the 500 dalton rule for transdermal absorption states that molecules above 500 daltons cannot get absorbed through the skin. So B12 will not like get absorbed on ordinary skin. Similarly, the rule for sublingual is that absorption only occurs with molecules less than 500 daltons. It has been stated that the nasal mucosa can absorb molecules up to 2000 daltons, so by snorting pure B12 powder intranasally, or using a B12 nasal spray, you should be able to absorb quite a bit. This study found that compared to intramuscular injection (which we assume has 100% bioavailability), intranasal B12 spray resulted in 6.1% bioavailability. This paper estimated that B12 nasal spray results in approximately 2 to 5% absorption. Inhaling B12 Into The Lungs Using E-Cigarettes UPDATE: There is now a fascinating and apparently very effective new method to add to the above, which is inhaling B12 using e-cigarettes. See: Methylcobalamin Inhalation Therapy.