‘Buy our sub-lingual vitamin B12 tablets and experience a sense of energy, heightened concentration and even weight loss!’
‘Suffering from mal-absorption issues? Don’t eat animal products? Want to bypass your absorption issues and get B12 delivered straight to your blood? Our vitamin B12 sublingual lozenges are the answer!’
Before you start to look for the price of those lozenges/tablets on this page hoping to order them right away, I’m going to have to disappoint you. First of all, the above statements are similar to what I’ve read or heard so far about these ‘magical’ sublingual tablets.
And secondly, we’re definitely not selling any of that magic here. So let’s get down to the facts and what you really need to know about this well-marketed form of B12 supplementation (possibly an ‘overly-marketed’ form).
What is Sublingual B12?
The term ‘sublingual’ means ‘that which can be placed under the tongue’. It’s available in the form of tablets, lozenges, sprays, liquid drops,and even lollipops containing B12 are being sold these days but that’s another story (I hopefully won’t be writing about how cool B12 lollipops are so don’t get your hopes up!).
Back to sublingual B12 – once you put these little things under your tongue (whether it’s a tablet, a few drops or a spray done under the tongue), you’re supposed to let them stay there till they dissolve and according to the people selling them, they enter your blood stream directly since they get absorbed through the tissues in your mouth (meaning your cheeks and the lining under your tongue). However, that’s not what ACTUALLY happens. Read on and you’ll know what I’m talking about.
Sublingual B12’s Dealbreaker Myth
Pharmaceutical companies and the likes have been marketing this form of B12 as being superior to other oral supplemental forms of B12 which are meant to be swallowed. They say that sublingual B12 is absorbed in the mouth and it doesn’t need to pass through your digestive system for absorption so those who have problems absorbing it can benefit from this form. That sounds pretty cool, so why I am being such a spoilsport?
Well that’s because the above claims of nutritionists and pharmaceutical companies are plain false.
Research has proven that there is NO DIFFERENCE whatsoever in the effectiveness of oral or sublingual B12. A study done in 2003 compared the effect of administering 500µg B12 per day in both the sublingual and oral forms. The research was done on B12 deficient patients and it was concluded that both these forms of B12 were equally effective in treating vitamin B12 deficiency.
When I read about the above research, I tried to look for a reason as to why the sublingual B12 isn’t more effective than the oral form (since the theory given by those who are selling it had me convinced until I could find an explanation for what the research claimed). And then I came across Don Goldberg. Here’s what I learnt from his blog.
Vitamin B12 deficiency is caused by numerous things, one of them being malabsorption. Pernicious Anemia is the most notable cause of this malabsorption (others include Crohn’s disease, Celiac, disease, etc) in which intrinsic factor is not produced (without which B12 cannot be absorbed). Some time ago, injections of B12 were thought to be the only way by which this form of B12 deficiency could be treated because these injections deliver B12 straight to your muscles (from where it is slowly absorbed and reaches its target organs), removing the need for absorption from your gastrointestinal system.
There was a problem in this perfect little story – injectable vitamin B12 could not be sold in the health/fitness stores. Plus, most of them need a prescription. Hmm…so what else could people with pernicious anemia take that they wouldn’t have to rely on their gut for absorption. Sublingual B12 was the clever answer ! A shrewd but intelligent marketing technique nonetheless.
That should solve our problems, no? Well here’s a tiny detail I skipped in the discussion above (yes, I did it on purpose to add some drama) : Sublingual B12 CANNOT be absorbed sublingually. Why? Simply because B12 is too large of a molecule to be absorbed from under your tongue.
Another question I had was if that’s really the case, how come the research done proved that BOTH sublingual and oral forms of B12 could help improve the B12 deficiency. Here’s why: When you take in sublingual B12, you end up swallowing some of it. That’s the one that enters your gut.
So basically, B12 given in high doses is what really cures the deficiency, it doesn’t matter if that dose is oral or sublingual because eventually B12 will be taken up by absorption through your gut whether you chose the sublingual route or the oral route. Chose whichever one you want, but technically, they will both be taken up the same way.
So to sum up, sub-lingual B12 is NOT absorbed through your oral cavity and the little amount that you do get is via absorption through the gut because you obviously end up swallowing at least some amount of the dose under your tongue. I’m not a pharmacist and in my years of studying medicine, nothing came up about the size of B12 molecules so I couldn’t be too sure regarding this theory.
I looked it up once again and interestingly, I finally confirmed through a couple of books and online references that the B12 moelcule is indeed too large to be absorbed in the mouth. The main cause behind its efficacy when given sublingually (and orally) is that its high dose causes it to be passively absorbed in the gut.
Who Should Take Sublingual B12?
Any one taking the oral form can take the sublingual vitamin B12 form and vice versa. The above discussion proves that the sublingual form is not superior to the oral form so it’s really a matter of personal preference. For those who have pernicious anemia or any other cause of B12 deficiency (gastric surgery, crohn’s disease, etc), injections are the initial form of B12 supplementation followed by oral supplementation of B12 shots for life, depending on their medical history, severity of deficiency, etc.
Are There Any Side Effects to the Sublingual Form of B12?
There are no side effects specific to this form but those due to vitamin B12 supplementation in general do apply. For more details regarding the possible side effects of B12 supplementation, please refer to this post (excluding the side-effects exclusively due to injections, such as pain at the site of injection, etc).
With that said, our discussion comes to an end for now. You can still use sub-lingual B12 as an alternative to the oral form if you’re a fan of keeping a tablet under your tongue (especially if it’s cherry flavored like some of them are), but I really don’t see a reason to use this form anymore. Our recommended form of B12 supplementation is methylcobalamin B12 shots, they provide the best value and absorption efficiency of all supplements.
Written by Dr. Aqsa Ghazanfar, main author of ‘The B12 Deficiency Survival Handbook’.
Br J Clin Pharmacol. 2003 Dec;56(6):635-8. Replacement therapy for vitamin B12 deficiency: comparison between the sublingual and oral route. Sharabi A, Cohen E, Sulkes J, Garty M. Recanati Center for Medicine and Research and Clinical Pharmacology Unit, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.