
- Longevity
- Weight management
- Metabolic health
Dr. Benjamin H. Krasne, M.D.
A board-certified physician who brings a rigorous, pharmacology-driven lens to longevity medicine and weight management.
Oral B12 supplements top out at around 1-2% absorption in most adults. B12 injections deliver 100% bioavailability, which is why they're the standard treatment for clinical deficiency and the preferred form for many members seeking real energy and cognitive support.
B12 deficiency is one of the most under-diagnosed nutritional issues in adults. It looks like fatigue, brain fog, depression, or even early dementia — and it's eminently fixable.
Vitamin B12 (cobalamin) is essential for DNA synthesis, red blood cell formation, and the function of the entire nervous system. The body cannot make it; we must get it from animal foods or supplementation. Once absorbed, it's used in two critical pathways: the methylation cycle (which affects neurotransmitter production, DNA repair, and many other things) and the breakdown of fatty acids and certain amino acids.
B12 deficiency is common — affecting an estimated 6% of US adults under 60 and rising substantially with age. Vegetarians and vegans are at high risk because B12 is essentially absent in plant foods. People on metformin, proton pump inhibitors (omeprazole, pantoprazole), or H2 blockers have impaired B12 absorption. Older adults often have reduced stomach acid that impairs B12 release from food. And people with pernicious anemia or post-bariatric surgery often cannot absorb oral B12 at all.
Oral B12 supplementation only addresses some of these. For people with true absorption issues, sublingual and patch forms have minimal benefit beyond placebo. Injectable B12 bypasses the gut entirely and produces dose-controlled tissue levels. This is why injection has been the standard of care for B12 deficiency for over 50 years and remains the most reliable approach.
B12 below 300 pg/mL with or without symptoms; below 200 is unambiguously low.
Long-term plant-based eating without supplementation routinely produces deficiency.
Both classes impair B12 absorption; chronic use is a risk factor.
Symptoms can predate the typical anemia. Methylmalonic acid is more sensitive than B12 alone.
From your first message to your medication arriving at your door — clinician-guided, every step.
A care team member meets with you to understand your goals, medical history, and treatment preferences. The first visit is no-cost and no-commitment — we want you to be confident before moving forward.
Connect by secure video or phone with a U.S.-licensed physician or nurse practitioner who reviews your full picture — labs, prior treatments, current medications, and lifestyle — and decides what is clinically appropriate.
If your clinician determines treatment is right for you, they issue a prescription that goes to a licensed U.S. pharmacy. We coordinate discreet shipping, or you can fill it locally. Follow-up visits are built in.
B12 comes in several forms; the two used clinically as injections are methylcobalamin and hydroxocobalamin (in the US; cyanocobalamin is more common in oral supplements).
Methylcobalamin is the active form of B12 used directly in the methylation cycle. It's the preferred form for members with MTHFR variants, neurological symptoms, or those seeking cognitive benefits. Most members report subjectively cleaner energy with methylcobalamin.
Hydroxocobalamin has a longer half-life — once injected, it lasts longer in tissues than methylcobalamin. This makes it preferred for some chronic-replacement protocols where less-frequent dosing is desired. It's also the form used as an antidote for cyanide poisoning, which is unrelated to longevity use but worth knowing.
Cyanocobalamin (the most common oral form) is shelf-stable but must be converted in the body to methylcobalamin or adenosylcobalamin before use. The conversion is efficient in healthy individuals; less efficient in some MTHFR variant carriers.
HealifyNow primarily prescribes methylcobalamin injectable for its bioactive form and reported subjective benefits, with hydroxocobalamin available for members who prefer less-frequent dosing.
Your clinician will review every relevant detail with you. Here are the most important points to know up front.
B12 has no known toxicity at therapeutic doses. The body excretes excess in urine.
No clinically significant interactions with prescription medications.
Rare. B12 contains cobalt, so members with documented cobalt allergy should not use injectable B12.
B12 is a deep pink/red color. Urine may turn pink for a day or two after injection. Harmless.
All medications must be prescribed by a licensed provider based on medical necessity. Treatment is not suitable for everyone. Results may vary.
For documented deficiency, the typical loading dose is 1 mg (1000 mcg) intramuscular or subcutaneous, given daily or every other day for 1-2 weeks, then weekly for 4-8 weeks, then monthly for maintenance. Your clinician will personalize based on labs and symptoms.
For non-deficient members seeking energy support, dosing is more conservative — typically 1 mg weekly or biweekly. Many members do well on twice-monthly maintenance once they're feeling well.
Subcutaneous injection is easier for self-administration and works essentially as well as intramuscular for most members. The technique is the same as semaglutide. Members who have done their own injections find it takes a few minutes per dose.
Most members notice subjective effects within 1-3 weeks: improved energy, better cognitive sharpness, often improved mood. If you have neurological symptoms (paresthesia, balance issues), those can take longer to resolve and may not fully reverse if the deficiency was prolonged.
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We built HealifyNow because telehealth done badly is everywhere — and telehealth done right still feels rare. Here is what makes us different.
No waiting rooms, no faxed forms, no insurance hoops. Quick consults, simple intake, prescriptions handled digitally.
Real physicians, nurse practitioners, and specialists with active licenses. Not chatbots, not offshore call centers.
Medications ship from licensed U.S. pharmacies in plain packaging. Most orders arrive in 2-5 business days.
Reach a real human seven days a week. Most messages get a clinical reply within a few hours, not days.
HealifyNow prescriptions are reviewed and authorized by independently licensed physicians — real doctors with real credentials from top medical institutions in the United States.

A board-certified physician who brings a rigorous, pharmacology-driven lens to longevity medicine and weight management.

A Columbia-trained physician and former collegiate athlete focused on metabolic function, body composition, and healthspan.

A board-certified OB-GYN and ACOG Fellow with more than four decades of experience in women's health.
Real people, real results. Names and details published with permission.
"Vegetarian for 20 years. B12 was 180 pg/mL, low end. Started weekly injections, energy came back in three weeks. Honestly didn't know how dragged-down I was until it lifted."
"On omeprazole for years for reflux. Had developed strange numbness in my feet that nobody could explain. B12 was 250, methylmalonic acid was high. Injections, three months — numbness mostly resolved."
"On metformin and Wegovy. Energy was inconsistent. HealifyNow checked B12 — borderline low. Started injections every two weeks. Now my afternoons aren't a wall."
HealifyNow makes it easy to move forward with confidence. Here are the answers to what people ask us most.
Same active vitamin, different delivery. IM/SC injection is dose-controlled, far cheaper, and self-administered. IV drips combine B12 with other vitamins in a saline base but the B12 component is the same.
Yes — most members self-inject after a brief video training visit. The technique is straightforward and similar to insulin or semaglutide injection.
Oral B12 absorption is highly variable and often poor — especially in older adults, vegetarians, those on metformin or acid-suppressing medications, and anyone with absorption issues. Injection guarantees absorption.
For documented deficiency (B12 below 200 typically), insurance often covers prescription B12 through your PCP. Our cash-pay program is for members who want a faster, more comprehensive approach or who don't meet insurance criteria.
Yes — we check B12 level, methylmalonic acid (a more sensitive deficiency marker), homocysteine, and CBC at baseline. This guides dosing and rules out look-alike conditions.
Yes. B12 has no significant interactions with other supplements. Many members combine B12 with folate (which is required alongside B12 in the methylation cycle) and other B vitamins.
B12 itself does not cause weight loss. It can help energy and mood, which indirectly supports lifestyle adherence. If you're on GLP-1 medications, ensuring adequate B12 helps you feel well during treatment.
Depends. If deficiency is from an absorption issue (pernicious anemia, post-bariatric, chronic PPI use), yes — ongoing injections are typical. If deficiency was from dietary inadequacy that's been corrected, maintenance can sometimes shift to high-dose sublingual oral.
Book a free consultation, answer a short health questionnaire, then meet a licensed clinician by secure video or phone. If B12 injections is medically appropriate, your clinician sends the prescription to a licensed U.S. pharmacy and it ships to your door.
Yes. Telehealth prescribing is legal when a licensed clinician evaluates you first. B12 injections is only prescribed when it's clinically appropriate, and it's filled by a licensed U.S. pharmacy.
B12 injections pricing is $125/month. Your first consultation is free, you don't need insurance, and your clinician confirms the exact cost before anything is prescribed.
B12 injections is typically prescribed for adults with low or deficient vitamin B12, or conditions that reduce B12 absorption. Your clinician reviews your health history, current medications and goals before deciding whether it's right for you.
Many members meet a clinician within a few days of booking. If B12 injections are prescribed, it ships in discreet packaging and most orders arrive within 2 to 5 business days.
Your clinician reviews your medical history, current medications, past treatments and goals by secure video or phone, explains the benefits and side effects, and agrees a plan with you. Labs may be ordered if needed.
Your care team explains how to self-inject, including dosing, injection sites and safe sharps disposal, and you can message them with questions.
Book a consultation. We test, treat, and confirm — instead of telling you to 'eat better.'