Your Program's Instructions Take Precedence
This calculator provides a general framework based on ASMBS guidelines. Your surgical program's specific recommendations always take priority over these general guidelines. Use this as a reference and starting point — not as a replacement for your program's protocol.
📊 Build My Supplement Stack
Select your procedure and stage of recovery. The calculator will generate a recommended supplement stack with doses, key considerations, and form guidance based on ASMBS micronutrient guidelines.
Understanding Your Post-Bariatric Supplement Stack
Every supplement in a post-bariatric protocol exists for a specific reason rooted in altered anatomy. Understanding why each one matters helps with long-term compliance — because when you understand the consequence of missing a dose, compliance becomes easier to maintain.
Bariatric Multivitamin
The foundation of the entire stack. A bariatric-specific multivitamin is formulated with higher doses of the nutrients most commonly deficient post-surgery and in forms that absorb adequately without a full complement of stomach acid. Standard over-the-counter multivitamins are not adequate for post-bariatric patients — they are dosed and formulated for normal anatomy. Chewable or liquid forms are recommended in the first 3–6 months; capsules or tablets may be used thereafter.
Calcium Citrate
Calcium carbonate — the form in most standard supplements and antacids — requires significant stomach acid to dissolve. After bariatric surgery, stomach acid is dramatically reduced. Calcium citrate does not require acid. This is not optional — only calcium citrate should be used post-bariatric. Must be taken in doses no larger than 500–600mg at a time, separated by at least 2 hours. Must be separated from iron by at least 2 hours.
Vitamin D3
Fat-soluble vitamin D requires fat and bile acids for absorption — both reduced after malabsorptive procedures. D3 is significantly more bioavailable than D2. Dry or water-soluble D3 absorbs best after bypass and DS. The target for post-bariatric patients is 40–60 ng/mL — significantly higher than standard lab "normal."
Vitamin B12
Intrinsic factor — produced by stomach cells — is required to absorb B12 from food. After sleeve and bypass, intrinsic factor production is dramatically reduced. Crystalline B12 (sublingual, chewable, or injectable) bypasses the intrinsic factor requirement and absorbs adequately. Swallowable B12 tablets are not recommended post-bariatric surgery.
Iron
Iron absorption requires stomach acid and occurs primarily in the duodenum — bypassed in RYGB and DS/SADI. Iron citrate and iron bisglycinate are better tolerated than ferrous sulfate. Must be taken 2 hours away from calcium. Vitamin C taken with iron enhances absorption. Menstruating patients and DS/SADI patients need the highest doses.
Timing matters as much as dose. The most common reason supplements fail to prevent deficiency is not wrong products — it is calcium and iron being taken together (they block each other's absorption). Use the Supplement Timing Scheduler to build a daily schedule with proper separation built in.