Published by Bari Liquid Force — a member of the American Society for Metabolic and Bariatric Surgery (ASMBS) Corporate Council. This is an independent plain-English summary of publicly available ASMBS guidance and is not endorsed by ASMBS.
The ASMBS nutritional guidelines are the standard reference for what to supplement after bariatric surgery — but the source document is written for clinicians, not patients. This page translates the key amounts into plain English so you can understand what your surgeon or dietitian is recommending and why.
After surgery, your anatomy absorbs several nutrients less efficiently, so a standard drugstore multivitamin is not enough. ASMBS guidance calls for a bariatric-specific multivitamin plus separate supplements for the nutrients hardest to maintain: B12, iron, calcium citrate, and vitamin D. The multivitamin itself covers thiamine, folate, zinc, copper, and the fat-soluble vitamins A, E, and K. The specifics come from the ASMBS Integrated Health Nutritional Guidelines, 2016 Update.
The table below summarizes commonly cited amounts from the 2016 update. Treat these as prevention targets for a general post-surgery patient — your own amounts depend on your procedure, labs, age, and risk factors.
| Nutrient | Common ASMBS amount (prevention) |
|---|---|
| Vitamin B12 | 350–500 mcg daily by mouth, or ~1,000 mcg monthly injection |
| Iron (elemental) | At least 18 mg (low-risk); 45–60 mg daily (higher-risk: RYGB, SG, BPD/DS, menstruating women) |
| Calcium citrate | 1,200–1,500 mg daily (LAGB, SG, RYGB); 1,800–2,400 mg daily (BPD/DS), in split doses |
| Vitamin D3 | At least 3,000 IU daily, titrated to a blood level above 30 ng/mL |
| Thiamine (B1) | At least ~12 mg daily (more if at higher risk) |
| Folate | 400–800 mcg daily (up to ~1,000 mcg for women of childbearing age) |
| Zinc | 8–22 mg daily |
| Copper | ~2 mg daily (about 1 mg copper per 8–15 mg zinc) |
More malabsorptive procedures require more of certain nutrients. Calcium is the clearest example: 1,200 to 1,500 mg daily after adjustable band, sleeve, or gastric bypass, but 1,800 to 2,400 mg daily after BPD/DS. Iron and the fat-soluble vitamins also trend higher for the more complex procedures. This is why "how much should I take" always comes back to which surgery you had.
A few details make a real difference. Calcium should be citrate, not carbonate, because carbonate needs stomach acid that surgery reduces — see calcium citrate vs carbonate. Calcium must be split into 500–600 mg doses and kept separate from iron by at least two hours. For the full B12 and iron breakdowns, see how much B12 after gastric bypass and how much iron after gastric bypass. Why any of this matters at all is covered in why some vitamins don't absorb well after surgery.
Usually not. A quality bariatric multivitamin covers many nutrients, but calcium citrate must be taken separately in split doses, and B12 and extra iron often need their own supplements. Most patients end up taking a bariatric multivitamin plus separate calcium citrate, vitamin D, and B12. For a full checklist, see our bariatric vitamins list.
Bari Liquid Force is a liquid-filled gel cap bariatric multivitamin providing 29 essential nutrients — including B12, iron, thiamine, folate, zinc, and copper — in a format designed for easier absorption after surgery. Pair it with separate calcium citrate and vitamin D per your care team's plan.
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A bariatric multivitamin plus separate B12, iron, calcium citrate, and vitamin D. The multivitamin also supplies thiamine, folate, zinc, copper, and vitamins A, E, and K.
No. Some amounts increase with more malabsorptive procedures — for example, calcium is higher for BPD/DS. Your care team sets amounts based on your surgery and labs.
Usually not. Calcium needs split doses separate from iron, and B12 and extra iron often need dedicated supplements.
No. It is an independent plain-English summary of the publicly available ASMBS 2016 guidelines, not endorsed by ASMBS, and not a substitute for your own care team's plan.