What Vitamins Do I Need After Bariatric Surgery?

Bariatric surgery is a powerful tool for improving health—but it also changes how your body absorbs nutrients. That’s why daily vitamin and mineral supplementation is essential. Whether you’ve had gastric bypass (RYGB), sleeve gastrectomy (SG), duodenal switch (BPD/DS), or SADI-S (Single Anastomosis Duodenal-Ileal Bypass with Sleeve Gastrectomy), understanding your long-term nutritional needs is key to staying healthy and preventing complications.

Why Supplementation Is Critical

After surgery, your digestive system is no longer able to absorb vitamins and minerals as effectively as before. This is due to changes in stomach size, acid production, and in some cases, the length of the intestines involved in nutrient absorption.

Without proper supplementation, deficiencies can occur quickly—even in the first few months. Common nutrient gaps include:

• Vitamin B12
• Iron
• Calcium
• Vitamin D
• Thiamin (Vitamin B1)
• Folate

If not identified and treated, these deficiencies can lead to fatigue, hair thinning, anemia, memory problems, weakened immunity, and long-term bone and nerve complications.

Supplementation Guidelines by Procedure

Each bariatric procedure affects nutrient absorption differently. The specific supplements you’ll need depend on the type of surgery you’ve had. Here’s a breakdown based on current clinical guidelines and the 2025 updated bariatric nutrition recommendations:

Roux-en-Y Gastric Bypass (RYGB)

RYGB involves rerouting the small intestine, which significantly affects nutrient absorption. This procedure increases your risk of vitamin and mineral deficiencies, so lifelong supplementation is essential. Most individuals will need:

• A bariatric-specific multivitamin with 45 mg of iron
• Calcium citrate: 1,200 mg per day, taken in divided doses of 500 mg two to three times daily (separate from iron).

Sleeve Gastrectomy (SG)

While SG doesn’t bypass the intestine, it removes a portion of the stomach that plays a role in nutrient absorption, including intrinsic factor for B12. Recommended supplements include:

• A bariatric-specific multivitamin with 45 mg of iron
• Calcium citrate: 1,200 mg per day, taken in divided doses of 500 mg two to three times daily (separate from iron).

SADI-S (Single Anastomosis Duodenal-Ileal Bypass with Sleeve Gastrectomy)

SADI-S combines sleeve gastrectomy with a bypass of part of the small intestine, leading to even higher malabsorption of key nutrients. It requires enhanced supplementation:

• A bariatric-specific multivitamin that includes additional fat-soluble vitamins, providing at least: 3,000 mcg (10,000 IU) of vitamin A, 300 mcg of vitamin K, 75 mcg (3,000 IU) of vitamin D, 15 mg of vitamin E, and 45 mg of iron.
• Calcium citrate: 1,800 mg per day, taken in divided doses of 500-600 mg, three times daily (separate from iron).

Biliopancreatic Diversion with Duodenal Switch (BPD/DS)

This is the most malabsorptive procedure and carries the highest risk of nutritional deficiencies. Supplementation needs are similar to SADI-S but often more intensive:

• A bariatric-specific multivitamin that includes additional fat-soluble vitamins, providing at least: 3,000 mcg (10,000 IU) of vitamin A, 300 mcg of vitamin K, 75 mcg (3,000 IU) of vitamin D, 15 mg of vitamin E, and 45 mg of iron.
• Calcium citrate: 1,800 mg per day, taken in divided doses of 500-600 mg, three times daily (separate from iron).

Regular lab monitoring and adjustments are critical after bariatric surgery, as each procedure alters nutrient absorption differently and long-term health, wellness, and quality of life depend on identifying and correcting deficiencies early.

What to Look for in a Bariatric Supplement

Not all vitamins are created equal—especially after bariatric surgery. Over-the-counter multivitamins are often formulated for the general population and fall short in both potency and bioavailability for someone who has had surgery.

Bariatric-specific supplements are designed to meet your unique needs, offering higher doses and more absorbable forms of key nutrients.

Look for the following when choosing vitamins after bariatric surgery

Complete formula (your bariatric-specific multivitamin should include all of the following):

• Vitamin A 1,500-3,000 mcg (5,000-10,000 IU)
• Vitamin C 120-180 mg
• Vitamin D 75 mcg (3,000 IU)
• Vitamin E 15 mg
• Vitamin K 90-300 mcg
• Thiamin (B1) 12 mg
• Folate 400–800 mcg
• Vitamin B12 350-500 mcg
• Iron 45 mg
• Zinc 16–22 mg
• Copper 2 mg
• Riboflavin (B2), Niacin (B3), Vitamin B6, Biotin, Pantothenic acid 200% DV

Appropriate doses: The amounts should align with current bariatric clinical guidelines, not the standard daily values found in OTC multivitamin’s.

Created for absorption: Some bariatric supplements go beyond standard formulations by using technologies that help your body absorb key nutrients more effectively. For example, Advanced Multi EA is the only bariatric multivitamin that uses micelle technology to support better absorption of fat-soluble vitamins after surgery.

Delivery format: Chewable vitamins are often preferred early after surgery. Over time, some patients can transition to capsules, depending on tolerance and provider guidance. Others prefer to stick with a chewy bite format, finding that great taste makes it easier to stay consistent with their daily routine.

Note: Chewy bites are designed to taste great, which means some nutrients—like iron—may be left out. If you’re using Multi Chewy Bites, be sure to pair them with a separate iron supplement, such as Bariatric Advantage Iron Capsule, to meet your full nutrition needs.

Building a Supplement Routine

Taking your vitamins every day is one of the most important habits you can build after bariatric surgery. But between busy schedules, pill fatigue, and changes in how your body feels, it’s easy to miss doses—or stop taking them altogether. The problem is, vitamin deficiencies don’t show up overnight. They develop slowly, and by the time symptoms appear, the damage may already be done.*

Here’s how to make vitamins after bariatric surgery easier and more consistent

• Set reminders: Use a smartphone alarm, calendar notification, or an app like Baritastic to track your doses.
• Pair with routines: Take your vitamins at the same time as regular activities—like brushing your teeth or brewing your morning coffee.
• Use a pill organizer: Weekly pill boxes reduce decision fatigue and help you visually confirm whether you’ve taken your supplements.
• Keep them visible: Store vitamins somewhere you’ll see them daily—on your kitchen counter or next to your toothbrush.
• Avoid taking everything at once: For example, calcium and iron interfere with each other’s absorption and should be taken at separate times of day.

It may take time to find what works best for you, but creating a system early on increases your chances of staying healthy long term. If you’re consistently missing doses, talk with your healthcare team about simplifying your routine.

If you want more guidance on building healthy habits, check out this video from Dr. BJ Fogg.

Sample Supplement Routines by Procedure

The type of bariatric surgery you’ve had plays a key role in determining your supplement needs. These sample routines are based on current clinical guidelines and can help you build a sustainable habit. Be sure to personalize your routine based on your healthcare provider’s guidance and lab values.

For Gastric Bypass (RYGB) or Sleeve Gastrectomy (SG)

Morning

Take a bariatric multivitamin with iron in the morning—unless you find it causes nausea or stomach upset. In that case, it may be better tolerated in the evening. Read more for tips to reduce gastrointestinal discomfort with supplements.

Afternoon

Calcium citrate – Dose 1 (500–600 mg)

Evening

Calcium citrate – Dose 2 (500–600 mg) +

Additional supplements if needed (vitamin D, probiotics, fiber, omega-3’s, etc.)

Tips for Success:

• Separate iron and calcium by at least 2 hours to avoid absorption interference
• Take calcium citrate with or without food
• Take bariatric multivitamin with a meal (once you can resume drinking)

For BPD/DS or SADI-S

These procedures involve a higher degree of malabsorption, so the supplement routine is more intensive and typically requires higher doses and greater frequency.

Morning

Take one dose of High ADEK bariatric multivitamin in the morning—unless you find it causes nausea or stomach upset. In that case, it may be better tolerated in the evening. Read more for tips to reduce gastrointestinal discomfort with supplements.

Midmorning

Calcium citrate – Dose 1 (500–600 mg)

Afternoon

Calcium citrate – Dose 2 (500–600 mg)

Midmorning

Calcium citrate – Dose 3 (500–600 mg)

Evening

Second dose of  High ADEK bariatric multivitamin

Additional supplements if needed (vitamin D, probiotics, fiber, omega-3’s, etc.)

Tips for Success:

• You may need to take supplements three to five times per day
• Use a vitamin tracker like Baritastic or a dedicated pill organizer
• Routine lab monitoring is essential due to the higher risk of deficiencies

Need a daily plan you can follow?

These printable supplement schedules show how to space out your vitamins after bariatric surgery throughout the day based on your surgery type. Keep them on your fridge, in your supplement drawer, or save them to your phone for easy reference.

Download sample daily schedule for RYGB or SG.

Download sample daily schedule for BPD/DS or SADI-S.

Why Bariatric-Specific Supplements Matter

Not all multivitamins are created equal—especially after bariatric surgery.

Standard over-the-counter (OTC) multivitamins are not designed for the unique nutrient needs that arise after bariatric procedures like RYGB or SG. In contrast, bariatric-specific formulations are developed with significantly higher doses of key nutrients like iron, B12, vitamin D, thiamin, and many more and they’re tailored to address reduced absorption after surgery.

What Happens Without Bariatric-Specific Vitamins?

Two landmark studies highlight the importance of taking the right kind of supplements.

• In a randomized trial looked at patients who took a bariatric multivitamin had 88% fewer iron deficiencies and significantly higher levels of B12 and folic acid than those using standard OTC vitamins.
• At the 3-year mark, a follow-up study found
  • Only 3% of bariatric multivitamin users developed anemia, compared to 16% with OTC supplements and 25% in non-users.
  • Vitamin B12 deficiency occurred in 4% of bariatric multivitamin users, compared to 15% of OTC users.
  • Vitamin D and zinc levels were also more stable in the bariatric-specific group.

These results aren’t just numbers—they reflect real health consequences. Patients not taking bariatric supplements experienced more fatigue from anemia, hair loss, cognitive issues, and experience lower body weight loss over time.

Why Do Some People Skip Their Bariatric Vitamins?

• They think they don’t need them: Deficiencies often develop slowly and silently. It can take months—or years—for symptoms to appear.
• Cost or inconvenience: Some patients opt for “less expensive” OTC options without realizing the long-term cost of deficiency-related complications.
  • In fact, one study showed that patients with nutritional deficiencies after bariatric surgery spent an average of $1,300 more per year on healthcare than those who stayed nutritionally stable.
• Misunderstanding: Without clear guidance, many patients assume a regular multivitamin is “good enough.”

What You Can Do

• Stick with bariatric-specific formulations from trusted sources, ideally those recommended by your surgeon or dietitian.
• If you stopped taking them, it’s never too late to restart—but lab work is key to guide your plan.
• If you’re unsure what to take, don’t guess. Bring your supplements (or lack of them) to your next appointment and ask your provider for feedback.

Skipping vitamins after bariatric surgery may not feel like a big deal in the moment, but research shows that taking bariatric-specific support isn’t just helpful—it’s essential for protecting your long-term health.

Nutrition Monitoring and Labs After Bariatric Surgery

Supplement routines aren’t one-size-fits-all—and they’re not static. Your body’s needs change over time, which is why routine bloodwork is essential. Monitoring helps catch deficiencies early, fine-tune your supplement regimen, and ensure you’re not over-supplementing.

When to Test

• First Year After Surgery: Every 3 to 6 months
• After Year One: At least annually, or more frequently if you’ve had abnormal labs in the past or a malabsorptive procedure (like BPD/DS or SADI-S)

Common Lab Tests to Monitor

• Complete Blood Count (CBC) and Ferritin
  • Screens for anemia and iron deficiency—common after all procedures
• Vitamin B12, serum MMA
  • Needed to prevent fatigue, nerve damage, and memory issues
• Vitamin D and Parathyroid Hormone (PTH)
  • Monitors bone health and calcium balance
• Thiamin (Vitamin B1)
  • Deficiency can lead to neurological issues and is often missed
• Calcium
  • Combined with PTH to evaluate calcium regulation and bone status
• Zinc, Copper, and Vitamin A (especially for BPD/DS or SADI-S)
  • Malabsorptive procedures require more frequent monitoring of trace minerals

Adjust Based on Your Results

Don’t rely on symptoms alone—many deficiencies don’t show up until they’re severe. Your healthcare provider may increase, reduce, or change the form of a supplement depending on your labs. For example:

• Persistently low B12 may require sublingual forms or higher doses
• Low iron or ferritin levels may require additional supplementation or, in some cases, iron infusions—which can be more costly and inconvenient than staying consistent with daily support
• Low vitamin D may require temporary mega doses followed by maintenance dose of 75 mcg per day

Always share your lab results with your registered dietitian or bariatric specialist to help guide next steps. A personalized approach ensures you stay on track long term.

What Research Shows

In a study of patients more than a year after gastric bypass, researchers compared those who continued taking their supplements with those who did not.

The results were significant. Among patients who remained consistent, fewer than 5% had deficiencies in iron, vitamin D, B12, folate, zinc, or thiamin.

In contrast, deficiency rates were much higher in those who had stopped supplementing:

• Iron: 83%
• Vitamin D: 74%
• Vitamin B12: 65%
• Folate: 61%
• Zinc: 57%
• Vitamin B1 (Thiamin): 35%

This reinforces what clinical teams observe regularly daily supplementation helps prevent long-term complications such as fatigue, memory issues, and nutrient-related anemia. Taking your supplements is not optional. It’s part of the long-term commitment to health after bariatric surgery—and it’s worth it.

Common Challenges with Vitamins After Bariatric Surgery

Even with the best intentions, sticking to vitamins after bariatric surgery can be tough. The key is to identify what’s getting in your way—and have a plan to work around it.

Trouble Tolerating Pills

Right after surgery, large pills may be difficult to swallow. Start with chewable supplements specifically made for bariatric patients. As you heal and tolerance improves, you can consider transitioning to capsules—just check with your provider first.

Forgetting to Take Supplements

One of the most common barriers is simply forgetting. Try:

• Setting phone alarms or Baritastic app reminders
• Keeping vitamins near your toothbrush, coffee maker, or another daily habit
• Using a pill organizer to visually confirm you’ve taken each dose
• Linking supplement intake with meals to build a consistent routine

Iron-Related Constipation

Iron is essential, but some forms can lead to constipation. If that happens:

• Ensure adequate fluid and fiber intake
• Ferrous bisglycinate is a gentler form and may be better tolerated
• Speak to your healthcare provider about adjusting the dose or timing

Tempted by Vitamin Patches?

Transdermal vitamin and mineral patches are often marketed as convenient—but they’re not recommended after bariatric surgery. Current research does not support their effectiveness in preventing or correcting deficiencies.

Pro tip: If a supplement is causing nausea or other side effects, don’t stop taking it entirely. Reach out to your provider or dietitian to explore other formulations or timing strategies.

Stay Supported

Long-term success isn’t just about supplements. Stay engaged with follow-up care, peer support, and ongoing education.

Join our next, free virtual support group!

Final Takeaway

Bariatric surgery changes how your body absorbs nutrients—but you can stay healthy with the right supplements, consistency, and follow-up. If you’re unsure where to start, speak with your dietitian or healthcare provider, and always choose products formulated for bariatric patients.

References

• Parrot J, Frank L, Rabena R, et al. ASMBS Integrated Health Nutritional Guidelines for The Surgical Weight Loss Patient — 2016 Update:Micronutrients. Surgery for Obesity and Related Diseases. 2016;12:955–959.
• Agaba E et al. Post Roux-en-Y Gastric Bypass: How Compliant are Your Patients and Who is Doing the Monitoring? J Obes Adv Bariatric Surg. 2015;2(1):1–6.
• Gaston A, Rhee CM, Streja E, et al. Healthcare costs and outcomes associated with bariatric surgery patients with and without vitamin and mineral deficiencies. J Manag Care Spec Pharm. 2015;21(10):946–955.
• Dogan, Kemal et al. Optimization of vitamin suppletion after Roux-en-Y gastric bypass surgery can lower postoperative deficiencies: a randomized controlled trial. Medicine. 2014;93(25):e169.
• Homan, Jens et al. An optimized multivitamin supplement lowers the number of vitamin and mineral deficiencies three years after Roux-en-Y gastric bypass: a cohort study. SOARD. 2016;(12)3 659-667.
• Benson-Davies, Sue et al. “Bariatric nutrition and evaluation of the metabolic surgical patient: Update to the 2022 Obesity Medicine Association (OMA) bariatric surgery, gastrointestinal hormones, and the microbiome clinical practice statement (CPS).” Obesity pillars vol. 13 100154. 5 Dec. 2024.