Vitamins and Supplements on Tirzepatide (Zepbound or Mounjaro)

Most people taking tirzepatide, whether Zepbound, Mounjaro or compounded tirzepatide, need better meals more than supplements. Current evidence does not support routine supplements for everyone on these drugs.¹ A 2025 advisory from four medical and nutrition societies puts food and exercise first: enough protein and fluids while your appetite is small, nutrient-rich meals, and strength training at least three times a week.²

The clearest case for a supplement is eating very little or losing weight very fast; then experts advise a daily multivitamin with minerals. A 2025 expert consensus recommends a vitamin and mineral supplement, a high-protein nutrition drink or both when food intake is very low. It also recommends supplements when weight loss is excessive, which it defines as more than 1.5 kg (3.3 pounds) a week beyond the first month. Nestlé Health Science, which sells nutrition shakes and supplements, funded it.^{3, 4} As a rough guide, the joint advisory says shortfalls are especially likely below about 1,200 calories a day for women or 1,800 for men.²

Tell your prescriber if you are eating very little or losing weight that fast. The consensus says fast weight loss may signal undernutrition and that the dose or meal plan may need adjusting.³

If you could become pregnant, take a daily supplement or multivitamin with 400 to 800 micrograms (mcg) of folic acid, as the U.S. Preventive Services Task Force recommends, unless your doctor has advised a different dose (see folic acid and birth control).⁵ After weight-loss (bariatric) surgery, keep taking the vitamins and minerals your surgical team prescribed.⁶ Other single nutrients, such as vitamin D, calcium or B12, are for when your diet falls short, your risk is high or a blood test shows a gap.^{1, 2} Iron on its own is different: take it only if a blood test shows you need it (see iron).^{1, 7}

Skip products sold to boost weight loss or act like GLP-1, check several others first (the list is just below), and run anything you add past your prescriber or pharmacist.⁸

Stop tirzepatide and call your prescriber right away for severe stomach pain that will not go away, which can be pancreatitis. Call right away, too, about nausea, vomiting or diarrhea that does not go away. For signs of a serious allergic reaction, call 911. For signs of low blood sugar, take fast sugar first, then call. The warning signs have the details.^{8, 9, 10}

Looking for one topic?

• What to skip or check first
• Protein and strength training
• Vitamin and mineral limits
• Multivitamins
• Folic acid, birth control and pregnancy
• Blood tests
• Tiredness
• Hair shedding
• Fiber, fluids and an upset stomach
• Warning signs
• Mounjaro and diabetes
• Weight-loss pills and berberine
• B12 or glycine in compounded tirzepatide
• Mistakes to avoid

Zepbound and Mounjaro are Eli Lilly's FDA-approved brands of tirzepatide.^{8, 11} Compounded tirzepatide, which a pharmacy makes for an individual patient, is not FDA-approved, and FDA does not review compounded drugs for safety, effectiveness or quality before they are sold.¹² The nutrition guidance here covers GLP-1 drugs as a group, which the 2025 advisory says includes tirzepatide.²

Supplements to skip, or check with your pharmacist first

Neither the Zepbound nor the Mounjaro label names a supplement to avoid, so this list comes from the page's other sources.^{8, 11} FDA notes that "natural" does not always mean safe and that some supplements change how medicines are absorbed or broken down.¹³

• Skip: pills, teas and powders sold for weight loss or as "natural GLP-1," such as PlexusDx's own weight-loss pack (see weight-loss pills).
• Skip: omega-3s, probiotics, collagen, creatine, CoQ10 or electrolyte powders as routine add-ons, including the omega-3s, probiotics, creatine and CoQ10 in some PlexusDx packs. None of the three expert papers behind this page recommends them for people on these drugs. Fluid lost to vomiting or diarrhea is different (see fluids).^{1, 2, 3}
• Skip: B12 for energy, unless a test shows you are low (see vitamin B12).
• Skip: biotin for hair: little evidence, and it can throw off blood tests (see hair shedding).¹⁴
• Skip: vitamin D, vitamin A or selenium above the upper limits in the table below.
• Ask first: berberine, chromium and other blood-sugar supplements, especially with diabetes medicines (see berberine).¹⁵
• Ask first: iron pills on their own: take iron only if a blood test shows you need it (see iron).¹
• Ask first: St. John's wort if you use birth-control pills, which FDA says it makes less effective (see birth control), and ginkgo or vitamin E with a blood thinner such as warfarin, since FDA says each thins the blood.¹³

What changes when you eat less on tirzepatide

In studies, people taking GLP-1 drugs ate 16% to 39% fewer calories, and the joint advisory warns that a drop that large can leave you short on vitamins and minerals. Its examples include iron, calcium, magnesium, zinc and vitamins A, D, E, K, B1 (thiamine), B12 and C.² A 2026 review found that most shortfalls reported so far caused no symptoms or were inferred indirectly, but that real problems can develop in susceptible people.¹

On the plate, the advisory favors fruits, vegetables, whole grains, dairy, poultry, fish, eggs, nuts, seeds and plant oils. It suggests limiting refined grains, added sugars, sugary drinks, red and processed meats and most fast food.²

Protein, and the strength training that makes it count

Enough protein helps you keep muscle and bone while you lose weight, especially alongside strength training, but the right amount is still debated. The joint advisory offers these markers:²

• The recommended dietary allowance (RDA) for adults is 0.8 gram of protein per kilogram of body weight a day. A kilogram is 2.2 pounds.
• Higher targets, 1.2 to 1.6 g/kg a day, have been proposed during active weight loss.
• For people with obesity, it is unclear whether to use actual weight, an adjusted or ideal weight, or lean mass, because actual weight can overstate needs. A flat 80 to 120 grams a day is an alternative that may be easier to stick with.
• Intake should not fall below 0.4 to 0.5 g/kg a day, and staying at 2 g/kg or more for long periods should be avoided.

For example, at 200 pounds (about 91 kg), 1.2 to 1.6 g/kg of actual weight works out to about 110 to 145 grams a day.²

The Nestlé-funded 2025 consensus (1.2 to 1.5 g/kg) and the Dietary Guidelines for Americans, 2025-2030 (1.2 to 1.6 g/kg) land in the same range.^{3, 16} With chronic kidney disease, set a target with a dietitian or your clinician first, because some people need only moderate amounts and too little can cause malnutrition.¹⁷

When your appetite is small, eat the protein part of a meal first. Some people reach their target with high-protein shakes, bars or fortified foods.²

Protein alone is likely not enough to keep muscle. The advisory says these drugs should be prescribed with a structured exercise program: strength training at least three times a week plus at least 150 minutes of moderate aerobic exercise a week, fitted to your fitness level. Large, rapid weight loss (14% or more over 3 to 4 months) is also linked to significant bone loss, it says.²

Vitamins and minerals: how much you need, and how much is too much

If you add a supplement, aim to fill a gap. Taking more than you need costs more and can raise the risk of side effects. A seal from an independent tester shows a product was made properly, contains what its label lists and has no harmful levels of contaminants, but not that it is safe or effective.¹⁸ The table shows National Institutes of Health (NIH) figures for adults; add up what all your products contain, including any PlexusDx pack, before comparing.

These figures are for adults who are not pregnant or breastfeeding. The RDA meets the needs of nearly all healthy people; the upper limit is the most per day unlikely to cause harm. For vitamin D, 1 mcg equals 40 international units (IU).¹⁹ The limits for iron, zinc and selenium count food and supplements; for magnesium, only supplements and medicines; for vitamin A, only preformed vitamin A (retinol), not beta-carotene. RAE (retinol activity equivalents) adjusts for how well the body uses each form of vitamin A.^{7, 21, 22, 24, 25} A clinician may prescribe more than a limit to treat a confirmed deficiency.⁷

Vitamin D. People with obesity might need more vitamin D to reach the same blood level.¹⁹ Even so, the Endocrine Society suggests against routine vitamin D tests for the general population, including people with obesity, and against extra vitamin D to prevent disease in healthy adults under 75. It does suggest extra vitamin D from age 75, in pregnancy and with high-risk prediabetes, and its advice does not apply if you have a medical reason for testing or treatment.²⁶

Too much vitamin D raises blood calcium, which can cause nausea, vomiting, muscle weakness, dehydration, excessive thirst and kidney stones, several of which overlap with tirzepatide's own side effects. Vitamin D toxicity almost always comes from supplements.^{8, 19}

Calcium. Calcium supplements are absorbed best with food and in doses of 500 mg or less, though calcium citrate depends less on stomach acid and can be taken without food. They can cause gas, bloating or constipation, on top of the constipation tirzepatide can cause.^{8, 20} Calcium carbonate can interfere with levothyroxine, so ask your pharmacist how to space them.²⁰ For levothyroxine and these drugs, see our page on GLP-1 medicines after thyroid surgery. The same advice, limits and cautions apply to PlexusDx's pack with vitamin D, calcium citrate and magnesium.

Vitamin B12. B12 is often promoted for energy, but NIH says it appears to have no benefit for performance unless you are deficient. The same goes for the B12 in PlexusDx's packs with B vitamins. Groups more likely to run low include older adults, vegetarians, people who have had stomach or bowel surgery, and people with digestive disorders. People with pernicious anemia, an autoimmune disease that causes B12 deficiency even when they eat enough of it, are also at risk. No upper limit has been set, because B12's potential for toxicity is low.²³ Metformin can lower B12 too (see Mounjaro).²³

Iron. A 2026 review ties iron supplements to a confirmed deficiency, so ask about a blood test before taking iron on its own.¹ High doses can cause stomach upset, constipation, nausea, abdominal pain, vomiting and diarrhea. People with hereditary hemochromatosis, which makes the body absorb too much iron, should avoid iron and vitamin C supplements. Iron taken at the same time as levothyroxine can make the thyroid medicine work less well.⁷

A multivitamin. This is the supplement for people eating very little: NIH says needs should be met mainly through food, but people on low-calorie diets might benefit from a multivitamin-mineral. Skip extra products that repeat its nutrients, because NIH says multivitamins raise the chance of going over an upper limit, more so with single-nutrient supplements on top.²⁷ A basic one is a once-a-day product with most nutrients at or below their Daily Values. Choose one made for your age and sex: formulas for people 50 and older, for example, often have little or no iron and more calcium, vitamin D and B12.²⁷ Match each nutrient on the label to your row in the table, most of all for iron.⁷ This page does not rank brands, and the same check applies to PlexusDx's packs with a multivitamin; the skip list covers the omega-3s and probiotic that some of them add.

Folic acid and birth control, if you could become pregnant. The U.S. Preventive Services Task Force recommends a daily supplement or multivitamin with 400 to 800 mcg of folic acid for anyone who could become pregnant, starting at least a month before conception. Your doctor may advise a different dose if you have had a pregnancy affected by a neural tube defect or are at very high risk.⁵ Tirzepatide may make birth-control pills work less well. The Zepbound and Mounjaro labels say to switch to a non-pill method, or add a barrier method such as condoms, for 4 weeks after you start and 4 weeks after each dose increase.^{8, 11} If you are or might be pregnant, or are breastfeeding, NIH says experts advise no more than 3,000 mcg (10,000 IU) of vitamin A a day from supplements. Too much preformed vitamin A can cause birth defects.²⁴ PlexusDx's pregnancy pack contains a prenatal multivitamin, iron and omega-3s. These folic acid and vitamin A figures apply to it, and because the iron RDA rises to 27 mg a day in pregnancy, follow your prenatal clinician's advice on iron.⁷

Both labels warn that tirzepatide may harm an unborn baby (for Mounjaro, based on animal studies). Zepbound's says to stop it when a pregnancy is recognized, because weight loss offers no benefit in pregnancy. Mounjaro's says to use it in pregnancy only if the possible benefit justifies the possible risk to the baby.^{8, 11} If you become pregnant, call your prescriber, and if you take Mounjaro for diabetes, do not stop it on your own.

Kidney disease or kidney stones. With chronic kidney disease, check every supplement, protein shake and electrolyte product with your clinician first. Damaged kidneys clear phosphorus and potassium less well, and magnesium toxicity becomes more likely.^{17, 21} After kidney stones, ask before taking calcium or vitamin D supplements or eating more animal protein. NIH says more supplemental calcium might raise the risk of stones. The joint advisory says people with past stones should be counseled to avoid high-oxalate foods, highly processed foods and animal-source proteins.^{2, 19, 20}

When a blood test beats guessing

No formal guideline sets a lab schedule for people on these drugs, and the 2025 consensus says routine vitamin and mineral screening is rarely necessary.^{1, 3} The joint advisory adds that follow-up during treatment should regularly recheck what you eat and drink and your nutrient levels, to catch new shortfalls early.² Ask your prescriber or primary care doctor about labs if any of these apply to you:

• bariatric surgery, a very low-calorie diet, celiac disease, another inflammatory condition that raises the risk of deficiency, or a past deficiency;²
• a vegan or very restricted diet, older age, or very fast weight loss;¹
• vomiting or very poor intake for days, which also needs a call right away (see warning signs);¹
• long-term use of metformin or a stomach-acid medicine;¹
• possible signs of deficiency: fatigue beyond what you would expect, excessive hair loss, flaky or itchy skin, muscle weakness, poor wound healing or unusual bruising.²

A 2026 review suggests starting with iron, vitamin D and B12, the nutrients that show up most consistently in the research. It suggests bringing in a registered dietitian early if your risk is high, you eat very little, stomach side effects keep coming back or you struggle to reach your protein and fluid targets.¹

PlexusDx sells at-home blood tests, including nutrient tests, and registered dietitian consultations. The advice above applies to them. Test when there is a reason (the Endocrine Society's advice against routine vitamin D testing covers a vitamin D test too), and see a dietitian for the reasons the review gives.^{1, 26} Your own doctor can order any test mentioned here. PlexusDx's Terms of Service do not include outside laboratory testing in a plan's price unless the plan expressly says so.

Tiredness. Fatigue is a listed side effect. In Zepbound's main weight trials, 5% to 7% of people on the 5, 10 and 15 mg doses reported fatigue, weakness, low energy or feeling unwell, compared with 3% on placebo; compounded tirzepatide was not studied.⁸ Take B12 for energy only if a test shows you are low (see vitamin B12).

Low iron can also cause tiredness, which the 2026 review says can be missed because people with obesity or diabetes often feel tired anyway.¹ Ask about a blood test if tiredness is more than you expected, does not ease, or comes with hair shedding or breathlessness on exertion. If it comes with dizziness, sweating, shakiness or confusion, which can mean low blood sugar or dehydration, take the first steps under warning signs, then call your prescriber.^{8, 28}

Hair shedding: what the label shows and what helps

Shedding after weight loss usually stops on its own. The American Academy of Dermatology (AAD) says excessive shedding is common after losing 20 pounds or more and usually shows up a few months later. It stops as the body readjusts, and hair tends to regain its normal fullness within six to nine months, though shedding can last longer if the trigger continues.²⁹

Where a supplement can help is a true shortfall. The AAD says too little biotin, iron, protein or zinc can cause noticeable hair loss, and hair can regrow once your body gets enough of the missing nutrient.³⁰ So eat enough protein, and test rather than guess.

Hair loss is also a listed side effect. In Zepbound's main weight trials, which did not study compounded tirzepatide, 4% to 5% of people on the drug reported it, compared with 1% on placebo. It was linked to weight reduction, was more common in women, and led no one to stop Zepbound.⁸ Mounjaro's label lists hair loss among reports received since its approval.¹¹

Biotin is commonly used for hair and nails, but NIH says claims that it improves them rest on a few case reports and small studies at best. High-dose biotin can also make some lab tests read falsely high or low. FDA has reported a death after biotin caused a falsely low result on troponin, a test used to diagnose heart attacks.^{1, 14, 31} If you take it, tell anyone who orders your blood work. PlexusDx's hair pack contains biotin, so the same evidence and lab-test caution apply to it.

Too much can backfire. The AAD says large amounts of vitamin A or selenium are toxic and can cause hair loss; NIH's upper limits for both are in the table above.³⁰ If shedding does not settle, or you see round bald patches, which can be a sign of a different condition called alopecia areata, see a dermatologist.²⁹

Fiber, fluids and an unsettled stomach

Stomach side effects are common. In Zepbound's main weight trials, which lasted up to 72 weeks, the share of people affected on the 5, 10 and 15 mg doses was:⁸

• nausea: 25% to 29% on Zepbound, 8% on placebo
• diarrhea: 19% to 23%, vs 8%
• constipation: 11% to 17%, vs 5%
• vomiting: 8% to 13%, vs 2%

Most nausea, vomiting and diarrhea happened while the dose was being raised and eased over time.⁸ Compounded tirzepatide was not studied in these trials.

Nausea. The joint advisory suggests smaller, more frequent meals and avoiding fatty or high-fiber foods for the first few days of treatment. Ginger or peppermint tea and acupressure bands can help.² If nausea keeps you from eating or drinking, ask your prescriber about an anti-nausea medicine. The advisory says these can help while you adjust, and that some, such as ondansetron, can worsen constipation.²

Diarrhea. Avoiding large or high-fat meals can help. If diarrhea is significant, the advisory says fiber capsules or powders can add bulk to the stool and an anti-diarrheal medicine can give short-term relief. Ask your pharmacist which fits you.²

Fiber. After the first days, build fiber up gradually, along with more water. The Nestlé-funded 2025 consensus recommends at least 25 grams of fiber a day for women, 30 for men and 35 for people with diabetes. It says a fiber supplement such as psyllium should be considered when food alone falls short.³ That advice is about fiber in general, not any one product, including PlexusDx's pack with a fiber formula.

Constipation. Start with fluids and fiber from food. If that is not enough, the advisory lists these options: daily magnesium (it says magnesium citrate is effective and well tolerated), fiber supplements and polyethylene glycol 3350, an over-the-counter powder laxative. Ask your prescriber or pharmacist which fits you.² Magnesium works by drawing water into the bowel, and high doses can cause diarrhea, nausea and cramping. NIH's upper limit for magnesium from supplements and medicines is 350 mg a day, and toxicity is more likely with kidney problems.²¹ None of this page's sources covers magnesium glycinate for constipation. PlexusDx sells magnesium glycinate capsules and packs that contain magnesium. The same limit and kidney caution apply to them, and this article does not recommend them for constipation or anything else.

Over-the-counter laxative labels add their own rules. Both labels say to stop and ask a doctor if you have rectal bleeding.^{32, 33}

The polyethylene glycol 3350 label also says:³²

• Ask a doctor or pharmacist first if you take a prescription drug.
• Ask a doctor first if you have nausea, vomiting or abdominal pain.
• Do not use it with kidney disease unless a doctor advises it.
• Stop and ask a doctor if you need a laxative for longer than a week, get diarrhea, or find that nausea, bloating, cramping or abdominal pain gets worse.

The psyllium label says:³³

• Take it with enough fluid, because it can swell and cause choking.
• Take it 2 hours apart from other medicines.
• Stop and ask a doctor if constipation lasts more than 7 days or you have no bowel movement.
• Get medical help right away for chest pain, vomiting or trouble swallowing or breathing after a dose.

Bowel blockage and severe constipation, including fecal impaction (hard stool stuck in the bowel), have been reported with tirzepatide. The warning signs list what to watch for.⁸

Fluids. The labels give no daily number. Even so, nausea, vomiting and diarrhea can dehydrate you, and kidney injury, in some cases needing dialysis, has been reported, mostly in people who became dehydrated.⁸ The 2025 consensus suggests more than 2 liters (about 68 ounces) of fluid a day, with extra care during exercise, vomiting, diarrhea or fasting. It says fluid may need careful monitoring with heart failure or kidney disease, so follow any limit your own clinician has set.³ Signs of dehydration include thirst, a dry or sticky mouth, passing little urine, darker yellow urine, headache and muscle cramps. Not urinating, dizziness, a rapid heartbeat or confusion point to severe dehydration, which MedlinePlus calls a life-threatening emergency. For fainting, a seizure or new confusion, call 911.²⁸

If vomiting or diarrhea does not go away, call your prescriber right away (see warning signs). Stop tirzepatide too if it comes with severe stomach pain that will not go away. The 2026 review says kidney function and blood electrolytes such as potassium should then be checked.^{1, 8} Ask your prescriber whether a rehydration drink makes sense.

Symptoms that need a clinician, not a supplement

Some symptoms people try to fix with a vitamin or a fiber powder are warning signs. Most of the signs below come from the Zepbound and Mounjaro Medication Guides. The 911, emergency room, fast-sugar, blockage, thiamine and weight-loss points come from the sources cited beside them. For the first three groups, act first and ask afterward. For everything else, ask your prescriber how it applies to you before you add a supplement or change treatment.

Call 911 or go to an emergency room for:

• signs of a serious allergic reaction: swelling of your face, lips, tongue or throat, trouble breathing or swallowing, severe rash or itching, fainting or feeling dizzy, or a very fast heartbeat. The Medication Guides also say to stop the medicine.^{8, 9, 11}
• passing out or a seizure, which can follow very low blood sugar or severe dehydration.^{10, 28}
• confusion, unsteady walking or double vision, especially after days of vomiting or barely eating or drinking. These can be signs of Wernicke encephalopathy, a brain disorder caused by too little thiamine (vitamin B1).³⁴

Stop using tirzepatide and call your prescriber right away for:

• severe stomach pain that will not go away, with or without nausea or vomiting, sometimes felt through to your back. It can be pancreatitis, which has been fatal in some cases.⁸

Call your prescriber right away about:

• nausea, vomiting or diarrhea that does not go away. Keep drinking fluids, and watch for the signs of dehydration under fluids. If vomiting lasts for days or you can barely eat or drink, the 2026 review says thiamine (vitamin B1) should be replaced urgently, along with fluids, because a small but clinically significant number of Wernicke encephalopathy cases have been reported.^{1, 8}
• signs of gallbladder problems, which happen more often with these drugs: upper stomach pain, fever, yellow skin or eyes, or clay-colored stools.⁸

Tell your prescriber about:

• signs of low blood sugar, such as dizziness, sweating, confusion, shakiness, a fast heartbeat or hunger. The risk is higher if you also take insulin or a sulfonylurea (a diabetes medicine that makes the body release more insulin), and it can happen in adults without type 2 diabetes too.⁸ The usual first step is fast sugar, such as glucose tablets or half a cup of fruit juice, and then a call.¹⁰
• signs of a bowel blockage: you cannot pass stool or gas, your belly stays swollen, you keep vomiting or you have belly pain that will not go away.³⁵
• a lump or swelling in your neck, hoarseness, trouble swallowing or shortness of breath, which can be signs of a thyroid tumor.⁸
• vision changes, if you have type 2 diabetes.⁸
• stomach problems that are severe or will not go away.⁸
• eating very little, or losing more than about 3.3 pounds (1.5 kg) a week beyond the first month. The consensus says such weight loss may signal undernutrition.³

Who should not use tirzepatide. Tirzepatide caused thyroid C-cell tumors in rats. It is not known whether it causes them in people, including a thyroid cancer called medullary thyroid carcinoma (MTC). This is the boxed warning on both the Zepbound and Mounjaro labels. Do not use it if you or a family member has had MTC, or if you have multiple endocrine neoplasia syndrome type 2 (MEN 2), an inherited condition that causes tumors in hormone-making glands. Do not use it if you have had a serious allergic reaction to tirzepatide or its ingredients. It is not recommended if you have severe gastroparesis, meaning very slow stomach emptying.^{8, 11, 36} If MTC is in your family or you have MEN 2, tell your prescriber before your next dose. For pregnancy, see folic acid and birth control.

If you have ever had an eating disorder, tell your prescriber too. The joint advisory calls a restrictive eating disorder a general reason not to use these drugs, and the 2025 consensus says they can make eating disorders worse.^{2, 3}

For the full list of signs, read the guide that comes with your own medicine (Zepbound, Mounjaro).^{8, 11} Compounded tirzepatide has no FDA label of its own, so if you use it, go through these signs and the list of who should not use it with your prescriber too.

FDA says many side effects reported for compounded tirzepatide look like those of the approved drugs. They are likely underreported, because state-licensed pharmacies that are not outsourcing facilities (a separate category of compounders that FDA inspects) do not have to report them. As of May 31, 2026, FDA had more than 730 such reports, though a report does not always mean the drug caused the problem. It has also received reports, some serious, that may be related to compounded semaglutide or tirzepatide prescribed at doses beyond the FDA-approved labels.^{37, 38}

Before surgery or sedation, tell every provider that you take tirzepatide and any supplements. Food or liquid getting into the lungs has been reported in people on these drugs during anesthesia or deep sedation, and some supplements raise bleeding risk or change the response to anesthesia.^{8, 18}

If you take too much tirzepatide, call your prescriber or Poison Help at 1-800-222-1222, or go to an emergency room. These are not all the possible side effects. You can report side effects to FDA at 1-800-FDA-1088 or through its MedWatch program.^{8, 37}

If you take Mounjaro for type 2 diabetes

Mounjaro is approved, along with diet and exercise, to improve blood sugar in adults and children 10 and older with type 2 diabetes. It is not approved for weight loss.¹¹

Metformin and B12. If you also take metformin, it may lower your vitamin B12. In 29-week trials, about 7% of people with normal levels dropped below normal. Metformin's label says to check blood counts every year and B12 every 2 to 3 years.³⁹

Low blood sugar. The risk rises when Mounjaro is used with insulin or a sulfonylurea. The Mounjaro and Zepbound Medication Guides both ask you to talk with your prescriber about low blood sugar and how to manage it before you start.^{8, 11} If you have not had that talk, have it now, and learn the signs and first steps under warning signs.

Supplements sold for blood sugar. NCCIH says the evidence that chromium, cinnamon or berberine helps blood sugar is weak, and that herbal supplements taken with diabetes drugs can cause unwanted side effects. Tell your providers about any you take, and never use one in place of your diabetes treatment.¹⁵ PlexusDx's pack marketed for blood sugar contains berberine and chromium; NCCIH's verdict applies to it too, and it is no substitute for diabetes treatment (more on berberine below).

Pills sold to boost weight loss or mimic GLP-1

No source behind this page shows a supplement adding to tirzepatide's weight loss, and NIH says vitamin D supplements do not appear to promote weight loss.¹⁹ What can add to tirzepatide's effect, the joint advisory says, is a structured nutrition and lifestyle program, and even there the findings are mixed.² For the weight loss seen in Zepbound's trials, which did not study compounded tirzepatide, see our page on weight loss month by month.

Weight-loss supplements are another matter: FDA does not review supplements for effectiveness before they are sold.¹³ It says many weight-loss pills, teas and fat burners are likely to contain dangerous hidden ingredients, and that its list of tainted products covers only a small fraction of those on the market.⁴⁰

"Natural GLP-1" products. Your intestine releases its own GLP-1 when you eat, but half of that hormone is broken down within 1 to 2 minutes.² Tirzepatide, which also acts on the receptor for a second gut hormone, GIP, lasts far longer: half of a dose is cleared in about 5 to 6 days.^{8, 11} Fiber, resistant starch and unsaturated fats may raise your own GLP-1 release, mostly in animal and small human studies, and the advisory says more research is needed.²

Berberine. Ask your prescriber before taking it with tirzepatide. Its common side effects (nausea, diarrhea, bloating and constipation) overlap with tirzepatide's, and it may interact with medicines. It should not be used in pregnancy or while breastfeeding, and none of this page's sources tested the two together.^{8, 15} NCCIH says the evidence that berberine helps blood sugar is weak, with variable results and some poor-quality studies.¹⁵

A meta-analysis published in late 2025 found only a small average difference: 0.88 kg (about 2 pounds) more weight lost than with a control. It pooled 23 trial reports whose reporting and design its authors said need to improve, and it says nothing about any particular product or about taking berberine with tirzepatide.⁴¹

PlexusDx's weight-loss pack contains berberine and green tea extract. No source here shows that either adds to tirzepatide's weight loss, and NIH says some green tea extracts have been linked to liver damage in at least 50 case reports.⁴²

When your compounded tirzepatide already contains B12 or glycine

Some compounded tirzepatide is mixed with a form of vitamin B12, such as cyanocobalamin, or with glycine, an amino acid.^{43, 44}

A 2026 analysis of 33 compounded semaglutide and tirzepatide products listed on compounding pharmacy websites in early 2025 found little justification for adding nutrients to these injections.⁴³ Scientists at Eli Lilly, which makes Zepbound and Mounjaro, reported in a 2026 journal article an impurity that forms when tirzepatide reacts with certain forms of B12. Its effects in people are unknown, and Lilly has a commercial stake in the question.⁴⁴ For FDA's rules on added ingredients and what is known about them, see how to choose a compounded tirzepatide provider.

To find out whether yours contains B12 or glycine, check the prescription label or ask the pharmacy that filled it. If it contains B12, ask your prescriber what the impurity report means for you. B12 in a shot does not show whether you were low to begin with. If you are in a risk group (see vitamin B12), ask about a blood test, and keep taking any B12 your doctor prescribed.

The same questions apply to PlexusDx's own products: the compounded tirzepatide that Lone Star Virtual Health's clinicians prescribe to people who enroll through PlexusDx. PlexusDx's Terms of Service say formulations and added ingredients may vary by pharmacy and fill, so check the label on each new fill. As of October 19, 2026, PlexusDx's compounded tirzepatide is prescribed as an injection once a week or as an ODT, a tablet that dissolves in the mouth, once a day. Every tirzepatide injection in its catalog includes vitamin B12 or glycine, so the B12 questions above, including the impurity report, may apply to you; no injection comes without one of the two. Only people in California pick B12 or glycine in the intake; everywhere else the pharmacy decides, and the checkout screen won't tell you which. Under Lone Star's policy, an added ingredient can be part of the reason for a compounded drug only when your clinical needs support it. PlexusDx has not shared a complete ingredient list for the tablets. No tirzepatide tablet is FDA-approved. Allergies you report are reviewed by the physician before any decision on treatment; the intake's allergy checklist does not name B12 or glycine, so enter them yourself if they apply.

Compounded tirzepatide has no FDA-approved uses of its own.¹² If your plan is PlexusDx's Microdose GLP-1, which uses compounded tirzepatide or semaglutide at low-dose strengths, its lower doses are off-label, meaning outside any FDA-approved use, whichever drug it contains. Zepbound's label, for example, approves 2.5 mg a week only to start treatment and 5, 10 or 15 mg for ongoing use.⁸ PlexusDx uses only state-licensed compounding pharmacies, known as 503A pharmacies. They are not outsourcing facilities, so federal law does not require them to report side effects to FDA.^{37, 38} Tell your prescriber about any side effect, and you can report it to MedWatch yourself.

Supplement and medicine mistakes to avoid on tirzepatide

• Don't double up. Never use two tirzepatide or GLP-1 products at once, whether FDA-approved or compounded. Zepbound's label says not to use it with other tirzepatide products or any other GLP-1 medicine, such as semaglutide (Ozempic, Wegovy), compounded or not.⁸
• Don't buy "research use" drugs. FDA has warned companies selling GLP-1-type drugs labeled "for research purposes" or "not for human consumption," and it urges people not to buy them because their quality is unknown and they may be harmful.³⁷ Other warning signs to check before buying are in how to check a compounded tirzepatide seller.
• Don't rely on unsourced timing rules. Zepbound's label gives no instruction to space vitamins or supplements away from your injection, so follow any spacing a product's own label gives, such as psyllium's.^{8, 33} The Zepbound label's caution is about pills in general. Tirzepatide slows stomach emptying, most of all after the first dose, which may change how medicines taken by mouth are absorbed, so prescribers watch drugs that need steady blood levels, such as warfarin.⁸
• Don't keep supplements to yourself. The Zepbound and Mounjaro Medication Guides ask you to tell your prescriber about the vitamins and herbal supplements you take. Keep a list and show it to your prescriber and pharmacist when anything changes.^{8, 11}

Sources

1. Micronutrient risk with GLP-1 receptor and dual incretin agonists in obesity: mechanistic pathways, clinical signals, and a monitoring framework. Simancas-Racines D, et al. Obesity Pillars, 2026, via PubMed Central. Accessed October 3, 2026.
2. Nutritional priorities to support GLP-1 therapy for obesity: a joint Advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society. Mozaffarian D, et al. Obesity, 2025, via PubMed Central. Accessed October 3, 2026.
3. Nutritional and lifestyle supportive care recommendations for management of obesity with GLP-1-based therapies: an expert consensus statement using a modified Delphi approach. Sievenpiper JL, et al. Obesity Pillars, 2025 (funded by Nestlé Health Science), via PubMed Central. Accessed October 3, 2026.
4. About us. Nestlé Health Science. Accessed October 3, 2026.
5. Folic Acid Supplementation to Prevent Neural Tube Defects: Preventive Medication (final recommendation, August 2023). U.S. Preventive Services Task Force. Accessed October 3, 2026.
6. Weight-loss Surgery Side Effects. National Institute of Diabetes and Digestive and Kidney Diseases, NIH. Accessed October 3, 2026.
7. Iron: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. Accessed October 3, 2026.
8. ZEPBOUND (tirzepatide) injection: prescribing information and Medication Guide, revised August 2026. Eli Lilly and Company, via DailyMed, National Library of Medicine. Accessed October 3, 2026.
9. Allergic reactions. MedlinePlus Medical Encyclopedia, National Library of Medicine. Accessed October 3, 2026.
10. Low Blood Glucose (Hypoglycemia). National Institute of Diabetes and Digestive and Kidney Diseases, NIH. Accessed October 3, 2026.
11. MOUNJARO (tirzepatide) injection: prescribing information and Medication Guide, revised August 2026. Eli Lilly and Company, via DailyMed, National Library of Medicine. Accessed October 3, 2026.
12. Human Drug Compounding. U.S. Food and Drug Administration. Accessed October 3, 2026.
13. Mixing Medications and Dietary Supplements Can Endanger Your Health. U.S. Food and Drug Administration. Accessed October 3, 2026.
14. Biotin: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. Accessed October 3, 2026.
15. Diabetes and Dietary Supplements: What You Need To Know. National Center for Complementary and Integrative Health, NIH. Accessed October 3, 2026.
16. Dietary Guidelines for Americans, 2025-2030 (PDF). U.S. Department of Health and Human Services and U.S. Department of Agriculture. Accessed October 3, 2026.
17. Healthy Eating for Adults with Chronic Kidney Disease. National Institute of Diabetes and Digestive and Kidney Diseases, NIH. Accessed October 3, 2026.
18. Dietary Supplements: What You Need to Know. NIH Office of Dietary Supplements. Accessed October 3, 2026.
19. Vitamin D: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. Accessed October 3, 2026.
20. Calcium: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. Accessed October 3, 2026.
21. Magnesium: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. Accessed October 3, 2026.
22. Zinc: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. Accessed October 3, 2026.
23. Vitamin B12: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. Accessed October 3, 2026.
24. Vitamin A and Carotenoids: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. Accessed October 3, 2026.
25. Selenium: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. Accessed October 3, 2026.
26. Vitamin D for the Prevention of Disease: An Endocrine Society Clinical Practice Guideline. Demay MB, et al. The Journal of Clinical Endocrinology & Metabolism, 2024, via PubMed. Accessed October 3, 2026.
27. Multivitamin/mineral Supplements: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. Accessed October 3, 2026.
28. Dehydration. MedlinePlus Medical Encyclopedia, National Library of Medicine. Accessed October 3, 2026.
29. Do you have hair loss or hair shedding?. American Academy of Dermatology. Accessed October 3, 2026.
30. Hair loss: Who gets and causes. American Academy of Dermatology. Accessed October 3, 2026.
31. Biotin Interference with Troponin Lab Tests - Assays Subject to Biotin Interference. U.S. Food and Drug Administration. Accessed October 3, 2026.
32. MIRALAX (polyethylene glycol 3350) powder, for solution: Drug Facts label. Bayer HealthCare LLC, via DailyMed, National Library of Medicine. Accessed October 3, 2026.
33. METAMUCIL THERAPY FOR REGULARITY (psyllium husk) powder: Drug Facts label. The Procter & Gamble Manufacturing Company, via DailyMed, National Library of Medicine. Accessed October 3, 2026.
34. Wernicke-Korsakoff syndrome. MedlinePlus Medical Encyclopedia, National Library of Medicine. Accessed October 3, 2026.
35. Intestinal obstruction and Ileus. MedlinePlus Medical Encyclopedia, National Library of Medicine. Accessed October 3, 2026.
36. Multiple endocrine neoplasia. MedlinePlus Genetics, National Library of Medicine. Accessed October 3, 2026.
37. FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss. U.S. Food and Drug Administration. Accessed October 3, 2026.
38. Compounding and the FDA: Questions and Answers. U.S. Food and Drug Administration. Accessed October 3, 2026.
39. Metformin hydrochloride tablets: prescribing information, revised July 2026. Laurus Labs, via DailyMed, National Library of Medicine. Accessed October 3, 2026.
40. Weight Loss Product Notifications. U.S. Food and Drug Administration. Accessed October 3, 2026.
41. The effect of berberine on obesity indices: a systematic review and meta-analysis. Elahi Vahed I, et al. International Journal of Obesity, 2026 (online November 2025), via PubMed. Accessed October 3, 2026.
42. Dietary Supplements for Weight Loss: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. Accessed October 3, 2026.
43. Compounded Semaglutide and Tirzepatide Products Use Unique Formulations but Efficacy and Safety Largely Unknown. Belcourt J, et al. The Annals of Pharmacotherapy, 2026, via PubMed. Accessed October 3, 2026.
44. A novel, widespread impurity in mass-compounded tirzepatide/B12 products: potential patient safety implications. Jordan B, et al. (Eli Lilly and Company). Expert Opinion on Drug Safety, 2026, via PubMed. Accessed October 3, 2026.

How we made this page

This page replaces three older PlexusDx posts on vitamins with Mounjaro, Zepbound and tirzepatide, along with many near-duplicate posts on the same questions. Those posts gave supplement doses, rules for spacing supplements around the injection and claims about absorption, none with sources, and they promoted a PlexusDx genetic test for choosing supplements. We kept none of it.

The guidance on this topic is scattered and uses different units: vitamin D in IU or micrograms, protein in grams per kilogram or grams a day, and upper limits that count food for some nutrients and only supplements for others. We used AI tools to line those documents up and to draft the page only from the sources listed on it. The protein advice rests mainly on the joint advisory, the 2025 consensus and the Dietary Guidelines; the table on NIH's fact sheets; the side-effect rates and most warning signs on the Zepbound and Mounjaro labels; and the emergency and first-aid steps on MedlinePlus and NIDDK.

A script matched the quotes in our evidence file behind each RDA and upper limit in the table, each label percentage and each recommendation we quote to the copy of its source saved on October 3, 2026. The draft then went to AI reviewers twice, six each time, each reading apart from the others for one thing: clinical safety, whether every number matches its source, regulatory risk, how a stranger with no stake in PlexusDx would judge it, whether a reader on a phone can act on it, and what it says about PlexusDx. An AI editor rewrote what they questioned. Then an AI reviewer new to the page, with no drafts to compare against, read it and opened some of its sources; the revisions that came out of that reading were checked once more by AI. That checking is not a medical review. We did not buy, test or receive any supplement for this page, and it has no affiliate links. Jay Hastings reviewed and approved this version on October 19, 2026. Dr. Asad K. Niazi, MD, MPH, reviewed the medical content on October 17, 2026. He is co-founder and CEO of Lone Star Virtual Health, the company that provides PlexusDx's prescribing clinicians, so he has a business relationship with PlexusDx.

PlexusDx sells compounded GLP-1 treatment, so we have a financial interest in this topic. It also sells supplement packs, which it markets as personalized from genetic and blood test results (this page does not evaluate that claim), magnesium capsules, at-home blood tests, registered dietitian consultations and genetic tests. The byline names the kinds of those products that overlap with this page. This article is not a review of them. Its verdicts on ingredients apply equally to any PlexusDx pack that contains them, and where that helps, a short clause in the section says so. It does not recommend or link to any PlexusDx product or test.

What the page says about PlexusDx's own products is ours, as of October 19, 2026. If a limit or warning here is wrong or out of date, our editorial policy shows how to report it.