Why Vitamins Sometimes Don’t Work Even with Supplements

1 Big Thing

If your vitamin levels stay low even though you take supplements, your body might not be absorbing nutrients properly. This is called malabsorption, and it means your gut isn’t doing its full job of breaking down food and absorbing vitamins into your bloodstream.

Why it matters

When your digestive system can’t absorb nutrients, it doesn’t matter how many supplements you take—your body simply can’t use them. That can lead to fatigue, weakness, nerve problems, brittle bones, or even anemia. Fixing this starts with understanding what’s causing the absorption problem.

Between the lines

Malabsorption isn’t one condition it’s a clue that something’s wrong with how your stomach, pancreas, or intestines are working. Once doctors find the cause, treatment is usually straightforward, and your body can begin to recover.

Go deeper

What causes malabsorption

Malabsorption happens when your digestive system has trouble absorbing nutrients like vitamins, minerals, fats, or proteins. It can result from several different issues:

• Celiac disease, where gluten damages the lining of your small intestine (1).
• Chronic pancreatitis, which reduces the digestive enzymes that break down food (2).
• Crohn’s disease or short bowel syndrome, where inflammation or surgery shortens or damages the gut (3).
• Small intestinal bacterial overgrowth (SIBO), which disrupts digestion (1).
• Atrophic gastritis or pernicious anemia, which stop the stomach from producing the protein needed to absorb vitamin B12 (4,5).

These conditions affect different steps in digestion from breaking down food, to absorbing nutrients through the intestinal wall, to transporting them into your bloodstream (1–3).

Why supplements sometimes fail

When absorption is damaged, your body may not be able to use nutrients from either food or supplements. For example, people with certain gut conditions might swallow vitamin B12 or D tablets every day and still remain deficient because the gut can’t move those vitamins into the bloodstream (4–7).

That’s why taking more pills isn’t always the answer. In some cases, vitamins must be given by injection or through an IV. These routes deliver nutrients directly into the blood, bypassing the gut altogether (2,5,8).

Vitamin B12: a common example

Vitamin B12 is essential for nerve health, blood formation, and brain function but it’s one of the first vitamins to drop in malabsorption. To be absorbed properly, B12 needs stomach acid, a protein called intrinsic factor, and a healthy small intestine. If any of these are missing such as in pernicious anemia, gastric atrophy, or after stomach or bowel surgery B12 levels will fall no matter how much you take orally (4–7).

The most effective treatment is B12 injections, usually 1000 micrograms every few weeks. This bypasses the gut and restores levels quickly (6,7).

Vitamin D and other nutrients

Vitamin D deficiency is also common in malabsorption, especially in conditions affecting fat absorption. Research shows that people with gut disorders may absorb 25-hydroxyvitamin D3 better than regular vitamin D3, making it a better supplement choice for them (9).

Other vitamins like A, E, K, iron, and folate can also drop during long-term malabsorption. These may need special formulations or parenteral (injected) delivery to correct (2,5,8).

How treatment works

Treatment depends on what’s causing the absorption problem. Once providers identify the cause, they can tailor care:

• A gluten-free diet helps people with celiac disease heal (1,4).
• Pancreatic enzyme replacements help those with chronic pancreatitis digest food (2).
• Targeted medications or anti-inflammatory therapies help with Crohn’s disease or short bowel syndrome (3,8).
• Vitamin injections or IV therapy restore low vitamin levels quickly and effectively (5–7).

Your provider will monitor your bloodwork regularly and adjust treatment as your gut heals. Many people start feeling better within a few weeks of starting the right therapy.

How to get vitamin injections with Well Revolution

If your vitamin levels are low and oral supplements aren’t helping, Well Revolution can connect you directly with licensed healthcare providers who can assess your symptoms, test for malabsorption, and prescribe vitamin injections when needed.

Through  Well Revolution you can:

• Consult a clinician online within minutes.
• Get blood tests ordered to check vitamin and nutrient levels.
• Receive prescriptions for vitamin B12 or other injections.

This means faster access to care and faster recovery without the long wait for specialist referrals.

Supporting your gut and recovery

While your provider manages the medical side, you can support healing by eating a balanced diet, staying hydrated, limiting alcohol, and avoiding heavily processed foods. Follow up regularly to monitor vitamin levels and overall progress.

With the right treatment and care, most people regain their energy, restore healthy vitamin levels, and return to feeling like themselves again.

Health concerns, no matter how minor they may seem, can severely impact your overall well-being and quality of life. If you're experiencing symptoms or have concerns about a specific health condition, remember that timely and expert advice is key. Navigating healthcare can be challenging, but finding the right primary care physician shouldn't be. Whether you're seeking medical advice, a prescription or care, immediate access to expert primary care is just a button away. Don’t leave your health to chance—consult a Well Revolution primary care provider today for peace of mind and professional care.

References

1. Lenti MV, Hammer HF, Tacheci I, et al. European Consensus on Malabsorption—Definitions, Clinical Phenotypes, and Diagnostic Testing. United European Gastroenterology Journal. 2025;13(4):599–613. doi:10.1002/ueg2.70012.
2. Lenti MV, Hammer HF, Tacheci I, et al. European Consensus on Malabsorption: Screening, Special Populations, Nutritional Goals, Supportive Care, Primary Care Perspective. United European Gastroenterology Journal. 2025;13(5):773–797. doi:10.1002/ueg2.70011.
3. van der Heide F. Acquired Causes of Intestinal Malabsorption. Best Practice & Research Clinical Gastroenterology. 2016;30(2):213–224. doi:10.1016/j.bpg.2016.03.001.
4. Guéant JL, Guéant-Rodriguez RM, Alpers DH. Vitamin B12 Absorption and Malabsorption. Vitamins and Hormones. 2022;119:241–274. doi:10.1016/bs.vh.2022.01.016.
5. Cederholm T, Bosaeus I. Malnutrition in Adults. N Engl J Med. 2024;391(2):155–165. doi:10.1056/NEJMra2212159.
6. Wolffenbuttel BHR, McCaddon A, Ahmadi KR, Green R. A Brief Overview of the Diagnosis and Treatment of Cobalamin (B12) Deficiency. Food Nutr Bull. 2024;45(1_suppl):S40–S49. doi:10.1177/03795721241229500.
7. Stabler SP. Vitamin B12 Deficiency. N Engl J Med. 2013;368(2):149–160. doi:10.1056/NEJMcp1113996.
8. Hashash JG, Elkins J, Lewis JD, Binion DG. Diet and Nutritional Therapies in Inflammatory Bowel Disease. Gastroenterology. 2024;166(3):521–532. doi:10.1053/j.gastro.2023.11.303.
9. Charoenngam N, Kalajian TA, Shirvani A, et al. Pharmacokinetics of 25-Hydroxyvitamin D3 and Vitamin D3 in Adults With Intestinal Malabsorption. Am J Clin Nutr. 2021;114(3):1189–1199. doi:10.1093/ajcn/nqab123.