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Selenium vs. B12: side effect and effectiveness comparison (a real world drug study)

Summary:

We compare the side effects and drug effectiveness of Selenium and B12. The phase IV clinical study is created by eHealthMe based on reports (from sources including the FDA) of 126,639 people who take Selenium and B12, and is updated regularly.

What is Selenium?

Selenium has active ingredients of selenium. It is often used in vitamin supplementation. eHealthMe is studying from 5,314 Selenium users. Check the latest studies of Selenium.

What is B12?

B12 has active ingredients of cobalamin. It is often used in vitamin b12 deficiency. eHealthMe is studying from 121,894 B12 users. Check the latest studies of B12.

On Jul, 07, 2026

126,639 people who take Selenium and B12 are studied.

Selenium vs B12 drug comparison reports.

Drugs being compared in this study:

  • Selenium (selenium)
  • B12 (cobalamin)

Most common side effects of the drugs, overall:

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Most common side effects of the drugs, in long term (1+ years) use:

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Drug effectiveness:

Selenium:

  • not at all: 1.53 %
  • somewhat: 37.4 %
  • moderate: 26.72 %
  • high: 27.48 %
  • very high: 6.87 %

B12:

  • not at all: 4.27 %
  • somewhat: 27.11 %
  • moderate: 34.07 %
  • high: 23.69 %
  • very high: 10.87 %

Want to compare Selenium with B12?

- Personalize this study to your gender and age (0-99+)

How to use the study?

DO NOT STOP MEDICATIONS without first consulting your doctor. If there are any serious or long term adverse effects discovered in the study, discuss the study with your doctor to ensure that proper medication management will be in place if applicable.

Related studies

Alternative drugs to, pros and cons of:

Browse all side effects of Selenium:

a b c d e f g h i j k l m n o p q r s t u v w x y z

Browse all side effects of B12:

a b c d e f g h i j k l m n o p q r s t u v w x y z

How the study uses the data?

The study is based on selenium and cobalamin (the active ingredients of Selenium and B12, respectively). Other drugs that have the same active ingredients (e.g. generic drugs or brand names) are also considered. Dosage of drugs is not considered in the study.

Who is eHealthMe?

With medical big data and proven AI/ML algorithms, eHealthMe provides a platform for everyone to run phase IV clinical trials. We study millions of patients and 5,000 more each day. Results of our real-world drug study have been referenced on 800+ peer-reviewed medical publications, including The Lancet, Mayo Clinic Proceedings, and Nature. Our analysis results are available to researchers, health care professionals, patients (testimonials), and software developers (open API).

WARNING, DISCLAIMER, USE FOR PUBLICATION

WARNING: Please DO NOT STOP MEDICATIONS without first consulting a physician since doing so could be hazardous to your health.

DISCLAIMER: All material available on eHealthMe.com is for informational purposes only, and is not a substitute for medical advice, diagnosis, or treatment provided by a qualified healthcare provider. All information is observation-only. Our phase IV clinical studies alone cannot establish cause-effect relationship. Different individuals may respond to medication in different ways. Every effort has been made to ensure that all information is accurate, up-to-date, and complete, but no guarantee is made to that effect. The use of the eHealthMe site and its content is at your own risk.

If you use this eHealthMe study on publication, please acknowledge it with a citation: study title, URL, accessed date.

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