High-Dose Thiamine Hydrochloride for Reducing Fatigue in Rheumatoid Arthritis Patients: A Randomized Placebo-Controlled Trial

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What is this study about?

The study looks at people with Rheumatoid arthritis who experience ongoing fatigue. It tests whether a high dose of the vitamin thiamine hydrochloride can lessen that tiredness, compared with a matching sugar pill called Placebo. The vitamin is taken as oral tablets.

The purpose is to find out if the high‑dose vitamin improves overall fatigue after four weeks. Participants are randomly assigned to receive either the vitamin tablets or the placebo, without knowing which they receive. They complete a questionnaire called the BRAF-MDQ at the start and after four weeks to report how tired they feel in physical, mental and emotional areas, and they also rate pain and overall health using simple scales. No other procedures are involved beyond the brief visits for the questionnaires.

1 baseline assessment

attend the first visit after joining the study. during this visit, complete the braf-mdq questionnaire that measures fatigue in several areas, answer the braf-nrs scales for severity, effect and coping, and fill out the eq-5d-5l questionnaire about overall health.

a health professional will count the number of swollen and tender joints out of 28, record pain using a visual analogue scale from 0 to 100, and assess physical disability with the health assessment questionnaire.

a blood sample will be taken to measure c-reactive protein, an indicator of inflammation.

2 randomization and blinding

after the baseline assessment, you will be randomly assigned to receive either the high dose thiamine tablets or matching placebo tablets. the study is double-blind, meaning you and the study staff will not know which treatment you receive.

3 medication period (4 weeks)

take the assigned tablets by mouth once daily for four weeks.

if you are assigned to the active treatment, the tablet contains thiamine hydrochloride (vitamin b1). the total daily dose is 1800 mg, which corresponds to six tablets of 300 mg each.

if you are assigned to the placebo, you will take the same number of matching tablets that contain no active ingredient.

continue the daily intake at the same time each day for the entire 4‑week period.

4 final assessment at week 4

return for a visit at the end of the 4‑week medication period.

repeat the same questionnaires and clinical measurements performed at baseline, including the braf-mdq, braf-nrs, eq-5d-5l, joint counts, pain scale, health assessment questionnaire, and c-reactive protein blood test.

the results will be compared with the baseline values to evaluate any change in fatigue and other symptoms.

Who Can Join the Study?

Have an established diagnosis of rheumatoid arthritis (a condition where the immune system attacks the joints, causing pain and swelling).
Be older than 18 years of age.
Be able to read and understand Danish and give informed consent (agree to join the study after it is fully explained).
Score higher than 50 mm on a 100 mm visual analogue fatigue scale (a line where you mark how tired you feel, from 0 = no fatigue to 100 = extreme fatigue).
Agree to use effective contraception (a reliable method to prevent pregnancy) during the study period.

Who Cannot Join the Study?

Inability to read, write, or think clearly enough to fill out the study questionnaires due to illiteracy or cognitive impairment (trouble with thinking or memory).
Taking the steroid medication prednisone at a dose higher than 10 mg per day.
Having abnormal TSH levels, which indicates a problem with the thyroid gland (thyroid‑stimulating hormone).
Known allergic reaction to thiamine hydrochloride, the medicine being tested.
Having iron deficiency (low iron stores, measured by ferritin less than 15 µg/L).
Having folate deficiency (low folic acid, less than 9 nmol/L).
Having Vitamin B12 deficiency (low cobalamin, less than 200 pmol/L), which can cause fatigue and anemia.
Having Vitamin D deficiency (low vitamin D, less than 50 nmol/L).
Being pregnant.
Having another serious illness that can cause high fatigue, such as cancer, chronic kidney disease, chronic heart failure, or diabetes.
Changing the treatment for the inflammatory rheumatic disease (like rheumatoid arthritis) within the past 3 months.

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

Site Name	City	Country	Status
Sydvestjysk Sygehus	Esbjerg	Denmark

Other Sites

Site Name	City	Country	Status
Odense University Hospital	Odense	Denmark
Slagelse Hospital	Slagelse	Denmark

Trial status

Country	Status	Recruitment Start
Denmark	Not yet recruiting	01.07.2026

Trial locations

Investigated drugs:

Thiamine Hydrochloride

APOVIT B1 vitamin ekstra stærk is a tablet that contains thiamine, also known as vitamin B1. Thiamine is a nutrient that helps the body turn food into energy and supports the normal function of nerves and muscles. In this study, participants take the thiamine tablet at a higher amount than usual to see if it can reduce the feeling of tiredness that often occurs in people with rheumatoid arthritis. The medication is taken by mouth and is being compared to a placebo to determine its effect on fatigue.

Rheumatoid arthritis – Rheumatoid arthritis is a chronic condition that causes inflammation in the joints, especially the hands, wrists, and feet. The inflammation leads to swelling, stiffness, and warmth in the affected joints. Over time the joint lining thickens and can damage the cartilage and bone, reducing movement. The disease often starts gradually and may flare up with periods of increased symptoms followed by quieter phases. It can also affect other parts of the body, such as the skin, eyes, and lungs, as the inflammation spreads.

Trial ID:

2024-519268-41-00

Trial Phase:

Therapeutic confirmatory (Phase III)

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High-Dose Thiamine Hydrochloride for Reducing Fatigue in Rheumatoid Arthritis Patients: A Randomized Placebo-Controlled Trial

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?