Should I take 150 mg of Vitamin B1 (Thiamine) at once or distribute it throughout the day?

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Last updated: March 15, 2025View editorial policy

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From the Guidelines

It is recommended to distribute the 150 mg of Vitamin B1 (Thiamine) throughout the day rather than taking it all at once, as this approach maximizes absorption and utilization of the vitamin. According to the espen micronutrient guideline 1, the suggested maintenance dose in proven deficiency is 50-100 mg/day, orally, which implies that taking a large dose at once may not be necessary.

Key Considerations

  • Vitamin B1 is water-soluble, meaning the body doesn't store excess amounts and will excrete what it cannot immediately use 1.
  • The guideline suggests that in case of suspicion of chronic deficiency without any acute disease, the oral route is adequate 1.
  • For optimal absorption, it is advisable to take vitamin B1 with food, and if stomach upset occurs, taking it with meals becomes even more important.

Distribution Recommendations

  • To distribute the 150 mg of Vitamin B1 throughout the day, consider taking 50 mg with each meal (breakfast, lunch, and dinner) to maximize absorption and utilization.
  • This approach is supported by the guideline's suggestion of 50-100 mg/day for maintenance dose in proven deficiency 1.

Important Notes

  • The recommended daily allowance for vitamin B1 is about 1.1-1.2 mg for adults, so a dosage of 150 mg daily should only be taken under healthcare provider supervision.
  • The espen micronutrient guideline 1 provides evidence-based recommendations for vitamin B1 intake in various clinical situations, and its suggestions should be followed to ensure optimal patient outcomes.

From the FDA Drug Label

OVERDOSAGE: Parenteral doses of 100 to 500 mg singly have been administered without toxic effects. However, dosages exceeding 30 mg three times a day are not utilized effectively. DOSAGE AND ADMINISTRATION: ...thiamine, 10 mg to 20 mg of thiamine hydrochloride are given IM three times daily for as long as two weeks.

  • The FDA drug label suggests that high doses of thiamine are not effectively utilized by the body.
  • It is recommended to distribute the dose throughout the day, as dosages exceeding 30 mg three times a day are not utilized effectively.
  • Therefore, it is recommended to distribute 150 mg of Vitamin B1 (Thiamine) throughout the day, rather than taking it all at once, to maximize effectiveness 2.

From the Research

Thiamine Dosage Recommendations

There are no specific guidelines on the optimal dose, mode of administration, frequency of administration, or duration of treatment for thiamine supplementation 3.

Distribution of Thiamine Intake

Some studies suggest that high-dose thiamine supplementation may be beneficial in certain conditions, such as preventing or accelerating recovery from exercise-induced fatigue 4 and preventing the development of experimental fatty liver driven by overnutrition 5. However, the optimal dosage regimen for these conditions is not well established.

Clinical Trials on Thiamine Dosage

A randomized controlled trial found no significant differences in cognitive function or neurological functioning between different thiamine dosage conditions, including 100 mg daily, 100 mg thrice daily, or 300 mg thrice daily, for 3 days in asymptomatic at-risk patients, and 100 mg thrice daily, 300 mg thrice daily, or 500 mg thrice daily, for 5 days in symptomatic patients 6.

Administration of Thiamine

Another study suggests that attaining high serum levels of thiamine during treatment may be important to restore cognitive function as quickly as possible, though the exact dosing and route needed for effective treatment is unknown 7.

Decision on 150 mg of Vitamin B1

Based on the available evidence, there is no clear recommendation on whether to take 150 mg of Vitamin B1 at once or distribute it throughout the day. The decision may depend on individual factors, such as the specific condition being treated or prevented, and should be made in consultation with a healthcare professional.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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