Written by Alexa Heathorn, MS, CNS-c, Science Writer. Daily supplementation of vitamins B1 and B2 for 4 weeks significantly reduced perceived stress, improved sleep quality, and increased daytime alertness in adults experiencing moderate stress.

Stress and anxiety are common psychological conditions impacting society, relationships, and quality of life¹. While these two conditions are often intuitively linked, they have distinct definitions and neuropsychological processes¹. Anxiety is defined as an emotional response to the anticipation of danger- real or imagined²– while stress is a physiological response to a real or perceived threat (or stresser)¹.

Despite their differences, stress and anxiety share overlapping mechanisms. Both suppress the calming neurotransmitter GABA, stimulate the release of cortisol and adrenaline, and increase reactive oxygen species (ROS), promoting inflammation within the brain¹. This inflammatory response has been shown to disrupt sleep- affecting duration, quality, and regularity- which in turn increases the risk for a host of downstream consequences, including immune dysfunction, metabolic disease, gut dysbiosis, and cardiovascular disease¹.

Given the widespread prevalence of these conditions and the limitations of current treatments- including high cost, side effects, and limited efficacy- there is growing interest in safe, accessible alternatives. Nutrition interventions, particularly micronutrients like vitamins B1 and B2, have gained traction for their roles in supporting brain health and regulating stress response. These vitamins play critical roles in antioxidant defense, neurotransmitter synthesis, and mitochondrial energy metabolism, which are all processes essential to nervous system function and resilience¹.

Early research has explored the individual effects of vitamin B1 (thiamine) and B2 (riboflavin) on mental health, showing potential benefits in stress reduction, mood stabilization, and sleep enhancement. Several studies have reported associations between low intake of B vitamins and higher levels of stress, poor sleep quality, and increased mood disturbances¹. Vitamin B1, in particular, has been linked to reduced symptoms in individuals with Major Depressive Disorder when used as an adjunct to conventional treatment¹. Riboflavin, on the other hand, has shown promise in neurological applications, including migraine prevention and antioxidant support¹.

However, much of the existing literature has focused on multivitamin complexes or single-vitamin interventions, making it difficult to isolate the specific effects of B1 and B2—especially in combination. A recent study sought to fill this gap by conducting a randomized, placebo-controlled clinical trial assessing the impact of combined B1 and B2 supplementation on stress, anxiety, and sleep¹.

This trial enrolled 43 Chinese students between the ages of 18 and 25 with elevated scores of anxiety, stress, and sleep disturbances. Participants were randomly assigned to either the intervention group or the placebo group for a four-week trial period. The intervention group received two tablets daily: one containing 100 mg of vitamin B1 (thiamine) and one containing 100 mg of vitamin B2 (riboflavin)¹. The placebo group received two sucrose tablets identical in appearance, color, odor, and taste to maintain blinding¹. After four-week intervention period, outcomes in anxiety, perceived stress, sleep quality, and sleepiness were assessed using validated questionnaires¹.

The results were as follows:

• Anxiety:
  • Scores in the B1 & B2 group dropped slightly (45.8 → 44.0), but not significantly. In contrast, the placebo group’s scores increased (44.1 → 45.1).
• Perceived Stress:
  • Stress levels significantly decreased in the supplement group (21.5 → 15.5, p < 0.001), while the placebo group remained stable (20.3 → 19.8, p = 0.725).
• Sleep Quality
  • The supplement group saw notable improvement—falling asleep faster, waking less, and feeling more rested (8.0 → 6.3, p = 0.008). The placebo group worsened (5.7 → 7.4, p = 0.037).
• Sleepiness
  • The supplement group felt more alert, with scores dropping from 13.0 to 9.1 (p < 0.001), while the placebo group saw minimal change (10.6 → 10.3, p = 0.61).
• Vitamin Levels
  • Lab testing confirmed that the vitamins in the supplements were well absorbed.
    • Vitamin B1 rose from 159 to 1,333 ng (p < 0.001, adjusted p = 0.039)
    • Vitamin B2 rose from 308 to 6,123 ng (p < 0.001, adjusted p = 0.004)

These results suggest that vitamin B1 and B2 may help lower stress and improve sleep and energy—without major side effects.

While the results to this study are promising, it is important to keep a few limitations in mind:

• Small sample size.
  • The study was relatively small, only including 43 participants, a larger group may have produced different or more generalizable results.
• Short duration.
  • The intervention lasted just 4 weeks which may not have been long enough to fully assess the effects.
• Limited population.
  • All participants were Chinese college students. As a result, these findings may not apply to other age groups, life stages, or ethnic backgrounds.

This study adds to a growing body of evidence that targeted nutrition—specifically B1 and B2 supplementation—may be a safe and effective way to reduce stress and improve sleep. After just four weeks, participants who received the supplements experienced significantly lower stress, better sleep quality, and greater daytime alertness.

While anxiety scores did not improve significantly, the gains in stress reduction and sleep are clinically meaningful. These findings suggest B1 and B2 may offer a natural, affordable, and low-risk option for supporting mental health—especially during high-stress periods.

Further research is needed to understand long-term effects, evaluate benefits in more diverse populations, and explore the biological mechanisms behind these improvements.

Source:  Tao, Yingxuan, Murong Wu, Boyao Su, Heng Lin, Qianzi Li, Tian Zhong, Ying Xiao, and Xi Yu. “Impact of Vitamin B1 and Vitamin B2 Supplementation on Anxiety, Stress, and Sleep Quality: A Randomized, Double-Blind, Placebo-Controlled Trial.” Nutrients 17, no. 11 (2025): 1821.

© 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/license
s/by/4.0/).

Click here to read the full text study.

Posted July 29, 2025.

Alexa Heathorn, MS, CNS-c, is a clinical nutritionist specializing in metabolic health, hormonal balance, and gastrointestinal restoration through root-cause functional nutrition. She earned her master’s degree in Nutrition from Bastyr University and is currently a Certified Nutrition Specialist (CNS) candidate. Alexa also works as a research writer and functional health consultant, translating complex science into actionable strategies for practitioners and wellness companies. Learn more at www.bloomedwellness.com.

References:

1. Tao Y, Wu M, Su B, et al. Impact of Vitamin B1 and Vitamin B2 Supplementation on Anxiety, Stress, and Sleep Quality: A Randomized, Double-Blind, Placebo-Controlled Trial. Nutrients. May 27 2025;17(11)doi:10.3390/nu17111821
2. In: Walker HK, Hall WD, Hurst JW, eds. Clinical Methods: The History, Physical, and Laboratory Examinations. Butterworths Copyright © 1990, Butterworth Publishers, a division of Reed Publishing.; 1990.