Overview

SCIENTIFIC SCORE
Possibly Effective
Based on 9 Researches
7.9
USERS' SCORE
Good
Based on 22 Reviews
8.4
Supplement Facts
Serving Size: 1 Tablet
Amount Per Serving
%DV
Vitamin B₁₂ (as Methylcobalamin)
1,000 mcg
41,667%

Top Medical Research Studies

8
Vitamin B12 promotes sleep in rats
We sought to determine the impact of vitamin B12 (VB12) on sleep patterns in rats, particularly considering its potential benefits for those struggling with insomnia. By giving rats a daily intravenous dose of VB12, we monitored their sleep using polysomnographic recordings over a four-day period.

During our observations, we noticed a significant increase in non-rapid eye movement (NREM) sleep on the second and third days of VB12 administration. Interestingly, REM sleep also showed a notable boost on the second day. The enhancements in sleep were particularly evident during the light period, indicating that vitamin B12 could play a role in promoting sleep at those times.

Additionally, we found that the rats receiving vitamin B12 exhibited serum levels that were 40 times higher than those in control rats, suggesting a robust absorption and impact of the vitamin. Overall, our findings indicate that administering VB12 peripherally does have positive effects on sleep in rats, especially during the light hours.
Read More
9
Vitamin B12 treatment for insomnia
We explored how vitamin B12, specifically methylcobalamin, could help treat persistent sleep-wake disorders in adolescents. In this study, two patients—a 15-year-old girl with delayed sleep phase syndrome and a 17-year-old boy with hypernychthemeral syndrome—struggled with sleep issues that significantly impacted their daily lives and school attendance.

Upon administration of high doses of methylcobalamin (3,000 micrograms per day), we observed immediate improvements in their sleep-wake patterns. Notably, the girl's sleep duration reduced from ten hours to seven, while her sleep onset time shifted from 2 a.m. to midnight. The boy’s sleep-wake cycle also improved, with a decrease in the cycle duration from 24.6 hours to 24 hours.

Interestingly, neither patient showed any signs of vitamin B12 deficiency, and their serum B12 levels were in the normal range or higher during treatment. This suggests that high-dose vitamin B12 might play a role in resetting and improving sleep-wake schedules in these adolescents, linking to the circadian rhythms that govern sleep.

While more research is needed, these findings present a promising perspective on how vitamin B12 may help alleviate certain insomnia symptoms in young people.
Read More
8
Vitamin B12 shows potential for insomnia
We investigated whether vitamin B12 (methylcobalamin) could assist adolescents struggling with persistent sleep-wake schedule disorders. Remarkably, two patients—a 15-year-old girl with delayed sleep phase syndrome and a 17-year-old boy with hypernychthemeral syndrome—saw impressive improvements after taking high doses of B12 daily.

The girl's sleep improved significantly, reducing her sleep time from 10 hours to 7 hours and enabling her to fall asleep earlier. The boy's sleep-wake cycle also showed a positive shift. Overall, these initial findings suggest that B12 might play a helpful role in addressing certain sleep disorders in young individuals.
Read More

Most Useful Reviews

9.5
Improved sleep quality
I confirm the results on myself! After giving birth, I experienced constant fatigue and insomnia. Initially, I didn't see any effects from the tablets, but I persevered. Gradually, I realised these vitamins are highly effective for me: I now fall asleep quicker, return to sleep effortlessly after waking during the night, and feel more refreshed in the morning. I strongly recommend this for anyone struggling with insomnia, especially fellow mothers!
Read More
9.5
Normalised sleep cycle
I feel sleepy, and the next morning I wake up refreshed. Taking Vitamin B12 under the tongue before bed has regulated my sleep pattern and alleviated my insomnia. I noticed that when my B12 levels were low, I felt irritable, but this supplement has provided better mental stability.
Read More
9.5
Helplessness lifted
I struggled daily with insomnia until I found this product. Now, I feel sleepy, and my eyes appear brighter and less tired each morning.
Read More

Medical Researches

SCIENTIFIC SCORE
Possibly Effective
Based on 9 Researches
7.9
  • All Researches
9
Vitamin B12 treatment for insomnia
We explored how vitamin B12, specifically methylcobalamin, could help treat persistent sleep-wake disorders in adolescents. In this study, two patients—a 15-year-old girl with delayed sleep phase syndrome and a 17-year-old boy with hypernychthemeral syndrome—struggled with sleep issues that significantly impacted their daily lives and school attendance.

Upon administration of high doses of methylcobalamin (3,000 micrograms per day), we observed immediate improvements in their sleep-wake patterns. Notably, the girl's sleep duration reduced from ten hours to seven, while her sleep onset time shifted from 2 a.m. to midnight. The boy’s sleep-wake cycle also improved, with a decrease in the cycle duration from 24.6 hours to 24 hours.

Interestingly, neither patient showed any signs of vitamin B12 deficiency, and their serum B12 levels were in the normal range or higher during treatment. This suggests that high-dose vitamin B12 might play a role in resetting and improving sleep-wake schedules in these adolescents, linking to the circadian rhythms that govern sleep.

While more research is needed, these findings present a promising perspective on how vitamin B12 may help alleviate certain insomnia symptoms in young people.
Read More
8
Vitamin B12 shows potential for insomnia
We investigated whether vitamin B12 (methylcobalamin) could assist adolescents struggling with persistent sleep-wake schedule disorders. Remarkably, two patients—a 15-year-old girl with delayed sleep phase syndrome and a 17-year-old boy with hypernychthemeral syndrome—saw impressive improvements after taking high doses of B12 daily.

The girl's sleep improved significantly, reducing her sleep time from 10 hours to 7 hours and enabling her to fall asleep earlier. The boy's sleep-wake cycle also showed a positive shift. Overall, these initial findings suggest that B12 might play a helpful role in addressing certain sleep disorders in young individuals.
Read More
8
Vitamin B12 aids sleep-wake disorders
We explored the effects of Vitamin B12 on patients with long-standing sleep-wake rhythm disorders. In one case, a 15-year-old blind girl with a 25-hour sleep cycle improved dramatically after starting a regimen of 1.5 mg of B12 three times a day. Her sleep pattern aligned with the 24-hour cycle, but, after stopping the supplement, her issues returned within two months.

Similarly, a 55-year-old man with delayed sleep phase syndrome also benefitted from B12, experiencing sustained improvement for over six months. These findings suggest Vitamin B12 may be a valuable treatment for certain sleep-wake rhythm disorders.
Read More
We explored the relationship between vitamin B12 levels and insomnia in a case involving a woman experiencing excessive daytime sleepiness alternating with insomnia. This case fit the criteria for a non-24-hour sleep-wake disorder, where traditional treatments failed to provide relief.

Upon further examination, we discovered deficiencies not just in vitamin B12, but also in vitamin D3 and folic acid. After addressing these deficiencies through supplementation, the subject reported a return to a 24-hour sleep-wake cycle.

However, it's essential to note that the improvement in sleep patterns remained detached from the external light-dark environment. This raises the intriguing question of whether vitamin B12's influence is direct or if it simply coexists with other factors influencing sleep.

While there were notable changes after treatment, isolating the specific effect of vitamin B12 on insomnia from the other vitamins administered remains a challenge. Thus, we observe that while vitamin B12 is part of the bigger picture, its individual effectiveness in treating insomnia cannot be confirmed from this study alone.
Read More
In our exploration of insomnia treatment, we worked with 60 patients diagnosed with the condition. They were split into two groups: one received the Magnesium-melatonin-vitamin B complex, while the other acted as a control. The specific goal was to determine if this combination, which included Vitamin B12, could effectively improve sleep quality over a three-month period.

We found that participants receiving the Magnesium-melatonin-vitamin B complex reported a reduction in insomnia symptoms, as indicated by the Athens Insomnia Scale scores. Initially, the average sleep problem scores were quite similar between both groups, showing they were compatible at the start. However, after three months, the treatment group saw their insomnia scores significantly drop, suggesting that the supplement had a beneficial impact.

While the findings point to the treatment's effectiveness, it's essential to note that Vitamin B12 was part of a combination therapy. This means we cannot isolate its specific contribution to the improvement seen. As such, while we can say that the combination helped with insomnia, we need further studies to understand the exact role of Vitamin B12 in this context.
Read More

User Reviews

USERS' SCORE
Good
Based on 22 Reviews
8.4
  • All Reviews
  • Positive Reviews
  • Negative Reviews
9.5
Improved sleep quality
I confirm the results on myself! After giving birth, I experienced constant fatigue and insomnia. Initially, I didn't see any effects from the tablets, but I persevered. Gradually, I realised these vitamins are highly effective for me: I now fall asleep quicker, return to sleep effortlessly after waking during the night, and feel more refreshed in the morning. I strongly recommend this for anyone struggling with insomnia, especially fellow mothers!
Read More
9.5
Normalised sleep cycle
I feel sleepy, and the next morning I wake up refreshed. Taking Vitamin B12 under the tongue before bed has regulated my sleep pattern and alleviated my insomnia. I noticed that when my B12 levels were low, I felt irritable, but this supplement has provided better mental stability.
Read More
9.5
Helplessness lifted
I struggled daily with insomnia until I found this product. Now, I feel sleepy, and my eyes appear brighter and less tired each morning.
Read More
9.5
Great for sleep
This really helps me sleep! I take vitamin B12 daily for insomnia, and it’s an excellent product. It tastes good and dissolves quickly. After struggling with insomnia, I now sleep 6-7 hours each night without issues. If you have this problem, I recommend giving B12 a try; you may find it beneficial.
Read More
9.5
Relieved insomnia
Vitamin B12 is known for enhancing alertness, cognition, energy, mood, and also for relieving insomnia.
Read More

Frequently Asked Questions

Insomnia is a common sleep disorder characterized by the inability to fall asleep, stay asleep, or wake up too early and not be able to go back to sleep. Individuals experiencing insomnia may find that it affects their daytime functioning, leading to issues such as fatigue, mood disturbances, and difficulty concentrating. Insomnia can be classified into two main types: acute insomnia, which lasts for a short period often triggered by stress or life changes, and chronic insomnia, which occurs at least three times a week for three months or longer, and may require more in-depth evaluation and treatment.

Numerous factors can contribute to insomnia, including stress, anxiety, poor sleep habits, medical conditions, and the use of certain medications. Treatment for insomnia typically involves a combination of lifestyle changes, cognitive behavioral therapy for insomnia (CBT-I), and sometimes medication. Establishing a consistent sleep routine, creating a comfortable sleep environment, and practicing relaxation techniques can help improve sleep quality. If insomnia persists, it is advisable to consult a healthcare professional for proper diagnosis and customized treatment options.

Vitamin B12, also known as cobalamin, is a water-soluble vitamin that plays a crucial role in several vital functions in the human body. It is essential for red blood cell formation, neurological function, and DNA synthesis. Naturally occurring in animal products, the vitamin can be found in high concentrations in meat, fish, eggs, and dairy, making it particularly important for those following a vegetarian or vegan diet, as plant-based sources of B12 are limited and often require supplementation.

A deficiency in vitamin B12 can lead to serious health issues, including anemia, fatigue, memory problems, and nerve damage. Due to its significance, it's crucial for individuals, particularly those at risk of deficiency, to ensure adequate intake through diet or supplementation. For most adults, the recommended daily allowance (RDA) is around 2.4 micrograms, though pregnant or breastfeeding women may require higher amounts. If you're considering B12 supplements, it's advisable to consult with a healthcare provider to determine the best option for your specific needs and health status.

Based on user reviews, results from taking this supplement for insomnia can vary significantly. Some users, like the individual who described feeling like a "new person" after discovering their vitamin B12 deficiency, reported noticeable improvements in sleep quality shortly after starting the supplement. Specifically, this user mentioned feeling it was effective for their insomnia after a relatively short duration (Read Review). Others noted effects within as little as 15 minutes after taking the supplement (Read Review).

Conversely, some users experienced no improvement even after several weeks. For instance, a reviewer remarked that after 25 days of use, they saw no changes regarding their focus or insomnia (Read Review). This highlights a range of responses among users, suggesting that while some may find relief quickly, others may need more time or possibly a different approach to their insomnia. As such, individuals may want to be patient and observe their body's response over a few weeks to determine if the supplement is effective for them.

The scientific research on Vitamin B12's effects on insomnia has shown promising potential, particularly in specific cases. For instance, studies involving adolescents with sleep-wake disorders have demonstrated significant improvements in sleep patterns after high doses of Vitamin B12, such as in a case where a 15-year-old girl experienced a reduction in sleep duration from ten hours to seven, and shifted her sleep onset from 2 a.m. to midnight ([8]). Similarly, another case documented a blind girl with a chaotic sleep-wake cycle who improved after taking Vitamin B12, aligning her rhythm closer to a typical 24-hour cycle, although the benefits ceased after discontinuation ([9]).

However, the relationship between Vitamin B12 and insomnia is complex and not entirely straightforward. Larger studies, including one assessing 512 adults in Greece, indicated that lower levels of Vitamin B12 correlated with increased insomnia symptoms (particularly in elderly and female subjects), but did not find a direct link to overall sleep quality ([3]). Furthermore, while some combined therapies using Magnesium, Melatonin, and Vitamin B12 showed reductions in insomnia symptoms, it remains unclear how much of this effect can be attributed specifically to Vitamin B12 since it was part of a multi-component treatment regimen ([6]). Overall, while there is some evidence supporting the use of Vitamin B12 in treating insomnia in certain populations, further research is essential to clarify its efficacy and the mechanisms at play.

Users have reported a variety of improvements in their insomnia symptoms after taking this vitamin B12 supplement, although individual experiences do vary. Some reviewers, like one new mother, shared that they experienced effective results over time, allowing them to fall asleep faster, return to sleep more easily after waking, and wake up feeling refreshed (Read Review). Others highlighted their newfound ability to regulate their sleep patterns, often feeling drowsy soon after taking the supplement, with noticeable improvements in morning alertness (Read Review).

Several users indicated even more rapid effects, with one noting they felt sleepy within 15 minutes of use, quickly alleviating their insomnia (Read Review). Additionally, many have reported improvements in their overall mood and energy levels alongside better sleep quality, which underscores the multifaceted benefits users are experiencing from this supplement (Read Review). Nevertheless, it’s worth mentioning that not all users found success; some reported no change after extended use (Read Review). Overall, while many users experienced positive results, it's important to keep in mind that responses can vary based on individual health conditions and needs.

Users have had varied experiences when combining this vitamin B12 supplement with other treatments for insomnia. Some reported significant improvements in their sleep quality, particularly when integrating Vitamin B12 with melatonin. One reviewer noted that the addition of methylcobalamin, which supports the nervous system, complemented their melatonin use, further aiding their insomnia issues (Read Review). Another user reported that taking Vitamin B12 helped regulate their sleep patterns, allowing them to feel refreshed in the morning (Read Review).

Conversely, some reviewers expressed that combining this supplement with other sleep aids did not yield the desired results. One user mentioned no improvements after 25 days of use despite higher expectations with the B12 supplement (Read Review). Additionally, a reviewer who previously used another brand successfully found that this particular one worsened their insomnia, indicating the importance of personalization when it comes to supplement choices (Read Review). This suggests that while many users can find beneficial combinations, individual responses to supplements can vary widely, making it essential to tailor approaches to their unique needs.

The research on vitamin B12 (specifically methylcobalamin) suggests that higher doses may be beneficial for treating insomnia, particularly in specific disorders related to sleep-wake rhythms. For instance, studies indicate that a daily dose of 3,000 micrograms (or 3 mg) showed significant improvements in adolescents with sleep disorders, including one case where a girl's sleep duration was reduced from ten hours to seven hours with enhanced sleep onset times [8]. Another investigation involving a 15-year-old blind girl suggested that a regimen of 1.5 mg taken three times daily (totaling 4.5 mg) effectively helped align her sleep-wake cycle with a 24-hour rhythm [9].

However, it is essential to note that the optimal dosage can vary based on individual circumstances and underlying conditions. Various studies indicate that while B12 supplementation might aid certain insomnia symptoms, further research is still required to fully understand its effectiveness and the ideal dosing strategy for different populations. Overall, high-dose vitamin B12 appears promising for certain types of insomnia, but personalized recommendations and medical guidance are necessary to determine the appropriate amount for individuals [4].

8.3
Miracle for insomnia
I struggled with insomnia and discovered through a blood test that my vitamin B12 was severely depleted. It was alarming, especially since my haemoglobin levels were low. After taking this vitamin, I experienced a remarkable improvement; I feel like a new person. Highly recommended!
8.8
Effective sleep aid
I always turn to this product for insomnia and foot numbness. While I'm uncertain about the numbness effects, it has proven effective for my insomnia. I take it before bed, and it dissolves under my tongue, making me sleepy within 15 minutes. The pleasant taste encourages regular use, despite some grittiness compared to previous brands. Overall, it's cost-effective if it helps me sleep.
4.8
No effect on focus
I did not observe any changes in my concentration, but my circadian rhythm has improved—I now sleep on time and wake up early. Initially, I aimed to address my insomnia, but after 25 days, I did not notice increased focus. I won’t repurchase and prefer to eat liver and meat for better results.
9.5
Improved sleep quality
I confirm the results on myself! After giving birth, I experienced constant fatigue and insomnia. Initially, I didn't see any effects from the tablets, but I persevered. Gradually, I realised these vitamins are highly effective for me: I now fall asleep quicker, return to sleep effortlessly after waking during the night, and feel more refreshed in the morning. I strongly recommend this for anyone struggling with insomnia, especially fellow mothers!
9.5
Normalised sleep cycle
I feel sleepy, and the next morning I wake up refreshed. Taking Vitamin B12 under the tongue before bed has regulated my sleep pattern and alleviated my insomnia. I noticed that when my B12 levels were low, I felt irritable, but this supplement has provided better mental stability.
8.8
Enhanced overall mood
After undergoing tests, my doctor advised me to take these capsules. Although I haven’t finished the full course, I already feel the benefits: improved mood, increased energy in the mornings, and better quality sleep with less insomnia. These results are significant for me.
7.5
Helpful with melatonin
The low price of methylcobalamin, which aids the nervous system and enhances melatonin effectiveness, suits me perfectly as I suffer from spinal stenosis and insomnia while taking 15-20 mg of melatonin.
1
Not effective
I avoid eating much meat or eggs, making B12 supplementation crucial. I previously tried another brand that effectively alleviated my insomnia, but this one has huge tablets that take a long time to dissolve, and my insomnia has worsened since switching. It didn’t work for me.
9
Vitamin B12 treatment for insomnia
We explored how vitamin B12, specifically methylcobalamin, could help treat persistent sleep-wake disorders in adolescents. In this study, two patients—a 15-year-old girl with delayed sleep phase syndrome and a 17-year-old boy with hypernychthemeral syndrome—struggled with sleep issues that significantly impacted their daily lives and school attendance.

Upon administration of high doses of methylcobalamin (3,000 micrograms per day), we observed immediate improvements in their sleep-wake patterns. Notably, the girl's sleep duration reduced from ten hours to seven, while her sleep onset time shifted from 2 a.m. to midnight. The boy’s sleep-wake cycle also improved, with a decrease in the cycle duration from 24.6 hours to 24 hours.

Interestingly, neither patient showed any signs of vitamin B12 deficiency, and their serum B12 levels were in the normal range or higher during treatment. This suggests that high-dose vitamin B12 might play a role in resetting and improving sleep-wake schedules in these adolescents, linking to the circadian rhythms that govern sleep.

While more research is needed, these findings present a promising perspective on how vitamin B12 may help alleviate certain insomnia symptoms in young people.
8
Vitamin B12 aids sleep disorders
We explored how vitamin B12 influences insomnia related to different sleep-wake rhythm disorders. In this study, two patients were treated with vitamin B12 to see if it could help regulate their sleep cycles.

The first patient, a 15-year-old blind girl, battled a free-running sleep-wake rhythm known as hypernychthemeral syndrome for 13 years. Despite several attempts to synchronize her sleep-wake cycle with the typical 24-hour environment, she struggled to do so. After starting a daily regimen of vitamin B12 (1.5 mg taken three times a day), we observed that her sleep-wake rhythm began to align with the 24-hour cycle and remained stable as long as she continued the treatment. However, her free-running rhythm returned within two months after stopping the vitamin B12.

The second patient, a 55-year-old man, had been dealing with delayed sleep phase syndrome since the age of 18. After taking vitamin B12 at the same dosage, he reported an improvement in his sleep-wake disorder that lasted over six months while he remained on the medication.

Although we noted some positive outcomes from vitamin B12 administration, it's essential to acknowledge that the findings are based on a small sample size, which may limit the broader implications of these results.
We assessed the relationship between vitamin B12 levels and insomnia symptoms in a diverse group of adults visiting primary healthcare clinics in Greece. Our research involved 512 participants, from which we gathered a variety of information including age, weight, and health history. Using standardized scales, we measured excessive daytime sleepiness, insomnia symptoms, and overall sleep quality.

Our findings highlighted that lower vitamin B12 levels, particularly below 342 pg/mL, were linked to increased insomnia symptoms. This association was particularly pronounced in certain groups, such as elderly, non-obese, and female participants. Interestingly, we found that excessive daytime sleepiness connected with low B12 levels only affected obese participants.

However, we did not find a significant connection between vitamin B12 levels and poor overall sleep quality. This indicates that while vitamin B12 may play a role in insomnia for specific individuals, its impact on sleep quality itself remains unclear. Therefore, while our study sheds light on these associations, further research is needed to explore the underlying dynamics between sleep and vitamin B12 more fully.
In our exploration of insomnia treatment, we worked with 60 patients diagnosed with the condition. They were split into two groups: one received the Magnesium-melatonin-vitamin B complex, while the other acted as a control. The specific goal was to determine if this combination, which included Vitamin B12, could effectively improve sleep quality over a three-month period.

We found that participants receiving the Magnesium-melatonin-vitamin B complex reported a reduction in insomnia symptoms, as indicated by the Athens Insomnia Scale scores. Initially, the average sleep problem scores were quite similar between both groups, showing they were compatible at the start. However, after three months, the treatment group saw their insomnia scores significantly drop, suggesting that the supplement had a beneficial impact.

While the findings point to the treatment's effectiveness, it's essential to note that Vitamin B12 was part of a combination therapy. This means we cannot isolate its specific contribution to the improvement seen. As such, while we can say that the combination helped with insomnia, we need further studies to understand the exact role of Vitamin B12 in this context.
We explored the relationship between vitamin B12 levels and insomnia in a case involving a woman experiencing excessive daytime sleepiness alternating with insomnia. This case fit the criteria for a non-24-hour sleep-wake disorder, where traditional treatments failed to provide relief.

Upon further examination, we discovered deficiencies not just in vitamin B12, but also in vitamin D3 and folic acid. After addressing these deficiencies through supplementation, the subject reported a return to a 24-hour sleep-wake cycle.

However, it's essential to note that the improvement in sleep patterns remained detached from the external light-dark environment. This raises the intriguing question of whether vitamin B12's influence is direct or if it simply coexists with other factors influencing sleep.

While there were notable changes after treatment, isolating the specific effect of vitamin B12 on insomnia from the other vitamins administered remains a challenge. Thus, we observe that while vitamin B12 is part of the bigger picture, its individual effectiveness in treating insomnia cannot be confirmed from this study alone.

References

  1. Ohta T, Ando K, Iwata T, Ozaki N, Kayukawa Y, et al. Treatment of persistent sleep-wake schedule disorders in adolescents with methylcobalamin (vitamin B12). Sleep. 1991;14:414.
  2. Okawa M, Mishima K, Nanami T, Shimizu T, Iijima S, et al. Vitamin B12 treatment for sleep-wake rhythm disorders. Sleep. 1990;13:15.
  3. Bouloukaki I, Lampou M, Raouzaiou KM, Lambraki E, Schiza S, et al. Association of Vitamin B12 Levels with Sleep Quality, Insomnia, and Sleepiness in Adult Primary Healthcare Users in Greece. Healthcare (Basel). 2023;11. doi:10.3390/healthcare11233026
  4. Radlberger RF, Kunz AB. Vitamin D deficiency promoting non-24 h sleep-wake disorder: a case report. Front Neurol. 2023;14:1141835. doi:10.3389/fneur.2023.1141835
  5. Xiong S, Liu Z, Yao N, Zhang X, Ge Q. The independent association between vitamin B12 and insomnia in Chinese patients with type 2 diabetes mellitus: a cross-sectional study. Nutr Diabetes. 2022;12:3. doi:10.1038/s41387-022-00181-8
  6. Djokic G, Vojvodić P, Korcok D, Agic A, Rankovic A, et al. The Effects of Magnesium - Melatonin - Vit B Complex Supplementation in Treatment of Insomnia. Open Access Maced J Med Sci. 2019;7:3101. doi:10.3889/oamjms.2019.771
  7. Chang HY, Sei H, Morita Y. Effects of intravenously administered vitamin B12 on sleep in the rat. Physiol Behav. 1995;57:1019.
  8. Ohta T, Ando K, Iwata T, Ozaki N, Kayukawa Y, et al. Treatment of persistent sleep-wake schedule disorders in adolescents with methylcobalamin (vitamin B12). Sleep. 1991;14:414.
  9. Okawa M, Mishima K, Nanami T, Shimizu T, Iijima S, et al. Vitamin B12 treatment for sleep-wake rhythm disorders. Sleep. 1990;13:15.
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