Overview

SCIENTIFIC SCORE
Questionable
Based on 5 Researches
5.5
USERS' SCORE
Good
Based on 149 Reviews
8.9
Supplement Facts
Serving Size:   1 Softgel
Amount Per Serving
%DV
Vitamin D3 (as Cholecalciferol) (from Lanolin)
125 mcg (5,000 IU)
625%

Top Medical Research Studies

We conducted a thorough investigation into whether high-dose intermittent vitamin D3 could alleviate symptoms of chronic fatigue syndrome (CFS) and improve vascular health. This double-blind, randomized placebo-controlled trial involved patients meeting established criteria for CFS. Participants received either 100,000 units of vitamin D3 or a placebo every two months for six months.

Over the course of the study, we measured key outcomes such as arterial stiffness, blood pressure, cholesterol levels, and fatigue levels through various tests. Surprisingly, our findings showed that vitamin D3 treatment did not lead to any significant improvements in these areas. We observed only a slight increase in vitamin D levels in the treatment group, but this did not translate into better vascular health or reduced fatigue.

In conclusion, we honestly found that high-dose vitamin D3 did not offer any notable benefits for patients struggling with chronic fatigue syndrome. This study highlights the complexities of treating CFS and suggests that vitamin D3 may not be the solution some had hoped for.
Read More
We conducted a study to see if high-dose vitamin D3 could improve vascular health and reduce fatigue in individuals suffering from chronic fatigue syndrome (CFS). This was a well-structured trial involving 50 participants, all of whom met specific diagnostic criteria for CFS. Participants were divided into two groups: one received 100,000 units of vitamin D3 every two months, while the other received a placebo over a period of six months.

Despite a noticeable increase of 22 nmol/L in vitamin D levels for those who received the treatment compared to the placebo group, we found no significant benefits. There was no change in arterial stiffness, a key vascular health indicator, nor improvements in overall fatigue as measured by the Piper Fatigue scale.

In essence, our findings indicate that high-dose oral vitamin D3 does not offer the hoped-for relief in vascular function or fatigue for patients with chronic fatigue syndrome. This suggests that other therapeutic options may need to be explored for individuals suffering from this condition.
Read More
9.5
Vitamin D treatment enhances alertness
We explored the impact of vitamin D treatment on a case of excessive daytime sleepiness (EDS), specifically in the context of chronic fatigue syndrome. A 28-year-old woman was found to have low levels of vitamin D after experiencing four months of overwhelming fatigue and sleepiness, despite being tested for sleep disorders.

After starting vitamin D supplementation, her condition improved remarkably within just two weeks. Along with a boost in alertness, her associated symptoms like muscle pain and headaches began to fade. By the end of the treatment, her score on the Epworth Sleepiness Scale, which measures daytime sleepiness, dropped significantly, indicating much better daytime function.

This case suggests that vitamin D may play a role in improving symptoms commonly linked to chronic fatigue syndrome. While more research is needed to fully understand the mechanisms behind this improvement, our findings open the door to potentially screening patients with chronic fatigue for vitamin D deficiency to expedite treatment.
Read More

Most Useful Reviews

9.5
Pain and fatigue relief
The Vitamin D helped alleviate my chronic fatigue syndrome. My joints no longer hurt, and I regained energy that had been lacking. I also stopped experiencing frequent headaches, and my nails and hair became stronger. Remarkably, I didn't catch a cold during this period.
Read More
9.5
Chronic fatigue alleviated
Upon discovering I was deficient, I began taking Vitamin D3, which nearly eliminated my chronic fatigue syndrome. I highly recommend getting tested and ensuring proper vitamin intake.
Read More
8.8
Gradual symptom relief
After regularly taking Vitamin D, I noted a gradual improvement in chronic fatigue syndrome. My energy levels increased, and I experienced decreased joint pain and improved skin health. It's essential for maintaining bone health in the future.
Read More

Medical Researches

SCIENTIFIC SCORE
Questionable
Based on 5 Researches
5.5
  • All Researches
9.5
Vitamin D treatment enhances alertness
We explored the impact of vitamin D treatment on a case of excessive daytime sleepiness (EDS), specifically in the context of chronic fatigue syndrome. A 28-year-old woman was found to have low levels of vitamin D after experiencing four months of overwhelming fatigue and sleepiness, despite being tested for sleep disorders.

After starting vitamin D supplementation, her condition improved remarkably within just two weeks. Along with a boost in alertness, her associated symptoms like muscle pain and headaches began to fade. By the end of the treatment, her score on the Epworth Sleepiness Scale, which measures daytime sleepiness, dropped significantly, indicating much better daytime function.

This case suggests that vitamin D may play a role in improving symptoms commonly linked to chronic fatigue syndrome. While more research is needed to fully understand the mechanisms behind this improvement, our findings open the door to potentially screening patients with chronic fatigue for vitamin D deficiency to expedite treatment.
Read More
8
We conducted a double-blind, placebo-controlled trial to evaluate the effects of an oral food supplement (OFS) on long COVID patients, particularly focusing on chronic inflammation and fatigue. The supplement included components like rosehip, propolis, royal jelly, and zinc, with vitamin C being a key ingredient.

Through our two-month study, which involved giving participants either the OFS or a placebo, we made some interesting observations. Notably, patients who took the OFS experienced a significant reduction in inflammatory markers, which are often linked to chronic fatigue syndrome. This included improvements in the neutrophil-to-lymphocyte and monocyte-to-lymphocyte ratios.

We also noted a substantial increase in vitamin D levels among those taking the supplement, which correlated with enhanced quality of life and decreased fatigue as measured by the fatigue severity scale. Our findings suggest that the combination of ingredients in the OFS, particularly its vitamin D content, can help alleviate some symptoms associated with long COVID, especially chronic fatigue.

However, since the supplement included multiple active ingredients, isolating the specific impact of vitamin D on chronic fatigue syndrome is challenging. Still, the overall results indicate positive changes for patients dealing with the lingering effects of COVID.
Read More
8
Beta-glucan shows cognitive improvements
We conducted a randomized, double-blind, placebo-controlled trial to explore how yeast beta-glucan, along with multivitamins, affects individuals suffering from Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). In our study, 65 participants received either beta-glucan combined with vitamins and zinc or a placebo for 36 weeks.

Interestingly, while our primary focus was on beta-glucan, which was shown to significantly improve cognitive fatigue, the role of vitamin D3 within this combination was not clearly established. This makes it challenging to directly assess the impact of vitamin D3 alone on chronic fatigue syndrome outcomes.

Overall, we discovered that beta-glucan supplementation could positively influence cognitive fatigue, offering promise for future research on nutritional support in ME/CFS patients. However, definitive conclusions about vitamin D3's effectiveness remain inconclusive due to the combined nature of the treatment.
Read More
We conducted a thorough investigation into whether high-dose intermittent vitamin D3 could alleviate symptoms of chronic fatigue syndrome (CFS) and improve vascular health. This double-blind, randomized placebo-controlled trial involved patients meeting established criteria for CFS. Participants received either 100,000 units of vitamin D3 or a placebo every two months for six months.

Over the course of the study, we measured key outcomes such as arterial stiffness, blood pressure, cholesterol levels, and fatigue levels through various tests. Surprisingly, our findings showed that vitamin D3 treatment did not lead to any significant improvements in these areas. We observed only a slight increase in vitamin D levels in the treatment group, but this did not translate into better vascular health or reduced fatigue.

In conclusion, we honestly found that high-dose vitamin D3 did not offer any notable benefits for patients struggling with chronic fatigue syndrome. This study highlights the complexities of treating CFS and suggests that vitamin D3 may not be the solution some had hoped for.
Read More
We conducted a study to see if high-dose vitamin D3 could improve vascular health and reduce fatigue in individuals suffering from chronic fatigue syndrome (CFS). This was a well-structured trial involving 50 participants, all of whom met specific diagnostic criteria for CFS. Participants were divided into two groups: one received 100,000 units of vitamin D3 every two months, while the other received a placebo over a period of six months.

Despite a noticeable increase of 22 nmol/L in vitamin D levels for those who received the treatment compared to the placebo group, we found no significant benefits. There was no change in arterial stiffness, a key vascular health indicator, nor improvements in overall fatigue as measured by the Piper Fatigue scale.

In essence, our findings indicate that high-dose oral vitamin D3 does not offer the hoped-for relief in vascular function or fatigue for patients with chronic fatigue syndrome. This suggests that other therapeutic options may need to be explored for individuals suffering from this condition.
Read More

User Reviews

USERS' SCORE
Good
Based on 149 Reviews
8.9
  • All Reviews
  • Positive Reviews
  • Negative Reviews
9.5
Pain and fatigue relief
The Vitamin D helped alleviate my chronic fatigue syndrome. My joints no longer hurt, and I regained energy that had been lacking. I also stopped experiencing frequent headaches, and my nails and hair became stronger. Remarkably, I didn't catch a cold during this period.
Read More
9.5
Chronic fatigue alleviated
Upon discovering I was deficient, I began taking Vitamin D3, which nearly eliminated my chronic fatigue syndrome. I highly recommend getting tested and ensuring proper vitamin intake.
Read More
8.8
Gradual symptom relief
After regularly taking Vitamin D, I noted a gradual improvement in chronic fatigue syndrome. My energy levels increased, and I experienced decreased joint pain and improved skin health. It's essential for maintaining bone health in the future.
Read More
9.5
No fatigue experienced
I initially took a high dosage of Vitamin D for chronic fatigue syndrome, leading to superb benefits. I stopped feeling fatigued and could engage in physical activities joyfully, a marked change from my previous condition.
Read More
9
More energy daily
I've been taking vitamins for three months, and the fatigue I used to experience in the evenings has decreased. I now have enough energy and motivation throughout the day. The price is reasonable, and I recommend this for anyone during the colder months, especially for managing chronic fatigue syndrome.
Read More

Frequently Asked Questions

Chronic Fatigue Syndrome (CFS), also known as Myalgic Encephalomyelitis (ME), is a complex and debilitating condition characterized by profound fatigue that doesn’t improve with rest and worsens with physical or mental activity. This crippling fatigue is often accompanied by a variety of symptoms, including sleep disturbances, cognitive difficulties, muscle pain, and joint pain. Unlike typical tiredness, the fatigue experienced in CFS is long-lasting, and it can significantly hinder everyday activities and overall quality of life.

The precise cause of CFS remains unknown, but it is believed to be influenced by a combination of genetic, environmental, immunological, and psychological factors. Diagnosis primarily relies on a careful assessment of symptoms, as there are no definitive laboratory tests available. Treatment options focus on symptom management and may include lifestyle changes, physical therapy, medication for pain management, and cognitive behavioral therapy. Given the complexity and variability of the condition, individuals with CFS should consult healthcare professionals who specialize in this area to develop personalized management strategies.

Vitamin D is a fat-soluble vitamin that's essential for maintaining healthy bones and teeth, supporting immune system function, and facilitating normal cell growth and development. It plays a crucial role in calcium absorption in the gut, which is vital for bone health. Unlike most vitamins, our bodies can produce Vitamin D when exposed to sunlight, specifically UVB rays, which is why it’s often referred to as the "sunshine vitamin." However, depending on your geographical location, lifestyle, and skin type, getting sufficient Vitamin D from the sun alone can be challenging, particularly during the winter months.

In addition to sunlight, Vitamin D can be obtained from certain foods such as fatty fish (like salmon and mackerel), fish liver oils, and fortified foods like milk and cereals. Some individuals may also consider supplements, especially if they're at risk for deficiency. Insufficient vitamin D levels are linked to various health issues, including rickets in children, osteomalacia in adults, and even an increased risk of chronic diseases. Regularly checking your vitamin D levels and consulting with a healthcare professional can help ensure you're meeting your needs for optimal health.

Chronic Fatigue Syndrome (CFS) is a complex disorder characterized by extreme fatigue that doesn't improve with rest and may be exacerbated by physical or mental activity. While the causes of CFS remain unclear, there is ongoing research into various interventions that may alleviate its symptoms, including vitamin D supplementation. Some studies suggest that low levels of vitamin D could be linked to fatigue and may play a role in immune function, potentially impacting CFS. However, definitive clinical evidence confirming that vitamin D can help specifically with CFS is still lacking.

If you suspect that low vitamin D levels could be contributing to your fatigue, it might be worthwhile to discuss this with your healthcare provider. They can recommend blood tests to assess your vitamin D status and evaluate the potential benefits of supplementation if necessary. It's important to approach any treatment plan for Chronic Fatigue Syndrome comprehensively, as this multifaceted condition often requires a combination of therapies tailored to individual needs.

Based on user reviews, individuals taking Vitamin D for Chronic Fatigue Syndrome report varying times to see results, with many experiencing improvements within a couple of weeks. For instance, one user noted a boost in energy levels within just two weeks of starting the supplement, stating they no longer felt fatigued and their mood brightened significantly (Read Review). Others mentioned more gradual improvements, such as increased energy levels and reduced chronic pain after several months of consistent use (Read Review).

In summary, while some users witness noticeable benefits as soon as two weeks into their regimen, others find that it may take longer—up to several months—to fully appreciate the positive effects on their condition. Users have emphasized the importance of consistency in dosage and also recommended getting tested to ensure adequate vitamin levels, which may lead to more pronounced improvements in symptoms (Read Review). Ultimately, individual experiences vary, and it might require patience to find the right dosage that works for you.

The scientific evidence regarding the efficacy of dietary supplements for alleviating symptoms of Chronic Fatigue Syndrome (CFS) presents a mixed bag. Research investigating the role of high-dose vitamin D3 in CFS treatment has shown limited benefits. In studies where participants received high doses of vitamin D3, such as 100,000 units every two months, the results indicated no significant improvements in fatigue levels or vascular health indicators compared to placebo groups ([5]). Therefore, while vitamin D deficiency is a concern, it does not appear to be a standalone solution for CFS relief.

On the other hand, an oral food supplement containing a combination of ingredients including vitamin C, rosehip, propolis, and royal jelly showed promising results in patients suffering from long COVID, which overlaps with CFS symptoms. This study noted significant reductions in inflammatory markers and improved fatigue related to vitamin D levels ([1]). However, because multiple active ingredients are involved, isolating the exact impact of each component, including vitamin D, remains challenging. Thus, while certain supplements show potential, definitive conclusions about vitamin D's effectiveness on its own in chronic fatigue syndrome are still lacking.

Based on user reviews, many individuals have reported significant improvements in their symptoms associated with chronic fatigue syndrome after beginning vitamin D supplementation. Users often notice a boost in energy levels, reduced joint pain, improved mood, and even enhancements in skin and hair health. For instance, one user observed that their energy returned, along with the alleviation of headaches and joint discomfort, stating, "I regained energy that had been lacking" (Read Review). Another reviewer mentioned that their chronic fatigue symptoms nearly vanished, emphasizing the importance of testing for vitamin deficiencies to achieve optimal results (Read Review).

While experiences differ, many users reported noticeable changes within weeks of consistent use, often highlighting improvements in daily functioning and overall well-being. For instance, users have reported feeling more alert during the day, reduced incidences of drowsiness, and enhanced mood stability (Read Review). Some even experience less fatigue in the evenings and find it easier to engage in physical activities (Read Review). As always, individual results can vary, but these anecdotal experiences underscore the potential benefits of vitamin D in managing chronic fatigue syndrome symptoms.

According to user reviews, many individuals have reported positive experiences when combining Vitamin D with other supplements to address Chronic Fatigue Syndrome (CFS). Several users mentioned taking Vitamin D along with omega-3 fatty acids and iron, noting that this combination led to significant improvements in energy levels, immune function, and overall health. For instance, one user stated that after complementing Vitamin D with omega-3, they experienced not only a boost in energy but also decreased hair loss, linking the combination to better outcomes overall (Read Review). Another user emphasized that their fatigue dissipated while regularly using both Vitamin D3 and omega, stating they were able to perform physical activities they had previously struggled with (Read Review).

Additionally, some users pointed out the importance of nutrient synergy, with one mentioning that irregularities in their health improved when adjusting their dosages of both Vitamin D and other supplements (Read Review). This suggests that a tailored approach to supplement intake may be beneficial for those struggling with CFS. Overall, while experiences vary widely, the positive feedback on combining Vitamin D with compatible supplements underscores the potential for enhanced relief from chronic fatigue symptoms.

Users report varying experiences with the right dosage of Vitamin D for managing Chronic Fatigue Syndrome (CFS). Many users suggest starting with a higher dosage, such as 10,000 IU, particularly after confirming deficiency levels through blood tests. One user noted a dramatic improvement in energy and mood after taking 10,000 IU, indicating that this dosage might be particularly effective for those suffering from fatigue-related symptoms (Read Review). Others have found success with lower doses, such as 5,000 IU, with reports of significant benefits including better energy levels and reduced joint pain (Read Review).

Overall, users emphasize the importance of personalizing dosage based on individual health needs and deficiencies, suggesting that those unsure should consult with their healthcare providers. By aligning the dosage with personal health conditions, many have experienced weighty improvements in CFS symptoms, suggesting that finding the right amount is key to effective management (Read Review).

9.5
Mood improvement
After just two weeks of using this vitamin, my chronic fatigue syndrome has improved significantly. I no longer feel fatigued, and my mood has brightened. It's been challenging to find quality supplements, but this one is definitely worth it!
9.5
Reduced fatigue and pain
Regular intake of vitamin D has notably reduced my chronic fatigue syndrome symptoms, including drowsiness and apathy. I have more energy, improved mood, and less chronic pain.
9.5
Chronic fatigue alleviated
Upon discovering I was deficient, I began taking Vitamin D3, which nearly eliminated my chronic fatigue syndrome. I highly recommend getting tested and ensuring proper vitamin intake.
9.5
Pain and fatigue relief
The Vitamin D helped alleviate my chronic fatigue syndrome. My joints no longer hurt, and I regained energy that had been lacking. I also stopped experiencing frequent headaches, and my nails and hair became stronger. Remarkably, I didn't catch a cold during this period.
9.3
Enhanced mood stability
With regular vitamin D intake, I have experienced a significant reduction in chronic fatigue syndrome symptoms. I find it easier to wake up, feel less tired, and even my mood has improved. My joints' chronic pain has lessened, and I've noticed better skin and overall health.
9.5
No fatigue experienced
I initially took a high dosage of Vitamin D for chronic fatigue syndrome, leading to superb benefits. I stopped feeling fatigued and could engage in physical activities joyfully, a marked change from my previous condition.
8.8
Stronger immune system
Taking vitamin D alongside omega-3 has noticeably enhanced my immune system. My hair loss has decreased, and my nails are in excellent condition. When I stop taking them, I feel the fatigue return.
9.5
Enhanced workout stamina
Initially sceptical about vitamins, after taking D3 for half a year alongside Omega and iron, I've forgotten the feeling of chronic fatigue syndrome. Workouts are much easier, allowing me to endure even cardio, which I once despised.
7.5
Restored vitality
These vitamins are fantastic! After feeling intense fatigue and struggling with daytime sleep, I noticed a turnaround after taking them for just a week. I've regained energy and maintain a regular schedule, though I'm experiencing some sleep issues that may require adjustments to my dosage.
10
Spirited mood
Vitamin D transformed my life! At over 50, I struggled with chronic fatigue syndrome and depression. After tests revealed my vitamin D was low, I took 10,000 IU for a couple of months, raising my levels significantly. My mood drastically improved, and I've had exceptional immunity since—no illnesses at all!
9.5
Boosted energy
Excellent vitamin D3 with no side effects! I'm following my hematologist's advice to take 5,000 IU daily. From the first week, I noticed significant improvements—it's easier to wake up, and the chronic fatigue syndrome I experienced is gone.
9.5
Improved energy
Hello! Initially, I took 5000 IU of Vitamin D3 and then increased it to 10000 IU after a blood test showed low levels. Before, I had chronic fatigue syndrome, but now I feel energetic and revitalised. I’ve used Iherb products for a long time and they consistently benefit my health.
We conducted a thorough investigation into whether high-dose intermittent vitamin D3 could alleviate symptoms of chronic fatigue syndrome (CFS) and improve vascular health. This double-blind, randomized placebo-controlled trial involved patients meeting established criteria for CFS. Participants received either 100,000 units of vitamin D3 or a placebo every two months for six months.

Over the course of the study, we measured key outcomes such as arterial stiffness, blood pressure, cholesterol levels, and fatigue levels through various tests. Surprisingly, our findings showed that vitamin D3 treatment did not lead to any significant improvements in these areas. We observed only a slight increase in vitamin D levels in the treatment group, but this did not translate into better vascular health or reduced fatigue.

In conclusion, we honestly found that high-dose vitamin D3 did not offer any notable benefits for patients struggling with chronic fatigue syndrome. This study highlights the complexities of treating CFS and suggests that vitamin D3 may not be the solution some had hoped for.
8
We conducted a double-blind, placebo-controlled trial to evaluate the effects of an oral food supplement (OFS) on long COVID patients, particularly focusing on chronic inflammation and fatigue. The supplement included components like rosehip, propolis, royal jelly, and zinc, with vitamin C being a key ingredient.

Through our two-month study, which involved giving participants either the OFS or a placebo, we made some interesting observations. Notably, patients who took the OFS experienced a significant reduction in inflammatory markers, which are often linked to chronic fatigue syndrome. This included improvements in the neutrophil-to-lymphocyte and monocyte-to-lymphocyte ratios.

We also noted a substantial increase in vitamin D levels among those taking the supplement, which correlated with enhanced quality of life and decreased fatigue as measured by the fatigue severity scale. Our findings suggest that the combination of ingredients in the OFS, particularly its vitamin D content, can help alleviate some symptoms associated with long COVID, especially chronic fatigue.

However, since the supplement included multiple active ingredients, isolating the specific impact of vitamin D on chronic fatigue syndrome is challenging. Still, the overall results indicate positive changes for patients dealing with the lingering effects of COVID.

References

  1. Noce A, Marrone G, Di Lauro M, Vita C, Montalto G, et al. Potential Anti-Inflammatory and Anti-Fatigue Effects of an Oral Food Supplement in Long COVID Patients. Pharmaceuticals (Basel). 2024;17. doi:10.3390/ph17040463
  2. Witham MD, Adams F, McSwiggan S, Kennedy G, Kabir G, et al. Effect of intermittent vitamin D3 on vascular function and symptoms in chronic fatigue syndrome--a randomised controlled trial. Nutr Metab Cardiovasc Dis. 2015;25:287. doi:10.1016/j.numecd.2014.10.007
  3. McCarty DE. Resolution of hypersomnia following identification and treatment of vitamin d deficiency. J Clin Sleep Med. 2010;6:605.
  4. Lacasa M, Alegre-Martin J, Sentañes RS, Varela-Sende L, Jurek J, et al. Yeast Beta-Glucan Supplementation with Multivitamins Attenuates Cognitive Impairments in Individuals with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Randomized, Double-Blind, Placebo-Controlled Trial. Nutrients. 2023;15. doi:10.3390/nu15214504
  5. Witham MD, Adams F, McSwiggan S, Kennedy G, Kabir G, et al. Effect of intermittent vitamin D3 on vascular function and symptoms in chronic fatigue syndrome--a randomised controlled trial. Nutr Metab Cardiovasc Dis. 2015;25:287. doi:10.1016/j.numecd.2014.10.007
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