Overview

SCIENTIFIC SCORE
Possibly Effective
Based on 15 Researches
7.6
USERS' SCORE
Good
Based on 13 Reviews
8.6
Supplement Facts
Serving Size:  1 Tablet
Amount Per Serving
%DV
Vitamin B12(as Methylcobalamin)
5,000 mcg
208,330%

Top Medical Research Studies

9
We examined a case of a 51-year-old Ugandan man who experienced recurring lower limb weakness linked to pernicious anemia, an autoimmune condition causing vitamin B12 deficiency. After initial treatments, his symptoms reappeared, leading to further testing that confirmed the diagnosis.

Treatment with vitamin B12 injections significantly improved his condition. This case emphasizes the need for healthcare providers to recognize the signs of vitamin B12 deficiency early, particularly in resource-limited settings, to ensure timely diagnosis and treatment.
Read More
We explored the intriguing case of a 56-year-old man diagnosed with Biermer's disease, also known as pernicious anemia, an autoimmune condition that leads to a lack of intrinsic factor and, consequently, vitamin B12 malabsorption. This patient presented with unusual symptoms: not just digestive concerns like melena, but also notable neurological effects such as memory issues and gait disturbances.

During our examination, we discovered symptoms indicative of cerebellar ataxia, along with a red and swollen limb that pointed toward deep vein thrombosis (DVT). The tests revealed severe macrocytic anemia and confirmed a deficiency in vitamin B12 while keeping folate levels normal. Following a thorough diagnosis—including gastroscopy, ultrasound, and blood tests—we initiated a treatment plan that included vitamin B12 supplementation and anticoagulant therapy.

The outcome of our intervention was promising, with significant clinical improvement observed in the patient’s condition. Our findings reinforce the essential role of vitamin B12 in managing this type of autoimmune disorder, particularly when neurological and cardiovascular complications arise.
Read More
We investigated the potential of vitamin B12 as a treatment for rheumatoid arthritis, particularly focusing on its ability to target an enzyme called peptidylarginine deiminase isoform 4 (PADI-4). PADI-4 plays a crucial role in a process called citrullination, which is often disrupted in autoimmune conditions like rheumatoid arthritis.

Our findings revealed that vitamin B12 effectively inhibits PADI-4, showing a preference for this enzyme over another similar one, PADI-2. This inhibition corresponds to a decrease in overall cellular citrullination, including the citrullination of histone H3, which is also mediated by PADI-4.

Additionally, we observed that hydroxocobalamin, a special form of vitamin B12, significantly reduced the severity of collagen type II antibody-induced arthritis in mice. It also lowered the expression of key inflammatory factors and cytokines associated with rheumatoid arthritis, such as IL-17A, TNFα, and IL-6.

These promising results suggest that vitamin B12 might be an effective therapeutic avenue for managing rheumatoid arthritis, warranting further investigation in future studies.
Read More

Most Useful Reviews

9
Pain relief
9 people found this helpful
I have rheumatoid arthritis and, in 2010, my pain worsened significantly. I discovered that a gluten-free diet alleviated most of my pain, but I still faced severe discomfort in my feet and hands. After researching B12 deficiency, I started taking Jarrow methyl B12 and I now experience minimal pain. I'm regaining my life.
Read More
9
Symptoms resolved
8 people found this helpful
As a vegetarian for four years, I neglected my B12 intake, causing gastrointestinal issues. After using this product, my discomfort vanished. I highly recommend it to vegetarians and vegans needing B12 for their autoimmune disorder.
Read More
9
Improved absorption
4 people found this helpful
Methylcobalamin is what you need! These dissolve under the tongue for better absorption. My B12 levels rose significantly after struggling to absorb it from food. I will continue purchasing this product.
Read More

Medical Researches

SCIENTIFIC SCORE
Possibly Effective
Based on 15 Researches
7.6
  • All Researches
9.5
Vitamin B12 supplementation benefits autoimmune patients
We explored the impact of vitamin B12 on patients with autoimmune disorders, particularly those experiencing symptoms often attributed to their underlying conditions. The study presented three cases of individuals with neuropathic pain, depression, fatigue, and muscle weakness, who had their symptoms initially misattributed to rheumatic diseases.

Upon starting vitamin B12 supplementation, these patients showed nearly complete resolution of their symptoms, highlighting the potential benefits of this vitamin in treating related health issues. Interestingly, several participants did not display obvious deficiencies in vitamin B12 levels according to lab tests, suggesting that even those who appear to have sufficient levels could still benefit from supplementation.

Furthermore, we delved into research indicating the nerve-protective properties of vitamin B12, which could play a crucial role in managing pain and neuropathy associated with long-standing rheumatic diseases. Therefore, we recommend that healthcare providers consider checking vitamin B12 levels early in the diagnostic journey for autoimmune conditions, and think about offering supplementation regardless of laboratory findings.
Read More
9
We examined a case of a 51-year-old Ugandan man who experienced recurring lower limb weakness linked to pernicious anemia, an autoimmune condition causing vitamin B12 deficiency. After initial treatments, his symptoms reappeared, leading to further testing that confirmed the diagnosis.

Treatment with vitamin B12 injections significantly improved his condition. This case emphasizes the need for healthcare providers to recognize the signs of vitamin B12 deficiency early, particularly in resource-limited settings, to ensure timely diagnosis and treatment.
Read More
9
Case of combined autoimmune disorders
We examined a fascinating case of a 54-year-old man experiencing the rare overlap of Guillain-Barré Syndrome (GBS) and autoimmune gastritis. After a thorough medical evaluation, which included MRI and biopsy, he was diagnosed with both GBS and a vitamin B12 deficiency linked to atrophic gastritis.

Treatment with intravenous immunoglobulin and methylcobalamin (vitamin B12) led to substantial improvement in his symptoms. This case highlights the importance of recognizing potential nutrient deficiencies, especially those impacting autoimmune disorders like GBS and autoimmune gastritis.
Read More
We explored the intriguing case of a 56-year-old man diagnosed with Biermer's disease, also known as pernicious anemia, an autoimmune condition that leads to a lack of intrinsic factor and, consequently, vitamin B12 malabsorption. This patient presented with unusual symptoms: not just digestive concerns like melena, but also notable neurological effects such as memory issues and gait disturbances.

During our examination, we discovered symptoms indicative of cerebellar ataxia, along with a red and swollen limb that pointed toward deep vein thrombosis (DVT). The tests revealed severe macrocytic anemia and confirmed a deficiency in vitamin B12 while keeping folate levels normal. Following a thorough diagnosis—including gastroscopy, ultrasound, and blood tests—we initiated a treatment plan that included vitamin B12 supplementation and anticoagulant therapy.

The outcome of our intervention was promising, with significant clinical improvement observed in the patient’s condition. Our findings reinforce the essential role of vitamin B12 in managing this type of autoimmune disorder, particularly when neurological and cardiovascular complications arise.
Read More
8
We examined the levels of vitamin B and creatine kinase (CK-NAC) in 50 patients with Guillain-Barré Syndrome (GBS). Through clinical assessments, we compared the patients' functional abilities and found that a deficiency in vitamin B was linked to greater disease severity and respiratory complications.

However, while vitamin B levels seemed to offer insight into GBS prognosis, elevated CK-NAC levels did not show a significant correlation with disease severity. This points towards the importance of monitoring vitamin B as a potential prognostic tool in managing GBS.
Read More

User Reviews

USERS' SCORE
Good
Based on 13 Reviews
8.6
  • All Reviews
  • Positive Reviews
  • Negative Reviews
9
Pain relief
9 people found this helpful
I have rheumatoid arthritis and, in 2010, my pain worsened significantly. I discovered that a gluten-free diet alleviated most of my pain, but I still faced severe discomfort in my feet and hands. After researching B12 deficiency, I started taking Jarrow methyl B12 and I now experience minimal pain. I'm regaining my life.
Read More
9
Symptoms resolved
8 people found this helpful
As a vegetarian for four years, I neglected my B12 intake, causing gastrointestinal issues. After using this product, my discomfort vanished. I highly recommend it to vegetarians and vegans needing B12 for their autoimmune disorder.
Read More
9
Improved absorption
4 people found this helpful
Methylcobalamin is what you need! These dissolve under the tongue for better absorption. My B12 levels rose significantly after struggling to absorb it from food. I will continue purchasing this product.
Read More
9
Quick relief
1 people found this helpful
I suffered from severe dysautonomia symptoms, and upon trying B12, I chose methylcobalamin over cyanocobalamin. This product provided immediate relief from B12 deficiency symptoms, and I feel it is safe to use.
Read More
9
Essential vitamin
1 people found this helpful
This B12 is crucial for the formation of blood and energy metabolism, especially in autoimmune disorders. The methylcobalamin form is directly usable by the body, making it very effective. The high dose offers immediate benefits.
Read More

Frequently Asked Questions

9
Quick relief
1 people found this helpful
I suffered from severe dysautonomia symptoms, and upon trying B12, I chose methylcobalamin over cyanocobalamin. This product provided immediate relief from B12 deficiency symptoms, and I feel it is safe to use.
9
Rapid deficiency recovery
I used this product alongside Active B12 dibencozide for 1.5 months, and I'm thrilled with the results. After suffering for over six months due to my autoimmune disorder, I recovered quickly. I gradually increased my dosage to two lozenges daily, as the injections weren't effective for me. Thank you for restoring my life!
9
Pain relief
9 people found this helpful
I have rheumatoid arthritis and, in 2010, my pain worsened significantly. I discovered that a gluten-free diet alleviated most of my pain, but I still faced severe discomfort in my feet and hands. After researching B12 deficiency, I started taking Jarrow methyl B12 and I now experience minimal pain. I'm regaining my life.
9
Symptoms resolved
8 people found this helpful
As a vegetarian for four years, I neglected my B12 intake, causing gastrointestinal issues. After using this product, my discomfort vanished. I highly recommend it to vegetarians and vegans needing B12 for their autoimmune disorder.
9
Essential vitamin
1 people found this helpful
This B12 is crucial for the formation of blood and energy metabolism, especially in autoimmune disorders. The methylcobalamin form is directly usable by the body, making it very effective. The high dose offers immediate benefits.
6
Pioneering B12 option
Years ago, I started using high-dose Methyl-B12 for my autoimmune disorder and chronic anaemia. Jarrow was exceptional, offering various doses without fillers or artificial sweeteners that would trigger my condition. While newer brands are now more affordable with similar effectiveness, I remain grateful to Jarrow for their critical support during a time with limited options.
9
Cramping relief
This is a high dose of B12. I gradually increased the dosage for my mother, who suffered pins and needles and cramping due to an injury. The 5000mcg dose stopped her symptoms entirely.
8
We examined the levels of vitamin B and creatine kinase (CK-NAC) in 50 patients with Guillain-Barré Syndrome (GBS). Through clinical assessments, we compared the patients' functional abilities and found that a deficiency in vitamin B was linked to greater disease severity and respiratory complications.

However, while vitamin B levels seemed to offer insight into GBS prognosis, elevated CK-NAC levels did not show a significant correlation with disease severity. This points towards the importance of monitoring vitamin B as a potential prognostic tool in managing GBS.
We explored a fascinating case of a 40-year-old woman suffering from long-standing, unclear symptoms, initially misdiagnosed with various conditions. After years of monitoring, her critically low vitamin B12 levels were finally recognized, revealing pernicious anemia as the root cause.

Thanks to treatment with B12 injections, we observed significant improvement in her neurological symptoms. This case illustrates the need for thorough evaluations in patients with non-specific symptoms, as addressing vitamin B12 deficiency can lead to meaningful improvements—even when classic signs are absent.
7
AIG risk linked to diet factors
We explored the clinical characteristics of Chinese patients with autoimmune gastritis (AIG), focusing on how dietary and lifestyle factors influence its occurrence.

In a comprehensive case-control study involving 479 participants, we discovered that a diet rich in vitamin B12 may help protect against AIG. Interestingly, factors like cooking oil usage and autoimmune thyroid disease increased AIG risk.

Our findings suggest that what we eat and our lifestyle choices can significantly impact the development and prognosis of autoimmune gastritis.
7
Vitamin B12 aids RA management
We observed an interesting connection between vitamin B12 and autoimmune disorders, specifically rheumatoid arthritis (RA). The research suggests that vitamin B12 plays a significant role in managing this chronic condition. While it doesn't work in isolation, its influence on energy levels and neurological function can be particularly beneficial for individuals struggling with RA-related fatigue.

In our exploration, we found that vitamin B12 deficiency can exacerbate feelings of tiredness, making daily life even more challenging for those affected by RA. Ensuring adequate levels of this vital vitamin might not only help boost energy but could also support overall health during treatment.

Overall, while vitamin B12 has not been singled out as a standalone solution, it contributes meaningfully to the multi-faceted approach required for effective management of rheumatoid arthritis. As we delve deeper into the underpinnings of autoimmune disorders, vitamin B12’s role remains an essential piece of the puzzle.

References

  1. Jatav VS, Sardana V, Bhushan B, Maheshwari D, Garg S, et al. Correlation of Serum Vitamin B and Muscle Enzyme (CK-NAC) Level with Severity of Guillain-Barre Syndrome and Its Prediction in Respiratory Failure. J Assoc Physicians India. 2025;73:48. doi:10.59556/japi.73.0892
  2. Mesgarankarimi A, Rezapour M, Tabrizi N. A long-standing undiagnosed case of vitamin B12 deficiency: a case report. J Med Case Rep. 2025;19:151. doi:10.1186/s13256-025-05149-7
  3. Ma XY, Hao Y, Xie YH, Cao Q, Sun DF, et al. Risk Factors Analysis and Predictive Model Construction for Autoimmune Gastritis: A Nationwide Multicenter Case-Control Study in China. J Gastroenterol Hepatol. 2025. doi:10.1111/jgh.16912
  4. Mswelo VE, David MM, Banturaki A, Munyambalu DK, Hassan HA, et al. Rural health challenges in Western Uganda: pernicious anemia masquerading as recurrent lower limb weakness-a case report. J Med Case Rep. 2025;19:60. doi:10.1186/s13256-025-05095-4
  5. Xiang H, Cai M. Coexistence of Guillain-Barré Syndrome and Subacute Combined Degeneration of the Spinal Cord Due to Autoimmune Gastritis: A Case Report and Literature Review. Cureus. 2024;16:e63084. doi:10.7759/cureus.63084
  6. Pluvinage JV, Ngo T, Fouassier C, McDonagh M, Holmes BB, et al. Transcobalamin receptor antibodies in autoimmune vitamin B12 central deficiency. Sci Transl Med. 2024;16:eadl3758. doi:10.1126/scitranslmed.adl3758
  7. Subtil J, Carvalho R, Rebelo AF, Subtil P. Autoimmune Polyglandular Syndrome Type 3: A Case Report. Cureus. 2024;16:e76152. doi:10.7759/cureus.76152
  8. Mansour M, Shamasnah A, Alsaadi D, Abu Saif S, Krama A. Evans syndrome as a presentation in systemic lupus erythematous, coexisting with Hashimoto's thyroiditis and pernicious anemia: a case report. J Med Case Rep. 2024;18:643. doi:10.1186/s13256-024-05002-3
  9. Hijjawi N, Tout FS, Azaizeh B, Aljaafreh B. The role of vitamins D, B12, C, and K in modulating inflammation and disease management in rheumatoid arthritis: a comprehensive review. Clin Rheumatol. 2025;44:591. doi:10.1007/s10067-024-07285-9
  10. Lang C, Huang P, Gao J, Chen Y, He Z. Co-existence of autoimmune polyglandular syndrome type 3b and undifferentiated connective tissue disease with subacute combined degeneration of spinal cord in children: a case report and literature review. BMC Pediatr. 2024;24:817. doi:10.1186/s12887-024-05262-4
  11. Haddad F, Boukhal Z, El Rhaoussi FZ, Tahiri M, Hliwa W, et al. Neurological and Cardiovascular Complications Revealing Biermer's Disease: A Case Report. Cureus. 2024;16:e58601. doi:10.7759/cureus.58601
  12. Fernandez I, Touzot F. Looking for ALPS: The value of a combined assessment of biochemical markers. Pediatr Allergy Immunol. 2024;35:e14135. doi:10.1111/pai.14135
  13. Yamada H, Toko M, Nakamori M, Ueno H, Aoki S, et al. Progressive multifocal leukoencephalopathy associated with systemic lupus erythematosus: longitudinal observation of lymphocytes, JC virus in cerebrospinal fluid, and brain magnetic resonance imaging. J Neurovirol. 2024;30:197. doi:10.1007/s13365-024-01203-0
  14. Yang CW, Hsu HY, Lee YZ, Lee SJ. Vitamin B12 inhibits peptidylarginine deiminases and ameliorates rheumatoid arthritis in CAIA mice. Biochem Biophys Res Commun. 2024;704:149668. doi:10.1016/j.bbrc.2024.149668
  15. Dułak NA, Rytlewska M, Jaskólska M, Chmielewski M. A new perspective on vitamin B12 deficiency in rheumatology: a case-based review. Rheumatol Int. 2024;44:737. doi:10.1007/s00296-024-05539-y
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