NERVEsustainTM vs. Metanx®

“METANX” is a registered trademark of Alfasigma USA, Incorporated. It is classified as a medical “food”, although it comes in a capsule, and requires a prescription to attain. METANX® boasts that it is specially formulated to meet the nutritional needs of those suffering from diabetic nerve damage, however, the only “active ingredients” described to address symptoms of nerve damage and improve blood flow to restore healthy nerves are L-methylfolate (the activated form of folate/vitamin B-9), vitamin B-6, and vitamin B-12. Unfortunately, due to the long list of other ingredients in this product, it may not be suitable for many patients with allergies, nor is it appropriate for vegans. It contains milk and soy, along with artificial coloring, shellac, sweeteners, oils, and other substances [1]. 

In comparison, Metabolic Maintenance offers a clean, vegan option for peripheral nerve support called NERVEsustainTM. The NERVEsustainTM formula includes the same active ingredients (L-methylfolate, B-6, and B-12), along with other beneficial nutrients, and it is free of allergens, preservatives, food coloring, and binders. Additionally, all Metabolic Maintenance products are packaged in amber glass bottles to avoid the plastic contaminants that may be found in plastic prescription containers. 

What are METANX® ingredients?

Silicified Microcrystalline Cellulose, Algae-S Powder [Schizochytrium Algal Oil (Vegetable Source), Glucose Syrup Solids, Mannitol, Sodium Caseinate (Milk), Soy Protein, High Oleic Sunflower Oil, 2% or less Sodium Ascorbate, Tricalcium Phosphate, Tetrasodium Diphosphate, Natural Flavors, Soy Lecithin, and Mixed Natural Tocopherols and Ascorbyl Palmitate (as antioxidants)], Pullulan, Pyridoxal 5’- Phosphate (Vitamin B-6), L-methylfolate Calcium (Vitamin B-9), Methylcobalamin (Vitamin B-12), Titanium Dioxide (color), Magnesium Stearate (Vegetable Source), Caramel (color), Riboflavin USP, Shellac, Propylene Glycol USP. Contains Milk and Soy [2].

What’s in NERVEsustainTM?

Metabolic Maintenance does not use binders, fillers, added excipients or any preservatives in their supplements. NEVERsustain contains, vitamin B-6 (as Pyridoxal 5’ Phosphate), Thiamine (Vitamin B-1; as Thiamine Mononitrate), Magnesium (as Magnesium Citrate), Riboflavin (Vitamin B-2; as Riboflavin 5’ Phosphate), Folate (Vitamin B-9; as L-Methylfolate, Calcium salt), Vitamin C (as Ascorbyl Palmitate), and Vitamin B-12 (as Methylcobalamin), provided in a vegetarian capsule.

What is Diabetic Nerve Damage (Peripheral Neuropathy)?

The job of the peripheral nervous system is to relay information back and forth between your central nervous system (brain and spinal cord) and the rest of your body. Peripheral neuropathy is caused by damage to nerves of the peripheral nervous system. This condition often presents itself as weakness, numbness and pain, sometimes described as stabbing, burning or tingling [3]. These symptoms are most often felt in hands and feet, but can also affect other areas of your body. Peripheral neuropathy can result from traumatic injuries, infections, metabolic problems, inherited causes, and exposure to toxins, but one of the most common causes is diabetes [3].

Nerve health is significantly affected by glucose balance. Imbalanced glucose levels can, over time, lead to symptoms of burning, tingling, and numbness stemming from peripheral neuropathy. These effects may be exacerbated by concurrent vitamin deficiency [4,5].

What Nutrients Support Nerve Health?

Healthy nerves rely on adequate levels of certain B vitamins (B-6, folate/ B-9, and B-12 in particular), but occasionally, a few roadblocks stand in the way of attaining those levels. Some commonly prescribed medications interfere with the absorption of certain vitamins or deplete levels of certain B vitamins [6]. We also know now that it is extremely common to inherit MTHFR genetic polymorphisms can affect the body’s ability to properly process folate (vitamin B-9). Activated folate, L-methylfolate, is the type of folate necessary to encourage healthy blood flow, in order to supply damaged nerves with the proper nutrients to stimulate repair [1].

Is L-methylfolate the same thing as folic acid?

The word folate is a blanket term for different forms of vitamin B-9. While the synthetic form of folate, folic acid, has a long history of use in both in nutritional supplements and food fortification, there are several biochemical steps between the folic acid you eat, and the active form your cells can actually use. Not everybody can perform these steps smoothly, leaving folic acid unmetabolized and needs for folate unfulfilled. L-Methylfolate is the bioactive form of folate, ready to be used by the body (without undergoing all of the biochemical steps that folic acid needs to be useful). L-Methylfolate is a more expensive ingredient than folic acid, so you will notice that specialty supplements that contain it are likely to carry a higher price tag. If you are folate deficient or have trouble processing folic acid due to an MTHFR mutation, it is well worth the investment to start meeting your body’s metabolic needs.

What is an MTHFR gene mutation (polymorphism)?

MTHFR is a gene that provides instructions to make an enzyme called methylenetetrahydrofolate reductase. Methylenetetrahydrofolate reductase is a necessary factor for dietary folate, and folic acid, to be transformed into active L-methylfolate (5-MTHF). It has been estimated that about half of the global population carry an inherited mutation in the MTHFR gene [7]. If you have inherited a genetic mutation, it is possible to be metabolically folate deficient, even when your diet is high in folic acid. 

Only a genetic test by your doctor can confirm whether or not you have a MTHFR mutation, but if you do, L-methylfolate supplementation could be the answer. L-Methylfolate bypasses the entire folic acid metabolism cycle and has been shown to be more effective than folic acid for increasing circulating folate in those with and without an MTHFR mutation [8].

What does NERVEsustainTM contain that METANX® doesn’t?

In addition to the active B-vitamins contained in METANX®, NERVEsustainTM includes other powerhouse nutrients in optimal levels known to aid in processes related to nerve support.

Riboflavin (also known as vitamin B-2) is involved in the healthy metabolism of other B vitamins, including folate and B-6. It is also a cofactor for the MTHFR enzyme, aiding in the remethylation of homocysteine to methionine, and helping to keep homocysteine levels under control.

Thiamine (vitamin B-1) is depleted by excessive alcohol consumption. Alcohol use can create alcohol-induced neuropathy, which can be made worse by the depleting effect of alcohol on body stores of thiamine [9].

Magnesium is an essential mineral involved in both the normal transmission of nerve signaling and the modulation of a normal insulin response. When glucose levels are high, the body requires more magnesium, which means those with diabetes are at a higher risk of deficiency [10].

 Ascorbyl Palmitate is a fat-soluble form of vitamin C. Vitamin C is a powerful antioxidant for tissue protection and some studies have shown it has the potential to boost the bioavailability of L-methylfolate [11].

Is a Medical Food Different From a Supplement?

Yes, though both are formulations of nutritional products, medical foods differ from nutritional supplements in several ways including how they may be marketed and distributed, as described below.

What is a Medical Food?

Medical foods are specially formulated and processed for the specific dietary management of a disease or condition. They are not drugs, and so are not subject to regulations that apply specifically to pharmaceuticals. They do need to go through a research process to show that the food is beneficial for the condition for which the medical food company is making claims. This research process is costly and is added to the cost of the final product. Though a prescription is not always required, the FDA does say the medical food should be taken “under the supervision of a physician” and often a prescription is necessary.

What is a Nutritional Supplement?

A dietary or nutritional supplement is a product intended for ingestion, taken to supplement the nutritional content of a person’s diet. 

Nutritional supplements cannot legally make claims that they can be used to treat conditions. However, formulas are often designed based on biochemical pathways that the vitamin or other nutritional factor is known to influence, and clinical studies often take place that provide evidence for a nutrient’s benefit for specific purposes. A prescription is not needed to purchase a nutritional supplement, however, Metabolic Maintenance always recommends you check with your physician before adding anything new to your health regimen.

Insurance and Costs?

One benefit of getting a product certified as a medical food, available through prescription, is that insurance will sometimes cover some or all of the cost. However, certain coverage plans do not cover METANX® at all. The average retail cost for METANX® is $105 for a 30-capsule prescription.

NERVEsustainTM nutritional supplement is not covered by insurance. In some cases, health savings accounts may be used for nutritional supplements. However, by avoiding the lengthy and expensive “medical food” certification process, we are able to offer the same active ingredients, of equal or superior quality, plus other nutritional benefits, at a much lower cost. Our 30-day/30-capsule supply is being introduced for a limited time for just $40. 

As cost is one of the biggest barriers between consumers and a product that may benefit their health immensely, Metabolic Maintenance is dedicated to making supplements available at a fair, competitive price, without compromising the integrity, quality, or purity of our products.

Where can I buy NERVEsustainTM?

Although consulting a doctor is always recommended before making a change to your diet or nutritional regimen, Metabolic Maintenance’s NERVEsustainTM is available through our website; no prescription necessary. It can be delivered to your door with no copay required, no waiting in line, and no trip to the pharmacy. Auto-pay/delivery can also be set up so that you will never have to go without your supplements.

What are the processes that guarantee this is a high-quality product?

There has been legitimate concern leveled at the nutritional industry about the quality of supplements available to consumers. Doctors and consumers have heard stories of products that contain little to no beneficial substance, or are contaminated with allergens or mislabeled. It is true, the FDA does not regulate the nutritional industry as tightly as the pharmaceutical industry. Unfortunately, this has led to some consumer mistrust, or an overall dismissal of the potential benefit of nutritional supplements. However, there are nutritional companies making high-quality products. Metabolic Maintenance follows current Good Manufacturing Practices as certified by the FDA. We source all of our nutrients from companies that are as rigorous in their standards as we are. We send our raw materials out to a lab for third-party testing to make sure they are the correct ingredients and free of contaminants. After we blend, we send the product out again to be tested to make sure our label claims are accurate.


  1. METANX Website. Covington, LA: Alfasigma USA, Inc.; Copyright 2019.
  2. METANX Package Insert. Covington, LA: Alfasigma USA, Inc.; Revised Feb., 2017.
  3. Mayo Clinic. “Peripheral Neuropathy”. Patient Care & Health Information: Diseases & Conditions. Accessed June 10, 2019.
  4. Wile D, Toth C. Association of metformin, elevated homocysteine, and methylmalonic acid levels and clinically worsened diabetic peripheral neuropathy. Diabetes Care. 2010 Jan;33(1): 156-161.
  5. Gupta K, Jain A, Rohatgi A. An observational study of vitamin B12 levels and peripheral neuropathy profile in patients of diabetes mellitus on metformin therapy. Diabet Metab Syndr. 2018 Jan-Mar;12(1):51-58.
  6. Martinez Figueroa A, Johnson RH, Lambie DG, Shakir RA. The role of folate deficiency in the development of peripheral neuropathy caused by anticonvulsants. J Neurol Sci. 1980 Dec;48(3):315-23.
  7. Kaiser Permanente. “Basic Information About the MTHFR Gene.” The Permanente Medical Group, Inc. Copyright 2015, last reviewed 2018.
  8. Greenberg, James A., et al. “Folic acid supplementation and pregnancy: more than just neural tube defect prevention.” Reviews in Obstetrics and Gynecology 4.2 (2011): 52.
  9. Hammond N, Wang Y, Dimachkie M, Barohn R. Nutritional neuropathies. Neurol Clin. 2013 May; 31(2):477-489.
  10. Barbagallo M, Dominguez L. Magnesium and type 2 diabetes. World J Diabetes. 2015 Aug 25; 6(10): 1152-1157.
  11. Verlinde PN, Oy I, Hendrickx ME, et al. L-ascorbic acid improves the serum folate response to an oral dose of [6S]-5-methyltetrahydrofolic acid in healthy men. Eur J Clin Nutr. 2008; 62 (10): 1224-1230.