Disclaimer: None of the information in this article constitutes medical advice, and is just the opinion of the writer(s). We recommend that patients follow their doctor’s guidance in regards to dietary fiber intake.
Metamucil is the most popular fiber supplement in the U.S. It’s so popular that many consumers use the brand as a generic term for fiber. But is Metamucil really the healthiest fiber option on the market?
In this article we’ll review the ingredients in some of Metamucil’s most popular formulations like their 4-in-1 fiber powder and their fiber gummies based on published medical research to determine if they’re healthy and likely to be effective for improving gut health.
Metamucil Sugar-Free Fiber Powder Review
Metamucil’s most popular products are their fiber powders, which can be added to water or drinks to increase dietary fiber intake throughout the day.
While it’s proven in medical research that improving fiber intake can have a range of health benefits such as decreased blood pressure, improved gut function and even weight loss, we find Metamucil’s formulations to be relatively unhealthy.
Metamucil’s Sugar-Free Orange Smooth Powder contains several ingredients we’d recommend avoiding. The first is aspartame which is an artificial sweetener which has been shown in an in vitro study to disrupt gut barrier function. Test tube studies are less conclusive than human studies, but we still found these results interesting.
A meta-review published in the Nature journal analyzed the results of both human and animal studies on artificial sweeteners, and concluded that they may cause impaired glucose tolerance. We want to note that there are several other studies we reviewed which showed no effect of sucralose consumption on metabolic parameters, but our stance is that it’s logical to avoid an artificial additive which provides no nutrition and has any level of health risk.
We find the inclusion of sucralose especially strange in the context of a fiber product, considering most consumers would be using this product to improve gut function.
The Orange Smooth Powder also contains artificial food colorant Yellow 6 which has been found in medical research in some cases to be contaminated with carcinogens (cancer-causing chemicals). We always recommend avoiding all artificial food dyes out of an abundance of caution.
Another ingredient in this fiber powder we find questionable is Natural and Artificial Orange Flavor. A medical study published in the Food Technology & Biotechnology journal found synthetic orange flavoring to cause acute toxicity in animal studies. The chemicals used to create Metamucil’s synthetic orange flavoring may be different than those used in the study, and the dosage is probably lower, but we have no idea why this ingredient is necessary in a consumer health product and would strongly recommend avoiding it.
Metamucil also contains citric acid, which is a multi-purpose additive originally derived from citrus fruits, however the vast majority of the world’s production of this ingredient comes from a fungus called Aspergillus niger, as documented by this medical review of citric acid.
The above-linked study details how manufactured citric acid may cause systemic inflammation in a small proportion of patients, which is why we recommend avoiding it considering it has no nutritive value in any case.
Overall this is the worst fiber product we’ve reviewed to date from a health perspective, which is unfortunate because of how popular it is. Metamucil is owned by Procter & Gamble, and we tend to notice that consumer products manufactured by multinational holding companies don’t appear to be very well-formulated, and the entire focus appears to be on taste and branding.
The fiber content per serving in Metamucil Orange Smooth Powder isn’t even very high at 6 grams (g). This is significantly less than the fiber in one single avocado based on United States Department of Agriculture (USDA) data.
We recommend avoiding this product due to all of the questionable additives.
Metamucil Premium Blend Fiber Powder Review
Metamucil sells a “Premium Blend” of fiber powder, with different additive ingredients. This product contains paprika extract and turmeric as natural colorants, which we believe to be much healthier choices than Yellow 6.
The Premium product only contains natural orange flavor and not the synthetic orange flavor which we strongly recommended avoiding.
This product contains stevia as a natural sweetener rather than aspartame, which we find to be a healthier option. Stevia actually appears based on medical studies to have a hypoglycemic (blood sugar lowering) and anti-inflammatory effect, and a much better safety profile in our opinion than aspartame.
Metamucil Premium does contain citric acid.
Overall this is a much healthier formulation. We wouldn’t recommend it generally due to the natural flavor and citric acid, but for consumers set on purchasing Metamucil products we’d definitely recommend the Premium Blend over the Sugar-Free Powder.
Metamucil Gummies Review
Metamucil sells a fiber gummy product in addition to their powders. This is a somewhat novel product category as all of the fiber products we’ve previously reviewed have been powder blends.
As we detailed in our review of Goli Ashwagandha Gummies, we typically don’t recommend gummy “health” products because they almost always contain added sugar which negates any potential health benefits from other ingredients.
In Metamucil’s case though, the gummies contain xylitol as a natural alternative sweetener. Xylitol is a sugar alcohol that appears based on medical research to be significantly healthier than processed sugar when used in small doses, and doesn’t appear to confer any of the metabolic health risks of sugar.
A medical review of xylitol’s health benefits published in the Applied Microbiology and Biotechnology journal found that xylitol benefitted blood sugar and obesity control processes, and had a significant benefit to the teeth and gums: it reduced plaque and gingival inflammation.
Metamucil gummies contain 5 g fiber per serving which is an impressive amount for a gummy product. They contain the ingredient annatto as a natural coloring agent, and this is a much better choice than the Yellow 6 in their sugar-free powder. Annatto is derived from a plant called Bixa orellana and has been found in studies to be non-toxic.
Like their other products, Metamucil’s gummies contain natural orange flavor and citric acid. We wouldn’t recommend the product due to the health concerns we have over these two additives as we’ve discussed in the previous section, but we do believe this is a pretty decent formulation for a gummy product. It’s arguably the healthiest gummy product we’ve reviewed to date.
Failed Third-Party Testing
ConsumerLab is an independent research firm that performs lab tests on popular consumer products.
They failed Metamucil’s 4-in-1 Sugar-Free Fiber Powder due to relatively high levels of lead, finding up to 14.6 micrograms (mcg) per serving.
This is enough of a sign for us to recommend avoiding the brand entirely, and we’re surprised that a brand owned by a huge multinational would contain levels of lead that would cause it to fail an independent test.
Benefiber Vs. Metamucil
We receive a lot of questions from consumers about whether Benefiber or Metamucil is healthier. Benefiber is another popular fiber supplement available at many retailers like CVS and Target.
We believe that Benefiber is the clearly superior option, because it only contains one ingredient: wheat dextrin. This is a soluble fiber processed from wheat grain.
The lack of questionable filler ingredients makes Benefiber the better option, and for patients with no gluten sensitivity we would actually recommend Benefiber as a fiber supplement option due to the clean, simple and non-toxic formulation.
In this section we’re only referring to the formulation of original Benefiber powder and not any of their other products.
Better Fiber Alternative
We generally recommend psyllium husk fiber supplements because of their demonstrated superiority over other types of fiber supplements in medical research.
An extensive medical review of fiber supplements published in the Nutrition Today journal compared the clinically-proven benefits of different types of fiber.
Only psyllium had demonstrated benefits for cholesterol, blood sugar control, sense of fullness, weight loss, constipation, diarrhea and Irritable Bowel Syndrome (IBS).
We recommend Yerba Prima fiber powder for two reasons: first, it only contains psyllium husk powder and no additive ingredients.
Second, the brand had the lowest lead levels in the ConsumerLab testing referenced earlier that failed Metamucil.
We have no commercial partnership with Yerba Prima and receive no compensation for recommending this product.