Dr. Mercola Fermented Beta Glucans Review
Dr. Mercola Fermented Beta Glucans are presented on this iHerb page as a 60 capsule bottle, though the page labels the item as discontinued and states that the product is no longer available. The page describes the supplement as a daily immune support formula. It explains that modern life places a heavy load of stressors on the immune system, including pollutants, toxins, lack of exercise or sleep, and aging, so the goal is to keep the immune system primed for a healthy, balanced response. According to the page, Fermented Beta Glucans can help balance and support the immune system and help optimize immune defenses for year-round respiratory, sinus and gut health. The formula combines two ingredients: Beta-1,3-glucan from Euglena algae and EpiCor yeast fermentate. The page states that this immune support duo works on four levels. It says the product promotes production of IgA antibodies to help protect against year-round environmental challenges, raises natural killer cell activity to support immune function, increases antioxidant activity to help protect cells and tissues from free radical and oxidative damage, and supports beneficial bacteria levels in the gut, which the page says plays a key role in immune health. The page describes the product as a daily conditioning workout for the immune system and says it is suitable for regular, everyday use. Suggested use for adults is one to two capsules daily, taken as a dietary supplement. Each serving of two capsules provides 500 mg of yeast fermentate, 400 mg of fermented Euglena gracilis algae, and 200 mg of beta glucans as beta-1,3-glucan, with a container count of 30 servings. The page also lists warnings. It advises keeping the product out of reach of children, not using it if the safety seal is broken, and consulting a physician before use for anyone who is nursing, pregnant, taking medication, or has a medical condition. The listing shows Dr. Mercola as the brand, NSF contents certification, the product category as seasonal and immune support, first availability in January 2019, a package quantity of 60 count, and a UPC of 810487031547. The page carries an iHerb product code of MCL-03154. The page includes a disclaimer that manufacturing changes may be pending and that users should read the label before use.
Study, Trial or Testing Result Summary
Members Only13 human studies · 10 improved
Both main ingredients are present at or above the doses used in studies. Fermented Euglena algae, at 400 milligrams here, has the strongest support, with five human studies all finding immune benefits. In 200 healthy adults, 1,000 milligrams a day for 8 weeks raised a marker of immune cell activation and lowered how often people had cold-like symptoms compared with placebo [1]. Another placebo-controlled trial found fewer days with cold-like symptoms and fewer severe symptoms in weeks 5 to 8 [2]. In stressed adults who caught frequent colds, 700 milligrams a day improved natural killer cell activity with no side effects [3]. In 34 endurance-trained adults, 367 milligrams a day of fermented Euglena for 90 days led to fewer sick days and fewer cold episodes than placebo [4]. A small study of 13 people found higher saliva antibody levels and better quality of life after 4 weeks [5]. The yeast fermentate, at 500 milligrams, matches the dose in a trial of 256 children, who had milder cold and flu symptoms and used less medicine, but caught colds just as often as those on placebo [6]. Farm animal studies also found better antibody levels and less illness with yeast culture feed, but these carry less weight [7][8]. Animal and cell studies are never counted.
See all 13 studies →Hide the studies
- In 256 healthy children aged 4 to 12, 500 mg daily of a yeast fermentate postbiotic for 84 days lowered cold and flu symptom severity and medication use compared with placebo, but did not change how often symptoms occurred.Efficacy of a yeast postbiotic on cold/flu symptoms in healthy children: A randomized-controlled trial.
- In 200 healthy Japanese adults (181 analyzed), 1,000 mg per day of Euglena for 8 weeks raised an immune cell activation marker and lowered the incidence of common cold-like symptoms compared with placebo.Incorporating Euglena gracilis into the habitual diet modulates immune function and reduces common cold-like symptoms: a…
- In 34 healthy endurance-trained adults, 367 mg per day of Euglena fermentate for 90 days led to fewer sick days, fewer cold symptoms and fewer episodes than placebo.Effect of a Euglena gracilis Fermentate on Immune Function in Healthy, Active Adults: A Randomized, Double-Blind, Placeb…
- In healthy adults aged 20 to 70 with stress and frequent colds, 700 mg per day of Euglena powder for 8 weeks improved natural killer cell activity compared with placebo, with no adverse events.Euglena gracilis (Euglena) powder supplementation enhanced immune function through natural killer cell activity in appar…
- In healthy Japanese adults, taking Euglena capsules daily for 8 weeks led to fewer days with cold-like symptoms and fewer severe symptoms in weeks 5 to 8 than placebo.Euglena gracilis Suppresses Cold Symptoms in Healthy Individuals: A Double-Blind, Randomized, Placebo-Controlled Trial.
- In 13 healthy people in a crossover trial, 4 weeks of Euglena biomass raised saliva antibody levels against its fiber and improved health-related quality of life, especially mental health, while placebo did not.Effects of Euglena gracilis EOD-1 Ingestion on Salivary IgA Reactivity and Health-Related Quality of Life in Humans.
- In 512 dairy calves over their first 70 days, adding yeast culture at 2% of grain improved stool quality, cut diarrhea and fever, lowered the risk of health problems and death after 13 days of age, and slightly improved neutrophil germ-killing activity.Effect of feeding yeast culture on performance, health, and immunocompetence of dairy calves.
- Feeding sows 24 grams of yeast culture daily during late pregnancy (raised to 40 grams during nursing) increased blood immunoglobulin G and improved milk yield, and their piglets gained 7% more weight each day.Effects of yeast culture supplementation from late gestation to weaning on performance of lactating sows and growth of n…
- In 40 transition dairy cows given 30 to 90 grams of a yeast product daily from 3 weeks before to 6 weeks after calving, blood antibody responses to a vaccine-like challenge rose with dose, mucosal antibody levels rose at 30 and 60 grams, and uterine inflammation markers were lower at the middle doses.Yeast product supplementation modulated humoral and mucosal immunity and uterine inflammatory signals in transition dair…
- Over 90 days, growing lambs given 7 grams of yeast culture daily had higher blood levels of several immunoglobulins, a sign of better immune status, and this effect looked somewhat stronger than with live yeast alone at 0.5 grams.Influence of probiotic and yeast culture supplementation on selected biochemical and immunological parameters of growing…
- In feeder calves and lambs, 0.75% yeast culture in the diet did not change overall health or growth, though sick calves needed fewer days of meds in one experiment and lambs had better nitrogen balance after fasting.Influence of yeast culture on feeder calves and lambs.
- In a mouse model of food allergy, oral live yeast reduced gut tissue injury and lowered an inflammatory signal (interleukin 17), but it did not change allergy antibodies in the blood, so the effect appeared local only, and only high doses worked.Effect of Saccharomyces cerevisiae UFMG A-905 in a murine model of food allergy.
- Feeding sows yeast culture at 2.0 g per kg of diet from late pregnancy through nursing lowered inflammatory signals in the blood and thymus of their weaned piglets after an artificial inflammation challenge.Yeast culture supplementation of sow diets regulates the immune performance of their weaned piglets under lipopolysaccha…
Review Totals and Summary
Members Only821 reviews · 94% positive
Across all stores, Dr. Mercola Fermented Beta Glucans has received a total of 562 ratings, and the themes discussed below are derived from the written reviews that could be read on their respective product pages. On one such page, only a single written review was available for the capsules, submitted by a verified buyer named William H. This reviewer awarded the product a perfect 5 out of 5 stars and indicated a clear recommendation. The primary feedback from this sole reviewer highlights the perceived efficacy of beta-glucans. William H. reported finding beta-glucans helpful for improving a few unspecified conditions. This positive experience is the only specific praise offered in the available written feedback. Given that this is the only rating on the page, the product's overall star breakdown is entirely 5-star, and 100% of reviewers (in this case, one) would recommend it. Regarding other common aspects of customer feedback, the single review does not provide any information or themes related to the product's taste, capsule size, price point, ease of use, or potential side effects. Similarly, no customer complaints were present in this feedback. The review itself was dated three years prior to the current summary. The product page displayed no other reviews, no customer questions, and no filtered results beyond this single entry. The histogram on the page confirmed one 5-star rating and zero ratings at any other star level, aligning with the overall average of 5.0 stars shown at the top of the page. Furthermore, there was no community signal regarding the usefulness of this review, as it had received zero helpful votes. While this single review offers a positive individual experience, it represents a very limited sample of customer sentiment for Dr. Mercola Fermented Beta Glucans capsules. Broader conclusions about the overall customer experience, including common benefits, potential drawbacks, or suitability for specific user groups, cannot be drawn from such a small dataset. However, the available feedback does indicate a positive initial impression from one user regarding the product's general helpfulness for various conditions.
Biohacker Summary
Members Only0 of 10 recommend it
Our biohacker panel has not discussed this product’s ingredients yet.
RAL Summary
Members OnlyTier 2 for Immune Health
Five human trials of Euglena at or near this dose, including placebo-controlled trials, found fewer cold-like symptoms and stronger immune markers, and 94% of 821 reviews are positive, which supports tier 2. The rules' stated reason leaned on a calf study, but animal studies are not needed here because the human Euglena trials carry the grade.
More Details
Members OnlyBody systems · Combine with · Possible side effects
Body systems: Immune system, Respiratory system
Combine with: To enhance overall immune resilience alongside Fermented Beta Glucans, consider combining with Vitamin C for its antioxidant and immune-boosting properties, Vitamin D3 for its crucial role in immune cell function, and Zinc, an essential mineral for immune system development and activity. Additionally, a high-quality probiotic could support gut health, which is intrinsically linked to a robust immune response.
Possible side effects: No major side effects reported; one Euglena trial specifically noted no adverse events.
Supplement Facts
Yeast Fermentate 500 mg · fermented Euglena 400 mg
| Yeast Fermentate | 500 mg | † |
| fermented Euglena | 400 mg | † |
Other ingredients: Hydroxypropyl Methylcellulose, Rice hulls.
Directions: Suggested use: Adults, as a dietary supplement, take one (1) to two (2) capsules daily.
Barcode (UPC) 810487031547 · Label source: NIH label database · Report a label change
Show entire label
Where to Buy
Amazon · iHerb · Walmart
More immune health products
Members OnlyThe highest ranked for the same goal
Read more
Our articles on this subject
- How to Improve Gut Health Naturally: Fiber, Foods and the Probiotic Strains With Human TrialsArticle · Sep 15, 2026
- How to Build a Longevity Supplement Stack: An Evidence-First ReviewArticle · Sep 7, 2026
Graded November 3, 2026 by the Reverse Age Lab evidence engine, from human studies, real reviews and our biohacker panel. How we grade. Is this medical advice? No. Rala organizes the published evidence; go over any change with your doctor, especially if you take meds.
Privacy policyConsumer health dataTermsDo Not Sell or Share My Personal InformationCookie settings