Synbiotic 365 Review: Is This Probiotic Formula Safe and Effective? Our Dietitian Explains
Medically Reviewed by Anthony Dugarte, MD
Last Updated on May 14, 2021
Synbiotic 365 is a probiotic supplement designed to help alleviate digestive discomfort by balancing gut flora and subsequently improving health. While it contains strains from Lactobacillus and Bifidobacterium, two well-researched probiotic families, it also contains a number of others with minimal evidence for human digestive use.
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Synbiotic 365 is a probiotic supplement made by United Naturals with 14 bacterial strains plus B vitamins.
It claims to contain 20 billion CFU – or colony-forming units – per capsule.
CFU indicates the number of viable cells. Many probiotics contain 1–10 billion CFU.
This product also contains chicory root inulin, which is a plant-derived carbohydrate that acts as a prebiotic.
Prebiotics are essentially food for probiotics living in your colon. (1)
Synbiotic 365 contains 14 strains of probiotic bacteria from the Lactobacillus, Bacillus, Bifidobacterium, Streptococcus, and Saccharomyces families.
Probiotics are bacterial microorganisms that provide health benefits to their host.
While there are certain bacteria we want to avoid, an optimal balance of good bacteria in the digestive system can help control harmful germs and improve immunity.
Furthermore, much of our overall health is dependent upon gut health through the gut-brain axis. (2)
While food sources of probiotics include fermented foods like tempeh, miso, natto, kombucha, kefir, and sauerkraut, supplements can be a convenient way to get more good bacteria.
My initial question about Synbiotics 365 as a registered dietitian is about the high number of probiotic strains. I’m curious whether this is significantly better than products with fewer strains.
Probiotics have a large amount of research behind their benefits, both from food and supplemental sources.
This includes their potential to improve the balance of the gut microbiome for immunity, digestion, and overall health.
Probiotics may lower the pH of the colon and improve bowel regularity. (5)
They may also help treat diarrhea associated with antibiotics or Clostridium difficile infections by replenishing good bacteria. (6)
Still, not all probiotics are created equal, and most research appears to be around Lactobacillus and Bifidobacterium.
Furthermore, some studies indicate that higher CFU produces the best results but depends on the strain. (7)
The good news is that even taking high doses doesn’t appear to be harmful to anything except your wallet.
Unfortunately, the company website offers no research support, let alone details around their formulation or its benefits.
What I could find about the main probiotics used in Synbiotic 365 is detailed below.
These strains are all part of a 20 billion CFU probiotic blend listed on the product packaging, and individual amounts are unavailable.
Lactobacillus and Bifidobacterium
A 2010 systematic review in the World Journal of Gastroenterology reviewed 5 randomized controlled trials involving kids and adults, concluding that B. lactis and L. casei were effective for constipation. (8)
Other studies on Bifidobacterium have found that B. longum may reduce depressive symptoms and be helpful for irritable bowel syndrome and that B. bifidum helps produce mood-boosting vitamins B12 and K. (9, 10)
Studies involving Lactobacillus have found that L. reuteri may have an analgesic and excitability effect in animals, and L. plantarum increases anti-anxiety neurotransmitters serotonin and dopamine in mice. (11, 12)
Synbiotic 365 also includes L. gasseri, L. paracasei, L. rhamnosus, L. salivarius, L. fermentum, and B. lactis, which are naturally found in the digestive tract and may protect the intestinal barrier, improve regularity, and have benefits for type 2 diabetes. However, some studies have found no benefit to supplementation. (13, 14, 15, 16)
S. thermophilus reduced gut uremic toxins in patients with kidney disease and potentially have anti-inflammatory characteristics in one 2019 study. (19)
It was also found to have an anti-tumor effect among mice with colon cancer in a 2020 study. (20)
However, I couldn’t find specific studies on its digestive benefits in humans.
A 2018 review on S. boulardii and irritable bowel disease (IBD) concluded that because existing trials have been small and short, there’s not enough evidence to determine whether it’s beneficial for IBD. (23)
A 2017 study on mice also concluded that S. boulardii could change gut microbiota in a way that alleviates acute liver failure. (27)
Below is our summary of the available evidence for the claimed benefits of Synbiotic 365 based on the available research:
|Alleviates digestive discomfort||Moderate Evidence|
The serving size of Synbiotic 365 is one capsule, so without any direction provided on the website, I assume it’s recommended to take one daily.
The website doesn’t indicate potential side effects, and probiotics are generally considered safe for healthy people, but every supplement comes with risks. (29)
Noticeable effects may be more likely when taking a probiotic with a large CFU, like Synbiotic 365, if someone isn’t used to doing so already.
Synbiotic 365 does not appear to contain potential allergens.
As with other supplements, it’s best to speak to a healthcare provider before adding this product to your routine.
One box of Synbiotic 365 contains 30 capsules. With the presumed dosage of 1 capsule per day, one box is a one-month supply.
The cost of one box is $45.00. You can also purchase three boxes at once for a price of $119.00 ($39.60 per month) or six boxes for $229.00 ($38.16 per month).
The refund policy for Synbiotic 365 is a lengthy page of jargon rather than a simple company guarantee that is easy to understand.
What I gather is that consumers may request a refund within 60 days of purchase.
The company will accept up to two empty containers of each product, but additional products purchased must be returned in their original and sealed condition.
If you return more than two open products, you will receive a prorated refund instead of a full refund.
The consumer is also responsible for paying refund return shipping costs.
You can purchase directly from the United Naturals website.
I also found Synbiotic 365 available on Amazon, but it appears to be sold by other companies, so this comes without a guarantee of quality.
On Amazon, the price for one 30-capsule box is significantly higher.
Probiotics vary significantly in the number of strains and CFUs. Synbiotic 365 appears to be in the mid to higher end of these numbers.
As for cost, Synbiotic 365 is priced higher than many similar products offering 15+ probiotic strains and upwards of 50–65 billion CFU.
I don’t think the price is justified when there are plenty of other probiotics on the market for a lower cost.
Many of these products are priced around $25 per one-month supply.
For better transparency and an easier customer experience, I would recommend that Synbiotic 365 offer information around specific product benefits, what makes it a better option than other probiotics, and link to actual research supporting their formulation.
While this product contains several strains with supporting evidence behind them, it’s hard to justify the long list of others.
Again, I think consumers would appreciate having research behind this formulation accessible on the site.
Additionally, there are plenty of fermented foods that can offer probiotic and prebiotic health benefits as part of everyday diet patterns.
Overall, I think there are probably similar but cheaper options on the market.
Always speak to your doctor before adding any supplement, including probiotics, to your routine.
If you have digestive health complaints, it’s important to have them evaluated by a healthcare professional to make sure any issues are appropriately addressed.
As a dietitian, I recommend that most healthy people prioritize getting probiotics from dietary sources first.
However, probiotic supplements may be helpful if dietary sources are lacking or if an individual has a specific complaint regarding gut health and knows what strain(s) to look for.
That being said, I don’t see the point in Synbiotic 365 containing so many additional strains outside of the well-researched Lactobacillus and Bifidobacterium without robust evidence behind their use for human digestive health. This seems unnecessary.
Again, I would recommend incorporating more fermented probiotic and prebiotic-containing foods first and having gastrointestinal issues evaluated by your doctor.
At WellnessVerge, we only use primary references for our articles, including peer reviewed medical journals or well-respected academic institutions.
- Towards a more comprehensive concept for prebiotics:
- The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems:
- The Gut-Brain Axis: The Missing Link in Depression:
- Probiotic Bacillus coagulans GBI-30, 6086 Improves Protein Absorption and Utilization:
- Probiotic and lactulose: influence on gastrointestinal flora and pH value in minimal hepatic encephalopathy rats:
- Use of probiotic Lactobacillus preparation to prevent diarrhoea associated with antibiotics: randomised double blind placebo controlled trial:
- Systematic review of randomised controlled trials: Probiotics for functional constipation:
- The Gut-Brain Axis: The Missing Link in Depression:
- Probiotic Bifidobacterium longum NCC3001 Reduces Depression Scores and Alters Brain Activity: A Pilot Study in Patients With Irritable Bowel Syndrome:
- Microbes and the gut‐brain axis:
- Alteration of behavior and monoamine levels attributable to Lactobacillus plantarum PS128 in germ-free mice:
- Administration of Lactobacillus salivarius LI01 or Pediococcus pentosaceus LI05 prevents CCl 4-induced liver cirrhosis by protecting the intestinal barrier in rats:
- Lactobacillus rhamnosus GG prevents epithelial barrier dysfunction induced by interferon-gamma and fecal supernatants from irritable bowel syndrome patients in human intestinal enteroids and colonoids:
- Lactobacillus salivarius AP-32 and Lactobacillus reuteri GL-104 decrease glycemic levels and attenuate diabetes-mediated liver and kidney injury in db/db mice:
- Randomised clinical trial: Bifidobacterium lactis NCC2818 probiotic vs placebo, and impact on gut transit time, symptoms, and gut microbiology in chronic constipation:
- The use of Bacillus subtilis as an antidiarrhoeal microorganism:
- Effects of Bacillus subtilis on the growth performance, digestive enzymes, immune gene expression and disease resistance of white shrimp, Litopenaeus vannamei:
- Gut Dysbiosis and the Intestinal Microbiome: Streptococcus thermophilus a Key Probiotic for Reducing Uremia:
- Streptococcus thermophilus Inhibits Colorectal Tumorigenesis Through Secreting β-Galactosidase:
- Streptococcus thermophilus NCIMB 41856 ameliorates signs of colitis in an animal model of inflammatory bowel disease:
- Characterization of Mucus-Related Properties of Streptococcus thermophilus: From Adhesion to Induction:
- Review of Saccharomyces boulardii as a treatment option in IBD:
- Influence of Saccharomyces boulardii CNCM I-745on the gut-associated immune system:
- Prospective randomized controlled study on the effects of Saccharomyces boulardii CNCM I-745 and amoxicillin-clavulanate or the combination on the gut microbiota of healthy volunteers:
- Saccharomyces boulardii CNCM I-745 influences the gut-associated immune system:
- Saccharomyces boulardii Administration Changes Gut Microbiota and Attenuates D-Galactosamine-Induced Liver Injury:
- The impact of meals on a probiotic during transit through a model of the human upper gastrointestinal tract:
- Probiotics for Gastrointestinal Conditions: A Summary of the Evidence:
- Probiotics for Clostridium difficile diarrhea: putting it into perspective: