Synbiotic 365 Review: Can It Address Your Digestive Issues?

By Anthony Dugarte, M.D., C.S.C.S
Updated on: May 9, 2020

What Is Synbiotic 365?

United Naturals claims that Synbiotic 365 will offer relief for digestive issues and bloating through a blend consisting of prebiotics, probiotics, and B vitamins.

Probiotics are the friendly bacteria that live in your gut. Prebiotics are a form of fiber that serve as a food source for probiotics and enhance their actions.

On their own, both may offer many health benefits related to digestion, immunity, weight loss, and more. Synbiotic supplements incorporate both pre- and probiotics, as their combined actions may offer even greater benefits.

In this article, we’ll review the science behind Synbiotic 365’s list of ingredients to help you determine if this supplement can help alleviate your digestive symptoms.

  • There is some research backing the individual ingredients
  • Added B vitamins are a bonus if you’re deficient
  • Favorable return policy
  • Favorable safety profile, though immunodeficient people should avoid
  • Research specific to synbiotics is needed to identify the potential role
  • Pricier compared to other synbiotic blends
  • A probiotic supplement with a high-fiber diet may be just as effective

Synbiotic 365’s Ingredients: Do They Work?

According to the supplement facts label listed on the United Naturals website, Synbiotic 365 contains:

  • Vitamin B1 (Thiamin) 2.4 mg
  • Vitamin B2 (Riboflavin) 2.6 mg
  • Vitamin B3 (Niacin) 32 mg
  • Vitamin B6 3.4 mg
  • Vitamin B9 800 mcg (480 mcg folic acid)
  • Vitamin B12 4.8 mcg
  • Vitamin B7 (Biotin) 60 mcg
  • Vitamin B5 (Pantothenic Acid) 10 mg
  • Probiotic Blend 20 billion CFU – Lactobacillus gasseri BNR17, OPTI-BIOME Bacillus subtilis MB40, Lactobacillus paracasei Lpc-37, Bifidobacterium lactic BI-04, Lactobacillus plantarum Lp-115, Streptococcus thermophilus St-21, Lactobacillus Casei Lc-11, Lactobacillus reuteri, Lactobacillus salivarius Ls-33, Lactobacillus rhamnosus Lr-32, Lactobacillus fermentum, Bifidobacterium bifidum Db-06, Bifidobacterium longum BI-05, Saccharomyces boulardii
  • Chicory Root Inulin 315 mg

In the following section, we’ll break up these ingredients into 3 main categories and highlight the available research supporting each group.


Vitamin B deficiency is common, especially in people that live a plant-based life. Deficiency can be associated with a variety of unwanted effects like nerve issues, dry skin, fatigue, and impaired mental capacity.

There are 8 B vitamins included in Synbiotic 365; with the exception of Biotin, this supplement offers close to, or well beyond, the RDA.

The folate in Synbiotic 365 plays a crucial role in growth and development, and also for preventing birth defects.

B12 supports the development of red blood cells; deficiency is associated with anemia.


Their genus identifies probiotic bacteria (e.g., Lactobacillus), which is like an extended family; their species (e.g., acidophilus), and their strain (La-14).

These friendly bacteria impact your digestion and support your immune function. They may also work to reduce allergies, as well as improve diarrhea and constipation. Each strain behaves differently and offers strain-specific effects.

L. casei may relieve digestive symptoms.

In 70 individuals with constipation, those treated with 65 mL of a Lactobacillus casei Shirota containing beverage had reduced symptoms when compared to placebo. A 100g (97 ml) drink with L. casei, L. bulgaricus, reduced the number of antibiotic-associated diarrhea cases in hospitalized patients.

Many L. plantarum species have been studied; the Lp-115 strain has been extensively investigated.

L. Plantarum N14 reduced inflammation in intestinal cells in a laboratory model. 100 mg/kg injections of L. plantarum K8 decreased enzymes associated with heart disease in mice.

  • L. Gasseri is also thought to aid digestion and reduce allergies.
  • L. Gasseri TMC0356 at 200mL decreased the level of antibodies associated with allergies in 15 subjects over 4-weeks. Subjects treated with L. gasseri OLL2716 at 109 CFU doses experienced improved indigestion symptoms over 3-months.
  • L. salivarius may offer antimicrobial effects.

In 59 children with oral disease, treatment with L. salivarius reduced bacterial and fungal levels.

In the Bifidobacteria genus, lactis may reduce inflammation and aid in the management of diabetes, bifidum shows promise for addressing constipation and lung infections, and longum may also be useful for constipation and airway infections, in addition to IBS and ulcerative colitis.

Bifidobacterium lactis strains can offer immune support and allergy relief. B. longum may provide the same benefits.

In a laboratory model, B. Longum CCUG 52486 had anti-inflammatory, especially in samples from elderly individuals. These effects were confirmed in a trial with human subjects; BB536 boosted antibody and white blood cell levels in elderly individuals.

S. boulardii is a fungal probiotic. Its potential benefits have been researched, though most of the available data is found in animal and laboratory models.


Fiber is a type of carbohydrate that can’t be digested or absorbed. Prebiotics, also classified as fiber, pass into your gut fully intact and serve as food for probiotic bacteria.

Additionally, they can absorb water and expand to make you feel full. Prebiotics may also improve blood glucose levels, promote weight loss, and enhance digestion.

The inulin in Synbiotic 365 may offer these benefits.

Inulin reduced hunger, desire to eat, and food consumption in obese adults randomized treated for 12-weeks. 12g of inulin daily for 4-weeks resulted in softer stools, increased stool frequency, and increased amounts of probiotics in constipated adults.

Side Effects and Safety

The company provides details for the total amount of ingredients in the probiotic blend, though they don’t offer amounts for each ingredient. Also, strains behave in a strain-specific manner and may provide different effects when compared to similar strains within the same family.

These factors make it challenging to compare many of these ingredients to those that have been specifically studied.

Probiotic strains are often tested at doses comparable to the probiotic blend in Synbiotic 365. These amounts are generally safe in pre-and probiotic blends, with only mild side effects reported.

Most often, these include digestive symptoms like abdominal pain, gas, bloating, and diarrhea. These can typically be relieved by lowering your dose or discontinuing use.

Lastly, Synbiotic 365 contains a fungal probiotic. While the risk for fungal infections may be small, they are not uncommon. Therefore, critically ill patients, as well as those with a compromised immune system, should avoid using Synbiotic 365.

Whether you’re considering Synbiotic 365 or another probiotic-containing supplement, have an in-depth conversation with a healthcare provider before ordering.

In addition to making recommendations that could maximize value, they can also help minimize any potential side effects based on your diagnosis.

How Much Does Synbiotic 365 Cost?

Synbiotic 365 is only available on the United Naturals website, priced as follows:

  • 1 Box: $45
  • 3 Boxes: $119 ($39.67 per box)
  • 6 Boxes: $229 ($38.17 per box)

All orders come with a 30-day refund policy, less S&H, which customers can request by calling support at 844-794-7728.

Synbiotic 365 vs. Competing Probiotic & Prebiotic Supplements

While Synbiotic 365’s exact formulation is less common, there are a number of synbiotic supplements currently available.

Syntol AMD ($40, 90 capsules), Dr. Axe Formula SBO Probiotic ($41, 60 capsules), HLC Synbiotic Intensive ($43, 7 sachets), NutriCology SymBiotics with FOS ($23, 40 servings), are a few examples.

These supplements are alike in that they’re priced competitively, and each combines a relatively similar blend of probiotics, prebiotics, vitamins, and minerals. These often include many of the same species among the Lactobacillus and Bifidobacteria genera, vitamins C and B, and various extracts like apple cider vinegar or black pepper fruit.

The differences between Synbiotic and competing supplements mostly relate to the quantities of each ingredient they contain, as well as the form in which they’re available (e.g., capsules vs. loose powder).

Alternatively, you can opt for a diet rich in both pre- and probiotics. A diet would include adding fermented foods like yogurt, sauerkraut, or kimchi, as well as fiber-rich whole grains and vegetables to your daily meal plan.

The Bottom Line

While pre- and probiotic blends both seem to offer many desirable health benefits, more research is needed to determine the role of synbiotics. Also, the added vitamins might not provide much value unless you’re deficient.

Additionally, Ultra Naturals does not provide specific quantities for the ingredient offered in their blend. This makes a comparison to the available literature challenging.

Nonetheless, similar blends are generally safe to use though individuals with impaired immune function should use fungus containing supplements with caution.

Given the need for more research regarding synbiotic supplements, you may be better off opting for a more cost-effective option. You can also choose an effective probiotic supplement and increase the fiber-rich foods in your diet.

Lastly, be sure to seek the opinion of a medical professional before use. Symptoms that you’re experiencing may be related to a more serious cause that should be cared for by a physician.

Customer Reviews

Start your review of Synbiotic 365:
  • 1152 Customer Reviews
  • 95% Recommend This Product
4.7 out of 5
5 star: 79% 4 star: 14% 3 star: 2% 2 star: 1% 1 star: 2%

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  • A review of my results of this product

    • By William B.,
    • Tacoma, WA,
    • Sep 9, 2020
    • Verified Reviewer
    • Length of Use: Less than 3 months
    Overall Experience:

    I was battling prostate cancer in December 2019, the radiation treatments affected my gut. Then I saw this product on the internet and watched the video. I was stunned by the results. The doctors gave me several medicines to help return my BM's to normal function. This product works. I am now enrolled in the monthly program.

    Pros and Cons:

    • It works
    • It is easy to take
    • It's not too expensive
    • No “cons” were specified in this review

    Bottom Line: Yes, I would recommend this to a friend

  • Love this product!

    • By Tim R.,
    • Mason, OH,
    • Sep 1, 2020
    • Verified Reviewer
    • Length of Use: 3–6 months
    Overall Experience:

    I'm very skeptical regarding these types of products. I watched the video thinking "yeah, yeah" but gave it a try. I've never felt better. I lost 10lbs and kept it off for four months now. A double win.

    Pros and Cons:

    • Results
    • Easy
    • Discounts
    • A little pricey

    Bottom Line: Yes, I would recommend this to a friend

  • Energy vitamin

    • By Sandra W.,
    • Wesley Chapel, FL,
    • Sep 1, 2020
    • Verified Reviewer
    • Length of Use: Less than 3 months
    Overall Experience:

    I feel more energized since taking this product. I've even lost 10 pounds since June 1st. My daily blood sugar levels have been in the 90s to 110. Also, my latest blood tests have improved significantly, lowering A1C from 7.4 to 6.9 and cholesterol and triglyceride numbers have dropped noticeably.

    Pros and Cons:

    • Energy elevated
    • Loss of weight
    • Improved blood sugar levels
    • No “cons” were specified in this review

    Bottom Line: Yes, I would recommend this to a friend

  • Not impressed

    • By Dani C.,
    • Bolingbrook, IL,
    • Aug 28, 2020
    • Verified Reviewer
    • Length of Use: 3–6 months
    Overall Experience:

    Need to cancel the subscription. I don't remember why I bought this, it doesn't do anything. I take it every day, the only thing good is I haven't had a cold since I started, but that might be because everyone is now washing their hands and covering their mouths.

    Pros and Cons:

    • Haven't caught a cold
    • Hate the way it tastes

    Bottom Line: No, I would not recommend this to a friend

  • The verdict is still out

    • By Mary Ann D.,
    • Crystal Beach, Ontario, Canada,
    • Aug 27, 2020
    • Verified Reviewer
    • Length of Use: Less than 3 months
    Overall Experience:

    As a probiotic user for at least 7 years now, I find the "365" very effective in more ways than just "gut".

    I am only 45 days into it but have noticed a difference in clarity and energy. Not too much difference in my gut health or weight but definitely a little better at this point.

    About 8 years ago I finally discovered that gluten was a big part of my problem so I eliminated most of it. I found probiotics helped considerably but the "365" offers so much more with all the complexes that I am sure I was lacking.

    I will continue to use "365" as I have noticed my appetite has decreased. At age 66 I am fairly active but noticed my ability to work outside for longer hours or walk/bike further has improved.

    Thank you.

    Pros and Cons:

    • My eyes seem brighter
    • Clarity of mind has improved
    • Appetite and cravings have decreased
    • Gut health seems to be improving the longer I use "365"
    • No “cons” were specified in this review

    Bottom Line: Yes, I would recommend this to a friend

  • Shirley's review

    • By Shirley B.,
    • Danville, VA,
    • Aug 23, 2020
    • Verified Reviewer
    • Length of Use: 1–2 years
    Overall Experience:

    I have been using Synbonic 365 for at least a year. I have realized that my system feels better as long as I am taking it regularly. I am 80 and 1/2 now, and everything doesn't always work like when I was younger and more mobile. I take a capsule first thing every morning with a full glass of water and feel like my day is off to a good start.

    The only con is that the subscription plan doesn't work for me. I bought 6 boxes to start with and by the time I had opened the 3rd box, I got an email that 3 more were coming. I can't afford to get more that soon.

    Pros and Cons:

    • Good combination of ingredients
    • Easy to take
    • Good packaging, sealed well
    • The subscription plan doesn't work for me

    Bottom Line: Yes, I would recommend this to a friend

  • Fantastic!

    • By Donna B.,
    • Saskatoon, Saskatchewan, Canada,
    • Aug 20, 2020
    • Verified Reviewer
    • Length of Use: Less than 3 months
    Overall Experience:

    I have suffered with stomach discomfort for years, and after one month of Synbiotic 365 have been almost symptom-free. It’s working well for me!

    Pros and Cons:

    • Easy to administer
    • No “cons” were specified in this review

    Bottom Line: Yes, I would recommend this to a friend

  • Comfort

    • By Mike B.,
    • Black Rock, Nova Scotia, Canada,
    • Aug 18, 2020
    • Verified Reviewer
    • Length of Use: 3–6 months
    Overall Experience:

    I have been taking Synbiotic 365 for 3 months. The results have been great. No more stomach issues. No more bowel issues. No more stomach medication. Wonderful. My fiancé is now taking them and loves they results. Thank you very much. I would recommend this product to any one. Thanks.

    Pros and Cons:

    • Works great
    • No “cons” were specified in this review

    Bottom Line: Yes, I would recommend this to a friend

  • Love this product!

    • By Sharon H.,
    • Orlando, FL,
    • Aug 18, 2020
    • Verified Reviewer
    • Length of Use: 3–6 months
    Overall Experience:

    I have issues with my gut going way back. I’ve had a bowel resection 25 years ago and have episodes when my diet gets sideways and I eat too many of the wrong foods like corn products and become sick for 12 hours followed by bloating and sore muscles from retching. I turned to this product after one of those episodes 3 months ago. The one-a-day capsule makes my gut feel right. No inflammation, nothing hurts, and I feel great. Highly recommend it. Worth a dollar a day for one’s health.

    Pros and Cons:

    • No inflammation, I feel great!
    • Appetite stabilization
    • Packaging ensures freshness
    • Price

    Bottom Line: Yes, I would recommend this to a friend

  • Was not a fan of probiotics

    • By Janice Y.,
    • Redlands, CA,
    • Aug 18, 2020
    • Verified Reviewer
    • Length of Use: 3–6 months
    Overall Experience:

    In the past, I had tried a few probiotics and didn't like the results that I had with bloating, etc. I have been very happy with the results of Synbiotic 365. I started cautiously by taking them every other day, but after a few weeks, I felt better on the days that I was taking the product, so now I don't miss a day. My digestive system is more regular, I tended towards constipation, and I have fewer digestive issues. Thanks for a great product.

    Pros and Cons:

    • No side effect
    • Digestive system is more regular
    • Packaging
    • Not certain about taking so many different organisms
    • Taking another new product on top of my MVMMs
    • Adding another cost - but it's worth it!

    Bottom Line: Yes, I would recommend this to a friend

  • Think it's working

    • By Barbara W.,
    • Bellevue, WA,
    • Aug 18, 2020
    • Verified Reviewer
    • Length of Use: 3–6 months
    Overall Experience:

    I believe the Synbiotic product is helping with my GERD. And I'm sleeping much better. What more can I say? Very helpful product for those of us suffering from Gastrointestinal reflux syndrome.

    Pros and Cons:

    • One capsule a day
    • Cost

    Bottom Line: Yes, I would recommend this to a friend

Showing 1-11 of 1152

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