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Synbiotic 365

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Synbiotic 365 is a dietary supplement that is alleged to help you address your digestive issues by combining probiotics and prebiotics. While the individual actions of these ingredients have scientific support, research confirming the benefits of synbiotics is lacking.


  • 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 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.

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

4.7 Stars out of 1230 Reviews
5 Star:79% 4 Star:14% 3 Star:2% 2 Star:1% 1 Star:2%
96% Recommend This Product
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Posted on Dec 31, 2018

Great start - poor finish

By Kendra H., Warner Robins, GA, Verified Reviewer

My husband and I were loyal users for about 9 months. From the start, this product seemed highly effective. We saw immediate results, including regular bowel movements and decreased bloating. But each time we ordered, they sent us a different "edition" of the product. The first edition was the one that worked. If you looked at the ingredients on the second and third edition, they were entirely different, and those editions did not work for us. All of the bloating and irregular bowel movements returned over the course of the second and third editions. We eventually discontinued. This supplement is way too pricey for it not to work. I'd like to know why the ingredients changed.

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

Helpful Review? 173 People Have Voted

Posted on Nov 1, 2018

Best ever!

By Laurie T., Corinth, NY, Verified Reviewer

I’m on opiates for back pain and have a very difficult time with my bowel movements, sometimes not going for days! I took a chance and ordered this product. After just a few days I started having bowel movements. They became more and more frequent, and now I’m beginning to go two or three times a day. I also noticed my stomach wasn’t bloated or sick as I would every day feel sick. I also noticed that I get up in the morning wide awake and cannot take any more small naps during the day. This is too hard to believe, but it’s true! All I can say is WOW! And I am very grateful for this product. It definitely is not s rip-off! I’m totally on board with this and suggest you do too.

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

Helpful Review? 112 People Have Voted

Posted on Dec 15, 2018

No product received

By Kathleen R., Romeoville, IL, Verified Reviewer

I have called three times and tried to talk to a customer rep only to be disconnected after five minutes. I called their helpline and waited ten full minutes never to reach anyone. I traced the shipment to Salt Lake City where it is lost. You cannot even think of getting through to the USPS at this time of year. Therefore I want my order number 224481962 ordered on December 7th canceled immediately.

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

Helpful Review? 103 People Have Voted

Posted on Jan 11, 2019

United Natural processed my incomplete order

By J. C. K., New York, Verified Reviewer

I was in the process of ordering Synbiotics 365 online. I filled out the payment info and I was pushed to buy more bottles and Enzym 365. I started getting alarmed by the aggressive sales technique, so I went online to check out reviews of the product. I read the reviews here and decided not to buy. I closed out the website without getting to the end to place the order. But I got an email from United Natural that says the order has been processed. I immediately replied, telling them I didn't complete the order. I got no response. I called the phone number in the email and I was told the office is only open Monday - Friday.

I'm pretty upset with the company right now. I'll report back whether the company cancels it.

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

Helpful Review? 101 People Have Voted

Posted on Jan 11, 2019

United Naturals doesn’t return your phone call

By Darrell B., Albuquerque, NM, Verified Reviewer

I tried this supplement for 30 days with no positive results. I called three times within the 30-day return window and they never returned my calls. Finally, on the 4th attempt, they answered and told me I was beyond the 30-day return window. For breaking their return guarantee, they belong in the scam group.

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

Helpful Review? 96 People Have Voted

Posted on Jan 23, 2019

Nothing special

By Judy S., Boise, ID, Verified Reviewer

I have been taking "365" for about three weeks and nothing significant has happened to change my digestion. Don't waste your money, just go buy good B complex vitamins and a good probiotic from your local drugstore or health food store. Ask your pharmacist or health food expert for a good brand. I foolishly ordered, didn't even try for a refund because of the comments by other people.

Remember, what you read online is not always true.

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

Helpful Review? 73 People Have Voted

Posted on Nov 26, 2018

Tremendous improvement

By Gail L., Sarasota, FL, Verified Reviewer

I have been taking SYN 365 for three months now and see a huge difference in how I feel. I have always been very healthy but want to continue to improve. I have found that I am no longer hungry all the time despite eating less now than I did before taking SYN 365. I find myself satisfied with less and better food choices and having more energy. I walk 3 miles a day or more and sleep soundly. No stomach issues with taking the supplement.

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

Helpful Review? 70 People Have Voted

Posted on Jan 20, 2019

Less than positive results

By Mary Ann M., California, Verified Reviewer

I ordered this probiotic as I was told a probiotic would be helpful for me. I have used it for a week and it has caused stomach cramping and diarrhea. I called to see how to obtain a refund, but the mailbox was full. I have now written them and I hope I get an answer as this is obviously not the product for me and I bought three boxes of it.

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

Helpful Review? 66 People Have Voted

Posted on Feb 4, 2019

Scam. Will not refund my money like they said.

By Beth T., Washington, Verified Reviewer

The product made my stomach worse. I have been trying to get my refund back since I returned it December 12th. This is now January 28th. They have given me excuse after excuse not to refund the money. I finally turned them over to my bank for fraud.

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

Company Response from United Naturals

Feb 22, 2019

Beth, please reach out to support@unitednaturals.com and include your order number and the subject "HIGHYA REVIEW" so I can look into this personally.

Helpful Review? 64 People Have Voted

Posted on Feb 12, 2019


By Nelson F., Ontario, Canada, Verified Reviewer

I purchased on January 10, 2019, and it is now February 4, 2019 and I have yet to receive my order. My credit card has been billed almost $500.00, yet no product. False info on United Naturals website, stating warehouse in Montreal, yet it does not exist.

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

Company Response from United Naturals

Feb 22, 2019

Nelson, I am sorry you are experiencing a delay with your order. As you know, when we ship from the United States to Canada we cannot control the amount of time that Customs holds the package for review. Sometimes they are released the same day and sometimes they take much longer.

Our website provides a Canadian address because we have a Corporate office there, not a shipping facility. Nothing on the website indicates that we would be shipping from Canada. I am sorry for any confusion.

Helpful Review? 60 People Have Voted

Posted on Jan 5, 2019

Expected more

By L. B., California, Verified Reviewer

I ordered this product, which I usually don't order online (never know if scam using Dr. Oz, etc.). I never received an email update about the order if it was received or on its way. I finally received the product and there was no "thank you for ordering, welcome, and here is an informational brochure." No, nothing! If I am spending as much as I did, there should have been something in this box. I should not have to go online for information on the product. Just a return label. Is this what you are expecting from all your customers? RETURNS. I will start using on the first day of the year as a resolution to a change in my way of life. I am getting back to making time again to the healthy lifestyle I have had for years and to see my body's downfall. So I will update you all and let you know if I will recommend to others.

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

Helpful Review? 58 People Have Voted
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