Jump To:
Our Editorial Review
Customer Reviews

Synbiotic 365

  This company has claimed this profile, is getting alerted on any new customer reviews entering this page, and may engage in dialogue with its customers to address their matters.

Companies cannot pay money or provide goods in order to remove or alter customer reviews.
Synbiotic 365

Overall Rating


1230 Customer Reviews

Write a Review


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
Start your review of Synbiotic 365:
Sort Reviews By
This company is actively collecting reviews from its customers. All reviews submitted are subject to moderation and approval to ensure they meet our Review Guidelines.

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 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 Feb 15, 2019

Didn't work, offered half of a refund

By Greg G., Oak Island, NC, Verified Reviewer

I wish I had read all the reviews before I ordered for a trial. The email received after placing my order said. "Congratulations...You will not regret it", but they failed to make good on their word. If your 30-day trial takes more than 30 calendar days, you will not get a full refund. But we'll see how my credit card company feels about it as I plan to dispute the charge. The product didn't work for me, and the reviews show that it's a pretty common occurrence.

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

Company Response from United Naturals

Feb 22, 2019

Greg, we offer a robust, 100% guarantee that starts the date of delivery and only requires you to have the return postmarked by day 30. That gives you an entire month to use the product to experience the results. Consistency is key, and we find giving more time allows for people to take days off and not experience the results they want. Our refund policy is top in class. I am sorry that the product didn't work for you.

Helpful Review? 32 People Have Voted

Posted on Feb 21, 2019

Void guarantee

By Andrew S., Centreville, VA, Verified Reviewer

You have 30 days from the day of purchase to return the product. This laughable. Take my scenario. I paid on 11/26, they shipped on 12/4, and I received on 12/11. That’s already two weeks in. Any physician with their degree will tell you it takes a minimum of two weeks to feel the benefits of most vitamins or pharmaceuticals. Ok, this happens to fall around Christmas time. Do you think some people purchasing your products may be giving it to loved ones for a Christmas gift? Poof, the guarantee is gone! Both my daughter-in-law and son took it for 30 days and it had not improved their heartburn and digestive issues such as stool consistency, cramps, etc. $200 tossed into the wind.

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

Company Response from United Naturals

Feb 22, 2019


I am sorry to hear you were not satisfied with our product. We provide a robust 30-day policy for our customers that starts the date of delivery and just needs you to have it postmarked back to us by the 30th day. This gives you a full month to experience the product. If you believe you were still in that time frame please reach out to support@unitednaturals.com so we can make this right.

Helpful Review? 35 People Have Voted

Posted on Mar 15, 2019

Order error

By Rachel G., Seymour, MO, Verified Reviewer

I was in the process of ordering 3 packages of Synbiotic when I was offered 3 more packages at a discount. I began to click the NO THANKS when the screen changed, and all I could see were the words "your order is not complete." I feel concerned because I have provided you with my credit card number, and I've not received a validation number for the 3-package automatic order. I do not want additional products at this time. Unfortunately, my ground-line phone is not functioning.

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

Company Response from United Naturals

Mar 15, 2019

Hi Rachel,

We're sorry you had an issue with our site. We found your order, which had already shipped, and was only for the three boxes you'd initially meant to order. No additional boxes were sent. We hope this is of help. Though you are having landline issues, I'm adding our phone number and e-mail address here as well, in hopes you have another method to contact us in case you are in need of further support: 1-844-794-7728 support@unitednaturals.com.

Thank you,

United Naturals

Helpful Review? 9 People Have Voted

Posted on Mar 27, 2019

Severe skin issues

By Valerie H., Verified Reviewer

I started getting severe breakouts of little blisters that itched SEVERLY and would break upon me scratching them. They didn't actually spread. I would just break out all over my body with clusters of little blisters that itched SO BADLY that I thought I was going to LOSE MY MIND. After a trip to STAT CARE and a trip to a DERMATOLOGIST, I finally stopped taking the Synbiotic and at the moment I am struggling to keep my hair as the severe itching and breakouts have moved to MY SCALP, AND MY HEAD is now covered with BLISTERS AND SEVERE ITCHING.

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

Helpful Review? 16 People Have Voted

Posted on Apr 2, 2019

Did not like

By M H., Boynton Beach, FL, Verified Reviewer

Made me feel worse - had to stop taking them. Wish I could return the balance for a credit.

I do not recommend this product.

It took me a long time to get my system feeling good.

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

Company Response from United Naturals

May 30, 2019

M H,

I am sorry you did not get the results you were looking for with the Synbiotic 365. As you can see from our reviews here, we have many satisfied users. However, everyone's body is different. Some people see results almost immediately, some take a little longer, and some don't get the results they wanted. This is why we are sure to back every order with a money back guarantee. I thank you for putting your faith in United Naturals and I hope you can find a product that gives you the results you are looking for.

Helpful Review? 7 People Have Voted

Posted on Apr 24, 2019

Have not received

By Rob K., Iowa, Verified Reviewer

I ordered Synbiotic 365 ten days ago and have not received the product. An email from UN stated that my probiotic will be shipped from a warehouse in Utah, however, the tracking number they provided showed the package is being shipped from North Carolina. There is also a note from DHL that there was a problem with the shipment. I'm not sure what's going on. I don't like the idea that my probiotics are just sitting somewhere in the U.S. in a hot truck!

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

Company Response from United Naturals

Apr 24, 2019


We maintain facilities in both UT & SC for shipping. Unfortunately, some shipping issues happen and are out of our control. Rest assured that we package our Synbiotic 365 in Nitrogen filled Blister Packs to protect the ingredients during transit. Your product will still be safe and effective for you to use. If you have any questions please reach out to support@unitednaturals.com.

Thank you!

Helpful Review? 2 People Have Voted
Showing 1-11 of 1230

Our Promise to You

In order to safeguard you and ensure helpfulness and relevance, our compliance team manually assess every customer review before it goes live.

We have a zero-tolerance policy for fake reviews, and companies cannot control or alter any reviews at any time.