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:
  • 1123 Customer Reviews
  • 95% Recommend This Product
4.7 out of 5
5 star: 79% 4 star: 15% 3 star: 1% 2 star: 1% 1 star: 2%

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  • Synbiotic 365 and my families

    • By Ralph S.,
    • Galveston, TX,
    • Jul 2, 2020
    • Verified Reviewer
    • Length of Use: 3–6 months
    Overall Experience:

    I purchased this product for my wife, daughter, and oldest grandson because they all have digestive problems. My wife has been taking it for a while now and has only good things about her results. It does help her have bowel movements, better digestion, better energy, just better, period. I am so pleased. I can say the same for my daughter. As for my grandson, getting him to talk is something else too. But it is helping too.

    Pros and Cons:

    • Feel better
    • Have better digestion
    • Have more energy
    • Have more normal bowel movements
    • I am not complaining but do wish it were less expensive, it is worth it though

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

  • It's been about two weeks...

    • Length of Use: Less than 3 months
    Overall Experience:

    So far, I'm noticing a balancing of energy.

    I've lost about a pound or two, but mostly, I love how light I feel. I do not feel the need to over or under eat.

    Despite not getting the sleep I should be, I'm finding my body's ability to maintain is stronger than what I'm used to. I'm excited to continue noting how it works.

    Pros and Cons:

    • I only have to take it once a day at the top of my day
    • I love my poops
    • I feel balanced
    • There's an odd aftertaste

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

  • Totally satisfied!

    • By Ivete S.,
    • White Plains, NY,
    • Jun 30, 2020
    • Verified Reviewer
    • Length of Use: Less than 3 months
    Overall Experience:

    I have suffered from constipation for as long as I can remember! I started taking Synbiotic 365 and it regulated my bowels! Couldn’t be happier! Just placed my second order!

    Pros and Cons:

    • Regulated by bowel movement
    • No “cons” were specified in this review

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

  • Good probiotic

    • By Cindy H.,
    • Oneonta, AL,
    • Jun 29, 2020
    • Verified Reviewer
    • Length of Use: 6–12 months
    Overall Experience:

    I like this probiotic. It seems to help. There are so many probiotics out there, who knows. I felt like the research on Synbiotic 365 was good.

    Pros and Cons:

    • You don’t have to refrigerate it! Great for travel.
    • The price.

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

  • Doesn't work

    • By Wendy F.,
    • Gypsum, CO,
    • Jun 27, 2020
    • Verified Reviewer
    • Length of Use: Less than 3 months
    Overall Experience:

    I'm not happy with this product, it did nothing as described, I didn't even finish the product. I'd like to return the other 2 boxes.

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

  • Change in my bowel movement

    • By Lisa C.,
    • Jun 27, 2020
    • Verified Reviewer
    • Length of Use: Less than 3 months
    Overall Experience:

    I love it, took it for almost 2 weeks straight, it helped with bloating. I gave one to my mom, she wants me to order her own 3 month's.

    Pros and Cons:

    • Less bloating
    • Change in BM texture
    • The added vitamins
    • No “cons” were specified in this review

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

  • It really does work!

    • By Debra N.,
    • Georgetown, KY,
    • Jun 26, 2020
    • Verified Reviewer
    • Length of Use: 3–6 months
    Overall Experience:

    Since taking it I have felt better, more energy, stomach is somewhat smaller, it is great! It really does work, helps with bloating, my stomach is looking smaller and I do feel better when I take it every day!

    Pros and Cons:

    • It really helps!
    • Easy to swallow!
    • It is really helping with my bloating!
    • No “cons” were specified in this review

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

  • It works

    • By Daniel O.,
    • West Virginia,
    • Jun 23, 2020
    • Verified Reviewer
    • Length of Use: Less than 3 months
    Overall Experience:

    Not much to say yet. However, it seems to be working. I would like to know if you have something that burns fat as you sleep.

    Pros and Cons:

    • The feel better
    • The weight loss
    • The diarrhea

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

  • 2 month Synbiotic

    • Length of Use: Less than 3 months
    Overall Experience:

    I’m 2 months into taking this probiotic. What I have experienced quickly is better sleep. I have not had any changes in my intestinal tract which is what I hope it helps. I’ve always had problems with constipation issues. But I reordered for 3 more months. I think it takes time.

    Pros and Cons:

    • Easy capsules to take
    • No indigestion from them
    • Better sleep
    • Hoping to see more intestinal help

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

  • Good probiotic but Vitamin B levels are an issue

    • By Rosemarie H.,
    • Guilford, CT,
    • Jun 16, 2020
    • Verified Reviewer
    • Length of Use: 3–6 months
    Overall Experience:

    This product is worth a 5-STAR rating, but here's the issue I found: I purchased this probiotic to help me recover from a very bad SIBO infection and to help repair my leaky gut that I am certain I still have. I had some bloodwork done and my doc was concerned that my Vit B level was very high. Not knowing why, I compared my other supplements and found Synbiotic 365 has a lot of Vit B in various forms, which when taken with my women's 55 and over Alive Daily Vitamin, is pushing my levels too high. What I am doing now is taking Synbiotic 365 one day and my daily Vit the next day, alternating. I would prefer to take the Synbiotic EVERY day but then I don't get the benefits of my daily vitamin.

    Pros and Cons:

    • Many good strains
    • Strains are potent with levels
    • Like the blister packs to keep the probiotic fresh
    • Vit B levels in Synbiotic taken with my daily vitamin make my B levels too high

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

  • Exceptional health benefits

    • By Frank P.,
    • Evanston, IL,
    • Jun 16, 2020
    • Verified Reviewer
    • Length of Use: Less than 3 months
    Overall Experience:

    I have experienced very positive health benefits from Synbiotic 365. My heartburn has been relieved enormously from just a few days of using. I highly recommend this product, and just as today, have ordered a three-month supply. Dr. Pedre is definitely a master of his trade as shown in his products. Please give this a try!

    Pros and Cons:

    • Digestion support
    • Individual packaging
    • Ease of storage
    • No “cons” were specified in this review

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

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