The No-BS Guide to Different Types of Probiotics

Overview

• You can’t judge a probiotic by its genus alone—the specific strain (like L. plantarum LP01) tells you what health benefits to actually expect from those microbes.
• Different strains from the same family work completely different jobs—one Lactiplantibacillus plantarum strain might keep cholesterol within a healthy range while its cousin may help you poop more comfortably.
• Common probiotic types include bacteria like Lactobacillus and Bifidobacterium, but you’ll also find beneficial yeasts like S. boulardii and spore-forming bacteria like Bacillus.
• Scientists split the Lactobacillus genus into 25 smaller groups like Lactiplantibacillus and Lacticaseibacillus—because precision matters in microbiology and microbiome science.
• When choosing a probiotic, look for scientific evidence behind the specific strains in the formula, not just the brand name or the “type” of bacteria.

The probiotic aisle can feel like a foreign language immersion course. Bottles covered in Latin names, mysterious letter-number combinations, and scientific terms that sound important, but mean… what, exactly? All you wanted was to know what the different types of probiotics are and which ones actually deliver on their promises. Is that too much to ask?! 😭

Believe it or not, there’s logic to all those tongue-twisting names. Probiotics are organized into their “types” at different classification levels—from big categories like Lactobacillus and Bifidobacterium, down to specific species like L. rhamnosus, and finally to individual strains like LGG. Each level tells you something different, but that last level—the strain—reveals what a probiotic actually does. 

Of course, you’ll also see probiotics sorted by format (liquid vs. capsule), storage needs (shelf-stable or fridge requirement), and who marketers think should take them. Some of these differences matter—like whether the delivery method protects bacteria from stomach acid—while others are just packaging decisions.

Ready to become fluent in probiotics? 🦠

Note: There are lots of links throughout this article for you to learn even more about the different types of probiotics!

What Exactly Is a Probiotic, Anyway?

Before we explore the microbial lineup, let’s nail down what we’re talking about. Scientists have a very specific definition for what qualifies as a probiotic: “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.”¹

Breaking that down into three parts:

• Live Microorganisms: They have to be consumed alive to do their job (dead bacteria = expensive dust)
• Adequate Amounts: You need to take enough of them—a dose shown to work in studies
• A Health Benefit: They must be scientifically validated to provide a specific benefit

This definition is your BS detector. Just grabbing any bottle that says “probiotic” might not give the results you’re looking for. (Learn more about the basics of probiotics here!)

Common Types of Probiotics: A Field Guide

Now that we know to think at the strain level, here are the most common groups you’ll see on labels and some specific strains and their researched benefits.

🧠 Microbe Trivia: In 1989, the first Lactobacillus strain got officially patented. Can you guess which one? (Answer at the end!)

Lactobacilli: The Multitaskers

Lactobacillus used to be the celebrity genus of probiotics, but scientists realized it was so diverse they had to break it up. (Think of it like splitting up a band that got too big—now we have 25 solo acts and types.)² So, name types like Lactiplantibacillus, Lacticaseibacillus, or Limosilactobacillus are a reflection of updated, more accurate science.

Lactobacillus strains and what they’re studied for:

• Lacticaseibacillus rhamnosus GG (LGG): One of the most extensively studied probiotic strains, LGG has been researched for its survival abilities in the gut. It may help support gut lining integrity and immune balance, with particular interest in its potential during antibiotic use.³ It also makes proteins that have been shown to interfere with certain harmful bacteria like Salmonella. 
• Lactiplantibacillus plantarum LP01: Nobody likes painful poops. 💩 In clinical research, this strain was associated with more regular bathroom visits and less straining in people dealing with occasional constipation.⁴
• Lactiplantibacillus plantarum LPLDL (also shown as ECGC 13110402): This specific strain has been clinically studied for its role in supporting cardiovascular health by helping maintain blood cholesterol levels already within a normal range.⁵
• Lacticaseibacillus casei CECT9104: While most skincare works from the outside, this strain is studied for its potential to support skin health through your gut. Research in children explored whether this gut-to-skin pathway could make a visible difference.⁶
• Lactobacillus gasseri BNR17: Initial studies have investigated this strain for its potential effects on weight loss in obese adults, particularly in reducing abdominal fat.⁷
• Limosilactobacillus reuteri LRE2: Your body needs vitamin B12 but can’t make it—which is where this strain shows promise. Researchers have observed its ability to produce B12 in the gut, though more studies are needed to understand the real-world impact of this microbial vitamin factory.⁸
• Lactobacillus salivarius LS01 (DSM 22775): This strain has been researched for its helpful effects on eczema-prone skin in adults dealing with atopic dermatitis (AD).⁹

Bifidobacteria: The Gut’s OG Residents

These bacteria are among the first beneficial microbes to colonize the infant gut. They’re fiber-fermenting specialists that break down complex carbohydrates your body can’t digest on its own, transforming dietary fiber into beneficial compounds that you can use.

Bifidobacterium strains and what they’re studied for: 

• B. longum BB536: This strain has been extensively researched for keeping your digestive system regular. In studies, it helped people go from struggling with occasional constipation to having more comfortable poops.¹⁰
• B. lactis CECT8145: This strain works through the gut-skin connection, with research in teenagers showing it can support clearer, healthier-looking skin from the inside out.⁶
• B. breve BR03: Another skin-supporting strain that reinforces your body’s natural barriers. It helps maintain protective layers in both your gut and skin, keeping good stuff in and bad stuff out.¹¹
• B. adolescentis BA5 (DSM 18350): Your gut can actually be a vitamin factory, and this strain is one of the workers. Research shows it may help intestines make folate (vitamin B9), a nutrient the body needs, but it can’t make enough on its own.¹²
• B. infantis M63: True to its name, this strain specializes in supporting the youngest guts. It helps establish and maintain a healthy microbiome in babies—giving new digestive systems strong foundations from the start.¹³
• B. lactis MB2409: Researchers put this strain under the microscope (literally “in vitro” lab studies) to understand how it might help keep cholesterol levels in check. While we need more human studies, initial data shows promise for cardiovascular support.¹⁴

The Wild Cards: Other Notable Probiotic Types and Strains

Beyond the common Lactobacillus and Bifidobacterium families, you’ll encounter other microbes that scientists have studied for their probiotic potential. These include beneficial yeasts, spore-forming bacteria, and newly discovered strains that expand our understanding of what probiotics can do.

The extended probiotic family includes:

• Saccharomyces boulardii: This beneficial yeast (not a bacterium) has been studied for its ability to support gut function during and after disruptions like travel or antibiotic use. While promising, research has shown mixed results and occasional safety concerns in specific populations.¹⁵
• Spore-Based Probiotics: Often from the Bacillus genus, these soil-dwelling microbes form protective shells to survive harsh conditions. Some studies show promise, but they emphasize the need for more strain-specific data.¹⁶
• Streptococcus salivarius M18: This strain was found to promote oral health, specifically in reducing bleeding gums and plaque formation.¹⁷
• Faecalibacterium prausnitzii KBL1027: A newly identified strain that protects mice from intestinal inflammation.¹⁸

🦠 Microbial Memo: Synbiotics combine probiotics with prebiotics (their favorite snacks). While not a different microbe type, this power couple can help beneficial bacteria perform better once they reach your gut. (Learn More: What is a Synbiotic?)

Beyond the Label: What Matters More Than Probiotic Types

You’ve met the microbial cast, but choosing the right one involves more than name recognition. Here’s what separates the real deals from the imposters.

The Survival Game: Delivery and Storage Types

Trying to decide between liquid probiotics and ones with capsules? Not all types of probiotic vehicles are created equal. 

The delivery format matters because your stomach is basically an acid bath designed to destroy bacteria—with a pH as low as 1.5, it’s more acidic than lemon juice! 🍋 Without protection, most probiotics don’t stand a chance. But advanced delivery systems can shepherd bacteria safely through to your intestines where they actually work.

Then there’s the fridge-or-shelf question. 

Some probiotics need constant refrigeration to keep bacteria alive, while others stay stable at room temperature thanks to freeze-drying technology. The difference isn’t about quality—it’s about how they’re manufactured. Shelf-stable probiotics won’t die if you forget them on the counter, and they’re easier for travel. But when made properly, both types are capable of delivering health benefits.

💡 Pro Tip: Look for capsules or delivery systems engineered to protect live bacteria from stomach acid. Enteric coatings, delayed-release technology, or capsule-within-capsule designs can increase probiotic survival. (It’s like giving the beneficial microbes in your probiotics their own hazmat suits for the journey.)

Strains: The Most Important “Types” of Probiotic

Just knowing the genus (Lactobacillus) and species (rhamnosus) isn’t enough. It’s the strain designation—those letters and numbers at the end, like “GG” or “HN001”—that tells you what it actually does.

Dirk Gevers, Ph.D., has spent over twenty years investigating how gut bacteria can shape human health. “What most people don’t realize is that probiotics are incredibly specialized. Each strain has evolved its own unique properties: how it adheres to your gut lining, what compounds it produces, how it interacts with immune cells, and more. When products don’t list specific strains, they’re essentially asking you to trust that any random Lactobacillus will do the job. But that’s not how the science of probiotics works.”

👉 TL;DR: If a probiotic doesn’t list full names for its strains, you’re basically being catfished by microbes. Swipe left.

Who, What, When, Where?

Different life stages and health situations call for different probiotic support. While there’s no one-size-fits-all solution, it’s worth considering your specific circumstances when choosing a probiotic.

Consider these factors when choosing a type of probiotic:

• Life Stage: Infants, children, teens, adults, and seniors (those that are 50, 60, or older) may have different microbiome needs
• Current Circumstances: Travel, antibiotic use, dietary changes, or stress can all affect your gut
• Specific Health Goals: Whether you’re looking for digestive support, immune balance, acne, psoriasis, IBS, or something else
• Gender and Hormones: While most probiotics for men work similarly to probiotics for women, some concerns are gender-specific (like vaginal health, pregnancy, breastfeeding, and menopause) 

Your microbiome is as unique as your fingerprint. What works for your yoga buddy might not be your gut’s cup of tea. Look beyond generic labels for products with strains studied for your specific needs.

How to Read Probiotic Labels Like a Pro

Decoding a probiotic label shouldn’t require a microbiology degree (though it sometimes feels that way). Here’s what to look for:

• Full Strain Names: Not just “Lactobacillus” but the complete designation like “L. rhamnosus GG”
• AFU vs. CFU: This is how probiotics are “measured”. Active Fluorescent Units (AFU) count all viable cells, while Colony Forming Units (CFU) only count those that can grow on a petri dish—AFU gives you the most precise picture.
• Clinical Evidence: Can the company point to published studies using their exact strains at the listed doses? 
• Expiration Dating: Live microorganisms don’t live forever. Look for products guaranteeing potency through expiration, not just at time of manufacture. (Because dead probiotics aren’t useful) 

Are Fermented Foods a Type of Probiotic?

Let’s talk about fermented foods real quick—those tangy, fizzy favorites created when beneficial microbes transform sugars into acids, gases, or alcohol. Some of those favorites include foods like yogurt, kimchi, kefir, kombucha, sauerkraut, and miso. Yes, they contain live microorganisms. No, that doesn’t automatically make them probiotics.

Remember the three-part definition? True probiotics need specific strains in specific amounts with proven benefits.¹

With fermented foods, you’re flying blind on:

• Which Strains? Could be anything fermenting in there
• How Many? Microbial counts are anyone’s guess
• What Benefits? No guarantee they’ll do anything specific

So while fermented foods can introduce beneficial microbes and taste great, they’re not a substitute for clinically-validated probiotics chosen for specific outcomes.¹⁹ (Think of them as the difference between “contains vegetables” and “contains exactly 5mg of vitamin C from ascorbic acid.”)

The Key Insight

The probiotic aisle bombards you with bottles shouting about billions of AFUs and “ultimate gut health blends.” But the real secret to choosing an effective probiotic has nothing to do with impressive numbers or microbial variety shows. While there are many types of probiotics, only one type of label is worth trusting—the kind that spells everything out instead of trying to catfish you and your gut health.

The difference between “contains Lactobacillus” and “contains L. rhamnosus GG” is like the difference between “this bottle has bacteria” and “this bottle has the exact bacteria studied for this exact benefit.” When you see the full strain name, you’re looking at a probiotic that’s done its homework. Every strain has its own resume. Some excel at easing constipation, others support immunity, and some even help your gut manufacture vitamins. Companies that list complete strain names are showing their work—proving they’ve invested in research. 

🌱 Choose strains, not stories. Your microbiome will thank you.

🧠 Microbe Trivia – Answer: The first patented Lactobacillus strain was LGG (Lacticaseibacillus rhamnosus GG) in 1989.

Frequently Asked Questions (FAQs)

What Are the Main Types of Probiotics?

Probiotics come in several types, from the broadest categories (genera) down to specific strains. The major groups include Lactobacillus bacteria (recently reclassified into 25 distinct genera), Bifidobacterium bacteria, Saccharomyces yeasts, and spore-forming Bacillus bacteria. 

For each type, you’ll find different species and strains with unique benefits. For example, within Bifidobacterium, you have B. longum BB536 for digestive regularity and B. lactis CECT8145 for skin health. It’s the most specific type—the strain designation—that tells you what health benefits to expect.

Which Probiotic Should I Take for Bloating?

Several strains may be able to help! Research shows B. longum BB536 reduces bloating and increases weekly poops from (approximately) 3 to 5-6 times. L. plantarum LP01 specifically reduces gas production and abdominal distension. For best results, look for products containing these exact strains at the doses used in clinical studies—typically 1-10 billion CFU daily.

How To Know Which Type of Probiotic to Take?

Match the strain to your goal. Skip choosing by “type” and focus on your specific health needs, and then look at the strain-specific research.

Here are a few strain examples for specific health needs:

• Can’t remember the last time you pooped? 💩 Look for B. longum BB536.¹⁰
• Trying to support heart health and keep your cholesterol at a good level? 🫀 Try L. plantarum LPLDL.⁵
• Dealing with eczema (atopic dermatitis or AD) and looking for gut-skin axis support? 🧴 Consider L. salivarius LS01 (DSM 22775.)⁹

The product should list exact strain names (those letters and numbers after the species) and point to human clinical studies showing that strain works for your specific concern.

What’s the Difference Between Lactobacillus and Bifidobacterium?

Location and specialty. Lactobacillus strains live throughout your digestive tract (mouth to colon) plus the vagina, where they produce lactic acid to maintain healthy pH levels and prevent pathogen overgrowth. Bifidobacterium strains prefer your large intestine, where they ferment dietary fibers into short-chain fatty acids that feed your gut lining and reduce inflammation.²⁰ 

Think of them as different departments in your gut’s workforce—Lactobacillus handles security (pH control), while Bifidobacterium runs waste management (fiber fermentation).

Are Synbiotics the Same Thing as Probiotics?

Not exactly—synbiotics are probiotics with a plus-one. While probiotics are the live beneficial bacteria, synbiotics combine those same bacteria with prebiotics (their favorite food). Think of it as the difference between adopting a pet and adopting a pet with a month’s supply of food. 

The prebiotics help fuel the probiotics on their journey through your digestive system, potentially making them more effective. So yes, every synbiotic contains probiotics, but it’s the prebiotic sidekick that makes it “syn.”