Is There a Difference Between Acidophilus and Probiotics? An Essential Guide

November 18, 2025 •

4 min read

According to the National Institutes of Health, the functional roles of Lactobacillus acidophilus have been widely studied since it was first named in 1900. For many, this raises the question: is there a difference between acidophilus and probiotics? In short, yes—acidophilus is a specific type of probiotic, a member of a much larger family of beneficial microorganisms.

Quick Summary

Acidophilus (full name: Lactobacillus acidophilus) is a specific species of bacteria, whereas 'probiotic' is a general term for any microorganism with health benefits. All acidophilus are probiotics, but not all probiotics are acidophilus.

Key Points

Scope: Probiotics are a broad category of beneficial microorganisms, while acidophilus is a single, specific species within that category.
Analogy: Thinking of probiotics as the category 'fruit' and acidophilus as the specific 'orange' helps to clarify the relationship.
Strain Specificity: Different strains of acidophilus, like NCFM®, have distinct effects, such as aiding lactose digestion.
Sources: Acidophilus is commonly found in fermented foods like yogurt and kefir, and specific supplements, but many other probiotic types exist in different sources.
Customization: The most effective probiotic depends on the specific health issue, making a strain-specific approach or a multi-strain blend more appropriate depending on the goal.
Efficacy: For a probiotic to be effective, it must be alive and in high numbers at the point of action.
Best Practice: Consulting a healthcare professional is wise when choosing a supplement, especially for specific conditions.

What Are Probiotics?

Probiotics are defined as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. The term 'probiotic' is a broad category that encompasses many different types of bacteria and even some yeasts. These beneficial microbes play a crucial role in maintaining the balance of your gut flora, which is essential for overall digestive and immune health.

Common examples of probiotic microorganisms found in supplements and fermented foods include:

Bacteria: Lactobacillus, Bifidobacterium, and Streptococcus thermophilus.
Yeasts: Saccharomyces boulardii.

Each species and even specific strain of probiotic can offer different health effects. For instance, some may primarily assist with digestion, while others may focus on supporting the immune system. The effects are highly specific to the strain.

What is Lactobacillus acidophilus?

Lactobacillus acidophilus, often simply called acidophilus, is a specific species of bacteria within the larger Lactobacillus genus. It is one of the most common and well-known types of probiotics, naturally found in the human intestines, mouth, and vagina. Its name comes from its ability to produce lactic acid through the fermentation of carbohydrates, such as lactose. This process creates an acidic environment that can be unfavorable for harmful pathogens.

Common sources of L. acidophilus:

Yogurt
Kefir
Miso
Tempeh
Some cheeses
Dietary supplements

The Analogy: Fruit vs. Orange

To better understand the relationship, consider this simple analogy: The term 'probiotic' is like the word 'fruit', and 'acidophilus' is like the word 'orange'. An orange is a type of fruit, but not all fruit is an orange. Similarly, Lactobacillus acidophilus is a specific type of probiotic, but many other kinds exist, such as Bifidobacterium lactis or Lactobacillus rhamnosus. This is why you will often see supplements labeled as containing 'probiotic strains,' with L. acidophilus listed as one among several.

The Importance of Strain Specificity

When it comes to probiotic supplements, the benefits are not determined just by the species but by the specific strain. For example, the strain Lactobacillus acidophilus NCFM® has been studied for its specific effects on lactose intolerance, helping to break down lactose and alleviate symptoms. In contrast, another strain of L. acidophilus might have different effects. This strain-level specificity is why many supplements contain a blend of different probiotic strains, each targeted for a particular function or to provide a broader range of benefits.

Crucially, probiotics must be alive and in high numbers to confer a health benefit. The specific strain, colony-forming units (CFUs), and how the supplement is manufactured can all impact its effectiveness. This highlights why consulting with a healthcare professional is recommended to choose the best probiotic for your specific needs.

Comparison: Acidophilus vs. Other Probiotics


Aspect	Probiotics (General Term)	Lactobacillus acidophilus (Specific Species)
Scope	A broad, inclusive category of beneficial microorganisms.	A specific member of the Lactobacillus genus and a type of probiotic.
Definition	Live microorganisms that provide health benefits when consumed in adequate amounts.	A specific strain of bacteria that ferments sugars into lactic acid.
Examples	Includes many bacterial species (Bifidobacterium, Lactobacillus spp.), as well as yeasts (Saccharomyces boulardii).	One distinct bacterial species (L. acidophilus) with its own unique strains, such as NCFM®.
Sources	Found in a wide variety of fermented foods and supplements, with different foods containing different mixes of microbes.	A common ingredient in yogurt, kefir, and specialized supplements.
Key Benefits	Broad range of benefits, including general digestion, immune support, and vitamin production, depending on the strains present.	Specifically known for aiding lactose digestion, balancing intestinal flora, and inhibiting pathogens.

Choosing the Right Probiotic Supplement

When selecting a probiotic, understanding the difference between the broad term and the specific species is essential for meeting your health goals. If you are targeting a specific condition, like lactose intolerance, a supplement containing a researched strain of L. acidophilus may be ideal. However, for general gut health, a multi-strain probiotic could offer a wider array of benefits by delivering a diverse mix of beneficial bacteria. Always read the label to identify the specific strains included and their intended uses. For those with compromised immune systems or specific health conditions, a healthcare provider should always be consulted before starting a new supplement regimen.

Conclusion

In summary, while the terms are often used interchangeably, there is a clear and important distinction between acidophilus and probiotics. Acidophilus (Lactobacillus acidophilus) is a specific and well-researched type of probiotic bacteria. The term 'probiotic,' on the other hand, is a much larger umbrella term covering any beneficial microorganism. Knowing this difference allows you to make a more informed choice about supplements and fermented foods, ensuring you select the right microbial support for your specific health needs.

For more detailed information on probiotics, you can visit the NIH Health Professional Fact Sheet.

Frequently Asked Questions

A good way to remember is with a simple analogy: probiotics are like 'fruit' in general, while acidophilus is a specific type of probiotic, like an 'orange'.

Besides Lactobacillus acidophilus, other common probiotics include species from the Bifidobacterium genus, such as B. lactis, and certain yeasts like Saccharomyces boulardii.

Not necessarily. While many yogurts contain L. acidophilus, the effectiveness depends on the specific strain, the number of live bacteria (CFUs), and whether they survive the digestive process. Look for reputable brands that specify the strains and CFU count.

People with compromised immune systems, such as those with HIV or undergoing chemotherapy, should consult a doctor before taking probiotics. Individuals with severe lactose intolerance should also check if acidophilus products contain lactose.

You can increase your intake by consuming fermented foods that contain it, such as yogurt, kefir, miso, and tempeh. For consistent, high-dose intake, supplements are also an option.

L. acidophilus is known to assist with lactose digestion, regulate intestinal flora, and inhibit potentially harmful pathogens. Specific strains can also offer benefits like supporting immune responses.

While generally considered safe, some people may experience mild side effects like bloating or gas, especially when first starting. Following dosage instructions on the product label is important, but a high intake typically doesn't cause serious issues for most people.