But there are two newer – and often misunderstood – members of the ‘biotics’ family that are gaining increasing attention in gut and immune health: postbiotics and paraprobiotics.

So what exactly are they, how do they work if they’re not alive, and why are they becoming so popular?

What are postbiotics and paraprobiotics?

Although the terms are sometimes used interchangeably, postbiotics and paraprobiotics are not the same thing.

Postbiotics

Postbiotics are the metabolic products or by-products produced by beneficial bacteria, or substances released when bacterial cells break down (a process known as lysis). These include compounds such as short-chain fatty acids, enzymes, peptides, and cell wall components.

In other words, postbiotics are the beneficial outputs of bacteria, rather than the bacteria themselves.

Paraprobiotics

Paraprobiotics are fully intact microbial cells that have been deliberately inactivated, most commonly through heat treatment. While these bacteria are no longer alive or capable of colonising the gut, their cellular structures remain intact.

These structures are able to interact with the gut lining and immune system in meaningful ways.

How can ‘dead’ bacteria still be beneficial?

It might seem counterintuitive that non-living bacteria could still support health, but research shows that both postbiotics and paraprobiotics can exert biologically active effects.

Certain components of bacterial cells – even when inactivated – can still:

• Interact with immune cells in the gut

• Support intestinal barrier integrity

• Help regulate inflammatory responses

• Protect against harmful or pathogenic microbes

In many cases, these effects are mediated through immune modulation, where bacterial components help “train” or balance the immune response rather than overstimulate it.

Why are paraprobiotics gaining popularity?

One of the major challenges with traditional probiotics is that they are live organisms, which means:

• They are sensitive to heat, moisture, and oxygen

• Their potency can decline during storage

• They may not survive transit through the stomach in all individuals

• They can cause bloating or discomfort in sensitive people

Paraprobiotics, on the other hand, are:

• Far more stable

• Easier to manufacture and store

• Consistent in dosing

• Very well tolerated, even in people with sensitive digestion or immune systems

This makes them an attractive option for individuals who do not tolerate traditional probiotics well, or for use in formulations where stability is essential.

What does the research say?

Most paraprobiotics studied to date are derived from Lactobacillus and Bifidobacterium species.

One particularly well-researched strain is Lactobacillus gasseri CP2305 HI, which has been investigated in multiple human clinical trials.

Stress and sleep

Several studies have shown that supplementation with L. gasseri CP2305 HI can:

• Reduce perceived stress and anxiety

• Improve sleep quality

• Support nervous system regulation during periods of psychological stress

Premenstrual syndrome (PMS)

Clinical trials using 10 billion cells per day have demonstrated reductions in premenstrual symptoms, particularly psychological symptoms such as low mood, irritability, and anxiety.

Digestive health

Research also suggests benefits for gut function, including:

• Improved bowel regularity

• Positive shifts in gut microbiota composition

• Increased beneficial bacteria such as Bifidobacteria

• Reduced populations of less favourable bacterial groups

Who might benefit from postbiotics or paraprobiotics?

These newer biotics may be particularly useful for:

• People who experience bloating or discomfort with probiotics

• Those with sensitive or reactive guts

• Individuals seeking immune or nervous system support

• Situations where probiotic stability is a concern

• Children or vulnerable populations where tolerability is key

So which is best?

Goal	Better option

The takeaway

Postbiotics and paraprobiotics represent an important evolution in our understanding of gut health.

Rather than focusing solely on introducing live bacteria, these approaches harness the beneficial signals and structures bacteria provide — often with better stability and tolerability.

In summary:

• Paraprobiotics are inactivated beneficial bacteria that remain biologically active

• Postbiotics are the beneficial compounds produced by bacteria

• Both can support gut, immune, and nervous system health

• Strong evidence exists for specific strains, particularly Lactobacillus gasseri CP2305 HI, in areas such as stress, sleep, PMS, and digestive health

As research continues to evolve, postbiotics and paraprobiotics are likely to become an increasingly important part of targeted, evidence-based gut support.

If you’re navigating gut, immune, or stress-related symptoms and want to understand which types of biotics may be most appropriate, a personalised naturopathic consultation can help clarify the best next steps.