PS128 is a Lactobacillus plantarum strain isolated from Taiwanese fermented mustard greens and sold as a food supplement, not a proven treatment.
For the full breakdown, see our best PS128 Supplement guide.
Most of the confusion around PS128 lives in the gap between those two facts.
PS128 is a proprietary strain of Lactobacillus plantarum, isolated from spontaneously fermented mustard greens in Taiwan and sold there as a food supplement since 2015. Sorting out what is PS128 probiotic and how does it work comes down to keeping three things apart: the bacterium, the studies run on it, and the products sold under its name.
What PS128 Is, According To The Sources
PS128 is a single patented strain, properly named Lactobacillus plantarum PS128 and written in newer literature as Lactiplantibacillus plantarum PS128. Taiwan’s food regulator approved it as a food supplement, and product documentation states PS128 items have been sold there since 2015.
A food-approval pathway is not a drug approval.
| Detail | What The Sources State |
|---|---|
| Strain | Lactobacillus plantarum PS128, also written Lactiplantibacillus plantarum PS128 |
| Origin | Spontaneously fermented mustard greens, Taiwan |
| Regulatory status | — |
| Capsule format | 30 billion CFU per capsule |
| Parkinson’s study protocol | Two capsules daily, 60 billion CFU total, for 12 weeks |
| Sachet format | 3 g per sachet; 1–2 daily for children over 2, 2–3 daily for adults |
| Recorded listing prices | About $20 to $195, varying by seller and format |
PS128 Probiotic Research: Where The Evidence Stands
The human evidence for PS128 is early: one small, open-label Parkinson’s disease study reported improvements, and its design could not prove the strain caused them.
Laboratory and animal work suggests a mechanism instead. PS128 survives passage through the stomach and may shift gut microbiota composition, intestinal immune signaling, oxidative stress, and neurotransmitter-related pathways. That is the gut–brain axis idea in one line, and in people it stays a hypothesis rather than a demonstrated mechanism.
The 2021 trial gave two PS128 capsules daily, 60 billion CFU in total, for 12 weeks, and 25 participants completed it. Motor scores, “on” and “off” periods, and Parkinson’s quality-of-life scores improved on statistical measures, but with no placebo group those gains could reflect expectation, time, or the participants’ existing medication. Everyone stayed on standard Parkinson’s drugs throughout, and the published PS128 Parkinson’s disease trial records the outcomes and the study number, NCT04389762.
A toxicology study found no genotoxicity in the assays used and no observable adverse effects in mice after 28 days of oral dosing up to 2,400 mg/kg body weight, which the authors treated as support for further study rather than proof that any particular human dose is safe. The trial’s consent document notes that probiotics can bring bloating or diarrhea and can trigger migraine in susceptible people.
How Much PS128 Do People Take?
No single standard PS128 dose exists. The two documented regimens differ by product form, and neither one is a general recommendation.
- Capsules used in research: two per day, each containing 30 billion CFU, for 12 weeks.
- Sachet label directions: children over age 2 take 1–2 sachets daily; adults take 2–3 daily, at 3 g per sachet.