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Probiotic Supplements
Compare probiotic supplements by strain, daily CFU, price, testing evidence and label transparency. Understand what the research says about different formulations.
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Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Testing evidence
Evidence status
Verified independent evidence
Manufacturer statement
Manufacturer page states: "Certificate of Analysis & Testing" and "Every Toniiq product lot is third-party tested for..."; the COA for Lactobacillus Reuteri shows report number 26-440265, lot 260542, and testing performed by Certified Group - Tustin.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Testing evidence
Evidence status
Verified independent evidence
Manufacturer statement
Manufacturer page states: "Certificate of Analysis & Testing" and "Every Toniiq product lot is third-party tested for..."; the COA for Lactobacillus Reuteri shows report number 26-440265, lot 260542, and testing performed by Certified Group - Tustin.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Daily CFU is the verified live count for the labelled daily serving. Compare the exact strains and whether that count is guaranteed through expiry; do not assume more CFU or more strains is better. Where directions give a range, the range is shown and daily cost uses the low end (no directions: one unit a day). Read the dose guide ↓
Manufacturer page states: "Certificate of Analysis & Testing" and "Every Toniiq product lot is third-party tested for..."; the COA for Lactobacillus Reuteri shows report number 26-440265, lot 260542, and testing performed by Certified Group - Tustin.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer product page includes a linked document labeled "Third Party Test Report" / "Heavy Metal Analysis" for Lactobacillus Reuteri, and the PDF states: "LAB RESULTS FOR: Lactobacillus Reuteri ... HEAVY METALS EU LIMIT LAB RESULT ... Arsenic 3mg/kg PASS ... Lead 3mg/kg PASS ... Mercury 0.1 mg/kg PASS ... Cadmium 1 mg/kg PASS"
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer product page includes a document link labeled 'Heavy_Metal_analysis_Bio_Cultures_-_Nov_2025.pdf' and the PDF text states 'LAB RESULTS FOR: Bio Cultures Probiotic' with heavy metals passing (arsenic, lead, mercury, cadmium).
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer site says "Laboratory Tested" and that it "test[s] each individual product to ensure it meets our strict Quality Assurance Standards." No independent lab report or certifying-body registry entry for this specific product was found.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Natures Aid’s own product page says: “Added to that you can rest assured that our Acidophilus Complex is vegan certified and completely dairy-free.” It also says the bacteria “have been submitted to rigorous testing” and “have proven colonisation of the Microbiome after oral supplementation,” but that is efficacy/performance language rather than independent contents/purity testing. The Vegan Society page confirms the Vegan Trademark is a real certification program, but I did not find a registry page specifically confirming this exact product.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer site says: "We are proud to hold ISO:90001 Quality Management System accreditation" and "British Standards Institution: ISO 9001:2015 Quality Management Systems, (Certificate no. FS 657303)." This is a general quality-system accreditation claim, not product-specific third-party testing/certification of this probiotic.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer site says the product has a "Gastric Guard Guarantee – bacteria is guaranteed to survive passage through stomach acid" and the UK site says "batch-tested formulations" and "GMP Certified Manufacturing," but I did not find an independently verifiable third-party COA or certification page for this specific product.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer site says: "Our Certifications ... SALSA ... Soil Association Organic Certified ... Food Standards Agency Rated 5/5 - Very Good" and the product page says "Lactospore® is a world-leading, science-backed probiotic, with confirmed efficacy based on over 20 years of clinical research." These are claims/marketing, but I did not find an independently verifiable product-specific COA, lab report, or registry entry for this exact product.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Amazon store page for L1fe Nutrition says: "Our supplements are only ever made in award winning ISO and BRC A certified facilities, all within the UK." The product page also says the brand uses "regular quality checks" and the Herb-ology listing says "manufactured in the UK under strict standards" with "quality checks," but I did not find any independently verifiable certificate/COA or registry entry for this specific product.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Natures Aid’s own Microbiome Range page says: “All the good bacteria chosen for the Natures Aid Microbiome range have been submitted to rigorous testing and have shown the ability to survive gastric acid and bile for over three hours. They have also been subject to human clinical trials and have proven colonisation of the Microbiome after oral supplementation.” The Vegan Society’s trademark search page also states that its Vegan Trademark is for products “free of all animal use, in ingredients and testing,” but I did not find a registry page confirming this specific product.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Innopure FAQ says: "All Innopure products are manufactured in the UK in small batches using trusted, certified partners. We follow strict quality standards, including Good Manufacturing Practice (GMP), and carefully test every batch for purity and consistency."
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
N2 Natural Nutrition’s About Us page says: “In the Quality Control department of the laboratory located in the European Community, microbiological and physical-chemical controls are carried out, corroborated with quality controls by external laboratories. The quality of each of our production batches is analysed.”
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Vitabiotics says Probiotis is 'a high-quality formulation of 10 billion cultures across seven important strains' and that it 'contains Lab4®, the group of gut bacteria with the most comprehensive research conducted in the UK'; Lab4 Probiotics says its strains were 'identified and rigorously screened' and that its facilities are certified for GMP/BRCGS/ISO/Kosher, but I did not find an independently verifiable product-specific COA, lab report, or registry entry confirming this specific Probiotis product was tested/certified.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer site says the product is "Certified by the Vegan Society" and the About Us page says "Many of our products are certified by The Vegan Society."
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer page states: "Certified by the Vegan Society" and the Amazon listing shows the same product as vegan-friendly; however I did not find a Vegan Society registry page for this specific Probio7 Advanced product during this investigation.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer page states: "Certificate of Analysis & Testing" and "Every Toniiq product lot is third-party tested for..."; the COA for Lactobacillus Reuteri shows report number 26-440265, lot 260542, and testing performed by Certified Group - Tustin.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer product page includes a linked document labeled "Third Party Test Report" / "Heavy Metal Analysis" for Lactobacillus Reuteri, and the PDF states: "LAB RESULTS FOR: Lactobacillus Reuteri ... HEAVY METALS EU LIMIT LAB RESULT ... Arsenic 3mg/kg PASS ... Lead 3mg/kg PASS ... Mercury 0.1 mg/kg PASS ... Cadmium 1 mg/kg PASS"
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer product page includes a document link labeled 'Heavy_Metal_analysis_Bio_Cultures_-_Nov_2025.pdf' and the PDF text states 'LAB RESULTS FOR: Bio Cultures Probiotic' with heavy metals passing (arsenic, lead, mercury, cadmium).
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer site says "Laboratory Tested" and that it "test[s] each individual product to ensure it meets our strict Quality Assurance Standards." No independent lab report or certifying-body registry entry for this specific product was found.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Natures Aid’s own product page says: “Added to that you can rest assured that our Acidophilus Complex is vegan certified and completely dairy-free.” It also says the bacteria “have been submitted to rigorous testing” and “have proven colonisation of the Microbiome after oral supplementation,” but that is efficacy/performance language rather than independent contents/purity testing. The Vegan Society page confirms the Vegan Trademark is a real certification program, but I did not find a registry page specifically confirming this exact product.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer site says: "We are proud to hold ISO:90001 Quality Management System accreditation" and "British Standards Institution: ISO 9001:2015 Quality Management Systems, (Certificate no. FS 657303)." This is a general quality-system accreditation claim, not product-specific third-party testing/certification of this probiotic.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer site says the product has a "Gastric Guard Guarantee – bacteria is guaranteed to survive passage through stomach acid" and the UK site says "batch-tested formulations" and "GMP Certified Manufacturing," but I did not find an independently verifiable third-party COA or certification page for this specific product.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer site says: "Our Certifications ... SALSA ... Soil Association Organic Certified ... Food Standards Agency Rated 5/5 - Very Good" and the product page says "Lactospore® is a world-leading, science-backed probiotic, with confirmed efficacy based on over 20 years of clinical research." These are claims/marketing, but I did not find an independently verifiable product-specific COA, lab report, or registry entry for this exact product.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Amazon store page for L1fe Nutrition says: "Our supplements are only ever made in award winning ISO and BRC A certified facilities, all within the UK." The product page also says the brand uses "regular quality checks" and the Herb-ology listing says "manufactured in the UK under strict standards" with "quality checks," but I did not find any independently verifiable certificate/COA or registry entry for this specific product.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Natures Aid’s own Microbiome Range page says: “All the good bacteria chosen for the Natures Aid Microbiome range have been submitted to rigorous testing and have shown the ability to survive gastric acid and bile for over three hours. They have also been subject to human clinical trials and have proven colonisation of the Microbiome after oral supplementation.” The Vegan Society’s trademark search page also states that its Vegan Trademark is for products “free of all animal use, in ingredients and testing,” but I did not find a registry page confirming this specific product.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Innopure FAQ says: "All Innopure products are manufactured in the UK in small batches using trusted, certified partners. We follow strict quality standards, including Good Manufacturing Practice (GMP), and carefully test every batch for purity and consistency."
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
N2 Natural Nutrition’s About Us page says: “In the Quality Control department of the laboratory located in the European Community, microbiological and physical-chemical controls are carried out, corroborated with quality controls by external laboratories. The quality of each of our production batches is analysed.”
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Vitabiotics says Probiotis is 'a high-quality formulation of 10 billion cultures across seven important strains' and that it 'contains Lab4®, the group of gut bacteria with the most comprehensive research conducted in the UK'; Lab4 Probiotics says its strains were 'identified and rigorously screened' and that its facilities are certified for GMP/BRCGS/ISO/Kosher, but I did not find an independently verifiable product-specific COA, lab report, or registry entry confirming this specific Probiotis product was tested/certified.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer site says the product is "Certified by the Vegan Society" and the About Us page says "Many of our products are certified by The Vegan Society."
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Manufacturer page states: "Certified by the Vegan Society" and the Amazon listing shows the same product as vegan-friendly; however I did not find a Vegan Society registry page for this specific Probio7 Advanced product during this investigation.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
One-time purchase prices; delivery and conditional discounts excluded. Daily cost uses the recorded label serving. Comparison amounts are not personal dose recommendations. Unknown Prime eligibility is not treated as confirmed.
Probiotic strains and labels explained
A useful probiotic label tells you exactly which strain is present, how many viable organisms the daily serving provides, when that count is guaranteed, and how the product should be stored. Strain count and headline CFU alone are not evidence grades.
Exact strain disclosed
Best basis for evidence matching
Look for
Genus + species + strain ID
Example
L. rhamnosus GG
Do not infer a studied strain from species alone.
Single strain
One defined microorganism
Strength
Can match a strain trial closely
Not a weakness
Fewer strains
A single well-studied strain can be more interpretable than an unstudied blend.
Multi strain blend
Several live strains
Compare
Exact blend + CFU
Do not assume
More strains = better
Evidence for individual strains does not automatically prove the finished blend.
Synbiotic formulation
Live microbes plus selectively used substrate
Requires
Evidence-based definition
Not enough
Bacteria + any fibre
Use a neutral 'with prebiotic' label unless the synbiotic criteria are actually supported.
Yeast probiotic
Live probiotic yeast
Example
S. boulardii
Do not convert
mg to CFU
Yeast probiotics are not bacterial blends and may be labelled in different units.
Legacy taxonomy
Old and current organism names
Example
Lactobacillus → Lacticaseibacillus
Check
The exact strain ID
Names can change. Check the strain identifier before matching an older study to a current label.
Understanding probiotic strains and daily CFU
CFU means colony-forming units: a count of viable microorganisms. For this comparison, daily CFU is the verified CFU per labelled serving multiplied by the labelled number of servings per day. Do not convert milligrams or other cell-count units into CFU.
There is no UK recommended daily probiotic intake or universal upper limit. The NHS stresses that different probiotic types may have different effects, and NIH technical guidance notes that the effective amount depends on the strain and product rather than one category-wide number. [1][4]
Count basis matters. CFU can fall during shelf life, so a count guaranteed through expiry is more informative than a count stated only at manufacture. [4] Current UK labels range from 5 billion to much higher daily counts, but that market spread does not create an evidence-based optimal range. [18]
What does the probiotic evidence say?
Probiotic evidence is strain- and question-specific. A strain or blend that works for one endpoint should not automatically be expected to work for another. [11]
For antibiotic-associated diarrhoea, pooled adult evidence suggests benefit from some formulations, but individual trials differ. A defined high-dose bacterial mixture reduced AAD in one adult trial, while a large hospital trial of Saccharomyces boulardii found no benefit. [12][13][14]
IBS evidence is similarly mixed. One 35624 trial found benefit at a specific intermediate dose, whereas broader reviews show that outcomes vary by strain and formulation. [10][11]
Probiotic evidence by research question
Evidence by goal
Goal
Evidence strength
What was assessed
Typical study context
Main limitation
IBS symptoms
Strain-specific; mixed overall
B. longum 35624 and other strain-specific probiotic trials
A 362-person dose-ranging 35624 trial found benefit at 10^8 CFU over 4 weeks; broader reviews show strain/outcome heterogeneity.
Diagnosed IBS populations and exact formulations; results do not transfer automatically to another strain or blend.
Antibiotic-associated diarrhoea
Supported for some specific formulations; not class-wide
Defined bacterial mixtures, LGG/S. boulardii and other formulations
Meta-analysis of 17 outpatient RCTs found lower pooled AAD, but large individual null trials also exist.
Strains, settings, antibiotic regimens and CFU differ.
Low bowel frequency
Modest, strain-specific evidence
B. animalis subsp. lactis BB-12
1,248 adults received 1B or 10B CFU/day for 4 weeks; dose effects were similar.
Healthy adults with low frequency; global GI wellbeing endpoint was not significantly different.
Functional constipation
Recent high-quality null evidence for one strain
B. animalis subsp. lactis HN019
229 adults, 8 weeks, at least 4.69B CFU/day by study end.
One population and strain; does not invalidate other probiotic preparations.
Read the full evidence-by-goal detail
IBS symptoms
NICE allows a practical trial of a probiotic for people with IBS, but does not define a universal strain or CFU target. People choosing to try one are advised to use the manufacturer dose for at least four weeks while monitoring symptoms. [3]
Antibiotic-associated diarrhoea
Some specific strains and mixtures reduce AAD risk in research, but other products have failed in well-conducted trials. [12][14] Match the exact strain/formulation rather than treating every probiotic as equivalent.
Low bowel frequency / constipation
Results vary even within one strain. BB-12 showed similar defecation-frequency effects at 1 and 10 billion CFU/day, while a recent HN019 trial did not outperform placebo. [15][16]
Timing, storage and label directions
There is no universal morning, evening or empty-stomach rule that applies to every probiotic. Follow the product's labelled directions and storage conditions. Some products require refrigeration while others are stability-tested for room temperature. [4]
For IBS, NICE advises following the manufacturer's dose rather than inventing a category-wide schedule. [3] Antibiotic-separation instructions should also remain product-specific unless evidence for that exact organism and formulation is verified.
Probiotic side effects and cautions
Who should be cautious?If any of the following apply to you, speak to a healthcare professional before taking Probiotics - see the full detail below for why.
People with a weakened immune system
People who are seriously ill or medically fragile
People with an existing health condition who are considering probiotics for treatment rather than general food-supplement use
People using a probiotic alongside prescribed treatment who need product-specific interaction/timing advice
For most people with a healthy immune system, probiotics appear to be generally safe, but detailed long-term safety data are limited. The NHS advises people with an existing health condition or weakened immune system to talk to a doctor before using probiotic supplements. [1]
Risk is more important in seriously ill or immunocompromised people because rare invasive infections from probiotic organisms have been reported in high-risk clinical settings. This does not mean ordinary healthy-adult products are unsafe; it means the comparison should not make a universal safety claim.
Combinations and interactions
A probiotic is a live microorganism with demonstrated benefit. A prebiotic is a selectively used substrate, while a synbiotic is a live-microorganism-plus-substrate formulation meeting its own evidence criteria. [6] A product that simply adds inulin or FOS should therefore be described as 'with prebiotic fibre' unless the synbiotic evidence standard is met.
Postbiotics are inanimate microorganism preparations/components with demonstrated benefit and are not live probiotics. [7] Their amounts must not be converted into CFU.
Who might consider probiotics?
The NHS notes that probiotics may be helpful in some situations, including some IBS symptoms, but also emphasises that products and probiotic types can have different effects. [1] For a general shopper, the most useful comparison is therefore whether a product clearly identifies the same strain/formulation that has evidence for the question they care about.
People with diagnosed gastrointestinal disease, significant immune compromise or serious illness should use clinical advice rather than relying on a retail score.
Testing and quality: what to look for
Good probiotic testing has several layers. Identity testing asks whether the declared genus, species and strain are present. Potency testing measures viable CFU. Stability evidence asks whether the finished product maintains its count through shelf life under the labelled storage conditions. Contaminant testing is a separate question.
The NHS specifically notes uncertainty around whether retail products contain the stated bacteria, enough bacteria, and organisms that survive long enough to reach the gut. [1] A generic GMP or 'third-party tested' claim is not the same as verified strain identity plus end-of-shelf-life CFU. The site's testing guide explains the evidence levels used in scoring. Read our testing guide
Testing evidence in this comparison
A testing claim is not the same as a verified report. No public evidence located does not mean a product has not been tested.
Testing review pending0
Recognised certification0
Verified independent evidence1
Manufacturer COA2
Testing claimed11
No public evidence located11
What does probiotics cost?
Current UK comparison set, based on the daily serving shown on each label.
£0.07Lowest daily cost
£0.25Median daily cost
£1.07Highest daily cost
Your questions, answered
How many billion CFU should a probiotic have?
There is no universal best number. Effective amounts depend on the exact strain, product and research question. A BB-12 trial found similar bowel-frequency effects at 1 and 10 billion CFU/day, showing why more is not automatically better. [15]
Is a probiotic with more strains better?
Not necessarily. Probiotic efficacy is strain- and formulation-specific, and an unstudied multi-strain blend should not inherit all of the evidence for its individual ingredients. [11]
What does guaranteed through expiry mean?
It means the manufacturer says the stated viable count will still be present at the end of shelf life when stored correctly. CFU can decline over time, so this is more informative than a count stated only at manufacture. [4]
Are probiotics and prebiotics the same?
No. Probiotics are live microorganisms with demonstrated benefit; prebiotics are substrates selectively used by host microorganisms. A synbiotic combines live microorganisms with an appropriate substrate under a separate evidence definition. [6]
Do probiotics help IBS?
Some products may help some people, but results differ by strain. NICE says people with IBS who choose to try a probiotic should use the manufacturer's dose for at least four weeks while monitoring the effect. [3]
