Key Takeaways:
- The best probiotic for constipation in most adults is Bifidobacterium lactis — it's the most consistently supported strain across independent meta-analyses
- In a review of 30 randomized controlled trials, probiotics increased stool frequency in 57% of participants vs. 44% in placebo groups
- Results take 3–4 weeks — don't judge effectiveness in the first week
- Women benefit especially due to progesterone's effect on gut motility; B. lactis is safe during pregnancy
- Combining probiotics with prebiotic fiber amplifies results
Introduction: Finding the Best Probiotic for Constipation
If you're searching for the best probiotic for constipation, you're not alone. Constipation affects 12–30% of people worldwide, and for many, standard remedies like laxatives provide incomplete or unsustainable relief — in fact, nearly half of people taking laxatives report being unsatisfied with their results.
Probiotics offer a well-tolerated, evidence-backed alternative. But not every probiotic works for constipation — strain selection matters enormously, and taking the wrong one is essentially the same as taking none. This guide focuses exclusively on the strains with the strongest clinical evidence for relieving constipation, improving stool frequency, and supporting regular bowel movements.
What the Research Says About Probiotics for Constipation
A systematic review and meta-analysis of 10 high-quality randomized controlled trials found that probiotic supplementation meaningfully decreases intestinal transit time in adults with constipation. A separate 2024 meta-analysis of six trials involving over 1,000 participants found that probiotics significantly improved constipation symptom scores, with 95% of individuals in the probiotic group experiencing at least one class of symptom relief.
The mechanism? Probiotics work through four main pathways:
- Restoring microbial balance - There is a well-established connection between chronic constipation and gut dysbiosis — an imbalance in the composition of gut bacteria. Probiotics work by competing with harmful bacteria for resources and creating conditions where beneficial bacteria can thrive.
- Producing short-chain fatty acids (SCFAs) — Bifidobacterium and Lactobacillus ferment dietary fiber into SCFAs like butyrate, which soften stool and directly stimulate gut motility by interacting with intestinal cells. Probiotics can also lower the pH of the colon by producing short-chain fatty acids to speed transit time.
- Modulating the gut-brain axis — Your gut and brain are in constant conversation through the gut-brain axis — a bidirectional communication network involving nerves, hormones, and immune signals. Probiotics influence this system by affecting the production of neurotransmitters like serotonin, which is critical to regulating gut motility. Roughly 90% of the body's serotonin is produced in the gut.
- Reducing low-grade inflammation — some chronic inflammation can impair normal bowel function. Some probiotics are anti-inflammatory, meaning that they can calm irritated intestinal tissue and improve gut barrier integrity.
The 5 Best Probiotics for Constipation
Based on clinical trial data, these are the best probiotics for constipation in adults — ranked by the strength and consistency of their evidence.
1. Bifidobacterium lactis (BB-12, HN019) — Best Overall
B. lactis is the most well-studied and consistently supported probiotic for constipation across multiple independent meta-analyses. Among all strains evaluated across 30 randomized controlled trials, B. lactis was the only strain to show a statistically significant effect on stool frequency as a standalone result.
🧡 Best for: Adults with infrequent bowel movements (2–4 per week), the elderly, pregnant women
⚖️ Dose: 10 billion CFUs daily has strong clinical support for the HN019 strain
2. Lactobacillus casei Shirota (LcS) - Best for Hard or Lumpy Stools
L. casei* Shirota has one of the longest research histories in digestive health. It survives stomach acid and bile exceptionally well when consumed in fermented milk. This means that more live bacteria reach the colon where they're needed. A 2011 study found that fermented milk with this probiotic strain reduced hard or lumpy stools in healthy people. A more recent 2024 study confirmed similar results, showing that consuming LcS made stools significantly softer.
🧡 Best for: Adults with hard or lumpy stools; those who want a strain with a long-standing GI safety record
3. Bifidobacterium longum BB536 — Best for Chronic Constipation
This strain has demonstrated sustained effects even after supplementation ends — a key advantage for chronic constipation sufferers. A 2023 randomized controlled trial in the American Journal of Gastroenterology confirmed its effectiveness in elderly individuals with chronic constipation, and it also relieves upper abdominal discomfort associated with sluggish bowels.
🧡 Best for: Elderly adults, chronic constipation (lasting 12+ weeks)
4. Lactobacillus plantarum P9 — Best for Constipation + Anxiety
L. plantarum adheres strongly to the gut lining and produces antimicrobial substances that support overall gut motility. A large-scale 42-day clinical study found it increased complete spontaneous bowel movements per week while also reducing constipation-related anxiety.
🧡 Best for: Those experiencing both digestive discomfort and stress-related gut issues
5. Lactobacillus reuteri — Gentlest Option
L. reuteri has a notably gentle side effect profile and has shown meaningful increases in bowel movement frequency over several weeks in double-blind, placebo-controlled trials. A 40-person trial in adults with chronic functional constipation demonstrated sustained improvements over one month.
🧡 Best for: People sensitive to digestive supplements; first-time probiotic users
Best Probiotics for Constipation and Bloating
If you're looking for the best probiotics for constipation and bloating, you're dealing with two symptoms that share a common root cause: slow gut motility and microbial imbalance. The good news is that the strains most effective for constipation frequently address bloating at the same time.
The best probiotics for constipation and bloating specifically are:
- Bifidobacterium lactis — shown to reduce both stool infrequency and abdominal bloating in clinical trials
- Lactobacillus plantarum — one of the most studied strains for bloating relief; strongly adheres to the gut lining and reduces gas-producing bacterial populations
- Lactobacillus casei Shirota — evidence for both constipation and bloating symptom relief
👀 What to look for on the label: A product combining a Bifidobacterium strain with Lactobacillus plantarum has the strongest evidence for the constipation-bloating combination specifically. Avoid blends where individual strains may fall below effective dose thresholds.
Best Probiotic for Female Constipation (Including Pregnancy)
Constipation affects women at roughly twice the rate it affects men — and the reason is largely hormonal. Progesterone relaxes intestinal smooth muscle and reduces peristalsis, slowing gut transit. This effect is most pronounced during pregnancy, the luteal phase of the menstrual cycle, and perimenopause.
Best Probiotic for Constipation in Women (Non-Pregnant)
Bifidobacterium lactis is the strongest evidence-backed choice for women with constipation. It addresses the slow motility driven by hormonal fluctuations and has been studied across multiple female-specific populations. Consistent daily use is key, as benefits often track across the menstrual cycle.
Best Probiotic for Constipation in Pregnancy
A 2024 clinical study enrolling both healthy and constipated pregnant women found probiotic supplementation effectively improved Constipation Severity Scale and Bristol Stool Scale scores — increasing defecation frequency, decreasing defecation time, and improving stool consistency. The probiotics worked by restoring gut microbiota diversity and increasing beneficial bacteria like Faecalibacterium and Bifidobacterium.
A separate study found that pregnant women consuming yogurt containing Lactobacillus acidophilus and Bifidobacterium lactis three times daily experienced reduced constipation, shorter gastrointestinal transit time, and increased defecation frequency.
Best strains for female constipation:
- Bifidobacterium lactis HN019 — strongest evidence, safe in pregnancy
- Lactobacillus acidophilus — commonly paired with B. lactis in pregnancy studies
- Bifidobacterium longum — particularly useful for chronic constipation in older women
Best Probiotic for Chronic Constipation
Chronic constipation — defined as constipation lasting more than 12 weeks — often has a deeper dysbiosis component than occasional constipation, and requires a strain with demonstrated long-term benefit.
The best probiotics for chronic constipation are:
- B. lactis HN019 — clinically studied at 10 billion colony forming units (CFUs) with sustained efficacy
- B. longum BB536 — shown to have lasting effects even after supplementation stops; particularly well-studied in chronic cases in older adults
- L. reuteri — demonstrated sustained improvement in bowel movement frequency over month-long trials in chronic functional constipation patients
Best Probiotic for Regular Bowel Movements
If your goal is simply to achieve more regular, predictable bowel movements rather than treating clinical constipation, the approach is slightly different — you want strains that support overall gut motility and microbiome balance rather than targeting a specific pathology.
The best probiotics for regular bowel movements are:
- Bifidobacterium lactis — consistently increases stool frequency toward the healthy range of 3–21 bowel movements per week
- Lactobacillus plantarum — increases complete spontaneous bowel movements (natural, effortless movements) per week
- Any strain combined with prebiotic fiber (inulin, FOS, or resistant starch) as a "synbiotic" — this combination is particularly effective for maintaining regularity long-term
🎈 Practical tip: Track your bowel movement frequency and consistency over 4 weeks to objectively assess whether your probiotic is working.
How to Use Probiotics for Constipation: Practical Guide
Dosage: Most effective clinical studies use 1–10 billion colony-forming units (CFUs) per serving daily. However, higher isn't always better — what matters most is matching the dose used in research for your specific strain.
Duration: Allow at least 3–4 weeks before judging effectiveness. Most studies run for 28 days to 2 months. The first 1–2 weeks are often an adjustment period.
Timing: Take with food to buffer stomach acid and improve bacterial survival. Some strains require refrigeration; others use encapsulation technology for shelf stability — check the label.
Amplify with prebiotics: Prebiotics (inulin, FOS, resistant starch) feed probiotic bacteria and help them produce constipation-relieving SCFAs. Taking probiotics alongside a prebiotic — called a "synbiotic" — amplifies results.
Food sources: Kefir, kimchi, sauerkraut, and yogurt contain probiotic strains and complement supplementation. However, CFU counts in food are lower and less consistent than supplements, making food alone insufficient for moderate-to-severe constipation.
Safety and Side Effects
Probiotics have an excellent safety profile in healthy adults — clinical studies consistently show they are well-tolerated with a low rate of adverse events.
Mild gas or bloating in the first 1–2 weeks is common as your microbiome adjusts; this typically resolves on its own. Individuals with compromised immune systems, those recovering from major surgery, or those with serious underlying health conditions should consult a healthcare provider before starting.
Frequently Asked Questions
Which probiotic is best for constipation?
Bifidobacterium lactis (strains BB-12 or HN019) has the strongest and most consistent evidence for constipation across multiple independent meta-analyses, specifically for increasing stool frequency in adults. For the elderly or those with chronic constipation, Bifidobacterium longum BB536 is also strongly supported.
What is the best probiotic for constipation in women?
The best probiotic for female constipation is Bifidobacterium lactis — it's safe, well-studied in women including during pregnancy, and directly addresses the slow gut motility driven by progesterone. Studies show it increases defecation frequency and improves stool consistency in pregnant women.
What are the best probiotics for constipation and bloating?
The best probiotics for constipation and bloating together are Bifidobacterium lactis and Lactobacillus plantarum — look for a product combining both. These strains target the shared root cause (slow motility and microbial imbalance) and have clinical evidence for both symptoms.
What is the best probiotic for chronic constipation?
For chronic constipation (lasting 12+ weeks), B. lactis HN019 and B. longum BB536 have the best evidence for sustained, long-term relief. Choose single-strain products at the clinically studied dose rather than blends where dosing is diluted.
What is the best probiotic for pooping regularly?
Bifidobacterium lactis is the top choice for regular bowel movements — it's the only strain with a statistically significant effect on stool frequency across a meta-analysis of 30 RCTs. Lactobacillus plantarum is also effective for increasing complete spontaneous bowel movements per week.
What is the best probiotic for regular bowel movements?
B. lactis paired with prebiotic fiber (a "synbiotic") is the most evidence-backed approach for achieving consistent, regular bowel movements. Track your results using the Bristol Stool Scale over 4 weeks.
How long do probiotics take to work for constipation?
Most people see meaningful improvement after 3–4 weeks of consistent daily use. Some experience changes sooner with higher-dose B. lactis, but avoid judging effectiveness in the first week or two while your gut is adjusting.
Can probiotics help with constipation every day?
Yes — daily probiotic use is well-supported for healthy adults and recommended for best results. Side effects are typically mild and temporary. Those with immune conditions should check with a physician first.
How many CFUs do I need for constipation?
Most effective clinical studies use between 1 billion and 10 billion CFUs per day. For B. lactis HN019, 10 billion CFUs daily has the strongest support. Higher doses are not necessarily more effective.
Can I get enough probiotics from food for constipation?
Fermented foods like kefir, yogurt, and kimchi support your probiotic routine, but CFU counts are inconsistent and typically lower than clinical trial doses. Food sources complement — but generally don't replace — a targeted probiotic supplement for constipation relief.