Probiotics: who should take them, when, and which kind

What are probiotics?

Probiotics are beneficial bacteria packed into a capsule. The word means live, helpful microbes.

Your gut is home to both good and bad bacteria. Ongoing stress, antibiotics and sugary foods can tip the balance toward the bad ones. Probiotics help restore that balance.

Just remember these three similar-sounding names.

Probiotic benefits: where they may help

• Diarrhea, constipation and gas: This is where people notice a difference most clearly. Diarrhea usually improves quickly; constipation improves gradually.
• While taking antibiotics: Antibiotics kill good bacteria too. Taking a probiotic during this time may help reduce antibiotic-related diarrhea.
• Immune balance: About 70% of your immune cells are in your gut. That's why people who catch colds often, or who have allergies, eczema or a runny nose from allergies, often look into probiotics.
• Vaginal health: Certain strains help maintain the vagina's acidic environment. People with recurring vaginal infections or bladder infections often try them.
• Skin and stress: Many people notice their skin breaks out when their gut is off. The gut and brain are also linked by nerves (the gut-brain axis), and research is ongoing.

Who needs them / who should avoid them

Especially worth considering if you:

• □ Often have diarrhea, constipation, gas or bloating
• □ Are taking antibiotics, or get prescribed them often (for example, by your OB-GYN)
• □ Catch colds often
• □ Have gut trouble along with allergies, eczema or allergic rhinitis
• □ Get vaginal or bladder infections again and again
• □ Are over 40 and your digestion or bowel habits aren't what they used to be
• □ Are pregnant and constipated

Talk to your doctor before taking them if you:

• Take immunosuppressants (for autoimmune conditions like rheumatoid arthritis, Crohn's disease or severe eczema)
• Just had major surgery or are in cancer treatment
• Are caring for a premature or newborn baby
• Have a serious illness that has greatly weakened your immune system

When the immune system is badly weakened, even beneficial bacteria can cross from the gut into the blood and cause sepsis (a serious infection that spreads through the body). It's rare, but deaths have been reported.

If your gut feels fine and you have no specific concern, probiotics aren't a must-have supplement.

How to choose a probiotic strain for your goal

The most important step is choosing a strain that matches your concern. Look for these strain names on the label.

For reference, Lactobacillus lives mostly in the small intestine, and Bifidobacterium mostly in the large intestine. If your gut is in rough shape or you're older, a Bifidobacterium-focused product tends to fit better.

Types of probiotics: live, heat-killed, synbiotics, capsules and powders

Many products labeled "synbiotic" are low in both bacteria count and prebiotic. You're often better off taking a probiotic and a fiber supplement separately.

When to take probiotics and how much

Bottom line: 5–10 billion CFU a day, at the same time every day. If you can't decide, before breakfast works well.

1. Before or after meals makes little difference. Many products are made to survive stomach acid. If taking it on an empty stomach upsets your stomach, take it after a meal. Consistency matters far more than timing.
2. Don't wash it down with hot water, coffee or green tea. Lukewarm or cold water is best.
3. Keep it at least 2 hours apart from antibacterial supplements. Propolis, berberine and grapefruit seed extract can kill the bacteria. For example, take your probiotic before breakfast and propolis at lunch.
4. If you take two probiotics, split them between morning and evening — for example, a gut probiotic and a women's probiotic.
5. Don't start several probiotic or fiber products at once. Gas and stomach pain can get worse. Add them one at a time.

How long until you can tell if it works?

• Gas, diarrhea, constipation: 4–12 weeks
• Immunity, vaginal health: 12 weeks to 6 months or more
• At first, give it at least 3 months before you decide.

How to choose a probiotic: 4 things to check on the label

1. Is the strain code listed? — The label should go beyond "Lactobacillus rhamnosus" and include a code like "GG" or "HN001." That's how you can tell whether it's a studied strain.
2. Is the strain from a trusted ingredient maker? — Well-known suppliers include Danisco (IFF; HOWARU, FloraFIT), Chr. Hansen, and Rosell/Lallemand.
3. Is the CFU count guaranteed or just added? — If the label says "at time of manufacture," the count may be much lower by the expiration date. "Through expiration" is more reliable.
4. Packaging — Blister packs, with each capsule sealed in foil, give the best protection from moisture and heat.

Be extra skeptical of products like these:

• Cheap products with 15–20 or more different strains (they may contain little of the good strains and pad the count with cheap ones)
• Products that promise results but don't list strain codes
• Products priced suspiciously low, like half off list price (counterfeits have actually been sold — buy from official sellers)

How to store probiotics: do they need to be refrigerated?

Only products labeled "Refrigerate" must be kept in the fridge. Everything else is fine at cool room temperature (77°F / 25°C or below). It's also fine to put a room-temperature product in the fridge.

• Heat is the biggest enemy. Just a few days above 104°F (40°C) can sharply cut the bacteria count. Never leave them in a hot car in summer.
• Watch out for summer deliveries. In hot weather, choose products shipped cold, or stock up during cooler months.
• Avoid moisture too. If it comes in a bottle, keep the lid tightly closed and don't throw out the desiccant packet.

Probiotic side effects and when to stop

In the first 1–2 weeks you may get gas, bloating, diarrhea, or even constipation. This is your gut bacteria adjusting, and it usually settles on its own.

If it's uncomfortable, try this:

1. Take it after meals
2. Cut back to every other day for about 2 weeks while you adjust
3. Lower the dose
4. If it still doesn't work, switch to a product with a different strain

Stop if any of these happen — this is not a "healing reaction" (getting worse before getting better).

• Gut trouble lasts more than 4 weeks
• Allergic reactions like hives or itching keep coming back for more than 2 weeks

Stop right away and see a doctor if:

• Your lips, eyes or throat swell (go to the ER)
• You have a fever above 99.6°F (37°C) that lasts several days
• Your whole body swells, or hives turn into blisters
• Your heart races, you're short of breath, or you feel confused

What to take with probiotics

Combinations

Works well with: Prebiotics, Fiber, Digestive enzymes, L-Glutamine, Colostrum, DGL Licorice, Cranberry, d-mannose, Lactoferrin, Omega-3, Magnesium

Space apart from: Propolis, Berberine, grapefruit-seed-extract

Frequently asked questions

Related concerns