when does colic peak and when does it get better?

Colic peaks at 5-6 weeks of age and declines significantly by 10-12 weeks, with most cases largely resolved by 3 months. This timeline comes from a 2017 meta-analysis of 8,690 infants. If you are at week 4 or 5, you are at or near the worst of it — week 12 is the realistic turning point.

do gas drops (simethicone) work for colic?

No — the evidence consistently shows they do not. A 1994 RCT by Metcalf et al. found no statistically significant difference between simethicone and placebo for crying duration. In the Savino 2010 probiotic study, simethicone was the comparison arm and performed only marginally better than colic's natural resolution. Gas drops are safe, but they don't meaningfully address colic.

does BioGaia (L. reuteri) help with colic?

Yes, for breastfed infants — and this is the strongest evidence-based intervention for colic. An RCT by Savino et al. (2010) found that breastfed colicky infants receiving L. reuteri DSM 17938 dropped from 197 to 51 minutes of crying per day by day 21, versus 196 to 145 minutes with simethicone. The effect in formula-fed infants is smaller and inconsistent.

does gripe water work for colic?

There are no published randomized controlled trials demonstrating that gripe water works for colic. Modern formulations typically contain fennel, ginger, or chamomile. It is not harmful, but there is no evidence base beyond anecdote.

what actually helps with colic?

The interventions with the best evidence are: L. reuteri DSM 17938 drops (BioGaia Protectis) for breastfed infants, anti-colic vented bottles (Dr. Brown's) for bottle-fed babies, and bicycle legs or tummy time to move trapped gas. Gas drops, gripe water, and chiropractic have no reliable evidence of benefit.

Colic and Gas: The 6-Week Peak | Sleep Through The Night

Your baby screams every evening for hours. You’ve tried everything. You’re exhausted and scared something is wrong.

Here’s what colic actually is, why it peaks right around now, and — more usefully — what the evidence says actually helps vs. what’s just placebo with good marketing.

The Diagnostic Criteria (And Why It Doesn’t Matter)

Colic is defined by the Wessel criteria: crying for more than 3 hours per day, more than 3 days per week, for more than 3 weeks, in an otherwise healthy infant. Most parents don’t care about that definition. They want to know why their baby is screaming and when it will stop.

Fair enough. Let’s talk about the why.

What’s Actually Happening in Their Gut

A newborn’s gastrointestinal system is immature in several specific ways:

Intestinal motility: The coordinated wave-like contractions that move food through the gut (peristalsis) are disorganized in the newborn period. Movement that should be smooth and rhythmic is instead irregular — sometimes sluggish, sometimes spasmodic. This creates cramping.

Enzyme systems: Lactase (the enzyme that breaks down lactose in milk) is present from birth, but in some infants the activity level is lower than needed to fully process the lactose load from each feeding. Partially digested lactose travels to the colon, where bacteria do the work instead.

The developing microbiome: At birth, the gut is essentially sterile. Over the first weeks of life, bacteria colonize rapidly — the species composition shifting constantly. This is critical for lifelong health. It is also temporarily chaotic.

The Gas Problem Is the System Working

When bacteria in the colon ferment lactose (and other carbohydrates the small intestine didn’t fully absorb), they produce short-chain fatty acids (SCFAs), carbon dioxide (CO₂), and hydrogen gas (H₂). This is normal fermentation — the same process that happens in adult guts, just more dramatic in newborns because:

Their gut flora is denser in fermentation-active bacteria
Their small intestine absorbs less efficiently
They have less experience moving gas through the system

When you add probiotics, you’re introducing more bacteria. This can temporarily increase gas production before the microbiome stabilizes. If your baby seems gassier after starting probiotics, that’s the system adapting — not a sign the probiotics are harmful.

The gas itself isn’t dangerous. It’s uncomfortable. The discomfort is real.

When Does This Peak?

A 2017 meta-analysis by Wolke et al., pooling data from 8,690 infants across multiple countries, found that inconsolable crying peaks at 5–6 weeks of age and declines significantly by 10–12 weeks. By 3 months, most infants with colic have largely resolved.

That’s the timeline. If you’re at week 4 or 5, you are at or near the worst of it. Week 12 is the light at the end of this particular tunnel.

Air Swallowing: Bottle vs. Breast

Bottle-fed babies swallow more air than breastfed babies, primarily because of how they latch to a bottle nipple and because flow rate is harder to control. This contributes to gas and discomfort.

Anti-colic bottles (Dr. Brown’s, MAM, Comotomo) use venting systems designed to reduce air ingestion. A study published in the Journal of Perinatology (2012) found that Dr. Brown’s bottles significantly reduced colic symptoms compared to standard bottles in a clinical trial. The mechanism is real — less ingested air means less gas. If you’re bottle feeding and dealing with significant gas, bottle type is worth addressing before more invasive interventions.

For breastfeeding: latch quality affects how much air is swallowed. A shallow latch = more air. A lactation consultant is a more useful intervention than gas drops.

What Actually Helps

Bicycle legs and abdominal massage. Moving the legs in a cycling motion while baby is on their back, or gentle clockwise abdominal massage, helps move trapped gas through the intestinal tract. No RCT has measured this specifically, but the mechanism is sound and the risk is zero. Do it.

Tummy time (while awake and supervised). Prone positioning applies gentle pressure to the abdomen and can help release gas. Also important for motor development. A legitimate two-for-one.

Probiotics — specifically Lactobacillus reuteri DSM 17938. This is the most studied probiotic for colic, and the results are modest but real. A landmark RCT by Savino et al. (2010) found that breastfed infants with colic who received L. reuteri reduced daily crying time from 197 minutes to 51 minutes by day 21, compared to a reduction from 196 to 145 minutes in the simethicone placebo group.

Read that again: 51 minutes vs. 145 minutes per day. That’s a meaningful difference.

Important caveats: the effect was demonstrated primarily in breastfed infants, not formula-fed. Subsequent studies in formula-fed infants have shown smaller or inconsistent effects. The product studied was Biogaia Protectis drops. Generic “probiotic” blends have not been well studied for this indication.

What Doesn’t Help

Simethicone (gas drops). As noted above, simethicone was the comparison arm in the Savino study — and it performed barely better than crying’s natural resolution. A 1994 RCT by Metcalf et al. directly compared simethicone to placebo and found no statistically significant difference in crying duration. The mechanism is theoretically plausible (simethicone breaks up gas bubbles in the stomach), but clinical evidence consistently shows it doesn’t work at the gut level where the gas is actually forming.

It’s safe. It just doesn’t do much.

Gripe water. Gripe water is an unregulated product with variable ingredients (historically it contained alcohol; modern versions typically use fennel, ginger, or chamomile). There are no published RCTs demonstrating efficacy for colic. It is not harmful, but there is no evidence base for it beyond anecdote.

Chiropractic manipulation. A Cochrane systematic review found insufficient evidence to conclude that spinal manipulation is effective for colic. The studies that exist are methodologically weak, sample sizes are small, and the comparison conditions are poorly controlled. The theoretical rationale (that vertebral misalignment causes colic) has no established biological mechanism. The risk of harm to infant spinal structure is non-zero.

Dietary Changes for Breastfeeding Parents

Maternal diet is frequently blamed — dairy, cruciferous vegetables, caffeine. The evidence here is weak and highly individual. There is no systematic evidence that eliminating dairy reduces colic in infants without a confirmed cow’s milk protein allergy (CMPA). CMPA is a separate condition from colic and presents with additional symptoms (blood in stool, significant reflux, skin reactions, failure to gain weight).

If you want to try an elimination diet, do it properly: 2–4 weeks of strict elimination, then a structured reintroduction challenge. Partially eliminating foods is hard on you and tells you nothing.

Most of the time, the screaming isn’t your diet. It’s their gut doing its developmental work on schedule.

The Bottom Line

Colic is real, it peaks at 5–6 weeks, and it largely resolves by 3 months. The only intervention with solid evidence for reducing crying duration is L. reuteri DSM 17938 drops, primarily in breastfed infants. Anti-colic bottles help with air swallowing in bottle-fed babies. Bicycle legs and tummy time cost nothing and help move gas.

Everything else — the gas drops, the gripe water, the chiropractic — is either placebo or unproven. You can try them if you need to feel like you’re doing something. Just know what you’re buying.

You’re not failing your baby. Their gut is just learning to exist.