Breast milk supply is one of those things about early parenting that you never knew to worry about until it happened. Maybe milk supply is too low and you’re desperately googling what kind of cookies increase milk supply. Or maybe there is too much milk and you’re uncomfortable, leaking, and, as one woman explained to me, “constantly smelling of parmesan.”
Both of these issues can be addressed to some extent, although there are not as many evidence-based solutions as the internet would lead you to believe.
Before we dive into the data, a quick note on being kind to yourself. With undersupply in particular, it can feel like you’re failing. I know for me personally, the idea that I wasn’t producing enough milk was almost devastating, especially in a fog of postpartum hormones. I’m here to say: it isn’t your fault, it isn’t a failing, it’s not something you did. And if you need to supplement with, or exclusively use, formula — that is also great. Please read this post.
Give yourself a pat on the back no matter how much milk you have. And now, to the data.
When does your milk come in?
Immediately after birth, you’ll have a small amount of milk — colostrum — which has a different composition than later milk. Over the first few days of your baby’s life, your milk will “come in”; technically this is called lactogenesis II.
The onset of milk coming in typically takes 48 to 72 hours but, especially with a first baby, may be delayed to four or five days. In that case, it is common to supplement with formula to prevent dehydration.
Once your milk fully comes in, there will be more supply — a lot more, typically — than with colostrum. But it still may be too much or too little.
What is an oversupply or undersupply of milk?
Neither of these is formally defined, but both can be thought of in comparison to the “right” amount of supply, which is the amount your baby wants. An undersupply is when you are not producing enough milk for the baby’s needs. An oversupply is when you produce too much. There are no clear diagnostic criteria.
Generally, people suspect an undersupply if a baby seems consistently hungry after nursing or is not gaining weight. The amount of milk you get when pumping may also be a signal, although sometimes babies are more efficient at getting milk than the pump, so that is not a perfect test. If you are worried about undersupply, it is a good idea to talk to your doctor. They can help you think about whether the baby’s weight gain is on track.
An oversupply is easier to recognize. Breasts that are full and painful before the baby is hungry. Producing many more ounces than necessary when pumping. Milk coming out so forcefully at the beginning of a nursing session that the baby may struggle to keep up. If you have an oversupply, you will probably know. Put differently: the only issue with oversupply is discomfort, meaning it cannot be “hidden” the way an undersupply might be.
The importance of supply and demand
One of the core concepts in economics is the idea of supply-and-demand equilibrium in a market. The way markets work is that, on one side, there are people who demand a product and, on the other side, people who supply it. The system is stable when you arrive at a price where the suppliers are willing to supply the same amount that the buyers demand. If the buyers start to demand more, the supply will rise to meet the demand (sometimes at a higher price). If buyers demand less, the supply will shrink (sometimes at a lower price). These adjustments may take a bit of time.
This is also basically how breast milk works, minus the price part (the only price is our sanity. Just kidding, sort of).
Fundamentally, the most important modifiable determinant of milk supply is milk demand. When your baby demands more milk, the supply rises to meet it. When they demand less, supply falls. This adjustment isn’t instantaneous — it typically takes a few days. This means that the primary evidence-based way to address an over- or undersupply is to change the demand. For an undersupply, nursing or pumping more will, on average, increase milk supply. For an oversupply, nursing or pumping less will help.
(A caveat with oversupply: having an oversupply can put you at increased risk for mastitis, so this is something to be aware of as you’re adjusting your nursing and pumping schedule.)
The first sentence of the paragraph above is important — in particular the word modifiable. Your biology is another determinant of milk supply, one that is not modifiable. The composition of your breast tissue, along with other hormonal factors, will play a role in how much milk you produce. Two people undertaking exactly the same breast milk production regime will end up with different amounts of milk. You can use the supply-demand insight to modify within your personal constraints, but those constraints are there.
It is also possible that, no matter how much you nurse and pump, you will not produce enough milk. This is sometimes diagnosed as insufficient glandular issue, or IGT, which is just a diagnostic way to say that you do not have enough breast tissue to produce enough milk. In this case, you will need to supplement with formula. Which is, I will say again, a great option.
What else can increase milk supply?
Beyond nursing or pumping, what about the various advice you get on the internet? Cookies and teas? Hydration? Beer? What about medications?
For the most part, the evidence on these is limited or discouraging. A rundown:
- Lactation cookies: A 2023 randomized controlled trial disproved the value of lactation cookies. Milk supply did not change any more in a group assigned to eat lactation-focused cookies (i.e. cookies containing ingredients thought to increase milk supply) than in the group assigned to regular cookies. We do not have direct evidence on the cookie ingredients on their own (oatmeal, flax, brewer’s yeast), but this evidence on cookies does point to those also being duds.
- Hydration: A 2014 review found relatively little evidence either way, but the studies it could identify on hydration showed no evidence that extra fluids increased breast milk supply.
- Fenugreek: There is slightly more evidence in favor of the use of the herb fenugreek in increasing milk supply. The existing studies are, however, mostly small, and it is difficult to accurately measure breast milk supply. Even in the most optimistic studies, the impacts are not very large.
- Beer: There is little evidence that drinking beer increases milk consumption (on the other hand, there are limited safety concerns when you drink in moderation). In small studies, it looks like there might be a very limited impact from some component of barley (which would appear in either alcoholic or non-alcoholic beer). Overall, no compelling reason to drink.
- Medications: There are several medications that are used globally to increase breast milk supply, but they are either not approved or not typically used in the U.S. The most commonly used one is domperidone, which small trials have shown to have some impact on milk supply. It is not approved for use in the U.S. for any indication, due to a concern about an increased risk of cardiac events. The second — largely used in South Africa — is sulpiride, which is a drug used to treat schizophrenia. Older studies have shown an increase in milk supply with its use. This drug is also not approved in the U.S. Bottom line: If you are in the U.S., there are no available medical treatments for low milk supply.
Overall, there is relatively little you can do in terms of lifestyle changes to impact your milk. I wish it were different!
What can you do about an oversupply of milk?
The discomfort from an oversupply of milk can leave breasts achy and sore and put you at increased risk for mastitis. One problem is that the obvious solution to this feeling of discomfort — which is to pump or nurse more — can make the issue worse. If you react to discomfort by pumping a lot, your body gets the picture that more milk is needed (see the supply-and-demand discussion above) and makes more, not less.
To deal with oversupply, you have to demand less. Often this means pumping less — just pumping to the point of comfort, rather than emptying the breasts. Over time, things will adapt.
Beyond that, the main concern is comfort, for mom and baby. Cold compresses or, oddly, cabbage leaves can relieve some symptoms. If your baby is overwhelmed with milk at the start of a feeding, you may want to hand-express some milk before having them latch on.
Overall: oversupply can generally be tamed, and usually relatively quickly.
The bottom line
- There are no clear diagnostic criteria for oversupply or undersupply of breast milk; it depends on your baby’s needs. An oversupply is when you produce more milk than your baby needs, and an undersupply is when you don’t produce enough to meet your baby’s needs.
- The only way to increase (or decrease) your breast milk supply is to “demand” more or less, either by pumping or nursing. There is relatively little else you can do in terms of lifestyle changes to impact your milk supply.
Log in
I wish I had known of this article when I was struggling with undersupply! How does one get diagnosed with IGT? And is it possible to have this diagnosis even if you otherwise have “dense breast tissue” per a mammogram? And does this mean some people physically cannot EBF if the undersupply cannot be modified beyond a point?
Thank you for acknowledging how devastating low milk supply can be, and how little is known about the cause/how few evidence-based treatments there are. I was very disappointed in the otherwise excellent, informed, caring IBCLCs who inappropriately recommended tongue-tie release, cranio-sacral therapy, infant chiropractic, and more or less random herbs. I think they meant well, but it’s really really hard for caring professionals to say, “We just don’t know, and there’s nothing we can do.” Also one of my IBCLCs got referral fees from the pediatric dentist who performed our tongue-tie release, so sometimes there are pretty shifty incentives for selling snake oil to heartbroken and sleep-deprived new parents.
If you’re exclusively breastfeeding (like I initially did), how does one manage oversupply? With pumping, you can express milk on a schedule but retrieve stored milk whenever the baby is hungry. With exclusive breastfeeding, I was discouraged to put the baby on a schedule. If I can figure that out, maybe I’ll breastfeed the second time. Otherwise, big nope.
I really thought I was ok to read this but boy did it bring back negative memories. Even now (over a year later) I struggle to be kind to myself for my breastfeeding journey not going the way I wanted it to.
Since it isn’t mentioned, a quick note that pseudoephedrine (aka the active ingredient in Sudofed and other behind-the-pharmacy-counter decongestants) massively lowers breastmilk supply. In fact, it’s one of the drugs used to help women dry up their supply so proceed with caution if you’re breastfeeding and have a cold or allergies.
Thanks, very helpful! Did you come across any information on diet? Do you need to eat the extra milk production calories to maintain supply? I struggle to eat all meals let alone an additional one and am in constant worry about supply dropping because of it.