How Breast Milk Is Made

The Office on Women's Health says the breasts make milk in response to the baby's suckling. ¹ The NHS says the more you breastfeed, the more the baby's sucking stimulates your supply and the more milk you make. ² Below is what recognised health bodies say about how milk is made, the let-down reflex, and supply and demand, quoted and linked.

Key takeaways

• The Office on Women's Health says the breasts make milk in response to the baby's suckling. ¹
• The NHS says the amount of milk you make increases or decreases depending on how often the baby feeds. ²
• The NHS says colostrum is very concentrated, so a baby only needs a small amount - about a teaspoonful - at each feed. ²
• The NHS says to speak to a midwife or health visitor if you are worried about breastfeeding or think your baby is not getting enough milk. ²

**A quick, honest note:** we're not medical professionals - everything here was researched by us from the public sources listed at the bottom of this page, and it isn't professional advice. Read our full note ↓

How is breast milk made?

The Office on Women's Health explains the hormones involved. It says the alveoli make milk in response to the hormone prolactin, and that prolactin levels rise when the baby suckles. ¹ It adds that oxytocin also rises when the baby suckles and triggers the let-down reflex, contracting small muscles in the breast to move milk through the ducts. ¹ The Office on Women's Health says many factors affect let-down, including anxiety, pain, embarrassment, stress, cold, too much caffeine, smoking, alcohol, and some medicines. ¹

How does supply and demand work?

The Office on Women's Health says the more the baby nurses - and the more often the breasts are emptied - the more milk the breasts will make. ¹ La Leche League says milk production is driven by supply and demand: the more milk the baby drinks, the more milk the body makes. ³ The NHS says the amount of milk you make will increase or decrease depending on how often the baby feeds, because each feed signals the body to make more milk for the next feed. ² La Leche League adds that a well-latched, well-positioned baby who breastfeeds frequently on demand will produce plentiful milk. ³

What is colostrum?

The NHS says the fluid the breasts produce in the first few days after birth is called colostrum. ² It adds that colostrum is a very concentrated food, so the baby only needs a small amount - about a teaspoonful - at each feed. ²

Why does night feeding matter?

The NHS says it is important to breastfeed at night because that is when the body produces more prolactin to build up milk supply. ²

When should I get help?

The NHS says to speak to a midwife or health visitor if you are worried about breastfeeding, or if you think your baby is not getting enough milk. ²

Frequently asked questions

How is breast milk made?

The Office on Women's Health says the alveoli make milk in response to prolactin, which rises when the baby suckles. ¹

What is the let-down reflex?

The Office on Women's Health says oxytocin rises when the baby suckles and triggers let-down, moving milk through the ducts. ¹

How does supply and demand work?

La Leche League says the more milk the baby drinks, the more milk the body makes. ³

Why breastfeed at night?

The NHS says that is when the body produces more prolactin to build up milk supply. ²

A note from us

We're the team behind Yael & Michal. We are not doctors, nurses, lactation consultants, or psychologists, and nothing here is professional advice.

Everything above was researched by us from public, reputable sources - we name and link every one of them below - and summarized as carefully as we could, as a free resource for other mothers. We do this because we wished something like it had existed for us.

When we name an organisation such as the CDC, the NHS, La Leche League, or the Israeli Ministry of Health, we are only citing their published guidance; it does not mean they endorse, sponsor, approve, or are affiliated with us. They have no involvement with this site, and we never use their logos or seals.

Yael & Michal sells nursing bras, which are comfort garments and not medical devices; we do not claim they prevent, treat, or cure any medical condition. The health information here is written for you as a free resource - it is separate from anything we sell.

We try hard to get it right, and we cite our sources so you can check us. But we are not a medical authority, and this cannot replace talking to a professional who knows you and your baby. Please check anything that matters with your doctor, midwife, or an IBCLC lactation consultant. This content has not been reviewed by a medical professional. Reading this site does not create a doctor-patient relationship, or any other professional relationship, between you and us.

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Sources

1. Office on Women's Health (womenshealth.gov). https://womenshealth.gov/breastfeeding/learning-breastfeed/making-breastmilk (retrieved 2026-07-10).
2. NHS (nhs.uk). https://www.nhs.uk/baby/breastfeeding-and-bottle-feeding/breastfeeding/the-first-few-days/ (retrieved 2026-07-10).
3. La Leche League International (llli.org). https://llli.org/news/increasing-breastmilk-supply/ (retrieved 2026-07-10).