Drug Levels and Effects:

Summary of Use during Lactation:

Hops (Humulus lupulus) contains bitter acids, flavonoids, phytoestrogens (e.g., 8-prenylnaringenin), and essential oil. Hops is a purported galactogogue.[1] Some animal evidence indicates that a polysaccharide in hops can increase serum prolactin.[2] However, a small study in humans found that a hops soup appeared to lower serum prolactin levels.[3] Galactogogues should never replace evaluation and counseling on modifiable factors that affect milk production.[4] No data exist on the excretion of any components of hops into breastmilk or on the safety and efficacy of hops in nursing mothers or infants. Hops is "generally recognized as safe" (GRAS) as a food by the US Food and Drug Administration. Hops can cause sedation and should be avoided while taking other sedating drugs and in patients with depression. Allergy to hops occurs rarely. Some sources recommend avoiding hops during breastfeeding because of its phytoestrogen content.

Dietary supplements do not require extensive pre-marketing approval from the US Food and Drug Administration. Manufacturers are responsible to ensure the safety, but do not need to prove the safety and effectiveness of dietary supplements before they are marketed. Dietary supplements may contain multiple ingredients, and differences are often found between labeled and actual ingredients or their amounts. A manufacturer may contract with an independent organization to verify the quality of a product or its ingredients, but that does not certify the safety or effectiveness of a product. Because of the above issues, clinical testing results on one product may not be applicable to other products. More detailed informationabout dietary supplementsis available elsewhere on the LactMed Web site.

Drug Levels:

Maternal Levels.

Relevant published information was not found as of the revision date.

Infant Levels.

Relevant published information was not found as of the revision date.

Effects in Breastfed Infants:

Relevant published information was not found as of the revision date.

Possible Effects on Lactation:

A soup of hops was tested for its effect on serum prolactin in three groups of subjects. The soup consisted of 100 to 200 grams of hops, cooked over low heat, and taken in 3 to 4 portions per day. In 5 healthy males, prolactin was measured before and after the soup twice, at 8 am and 3 am. At 8 am, prolactin was unchanged after the soup. At 3 am, serum prolactin averaged 43.4 mcg/L before the soup and 15.4 mcg/L after the soup. In healthy women who took a dose of metoclopramide, the hops soup blunted the metoclopramide-induced prolactin increase at 1 and 3 hours after the dose. In 6 women with galactorrhea, peak serum prolactin was unchanged before and after metoclopramide when hops soup was taken.[3]

Studies in animals indicate that a polysaccharide found in barley and hops is apparently responsible for an increase in prolactin after beer ingestion.[2][5] Refer to the LactMed record onAlcoholfor details.


1. Ayers JF. The use of alternative therapies in the support of breastfeeding. J Hum Lact. 2000;16:52-6. PMID:11138225
2. Sawagado L, Houdebine LM. Identification of the lactogenic compound present in beer. Ann Biol Clin. 1988;46:129-34. PMID:3382062
3. Kuang AK. [Hordeum dislichon--effects on serum prolactin and clinical trial on patients with galactorrhea]. Zhong Xi Yi Jie He Za Zhi. 1984;4:134-6. PMID:6234087
4. The Academy of Breastfeeding Medicine Protocol Committee. ABM clinical protocol #9: use of galactogogues in initiating or augmenting the rate of maternal milk secretion (First revision January 2011). Breastfeed Med. 2011;6:41-9. PMID:21332371
5. Koletzko B, Lehner F. Beer and breastfeeding. Adv Exp Med Biol. 2000;478:23-8. PMID:11065057

Substance Identification:

Substance Name:


Scientific Name:

Humulus lupulus

Drug Class:

  • Complementary Therapies

  • Food

  • Phytotherapy

  • Plants, Medicinal

  • Administrative Information:

    LactMed Record Number:


    Last Revision Date:

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