Galactagogue

The anethole dimers dianethole and photoanethole are structurally dopamine-like and are proposed to competitively block dopamine’s tonic inhibition of prolactin, raising milk output ^{1Reference 1Albert-Puleo · 1980ReviewFennel and anise as estrogenic agents — reviewView study →}. That is the same route as the pharmaceutical galactagogues.

Fennel infusion is used near-universally across Western, Chinese, Ayurvedic and Iranian practice, and registered trials exist ^{2,3Reference 2Badgujar et al. · 2014ReviewFoeniculum vulgare Mill: a review of its botany, phytochemistry, pharmacology and toxicology — reviewView study →Reference 3Rahimi et al. · 2013Medicinal properties of Foeniculum vulgare Mill. in traditional Iranian medicine and modern phytotherapy}.

High-quality human evidence for fennel alone raising measured milk volume is thin. Most of the data are traditional, mechanistic, or drawn from mixed herbal teas, so the herb’s specific contribution is not isolated ^{1Reference 1Albert-Puleo · 1980ReviewFennel and anise as estrogenic agents — reviewView study →}.

The same oestrogenic anethole polymers that plausibly drive the effect reach the infant through milk, and the balance of benefit against exposure is unsettled. Estragole sits on top of that: genotoxic and carcinogenic in isolated high-dose studies ^{4Reference 4Villarini et al. · 2014In vitroCytotoxic, genotoxic and apoptosis-inducing effects of estragole isolated from fennel — in vitroView study →}, substantially inactivated within the whole-plant decoction matrix ^{5Reference 5Gori et al. · 2012ReviewCan estragole in fennel seed decoctions really be considered a danger for human health? — safety reviewView study →} but not absent, with explicit caution against prolonged high-dose use in children ^{2Reference 2Badgujar et al. · 2014ReviewFoeniculum vulgare Mill: a review of its botany, phytochemistry, pharmacology and toxicology — reviewView study →} and a Commission E limit of several weeks ^{6Reference 6Bone et al. · 2013Principles and Practice of Phytotherapy (2nd ed.)}.

No lactogenic pathway is established, and the one trial that measured prolactin found no significant change ^{7Reference 7Rouhi et al. · 2025RCTInvestigating the Effectiveness of Fenugreek on the Quantity of Breast Milk and the Level of Prolactin in Mothers of Preterm Newborns: A Randomized Controlled Clinical TrialView study →}.

A network meta-analysis found fenugreek significantly increased milk volume against placebo, but ranked it substantially below comparators such as Coleus amboinicus and palm date ^{8Reference 8Khan et al. · 2018Meta-analysisEffectiveness of fenugreek as a galactagogue: A network meta-analysisView study →}, and Cochrane rated the certainty of oral-galactagogue evidence low and drew no firm conclusion ^{9Reference 9Foong et al. · 2020Systematic reviewOral galactagogues (natural therapies or drugs) for increasing breast milk production — systematic reviewView study →}. Individual trials diverge: a fenugreek-containing herbal tea raised measured volume and infant weight regain ^{10Reference 10Turkyılmaz et al. · 2011RCTThe effect of galactagogue herbal tea on breast milk production and short-term catch-up of birth weight — randomized trialView study →}, while a 2025 preterm-mothers RCT found more milk on day 7 and nothing by trial end ^{7Reference 7Rouhi et al. · 2025RCTInvestigating the Effectiveness of Fenugreek on the Quantity of Breast Milk and the Level of Prolactin in Mothers of Preterm Newborns: A Randomized Controlled Clinical TrialView study →}.

Blinding is effectively impossible. Fenugreek’s sotolone gives the mother and her milk an unmistakable maple-syrup odour, so mothers know which arm they are in, and lactation outcomes are heavily expectancy-sensitive.

Several of the positive trials also use multi-herb teas or blends, so fenugreek’s own contribution is not isolated in those either.

A small RCT in mothers of preterm newborns found a silymarin preparation increased daily milk production against placebo ^{15Reference 15Peila C et al. · 2015RCTEvaluation of the galactogogue effect of silymarin on mothers of preterm newborns (<32 weeks) — randomised controlled trialView study →}, and further randomised trials of a silymarin–phosphatidylserine–galega combination reported increased and more sustained volume ^{12Reference 12Serrao et al. · 2018RCTThe long-term efficacy of a galactagogue containing silymarin-phosphatidylserine and galega on milk production of mothers of preterm infants — RCT follow-upView study →}.

No lactogenic pathway is established, and several of the studies use multi-ingredient products, so milk thistle’s own contribution is hard to isolate.