Prolactin (PRL) is an anterior pituitary hormone best known for lactation. Physiologically, dopamine from the hypothalamus inhibits prolactin secretion; TRH, estrogen, and stress can stimulate it.

Prolactin
Prolactin structure (PDB 1N9D)
Prolactin structure (PDB 1N9D)
Abbreviation PRL
Molecular formula N/A, single-chain polypeptide (~23 kDa)
Type Pituitary peptide hormone
Administration Endogenous only
Bioavailability N/A; inhibited by dopamine, stimulated by Serotonin, Estrogen, TRH
Synonyms Luteotropic hormone (LTH), lactotropin, mammotropin
Source Anterior pituitary lactotrophs; local production in several tissues
Ray's verdict Generally hurts
Strongly negative, a reliable marker of stress and estrogen excess.

Chronically elevated prolactin in non-pregnant adults is a marker of stress and relative Estrogen excess, often alongside low Thyroid and high Serotonin.[1][2]

Evidence occasionally turns up implicating estrogen in thinning of the skin and bones (see the discussions of osteoporosis and prolactin, and of prolactin and estrogen, in the Yearbook of Endocrinology, in the 1980s).

— Ray Peat[3]

History

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Etymology

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The name combines Latin pro- ("for") with lactare ("to suckle"), describing its role in stimulating milk production.

Oscar Riddle identified and named prolactin in 1932, using its effect of stimulating "crop milk" production in pigeons as the basis for measuring it. Henry Friesen isolated human prolactin as a hormone distinct from growth hormone in 1970.

Prolactin's close structural relationship to growth hormone led some researchers to propose a pituitary "death hormone" appearing at puberty and triggering aging, since such extracts tended to contain both hormones together; Ray Peat considered this a description of puberty itself rather than a distinct hormone.[4]

Stress and exercise

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Intense interval exercise in trained male athletes increased plasma prolactin by ~230% (along with estradiol +45% and testosterone +38%) immediately post-exercise.[5] In a human RCT, aspirin (800 mg/day for 3 days) significantly blunted the total prolactin response to treadmill exercise, alongside ACTH, cortisol, and GH, implicating prostaglandins in exercise-related pituitary activation.[6]

In male chronic smokers, higher-nicotine cigarettes (2.0 mg) raised plasma prolactin, with cortisol and growth hormone, versus low-nicotine cigarettes (0.2 mg).[7] Plasma nicotine after smoking correlated with prolactin (r=0.53); nicotine concentration correlated with increased prolactin release, unlike most abused drugs that release dopamine and decrease prolactin.[8]

A male runner's estrogen is often doubled after a race, and hospitalized seriously ill patients often have greatly increased estrogen.[1] The exercise-estrogen claim is consistent in direction with the 1993 male-athlete study above, though magnitudes vary by protocol.

Function/Mechanism of Action

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Prolactin, like estrogen, interferes with thyroid function and oxygen consumption, and repeated lactation was once thought to cause osteoporosis and tooth loss.[9]

Prolactin is tied to the stress-hormone cascade amplified by PUFA: when stored polyunsaturated fats are liberated during stress, they stimulate ACTH, cortisol, adrenaline, glucagon, and prolactin in a self-amplifying loop; saturated fats terminate this reaction.[2]

See Serotonin for documented sources on serotonin activating prolactin secretion. Serotonin excess, gut Endotoxin, and Estrogen dominance are upstream drivers, not single-cause explanations. In rats, the SSRI fluoxetine combined with the serotonin precursor 5-HTP produced a large rise in prolactin that neither compound produced alone; pretreatment with the serotonin-receptor blocker methysergide prevented the rise, direct evidence that the effect runs through serotonin receptors rather than some other action of the drugs.[10] Estrogen itself feeds this pathway: cultured rat pituitary cells only expressed 5-HT4, 5-HT5, and 5-HT6 serotonin receptor mRNA when estradiol was present, and with estradiol on board, activating the 5-HT4 receptor specifically triggered prolactin release, a direct mechanistic link between estrogen, serotonin receptor expression, and prolactin secretion.[11]

Like estrogen, prolactin stimulates cell division in its target tissues, and its secretion is itself driven by estrogen-induced mitosis of the pituitary's prolactin-producing cells.[12] Estrogen also causes "erasure" of learned information in trained animals, an effect prolactin shares.[13]

Prolactin release rises in proportion to the amount of visceral (abdominal) fat a person carries, independent of overall body weight, in a study of obese women measuring prolactin secretion rate directly.[14] Whether prolactin promotes visceral fat gain or visceral fat drives prolactin release (or both) isn't established by this correlational data alone.

A 2025 MRI study of 32 people with hyperprolactinemia versus 40 controls found reduced global cerebral blood flow, concentrated in the frontal and temporal cortex, along with disrupted functional connectivity between brain networks; bromocriptine treatment produced a partial upward trend in blood flow.[15]

Prolactin also acts alongside parathyroid hormone (PTH) in a self-reinforcing loop on bone:

Prolactin, which is increased under the influence of estrogen or serotonin, causes the body to lose calcium (drawing it from the bones), and it stimulates the secretion of PTH, which compensates for the calcium loss by increasing its mobilization from bones.

— Ray Peat[16]

Prolactin's bone-wasting effect works partly by increasing interleukin-6 (IL-6), which in turn stimulates more prolactin release; serotonin and IL-6 also stimulate each other, and PTH and serotonin stimulate each other in the same direction, so estrogen, serotonin, PTH, IL-6, and prolactin form a mutually reinforcing cluster of bone-wasting, inflammatory signals rather than acting as independent variables.[17]

In the small intestine, prolactin raises calcium absorption in female rats, and bromocriptine (which lowers prolactin) blocks that effect; young animals respond more than adults (review of animal work).[18]

An intravenous calcium drip cut the prolactin rise after a TRH injection by about a third in 11 healthy women; a calcium-channel blocker left that response unchanged (human study).[19] Calcium infusions also lowered serum prolactin in most children studied for calcium disorders (clinical series).[20] Those were acute infusions, not dietary calcium, so they do not show that eating more calcium lowers everyday prolactin.

Breast cancer risk

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Prolactin acts on breast tissue alongside estrogen and progesterone as a third proliferative hormone, stimulating cell division directly and through prolactin receptors that are frequently overexpressed in breast tumors.[21]

A pooled analysis of three prospective cohorts found higher circulating prolactin associated with a modestly increased risk of breast cancer overall (relative risk 1.3 for top versus bottom quartile), with the association strongest in women whose tumors were estrogen-receptor-positive (relative risk 1.6).[22] A later 20-year follow-up from the same research group confirmed prolactin as a durable long-term risk marker rather than a short-term fluctuation.[23]

Reproductive and gonadal function

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Prolactin suppresses the hypothalamic-pituitary-gonadal axis at its source. It inhibits pulsatile activity of kisspeptin neurons in the hypothalamus, which normally drive pulsatile GnRH release; without that pulsatile GnRH signal, the pituitary releases less LH and FSH.[24] Lower LH reduces the Leydig-cell enzymatic conversion of cholesterol to testosterone and DHT; lower FSH reduces Sertoli-cell support for sperm maturation.[25] An early study in men linked plasma prolactin levels to androgen metabolism.[26]

In cross-sectional data from infertile men, hyperprolactinemia correlates with lower testosterone in men undergoing fertility evaluation,[27] and with lower FSH, LH, and total testosterone together in a separate cohort of men in infertile couples.[28] The relationship also runs in reverse: dopamine-agonist treatment (cabergoline) that lowers prolactin in men with prolactinoma normalized testosterone in roughly 60% of patients within six months.[29] In a small older trial, bromocriptine (a dopamine agonist) given to 10 men with hyperprolactinemia-related infertility improved sperm motility in the 3 men with the most abnormal semen parameters; their wives conceived within 5-8 weeks, resulting in two live births and one first-trimester miscarriage. Testosterone was not reported in that trial.[30]

The relationship between testosterone and prolactin isn't one-directional, though. Exogenous testosterone can itself raise prolactin, since aromatization converts some of it to estrogen, and estrogen stimulates prolactin release from the pituitary; a case report of testosterone-replacement-induced hyperprolactinemia documented prolactin rising when testosterone therapy started and falling when it stopped.[31] This complicates treating hypogonadal men who also have a prolactin-secreting pituitary tumor: giving them testosterone alone can raise estrogen and prolactin further. A case report managed this by combining testosterone with an aromatase inhibitor and high-dose cabergoline.[32] A 2023 review of aromatase inhibitors in male prolactinoma found the same combination effective more broadly: adding an aromatase inhibitor (anastrozole or letrozole) to a dopamine agonist improved control of prolactin levels and tumor shrinkage in men who needed testosterone replacement but were otherwise dopamine-agonist-resistant.[33]

Bone and pituitary tumors

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Prolactin has a bone-weakening effect independent of estrogen, and is often produced in excess around menopause.[34] Estrogen-driven mitosis of prolactin-secreting pituitary cells means that, by age 50, most people show some degree of pituitary tumefaction from this cell population; correcting thyroid and progesterone addresses the underlying estrogen dominance rather than the prolactin excess alone.[35]

The prolactin-secreting pituitary tumor (prolactinoma), once rare, became the most common pituitary tumor type following the spread of estrogen-containing oral contraceptives; bromocriptine, which shifts brain chemistry toward dopamine dominance, both suppresses prolactin and causes these tumors to regress, as does progesterone.[36]

Skin and hair

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Excess prolactin activates sebum production, and since tryptophan promotes the serotonin that stimulates prolactin release, high milk or tryptophan intake combined with low vitamin B6, thyroid, or progesterone can favor acne.[37]

Human scalp hair follicles express prolactin and prolactin receptors and produce prolactin locally, so the follicle is both a source and a direct target, not only a downstream receiver of pituitary prolactin.[38] In organ culture, high-dose prolactin (400 ng/mL) produced significant inhibition of hair-shaft elongation (~1.6 mm growth over 8 days in controls versus 1.3 mm with prolactin, about 19% less), with reduced keratinocyte proliferation and increased apoptosis in the hair bulb.[38] After 8 days only 45% of treated follicles remained in anagen VI versus more than 70% of controls, while 25% had reached mid-catagen versus 3% of controls, a premature shift into the regression (catagen) phase.[38]

What you see is an excess of prolactin and cortisol in the people losing their hair, both men and women.

— Ray Peat[39]

Both hirsutism and hair loss are associated with high prolactin. And the thyroid supplement is a very reliable way to control prolactin in most women. Vitamin A and calcium also help to inhibit excess prolactin.

— Ray Peat[40]

In a case-control study of men aged 19 to 30, the 57 with early pattern hair loss had higher blood prolactin than 32 men without hair loss, along with higher testosterone, DHEAS and LH and lower SHBG and FSH.[41]

Medical uses/Effects

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Genuinely elevated prolactin occurs in prolactinomas and some medications (e.g. antipsychotics, SSRIs). Bromocriptine and other dopamine agonists lower prolactin by standard pharmacology. Addressing thyroid, estrogen/progesterone balance, and serotonin/endotoxin drivers takes priority over targeting prolactin alone. See Harm reduction.

A 2025 systematic review of 804 patients with elevated prolactin found 456 had subclinical hypothyroidism and 314 had overt hypothyroidism; treating these patients with thyroid hormone resolved or improved the hyperprolactinemia in most cases without needing a dopamine agonist. Thyroid hormone acts as a prolactin antagonist.[42] Whether high prolactin causes the hypothyroidism or the reverse isn't settled by this data, but the reviewed thyroid-treatment trials support directly lowering prolactin via thyroid correction, not just symptom overlap.

Prolactin and TSH tend to increase together, so when you didn't need the prolactin to be high, the TSH, which might have been keeping your thyroid active despite high estrogen, could have decreased, letting the gland be suppressed by estrogen (and maybe PUFA). ... Optimally, the TSH should be very low, but the thyroid gland should keep functioning without needing much stimulation.

— Ray Peat[43]

Peat put target prolactin around 9 to 12; salt and thyroid usually lower it, while even a small dose of vitamin B6 (~10 mg/day) can lower prolactin.[44] In three women with galactorrhea-amenorrhea and high prolactin, pyridoxine (vitamin B6) at 200 to 600 mg/day stopped the galactorrhea, kept prolactin in the normal range and restored ovulatory menses; symptoms returned after stopping it.[45] Dietary salt similarly tends to inhibit excessive prolactin release.[46] Zinc antagonizes prolactin as well: perifused rat pituitary cells showed acute, selective, and reversible inhibition of prolactin release when exposed to zinc, without any change in TSH, LH, or growth hormone output,[47] and oral zinc loading (25-50 mg) lowered plasma prolactin below baseline in healthy men and women.[48]

Vitamin E and vitamin K both act as estrogen antagonists (vitamin E also as an aromatase inhibitor), which lowers prolactin indirectly by reducing the estrogen stimulus to the pituitary's prolactin-producing cells. Avoiding PUFA supports the same estrogen-lowering effect. In a placebo-controlled trial, vitamin E (300 mg/day for 8 weeks) cut serum prolactin from 50.8 to 15.4 ng/ml in uremic patients on hemodialysis without affecting FSH, LH, or free testosterone, a drop the authors attributed to central inhibition of prolactin secretion rather than the peripheral estrogen-antagonist route above.[49] Sun exposure supports dopamine production, prolactin's main antagonist, while also lowering serotonin and nitric oxide. Liver and oysters supply minerals and vitamins associated with lower prolactin, and adequate sleep supports normal prolactin regulation as well.

A single oral dose of zinc lowered plasma prolactin below baseline within two hours in healthy men and women.[50] Adenosine cut prolactin release from rat pituitary cells in culture, and the cells made enough adenosine on their own to hold their secretion down.[51] Neither study tested the scalp or hair loss.

Psychosocial factors

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Early-life family environment may influence prolactin regulation in adulthood. An absent, violent, or alcoholic father during childhood can predispose women to develop hyperprolactinaemia later in life, possibly as a long-term adaptation to early loss or stress.[52] This psychosocial pathway is distinct from the better-known physiological drivers (estrogen, serotonin, TRH, dopamine withdrawal).

Hyperprolactinemia

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The tryptophan and serotonin happen to turn on a trigger that increases prolactin and thyroid stimulating hormone. They tend to go together. And if your thyroid doesn't respond adequately to the rising thyroid stimulating hormone, it isn't able to lower the prolactin.

— Ray Peat[53]

The Endocrine Society guideline starts by establishing the cause of a raised prolactin (medication, another medical condition, or a prolactin-secreting pituitary tumor) before any treatment is chosen.[54]

In a non-randomized controlled study, women with mildly raised prolactin and infertility or repeated miscarriage who were given the drug bromocriptine plus a synthetic progestin (a progesterone-like drug) had ovulation return, and fewer miscarried than women in older records treated less continuously (3% vs 18%).[55]

Estrogen, darkness, and stress all promote prolactin secretion; sodium suppresses it, while taking water without sodium stimulates it, suggesting hypotonic/sodium-deficient tissue fluid is a common factor across situations that raise prolactin. Excess prolactin contributes to osteoporosis in humans, and estrogen given to postmenopausal women itself raises prolactin, a feedback loop worth knowing about before starting HRT.[56]

In healthy men, a large plain water load raised prolactin slightly within half an hour, while in women the rise was not significant, though more dilute blood went with higher prolactin. The rise was too small to suggest prolactin regulates short-term water balance.[57]

See also Homosexuality for proposed endocrine correlates of sexual orientation discussed in that literature.


In a case-control study, people with prolactin-secreting pituitary tumors did worse than healthy controls on attention and working memory tests, and higher prolactin went with lower scores on several of them.[58]

References

[edit]
  1. ↑ 1.0 1.1 Ray Peat, "Estrogen and Progesterone," raypeat.com.
  2. ↑ 2.0 2.1 Ray Peat, "Unsaturated Vegetable Oils: Toxic," raypeat.com.
  3. ↑ Not the "female hormone," but the shock hormone
  4. ↑ Ray Peat, "Generative Energy", p. 119
  5. ↑ Endocrine response to intense interval exercise.
  6. ↑ Acetylsalicylic acid inhibits the pituitary response to exercise-related stress in humans.
  7. ↑ Wilkins JN, Carlson HE, Van Vunakis H, Hill MA, Gritz E, Jarvik ME. "Nicotine from cigarette smoking increases circulating levels of cortisol, growth hormone, and prolactin in male chronic smokers," Psychopharmacology (Berl). 1982;78(4):305-308. PMID 6818588.
  8. ↑ Xue Y, Morris M, Ni L, Guthrie SK, Zubieta JK, Gonzalez K, McConnell DS, Domino EF. "Venous plasma nicotine correlates of hormonal effects of tobacco smoking," Pharmacol Biochem Behav. 2010 Apr;95(2):258-262. PMID 20100507.
  9. ↑ Ray Peat, "Osteoporosis, aging, tissue renewal, and product science," raypeat.com.
  10. ↑ Clemens JA, Sawyer BD, Cerimele B. "Further evidence that serotonin is a neurotransmitter involved in the control of prolactin secretion." Endocrinology. 1977;100(3):692-698. PMID 401022.
  11. ↑ Papageorgiou A, Denef C. "Estradiol induces expression of 5-hydroxytryptamine (5-HT) 4, 5-HT5, and 5-HT6 receptor messenger ribonucleic acid in rat anterior pituitary cell aggregates and allows prolactin release via the 5-HT4 receptor." Endocrinology. 2007;148(3):1384-1395. PMID 17122082.
  12. ↑ Ray Peat, "Progesterone in Orthomolecular Medicine", p. 7
  13. ↑ Ray Peat, "Progesterone in Orthomolecular Medicine", p. 4
  14. ↑ Kok P, Roelfsema F, Frölich M, Meinders AE, Pijl H. "Prolactin release is enhanced in proportion to excess visceral fat in obese women." J Clin Endocrinol Metab. 2004;89(9):4445-4449. PMID 15356045.
  15. ↑ Xu M, Liu B, Yang A, Luan J, Li S, Zhu L, Shu N, Ouyang G, Wang Y, Wang Y, Ma G. "Effects of hyperprolactinemia and bromocriptine treatment on cerebral blood flow and functional brain states." Neuroradiology. 2025. doi:10.1007/s00234-025-03686-y.
  16. ↑ Ray Peat, "Calcium and Disease: Hypertension, organ calcification, & shock, vs. respiratory energy," raypeat.com.
  17. ↑ Ray Peat, "Calcium and Disease: Hypertension, organ calcification, & shock, vs. respiratory energy," raypeat.com.
  18. ↑ Charoenphandhu N, Krishnamra N. "Prolactin is an important regulator of intestinal calcium transport," Canadian Journal of Physiology and Pharmacology. 2007;85(6):569-581. doi:10.1139/y07-041. PMID 17823618.
  19. ↑ Röjdmark S, Andersson DE, Sundblad L. "Calcium and calcium-antagonistic effects on prolactin and growth hormone responses to thyrotropin-releasing hormone and L-dopa in man," Journal of Clinical Endocrinology & Metabolism. 1981;53(3):594-598. doi:10.1210/jcem-53-3-594. PMID 6790560.
  20. ↑ Kruse K, Kracht U. "Inhibitory effect of calcium on serum prolactin," Acta Endocrinologica. 1981;98(3):339-344. doi:10.1530/acta.0.0980339. PMID 7293666.
  21. ↑ Schuler LA, O'Leary KA. "Prolactin: The Third Hormone in Breast Cancer," Front Endocrinol (Lausanne). 2022;13:910978. doi:10.3389/fendo.2022.910978. PMID 35784527.
  22. ↑ Tworoger SS, Eliassen AH, Sluss P, Hankinson SE. "A prospective study of plasma prolactin concentrations and risk of premenopausal and postmenopausal breast cancer," J Clin Oncol. 2007;25(12):1482-1488. PMID 17372279.
  23. ↑ Tworoger SS, et al. "A 20-year prospective study of plasma prolactin as a risk marker of breast cancer development," Cancer Res. 2013;73(15):4810-4819. PMID 23783576.
  24. ↑ Hoskova K, Bryant NK, Chen ME, Nachtigall LB, Lippincott MF, Balasubramanian R, Seminara SB. "Kisspeptin Overcomes GnRH Neuronal Suppression Secondary to Hyperprolactinemia in Humans." J Clin Endocrinol Metab. 2022;107(1):e534-e543. PMID 35323937.
  25. ↑ De Rosa M, Zarrilli S, Di Sarno A, Milano N, Gaccione M, Boggia B, Lombardi G, Colao A. "Hyperprolactinemia in men: clinical and biochemical features and response to treatment." Endocrine. 2003;20(1-2):75-82. PMID 12668871.
  26. ↑ Magrini B, Ebiner JR, Burckhardt P, Felber JP. "Study on the relationship between plasma prolactin levels and androgen metabolism in man." J Clin Endocrinol Metab. 1976;43(4):944-947. PMID 977731.
  27. ↑ Ambulkar SS, Darves-Bornoz AL, Fantus RJ, Wren J, Bennett NE, Halpern JA, Brannigan RE. "Prevalence of Hyperprolactinemia and Clinically Apparent Prolactinomas in Men Undergoing Fertility Evaluation." Urology. 2022;162:83-88. PMID 33766719.
  28. ↑ Green KI, Amadi C. "Status of Serum Prolactin Levels among Male Cohort in Infertile Couples." Int J Appl Basic Med Res. 2020;10(3):175-179. PMID 33376697.
  29. ↑ Colao A, Vitale G, Cappabianca P, Briganti F, Ciccarelli A, De Rosa M, Zarrilli S, Lombardi G. "Outcome of cabergoline treatment in men with prolactinoma: effects of a 24-month treatment on prolactin levels, tumor mass, recovery of pituitary function, and semen analysis." J Clin Endocrinol Metab. 2004;89(4):1704-1711. PMID 15070934.
  30. ↑ Laufer N, Yaffe H, Margalioth EJ, Livshin J, Ben-David M, Schenker JG. "Effect of bromocriptine treatment on male infertility associated with hyperprolactinemia." Arch Androl. 1981;6(4):343-348. PMID 7247577.
  31. ↑ Sodi R, Fikri R, Diver M, Ranganath L, Vora J. "Testosterone replacement-induced hyperprolactinaemia: case report and review of the literature." Ann Clin Biochem. 2005;42(Pt 2):153-159. PMID 15829128.
  32. ↑ Gillam MP, Middler S, Freed DJ, Molitch ME. "The novel use of very high doses of cabergoline and a combination of testosterone and an aromatase inhibitor in the treatment of a giant prolactinoma." J Clin Endocrinol Metab. 2002;87(10):4447-4451. PMID 12364416.
  33. ↑ Akirov A, Rudman Y. "The Role of Aromatase Inhibitors in Male Prolactinoma." J Clin Med. 2023;12(3):1058. PMID 36835974.
  34. ↑ Ray Peat, "From PMS to Menopause", p. 14
  35. ↑ Ray Peat, "Progesterone in Orthomolecular Medicine", p. 35
  36. ↑ Ray Peat, "Nutrition for Women", p. 63
  37. ↑ Ray Peat, "Nutrition for Women", p. 63
  38. ↑ 38.0 38.1 38.2 Foitzik K, Krause K, Conrad F, Nakamura M, Funk W, Paus R. "Human scalp hair follicles are both a target and a source of prolactin, which serves as an autocrine and/or paracrine promoter of apoptosis-driven hair follicle regression," Am J Pathol. 2006;168(3):748-756. PMID 16507890.
  39. ↑ Ray Peat, "Ask the Herb Doctor: Hair Loss, Inflammation, Osteoporosis", KMUD, 13:49
  40. ↑ Ray Peat, "Ask the Herb Doctor: Hair Loss, Inflammation, Osteoporosis", KMUD, 41:38
  41. ↑ Sanke S, Chander R, Jain A, Garg T, Yadav P. 2016. "A Comparison of the Hormonal Profile of Early Androgenetic Alopecia in Men With the Phenotypic Equivalent of Polycystic Ovarian Syndrome in Women." JAMA Dermatol 152(9):986-91. doi:10.1001/jamadermatol.2016.1776 Prolactin mean 14.14 vs 9.97 ng/mL, P = .01.
  42. ↑ Khan AA, Sharma R, Ata F, Khalil SK, Aldien AS, Hasnain M, Sadiq A, Bilal ABI, Mirza W. "Systematic review of the association between thyroid disorders and hyperprolactinemia." Thyroid Res. 2025;18:1. PMID 39754184.
  43. ↑ Prolactin - Ray Peat Email Exchanges
  44. ↑ "Prolactin," Ray Peat email exchange
  45. ↑ Treatment of women with the galactorrhea-amenorrhea syndrome with pyridoxine (vitamin B6).
  46. ↑ Ray Peat, "Generative Energy", p. 105
  47. ↑ Judd AM, Macleod RM, Login IS. "Zinc acutely, selectively and reversibly inhibits pituitary prolactin secretion." Brain Res. 1984;294(1):190-192. PMID 6697238.
  48. ↑ Brandão Néto J, de Mendonça BB, Shuhama T, Marchini JS, Madureira G, Pimenta WP, Tornero MT. "Zinc: an inhibitor of prolactin (PRL) secretion in humans." Horm Metab Res. 1989;21(4):203-206. PMID 2753470.
  49. ↑ Yeksan M, Polat M, Türk S, Kazanci H, Akhan G, Erdogan Y, Erkul I. "Effect of vitamin E therapy on sexual functions of uremic patients in hemodialysis." Int J Artif Organs. 1992;15(11):648-652. PMID 1490755.
  50. ↑ Brandão Néto J, de Mendonça BB, Shuhama T, et al. "Zinc: an inhibitor of prolactin (PRL) secretion in humans," Horm Metab Res. 1989;21(4):203-206. doi:10.1055/s-2007-1009191. PMID 2753470. n=17; 25, 37.5 and 50 mg oral zinc; blood sampled over 120 min.
  51. ↑ Dorflinger LJ, Schonbrunn A. "Adenosine inhibits prolactin and growth hormone secretion in a clonal pituitary cell line," Endocrinology. 1985;117(6):2330-2338. doi:10.1210/endo-117-6-2330. PMID 2998734. GH4C1 cells; adenosine at 50 µM or more inhibited PRL and GH secretion by 40%.
  52. ↑ Danny Roddy (@dannyroddy), "Absent, violent, or alcoholic fathers can 'imprint' hyperprolactinemia," X/Twitter, 2026, citing clinical literature on familial patterns of hyperprolactinaemia.
  53. ↑ Ray Peat, "One Radio Network: Dr. Peat Answers Questions Regarding Health, Diet and Nutrition Part 2", One Radio Network (1 Jan 2014), 13:38
  54. ↑ Melmed S, Casanueva FF, Hoffman AR, et al. "Diagnosis and treatment of hyperprolactinemia: an Endocrine Society clinical practice guideline." J Clin Endocrinol Metab. 2011;96(2):273-288. PMID 21296991.
  55. ↑ Sokhadze K, Kvaliashvili S, Kristesashvili J. "Reproductive function and pregnancy outcomes in women treated for idiopathic hyperprolactinemia: A non-randomized controlled study." Int J Reprod Biomed. 2020;18(12):1039-1048. doi:10.18502/ijrm.v18i12.8025. PMID 33426414. Progestin used: dydrogesterone. 96 treated women (prolactin 39-68 ng/ml) vs 78 historical controls; first-trimester loss 3.1% vs 17.95%, p = 0.002; ovulation compared only before vs after treatment; pregnancy rates not compared between groups; preterm birth difference not significant.
  56. ↑ Peat, Raymond. "Darkness, Water, Osteoporosis."
  57. ↑ Adler RA et al. 1975. "Failure of oral water loading and intravenous hypotonic saline to suppress plasma prolactin in man." J Clin Endocrinol Metab. doi:10.1210/jcem-41-2-383 Human study, healthy volunteers, no placebo arm. Water load 20 ml/kg: mean prolactin 7.6 to 12.3 ng/ml in 10 men; non-significant rise in 11 women, with prolactin inversely correlated with plasma osmolality; 0.45% or 5% saline IV had no effect in 5 men.
  58. ↑ Bala A et al. 2022. "Attention and working memory in patients with prolactinomas: a case-control study." Sci Rep 12(1):22565. 27 prolactinoma patients vs 27 healthy controls; deficits on d2, Color Trails, Everyday Attention, Digit Span and Symbol Span; no link with tumor size. doi:10.1038/s41598-022-26331-7. PMID 36581642.