Prolactin

The pituitary hormone that rises sharply after orgasm. Its relationship with dopamine is mechanical rather than mysterious: dopamine holds prolactin down, so when dopamine withdraws, prolactin rises. That makes the post-orgasm surge a readout of what dopamine has just done, not an event in its own right.

Orgasm increases it.

10.1155/2018/9253083 — The inhibition of dopamine transmission in the hypothalamus leads to an increase in prolactin released from the anterior pituitary (as dopamine is the main prolactin inhibiting factor). doi 10.1155/2018/9253083 · PMC6851580

Micronutrient status reduces it.

The micronutrient effect on prolactin is nutrient-specific — B6 yes, zinc null. Vitamin B6: PMC8426548, 16-week trial in male treatment-resistant schizophrenia with antipsychotic-induced hyperprolactinemia — “the vB6 group showed a 68.1% reduction in serum prolactin levels (from 95.52 ± 6.30 to 30.43 ± 18.65 μg/L) while the ARI group showed only a 37.4% reduction”. Zinc is null and it is recorded here deliberately: PMC2366825 — “we concluded that acute or chronic Zn administration does not inhibit PRL secretion in basal condition or by TRH effect in hyperprolactinemic patients” (n=8, prolactinoma/idiopathic). the B6 result is in medication-induced hyperprolactinemia in males with schizophrenia, not in physiological prolactin variation; the zinc null is a small n=8 series. PMC8426548

Lowers cortisol increases it.

Stress is a recognized physiologic cause of hyperprolactinemia. Levine & Muneyyirci-Delale, “Stress-Induced Hyperprolactinemia: Pathophysiology and Clinical Approach”, Obstet Gynecol Int 2018 (doi 10.1155/2018/9253083): “Stress is also an important physiologic cause of hyperprolactinemia, and its clinical significance is still being explored.” a review, not an interventional trial; the review itself states the clinical significance of the stress-prolactin link is still being explored. doi 10.1155/2018/9253083

Vitamin D status reduces it.

Vitamin D lowers prolactin in macroprolactinaemia, and vitamin D status gates other agents. “The Association between Macroprolactin Levels and Vitamin D” (doi 10.1055/s-0035-1555877): “Vitamin D administered to patients with macroprolactinemia increased 25-hydroxyvitamin, reduced total prolactin and macroprolactin... The effect of vitamin D on total prolactin and macroprolactin correlated with their baseline values and baseline 25-hydroxyvitamin.” Independently, PMC10221981 reports that “metformin has been found to reduce prolactin levels only if 25-hydroxyvitamin D levels were within the reference range, and this effect correlated with 25-hydroxyvitamin D levels.” the effect is demonstrated in macroprolactinaemic / vitamin-D-insufficient patients and is baseline-dependent — it is not evidence that vitamin D lowers prolactin in replete, normoprolactinaemic people. The cardiometabolic study is a pilot. doi 10.1055/s-0035-1555877 · PMC10221981

Motivation reduces it.

Dopamine is then transported via the hypophysial portal blood to the anterior pituitary gland, where it binds dopamine D2 receptors on lactotrophs and inhibits PRL secretion. PMC10778701

It increases Motivation.

In the presence of prolactin, spontaneously oscillating TIDA cells depolarized, switched from phasic to tonic discharge, and exhibited broadened action potentials. 10.1523/JNEUROSCI.0129-12.2012. doi 10.1523/JNEUROSCI.0129-12.2012

It increases The pause afterwards.

A number of physiological, hormonal and neurochemical changes occur at orgasm; some of these cause, and are caused by, events that inhibit sexual excitation and induce a refractory period. Note: prolactin is a readout of dopamine withdrawal, not the cause of refractoriness. Sexual Medicine Reviews 13(3):381 — Orgasms, sexual pleasure, and opioid reward mechanisms.

It increases Clear skin.

Hyperprolactinemia is associated with acne in females — and the mechanism is contested. Langan et al., “Prolactin as a candidate sebotrop(h)ic hormone?”, Exp Dermatol 2018 (doi 10.1111/exd.13545): “Clinically, hyperprolactinaemia is principally associated with acne development in females, whilst decreased shaving frequency and body hair are the most common skin manifestations of hyperprolactinemia in males.” The same paper qualifies it: “hyperprolactinaemia may not be associated with acne development per se, but rather may reflect increased adrenal androgen production”, and prolactin has been shown to decrease 5-alpha-reductase activity in vitro. Sex-specific: in males the associated hypoandrogenism “may not be conducive to acne development”. a hypothesis-generating review; no interventional trial. doi 10.1111/exd.13545

It reduces Female libido.

Elevated prolactin inhibits sexual desire. “Impact of hyperprolactinemia on sexual function”, J Sex Med 2024;21(3):197: “Prolactin receptors are expressed in various areas of the brain that are involved in the sexual response cycle... elevated prolactin levels generally have an inhibitory effect on sexual behavior and activity”, and prolactin rises after orgasm in both sexes. Corroborated by Levine 2018 (doi 10.1155/2018/9253083), which lists “decreased libido, dyspareunia” among hyperprolactinemia findings in women. the inhibitory-effect evidence is largely animal-model; the human data are clinical associations in hyperprolactinaemic patients, not dose-response in healthy people. doi 10.1155/2018/9253083

It reduces Reproductive trigger hormone.

Prolactin acts on prolactin receptors on KNDy neurons to suppress kisspeptin expression. PMID 23006326

It reduces Reproductive trigger.

Reduced kisspeptin drive lowers pulsatile GnRH release from the hypothalamus. doi 10.1210/clinem/dgac208 · PMID 3917455 · PMC5686678

It reduces Follicle-stimulating hormone.

Loss of GnRH pulsatility reduces pituitary LH and FSH secretion. doi 10.1210/clinem/dgac208 · PMID 3105612 · PMC5686678

It reduces Testosterone.

Gonadotropin withdrawal in hyperprolactinemia produces hypogonadotropic hypogonadism. PMID 3917455 · PMC5686678

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