# Prolactin

Category: Hormones

Prolactin is a hormone secreted by the pituitary gland during pregnancy, and during stress. It promotes milk production, removes calcium from the bones, and inhibits progesterone formation.

11 passages · 3 authors · 2006–2026 · Most-cited: [Ray Peat](https://bioenergeticoracle.com/md/voices/ray-peat/index.md)

Canonical page: https://bioenergeticoracle.com/concepts/prolactin

## Synthesis

**Prolactin** is a pituitary hormone that Ray Peat identified as a fundamental **stress hormone**, rising not only during pregnancy and lactation but also in response to aging, estrogen, serotonin, and endotoxin. [Source 1, 6, 7] Peat argued that prolactin is a potent *metabolic inhibitor*, suppressing mitochondrial function, decreasing oxidative metabolism, and interfering with thyroid hormone action while promoting glycolysis and lactate production. [Source 1, 7] He traced its pathological effects across multiple tissues, noting that it mobilizes calcium from bones, inhibits progesterone formation, and acts on secretory membranes in the kidney, gut, and skin. [Source 1, 6] Dinkov has extended this by emphasizing that prolactin serves as the best blood surrogate for tissue estrogenic activity and serotonin, with a correlation coefficient over 0.9, making it a far more reliable marker of stress than direct steroid measurements. [Source 11]

The relationship between prolactin and thyroid function is central to Peat's framework. Prolactin and **TSH** tend to increase together, and Peat observed that prolactin directly decreases thyroid gland activity. [Source 1, 2] He considered mild hypothyroidism the likely underlying cause of elevated prolactin, recommending thyroid supplementation, salt, and even small amounts of vitamin B6 (around 10 mg daily) to lower it. [Source 2] This bioenergetic perspective reframes prolactin not as an isolated reproductive hormone but as an indicator of systemic energy failure. Dinkov has noted that prolactin is chronically elevated in virtually all chronic diseases and that levels considered "normal" by contemporary lab ranges—recently raised to an upper limit of 22 ng/mL for males—are far above the historical healthy mean of around 5 ng/mL. [Source 4, 8, 10]

Peat documented a direct causal chain linking estrogen to prolactin-driven tissue destruction. He highlighted the epidemic of pituitary tumors requiring surgery that followed the introduction of the birth control pill, a 300-fold increase in prolactin surgeries driven by estrogen's stimulatory effect on prolactin secretion. [Source 5] He also criticized the widespread use of estrogen to prevent osteoporosis, pointing out that estrogen increases prolactin, which in turn mobilizes calcium from bone and contributes to the very bone loss it was meant to treat. [Source 3, 6] The same pathway explains why **SSRI antidepressants**, which increase serotonin and consequently prolactin, were found to cause osteoporosis with prolonged use. [Source 3] Serotonin produced in the intestine was later discovered to be a basic cause of bone loss, connecting intestinal health directly to prolactin-mediated pathology. [Source 3]

In the context of hair loss, Peat rejected the **dihydrotestosterone (DHT)** hypothesis as biologically absurd, noting that young males with the highest androgen levels have the lowest rates of baldness. [Source 7] He instead framed balding as a bioenergetic problem driven by prolactin, which he described as a "molting" hormone in insects analogous to hair shedding in humans. [Source 7] Roddy has elaborated that prolactin terminates the *anagen* (growth) phase of the hair follicle, shifting it into catagen and telogen, and that it activates the enzyme liberating arachidonic acid for inflammatory prostaglandin production. [Source 4, 9] Dinkov has pointed to the development of prolactin receptor antagonists like ABS-201, which completely reversed balding and even graying in macaques, as direct validation of Peat's view. [Source 7] Roddy characterizes the balding individual as perpetually experiencing a *winter metabolism* marked by higher prolactin, cortisol, estrogen, and histamine, with thyroid hormone serving as the master regulator that, through carbon dioxide production, inhibits excess prolactin and parathyroid hormone. [Source 9]

## People also ask

### How does prolactin contribute to hair loss?

Peat argued that prolactin acts as a "molting" hormone, terminating the growth phase of the hair follicle and shifting it into shedding phases, while also activating inflammatory prostaglandin production. Roddy characterized this as a "winter metabolism" state driven by stress hormones rather than DHT.

### Why did Peat consider prolactin a better stress marker than estrogen?

Dinkov emphasized that prolactin serves as a reliable blood surrogate for tissue estrogenic activity and serotonin, with a correlation coefficient over 0.9, making it a far more accurate indicator of systemic stress than direct steroid measurements.

### What is the connection between prolactin and bone loss?

Peat documented that estrogen increases prolactin, which then mobilizes calcium from bone, explaining why both estrogen therapy and SSRI antidepressants, which raise serotonin and prolactin, can contribute to osteoporosis.

## Related concepts

- [Progesterone](https://bioenergeticoracle.com/md/concepts/progesterone/index.md)
- [Serotonin](https://bioenergeticoracle.com/md/concepts/serotonin/index.md)
- [Adrenaline](https://bioenergeticoracle.com/md/concepts/adrenaline/index.md)
- [Age Pigment (Lipofuscin)](https://bioenergeticoracle.com/md/concepts/age-pigment-lipofuscin/index.md)
- [Albumin](https://bioenergeticoracle.com/md/concepts/albumin/index.md)
- [Aldosterone](https://bioenergeticoracle.com/md/concepts/aldosterone/index.md)

## Cited passages

Passage numbers match the `[Source N]` markers in the synthesis above.

### Source 1 — Glossary

Ray Peat · Glossary

> Prolactin
>
> Prolactin is a hormone secreted by the pituitary gland during pregnancy, and during stress. It promotes milk production, removes calcium from the bones, and inhibits progesterone formation.
>
> Arachidonic acid stimulates prolactin secretion, and prolactin acts on the thyroid gland to decrease its activity, and on other tissues to increase their glycolysis (with lactate production), while decreasing oxidative metabolism

### Source 2 — Prolactin

Ray Peat · Email · 2015

> # Prolactin
>
> High prolactin
>
> Either vitex or bromocriptine would probably stop it, but I think it's probably caused by mild hypothyroidism, and that the best way to handle it would be with a thyroid supplement, and that would probably help your libido too.
>
> 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, from the nuts and any non-ruminant meats). Optimally, the TSH should be very low, but the thyroid gland should keep functioning without needing much stimulation.
>
> Salt and thyroid usually lower it, but you might want to try a little vitamin B6; even a small amount, about 10 mg per day, can lower prolactin.

### Source 3 — Osteoporosis, aging, tissue renewal, and product science

Ray Peat · Article · 2012 · https://raypeat.com/articles/articles/osteoporosis-aging.shtml

> Prolactin, like estrogen, interferes with thyroid function and oxygen consumption (Wade, et al., 1986; Strizhkov, 1991; Spatling, et al., 1982). Many years ago, repeated lactation was considered to cause osteoporosis and loss of teeth, and prolactin, which mobilizes calcium from bones for the production of milk, was recognized as an important factor in bone loss. Drugs that increase prolactin were found to cause osteoporosis. In the 40 years since the drug industry began its intense promotion of estrogen to prevent and treat osteoporosis, there has been very little attention to the fact that estrogen increases prolactin, which contributes to osteoporosis, but some people (e.g., Horner, 2009) have noticed that oral contraceptives and menopausal hormone treatments have damaged the bones of the inner ear, causing otosclerosis and impaired hearing, and have suggested that prolactin mediates the effect.
>
> A few years ago, the "serotonin reuptake inhibitor" antidepressants, already known to increase prolactin by increasing the effects of serotonin, were found to be causing osteoporosis after prolonged use. Estrogen increases serotonin, which besides promoting the secretion of prolactin, also stimulates the production of parathyroid hormone and cortisol, both of which remove calcium from bone, and contribute to the calcification of blood vessels. The association between weakened bones and hardened arteries is now widely recognized, but researchers are being careful to avoid investigating any mechanisms that could affect sales of important drug products, especially estrogen and antidepressants.
>
> Following the recognition that the SSRI drugs were causing osteoporosis, it was discovered that the serotonin produced in the intestine causes bone loss, and that inhibiting intestinal serotonin synthesis would stop bone loss and produce a bone building anabolic effect (Inose, et al., 2011). One group that had been concentrating on the interactions of genes commented that, recognizing the effects of intestinal serotonin, they had suddenly become aware of "whole organism physiology" (Karsenty and Gershon, 2011).
>
> In previous newsletters I have talked about the ability of intestinal irritation and the associated increase of serotonin to cause headaches, asthma, coughing, heart and blood vessel disease, muscular dystrophy, flu-like symptoms, arthritis, inflammation of muscles and nerves, depression, and inflammatory brain diseases.

### Source 4 — 10. Reversing Hair Loss In Men and Women | Danny Roddy

Danny Roddy · Interview · Sep 22, 2021

> **Danny Roddy:** I have a paper that said like women with kind of like bad fathers tended to have hyperprolactinemia, you know? And so again, that could speak to stressful events that happened in our lifetime and causing kind of a lifelong trajectory of higher stress hormones and things like that. But where was I going with that? Anyways, prolactin has been studied in its relation to the cycling of the hair follicle. I think it terminates the antigen phase and shifts it into the catagen and then telogen phase. And so again, this hasn't been fully explored. You know, you have to pick up pieces here and there from it, but it's clearly something that rises in stress. It's clearly something that rises in old age. And for what it's worth, you know, almost everybody I've talked to in, I don't know, the last like five more plus years always has a prolactin of at least around 10 and usually higher than that. And so I think even 10 is, it will be in within a normal reference range, but that doesn't mean much. I think 10 is probably too high. And you can find old papers would say the mean average for a man or a woman is about five. And so again, it's not to say everything rests on that specific hormone test because these things are always fluctuating, but that's an interesting hormone to test as a measure of stress, especially if a person is losing hair.

### Source 5 — One Radio Network: Ray Peat with Patrick Timpone — July 18, 2022

Ray Peat · Interview · Jul 18, 2022

> **Patrick Timpone:** Well, well, very pleasant good morning to you. Welcome to part two of our little show today on the third Monday of the month. We have the pleasure of following Dr. Massey, is having Dr. Ray Peat on. He's kind of a legend in nutrition, Ph.D., biology, University of Oregon, specializing in physiology. He taught schools all around. He was in Mexico for a long time. He started his work with progesterone. and related hormones in 1968. Wow, that's a year I started radio, 1968. Dr. Ray Peete was doing hormones and I was playing Frank Sinatra records. 1978, Dr. Peat. You and I have been around a little bit. Good morning.
>
> **Ray Peat:** Yeah.
>
> **Patrick Timpone:** Nice to have you here. How are you?
>
> **Ray Peat:** Just about the same as you. I finished my dissertation related to estrogen metabolism. The news was that there was a tremendous pituitary tumor development of tumors with excess production of prolactin.
>
> **Patrick Timpone:** Yeah, you heard us talking about prolactin.

### Source 6 — Blocking Tissue Destruction

Ray Peat · Article · 2006

> Prolactin (which is promoted by estrogen, and inhibited by progesterone) increases with stress and with age. It probably affects every tissue, but it seems to have its greatest effects on the secretory membranes. It is known to have strong effects on the kidney, gut and skin (sweat and oil glands, hair follicles, and feathers in birds), and on the gills of fish. Its involvement with milk production suggests that it might mobilize calcium from bones, and in fact it does contribute to osteoporosis. This was foreseen by G. Bourne, in his book on the metabolism of hard tissues, when he suggested that estrogen, acting through the pituitary, might be expected to promote osteoporosis.
>
> Since reading Bourne's book, I have doubted that it was rational to use estrogen to prevent osteoporosis, especially when it is known to be carcinogenic and when the ratio of estrogen to androgens and progesterone increases after menopause. Now that several publications have appeared clearly showing that estrogen increases prolactin, that prolactin increases with cancellous bone; adrenal androgens. Thyroid rate of formation, overall metabolic rate.
>
> ## Arthritis and Natural Hormones
>
> A very healthy 71 year-old man was under his house repairing the foundation, when a support slipped and let the house fall far enough to break some facial bones. During his recovery, he developed arthritis in his hands. It is fairly common for arthritis to appear shortly after an accident, a shock, or surgery, and Han Selye's famous work with rats shows that when stress exhausts the adrenal glands (so they are unable to produce normal amounts of cortisone and related steroid hormones), arthritis and other degenerative diseases are likely to develop.
>
> But when this man went to his doctor to get something for his arthritis, he was annoyed that the doctor insisted on giving him a complete physical exam, and wouldn't give him a shot of cortisone. The examination showed low thyroid function, and the doctor prescribed a supplement of thyroid extract, explaining that arthritis is one of the many symptoms of hypothyroidism. The patient agreed to take the thyroid, but for several days he grumbled about the doctor fixing something that wasn't wrong with him, and ignoring his arthritis. But in less than two weeks, the arthritis had entirely disappeared. He lived to be 89, without a recurrence of arthritis.

### Source 7 — Prolactin receptor antagonist cures baldness and reverses hair graying

Georgi Dinkov · Article · May 24, 2026 · https://haidut.me/?p=3063

> For decades, mainstream medicine has promoted the absurd idea that dihydrotestosterone (DHT) is the primary driver of male pattern baldness. This has led to a multi-billion dollar industry of anti-androgenic drugs (finasteride, dutasteride) that come with devastating side effects: sexual dysfunction, depression, and even persistent post-finasteride syndrome. Ray has long pointed out the glaring logical flaw in this hypothesis: if DHT caused baldness, then young males — whose testosterone and DHT levels are highest — would have the highest rates of baldness. Instead, balding increases with age as androgen levels decline. Ray framed the issue in bioenergetic terms: prolactin — a stress hormone that rises with age, estrogen dominance, and endotoxin — is a potent metabolic inhibitor that drives hair loss and graying. Ray even pointed out that prolactin is a “molting” hormone in insects and that this process is analogous to balding in humans. This view by Ray has already been corroborated several times at the level of greying. Anti-prolactin drugs of the ergot class (e.g. bromoctiptine) have been shown to reverse even advanced staged of hair graying. The article below describes a new AI-designed drug, ABS-201, which targets the prolactin receptor. In preclinical trials, it completely reversed balding and even reversed graying in macaques. This is a direct validation of the bioenergetic view.
>
> As the article below demonstrates, Absci has developed ABS-201, a prolactin receptor antagonist that shunts dormant hair follicles back into the anagen (growth) phase. In preclinical trials on macaques (primates that experience balding like humans), six months after treatment, the macaques had their full heads of hair again. In mice, ABS-201 resulted in full hair regrowth after 22 days, whereas minoxidil only produced hair growth in one-third of the mice. Remarkably, the drug also reversed premature graying — the monkeys’ hair changed back from gray to black.
>
> This finding directly corroborates what Ray (and to a much lesser degree) I have said for years:
>
> - Prolactin is a potent metabolic inhibitor. It suppresses mitochondrial function, increases oxidative stress, promotes fibrosis, and interferes with thyroid hormone action — all of which damage hair follicles.

### Source 8 — Animal-based vs. Ray Peat diet, a conversation with Georgi Dinkov

Georgi Dinkov · Interview · Dec 20, 2022 · https://www.youtube.com/watch?v=9ZM9sCfmAGc

> **Paul Saladino MD:** The lab work I just did, they said the upper limit was 13 or something. Mine was seven. I think that's good.
>
> **Georgi Dinkov:** Basically, you want to be at the bottom 50th percentile because that's actually historically will put you to where most of the healthy male prolactin was. I think for females, they give several ranges depending on which part of the cycle they are, whether they're pregnant, menopausal and whatnot. But again, if they give you a cycle for a female or a male that says like, oh, you're in this stage of your life, so production should be higher. No. It's like saying cortisol. Oh, you are older. So cortisol should be like two times what is for a young person. No. Cortisol has pro-aging effects. In fact. I think a human and animal study show that you can reproduce all of the phenotype of all of the signs of aging external by administering a very high dose of cortisol for a prolonged period of time. So cortisol is most certainly pro-aging hormone. It's just there for like, it's acute management. If somebody's chasing you, right, something is endangering you, you need to produce a lot of energy. And it doesn't matter if you're going to, you know, shred a little muscle. The idea is that you will stop anyway. So the product, yes, if the upper limit is 13, I think something like seven is great. In the U.S., the range that LabCorp and Quest report, the upper range for males was recently raised to 22. Used to be 18, maybe like three or four years ago. Before it used to be 16. So now it's like 22. 22 is, I mean, not a good number. I would say if you have to be below, in my opinion, below 15 to be like in a decent health. And several studies show that men who have prolactin over 15, but still in range, complain of sexual dysfunction. And conversely, anti-prolactin, just like bromocriptine, are very commonly used to treat sexual dysfunction in males who do not have any other endocrine problem, like a low testosterone or anything like that.

### Source 9 — Antihistamines for Male Pattern Baldness?

Danny Roddy · Video Transcript · May 10, 2016 · https://www.youtube.com/watch?v=f5d-Le0oyTQ

> Prolactin responds readily to cycles of light and darkness, temperature, nutrition, stress, and the feeding rhythm. An excess of prolactin is associated with the development of pattern baldness in both sexes. One way prolactin exerts a negative effect on hair is by reducing the intracellular level of cyclic AMP or CAMP, a secondary regulatory substance that is associated with normal cellular differentiation and function in hair growth. Prolactin also activates the enzyme that liberates arachidonic acid from cells for prostaglandin production. Moreover, alterations in mood can sometimes be attributed to higher prolactin levels and might be another aspect of the so-called balding personality that I have mentioned previously. Prolactin tends to rise with another adaptive hormone that activates mast cells, parathyroid hormone. Both parathyroid hormone and prolactin decrease the concentration of carbon dioxide, which helps stabilize mast cells. Thyroid hormone is the master regulator of carbon dioxide and in sufficient quantities, carbon dioxide inhibits an excess of both prolactin and parathyroid hormone. My perennial argument for the last few years has been that pattern hair loss means that something is wrong. A non-technical way of viewing the problem might be that the balding person is perpetually experiencing the effects of a winter metabolism. or a chronic light deficiency, lower vitamin D level, higher local levels of estrogen, histamine, cortisol and prolactin, some degree of insulin resistance, hypertension, higher circulating free fatty acids, higher levels of the inflammatory prostaglandins, deranged calcium metabolism and a reduced resting pulse rate and body temperature. Another way of looking at those facts is that red light, thyroid, calcium, vitamins D, K2, and A, sugars, salt, aspirin, caffeine, niacinamide, and maybe even a small dose of an antihistamine drug like ciproheptadine would be simple, cheap, and effective therapies for protection against the inflammation, fibrosis, and maladaptive stress reactions associated with pattern baldness. The heavy focus on androgen hormones and the genes as causes of baldness have led people to believe that pattern hair loss is a compartmentalized problem rooted in vanity that has nothing to do with their metabolism or lifestyle.

### Source 10 — A Bioenergetic View of Weight Loss [Generative Energy #9]

Danny Roddy · Interview · Oct 16, 2015 · https://www.youtube.com/watch?v=3OhCZ5YEou8

> **Danny Roddy:** I had a gentleman email me and he said his physician wouldn't order prolactin because he wasn't an ovulating female.
>
> **Georgi Dinkov:** Yeah, that's the problem. I also talked to my doctor about it too and he had to find a reason to order a prolactin test and couldn't because I didn't have any of the symptoms of hyperprolactinemia. So eventually I ended up paying for the test myself just because I wanted it. And he told me that, first of all, there's very little discussion on prolactin and its effects in males. So when most doctors go to medical school, there's very little discussion about that. And it's usually, if there is at all, it's in the context of prolactin producing adenomas. So in other words, it's a benign tumor of the pituitary gland. And those conditions are relatively rare. But in terms of how prolactin is elevated in a number of chronic diseases and how it is associated with a number of cancers in males, specifically prostate and lung cancer, whenever I told him about this, he said it's the first time he hears about it. He only knew about prolactin in the context of pituitary tumors. And it's a shame because prolactin is just as important to females as it is to males. It's a very good marker of stress and pathology in general.

### Source 11 — A Bioenergetic View of Weight Loss [Generative Energy #9]

Danny Roddy · Interview · Oct 16, 2015 · https://www.youtube.com/watch?v=3OhCZ5YEou8

> **Danny Roddy:** In the first episode, we talked about the liberation of fat and then the fatty acids being synthesized into prostaglandins and prostaglandins are estrogenic and they increase the activity of aromatase and then estrogen increases the activity of prolactin. Why should people care about prolactin and what's the use of measuring it?
>
> **Georgi Dinkov:** Basically, prolactin is acutely elevated due to stress. It's also chronically elevated in virtually all chronic diseases. And prolactin is a very good marker for tissue estrogenic activity, unlike blood estrogens, which are known to vary from person to person. And sometimes they've been found to be inversely correlated with the activity of the enzyme aromatase and the total amount of estrogens in the body. And this seems to be especially true in females. And there are a few studies out there that basically try to determine when are blood tests for hormones reliable. And they found that they're almost never reliable. unless you're willing to do a biopsy, right, which is not a blood test, a muscle tissue or some other tissue being cut out of you and analyzed. If you're using blood tests for steroids, they're almost never reliable unless there is a pathological condition like adrenal hyperplasia or some kind of adrenal mass or tumor that produces so much hormone that it spills out into the blood. In other words, you only detect extremely pathological conditions. But for most people, they're actually surrogates of estrogenic activity. And it seems like the best surrogate so far for the activity of both the enzyme aromatase, the total amount of estrogen in the tissues, and also serotonin. The best surrogate so far seems to be prolactin. Its correlation coefficient with estrogen in tissues is over 0.9, one being a perfect one, right? So you see it's fairly close. And with serotonin, it's 0.87. So it's still pretty close. And levels of prolactin in the blood seem to be perfectly correlated with levels of prolactin in the brain. And this has been confirmed both with animal and human autopsies. So it's a test that can be easily ordered by a doctor and it will tell you several things. I would say prolactin is a very good indication of how much stress you are under. and how well your metabolism is working. If prolactin is high, you're not healthy.

_Generated 2026-07-20 from the Bioenergetic Oracle corpus._