Progesterone

Progesterone
Abbreviation	P4
Molecular formula	C₂₁H₃₀O₂
Type	Steroid hormone (progestogen)
Administration	Oral (dissolved in vitamin E/tocopherol), topical, sublingual, suppository, injection
Bioavailability	Oral in tocopherol: ~100% (lymphatic absorption); Oral micronized powder: ~10% (highly variable); Suppositories: ~1-6%; Topical: ???
Synonyms	P4, corpus luteum hormone, luteohormone, progestin (generic class)
Source	Endogenous: ovaries, adrenals, brain, placenta; Exogenous: synthesized from wild yam (Dioscorea), soybeans, fenugreek, Progest-E,
Ray's verdict	"The most protective hormone the body produces"

Introduction

Progesterone is a key protective steroid hormone emphasized in Ray Peat's work as essential for stress resistance, metabolic balance, and countering estrogen's potentially harmful effects, it supports cellular energy production and protects tissues, especially the brain. Produced primarily by the ovaries in women (and adrenals/brain in both sexes), it acts as a precursor to other hormones like cortisol, aldosterone, and testosterone, while opposing excess estrogen to prevent issues like osteoporosis, cancer susceptibility, and aging. Peat describes it as the "basic hormone of adaptation," with over 500 physiological functions, including brain protection, improved respiration, bone growth, and anxiety relief. Unlike synthetic progestins used in birth control, natural progesterone supports natural hormone production without blocking luteinizing hormone (LH) or causing unnatural side effects.

Progesterone, not estrogen is the main female hormone.

History/Ethymology

German Progesteron, which had been coined 1930 from pro + Latin gestare, literally "to carry about, on notion of "substance which favors gestation.

Structure/Chemical properties

Natural vs. synthetic Progesterone

Natural progesterone, derived from plant sources like wild yams and dissolved in vitamin E for efficient absorption, mimics the body's own hormone and is rapidly metabolized. It enters the bloodstream quickly upon oral contact (e.g., sublingually) and supports over 500 functions, including anti-stress effects and glandular restoration.

Synthetic progestins (e.g., in birth control pills) bind to progesterone receptors but have an unnaturally long half-life, and block natural LH and progesterone production. They offer limited function, often unrelated to true progesterone, such as thinning the uterine lining, and can lead to health risks like cervical thickening and cancer. Ray warned against the synthetic derivatives, and advocated for bioidentical natural forms for safety and efficacy.

Function/Mechanism of action

Its effects are systemically opposite to estrogen, balancing excitation and relaxation in the body.

Medical uses/Effects

Benefits

Progesterone is regenerative and anti-estrogenic:

• Reduces cortisol production, prevents osteoporosis, skin aging, brain damage, and abdominal fat.
• Protects against epileptic seizures, improves memory and respiration (e.g., for emphysema), and enhances heart efficiency.
• Promotes bone growth, relieves arthritic symptoms, and supports immunity via the thymus gland.
• Opposes estrogen's carcinogenicity, and is used to treat some cancers and alleviate menopausal symptoms like hot flashes without needing estrogen.
• In men, it complements testosterone, improves sexual function in deficiencies and provides broader protective effects than testosterone alone.
• High brain concentrations make it neuroprotective, and adequate levels (via diet and thyroid support) reduce the need for supplementation.

Hormone	Effect on Cells	Nitric Oxide	Water State in Cells	Systemic Action
Progesterone	Calms, protects, orders water	Lowers	Stabilizes ordered water	Anti-stress, protective
Estrogen	Excites, activates cells	Increases	Releases water from proteins	Stimulating, excitatory

Progesterone increases intelligence of children when given to pregnant mothers.

Dosing

Dosing guidelines

Dosing varies by sex, age, and symptoms; start low (e.g., 10 mg) and adjust based on response. Use bioidentical progesterone in vitamin E (e.g., Progest-E, ~3 mg/drop), combined with a moderate-protein diet (70-100 g/day), vitamin A, and thyroid support to minimize possible deficiencies. High estrogen levels can block progesterone’s effectiveness, requiring liver and thyroid support to restore balance. Consult a practitioner for more personally catered advice.

Women

• Reproductive Age (with PMS or imbalance): 10-15 mg/day (3-4 drops) during the 14-28 days of the cycle.
• Perimenopausal: 10-12 mg/day (3-4 drops), cycled two weeks on/off to sustain the natural rhythm of the monthly cycles.
• Postmenopausal: 10 mg/day (2-3 drops, repeatable); slender women may need less.

General: Repeat doses as needed for symptom relief; normal production is 10-20 mg/day (up to 30 mg in luteal phase).

Supplementation during the menstrual cycle

Supplement progesterone primarily in the luteal phase (post-ovulation, days 14-28) to mimic natural production and alleviate PMS, cramps, or estrogen dominance. Start 2 days after ovulation (around day 16) until day 1 of menses. Cyclic use (two weeks on/off) maintains normal cycles in perimenopause.Avoid continuous use to prevent cycle suppression; a drop in levels triggers menstruation.

The chart below illustrates typical hormone fluctuations over a 28-day cycle, highlighting the progesterone supplementation window (shaded luteal phase).

Note: Values are approximate averages; individual levels vary. Test via blood/saliva for precision.

Men

Men produce ~0.1-1.2 ng/ml naturally; supplement for estrogen excess or stress.

Low doses (e.g., 5-10 mg/day) improve sexual function and produce anti-stress effects without feminization.

Ray confirms progesterone can be used in men.

Start with 1-2 drops (3-6 mg) daily, and can increased to 10 mg as long as androgen suppression doesn't occur. If the latter does occur, stopping the supplementation will reverse the symptoms within a few days.

Side/adverse effects

Warnings

• High doses (> several grams) may cause euphoria or anesthesia; titrate slowly (10 mg increments, wait 10 min).
• May temporarily increase thyroid activity by releasing the stored colloid, a pocket of thyroid hormones inhibited by estrogen; address to reduce the goiter or colloid size with a thyroid supplement first.
• In estrogen dominance, correct the imbalance via diet/pregnenolone/thyroid first before supplementing since the liver's inability to quickly excrete the tissue-bound estrogen may result in high estrogen symptoms.
• Not indefinite unless ovaries removed; monitor for "estrogen kickback" symptoms and adjust.

In males overdose might cause temporary androgen suppression (even ED)

Hans Selye's "wet rag" rat in her progesterone-induced deep sleep, who was mistakenly thought to have died.