Progesterone

When LOW (on AAS -- expected):

• Progesterone is suppressed because HPTA shutdown reduces testicular and adrenal steroidogenesis
• Low progesterone on cycle is not a concern requiring treatment
• Progesterone recovery is a useful marker of HPTA restoration during PCT
• No supplementation needed while on AAS

When ELEVATED (from 19-nor compounds):

• Nandrolone (Deca/NPP) and Trenbolone have direct progestogenic receptor activity
• Serum progesterone may or may not be elevated -- 19-nors act at the progesterone receptor directly
• Progestogenic side effects: gynecomastia (synergistic with estrogen), sexual dysfunction, water retention, mood changes

Management of 19-nor progestogenic sides:

• Cabergoline -- 0.25-0.5mg 2x/week (dopamine agonist; prolactin and progesterone-mediated gyno often coexist on 19-nors)
• P5P (active Vitamin B6) -- 50-100mg/day (mild prolactin/progesterone support)
• Control estradiol alongside -- progestogenic gyno is synergistic with elevated E2; manage E2 first
• Tamoxifen -- 10-20mg/day (blocks at the breast tissue receptor; effective for progesterone-related gyno when combined with E2 management)
• If progestogenic sides are severe: reduce 19-nor dose or discontinue the compound

Supplements (supporting recovery in PCT):

• Vitamin B6 (P5P) -- 50-100mg/day
• Zinc -- 30mg/day (supports overall hormonal recovery)
• Vitex (Chasteberry) -- 400mg/day (may modulate progesterone receptor activity; evidence is limited in males)

When to investigate further:

• Elevated progesterone off-cycle without 19-nor use: investigate adrenal function (21-hydroxylase deficiency, adrenal hyperplasia)
• Persistently elevated progesterone with symptoms: endocrinologist referral

References:

• Kanayama, G., Hudson, J. I., & Pope, H. G., Jr. (2008). Long-term psychiatric and medical consequences of anabolic-androgenic steroid abuse. Drug and Alcohol Dependence, 98(1-2), 1-12. DOI: 10.1016/j.drugalcdep.2008.05.004
• Prasad, A. S., Mantzoros, C. S., Beck, F. W. J., Hess, J. W., & Brewer, G. J. (1996). Zinc status and serum testosterone levels of healthy adults. Nutrition, 12(5), 344-348. DOI: 10.1016/S0899-9007(96)80058-X