CPA (시프로테론 아세테이트)

抗雄激素 A

Cyproterone Acetate (Androcur)

Cyproterone Acetate (CPA)

Oral

Cyproterone Acetate (CPA, heavily branded as Androcur) is genuinely one of the most widely used anti-androgens in global transgender medical pathways (outside the US). At exceedingly low doses (5-12.5 mg/day), it crushes testosterone flawlessly and is heavily recommended by Endocrine Society 2017 and WPATH SOC 8 guidelines. However, if improperly dosed, it carries catastrophic tumor risks.

50 mg is a Severe Overdose

Outdated community regimens and incompetent doctors frequently prescribe CPA at 50 mg/day or even 100 mg/day. These absolute mega-doses were designed for men fighting advanced prostate cancer, not for gender-affirming hormone therapy (GAHT). Clinical studies irrefutably prove that a mere 5-12.5 mg/day is entirely sufficient to suppress T into the female baseline ^[1] . Taking 50 mg does not suppress your T any faster; it simply skyrockets your risk of brain tumors, liver toxicity, and severe clinical depression. If you are taking 50 mg right now, immediately cut your dose.

Pharmacology

The Mechanism

CPA destroys testosterone through a multi-pronged assault ^[2] :

1. The Progestin Feedback Loop (Primary): As an overwhelmingly powerful progestogen, CPA tricks the hypothalamus into halting the release of GnRH. This stops the pituitary gland from signaling your testicles, flatlining testosterone synthesis entirely.
2. Mild Receptor Antagonism: It mildly blocks whatever testosterone remains from binding to your cell receptors (though this effect is frail compared to Bicalutamide).
3. 5α-reductase Sabotage: It mildly hinders T from converting to DHT.

In GAHT, CPA drops your testosterone by shutting down the manufacturing plant entirely ^[1] . Your blood tests will actually show a crashed T level.

Low-Dose Efficacy

Countless cohorts prove that low-dose CPA runs circles around the high-dose myth ^{[1] [3]} :

• 10 mg/day routinely drops T beneath the 50 ng/dL female threshold.
• 5 mg/day is frequently enough when operated alongside a proper estrogen dose.
• Cranking the dose up to 50 mg/day yields no additional drop in T.

Dosage Recommendations

Protocol	Dose	Notes	Sourcing
Recommended Start	5 mg/day OR 12.5 mg/every other day	The standard low dose when paired with E2.	Meyer 2020; WPATH SOC 8
Common Maintenance	5-12.5 mg/day	Adjust based on your T labs.	ES 2017
The Absolute Ceiling	12.5 mg/day	Any dose pushing ≥25 mg triggers explosive tumor risks.	Lee 2022; EMA 2020

How to Take 12.5 mg

Because Big Pharma produces CPA for prostate cancer, the pills almost always come in massive 50 mg tablets. You must buy a pill cutter and slice the pill into quarters. Taking one quarter (12.5 mg) daily, or even one quarter every other day (averaging ~6.25 mg/day), is the safest and most effective method.

Step-Down Protocol

If you are currently taking 50 mg/day and need to fix it ^[3] :

• Drop to 25 mg: Hold here for 2 weeks to let your body adjust without aggressive T spikes.
• Drop to 12.5 mg: Hold here for 2 weeks.
• Verify through bloodwork at the 3-month mark. Do not lower your estrogen while stepping down the CPA.

The Meningioma Risk

Meningioma — CPA's Most Lethal Threat

Prolonged exposure to CPA at doses of ≥ 25 mg/day is irrefutably linked to triggering Meningiomas (mostly benign, but highly dangerous tumors growing on the membranes of your brain and spinal cord) ^[4] :

• Taking ≥ 25 mg/day for over a year spikes your odds of developing a brain tumor roughly 12 times higher than normal.
• A sweeping cohort study in 2026 fully cemented this crisis specifically within transgender women ^[5] .
• Because of this, the European Medicines Agency (EMA) issued heavy legal restrictions in 2020, demanding doctors only prescribe CPA at high doses when literally no other option exists ^[6] .

The Warning Signs: If you suffer from relentless worsening headaches, blurry/double vision, or spontaneous seizures while on CPA, stop the drug instantly and demand a cranial MRI.

Additional Side Effects

Liver Toxicity

CPA stresses the liver ^[2] :

• Rare at 12.5mg, but monitoring is mandatory.
• If your liver enzymes (ALT/AST) spike to > 3x the upper limit of normal, you must abandon CPA.

Prolactin Spikes

Because CPA is intensely progestogenic, it can cause your pituitary gland to flood your body with prolactin ^[1] :

• Mild elevation is normal and harmless.
• If prolactin breaches > 50 ng/mL, your doctor must scan you to rule out a prolactinoma (a benign pituitary tumor).

Clinical Depression

As a heavy progestin, CPA has documented psychological side-effects ^[3] :

• Severe fatigue, listlessness, and depressive episodes are heavily reported.
• If you have preexisting manic-depression or severe clinical depression, CPA is a highly risky gamble.

VTE (Blood Clots)

CPA inherently increases your blood’s ability to clot ^[7] . Stacking oral CPA with oral Estrogen creates a terribly dangerous compounding effect. Users on CPA should forcefully migrate toward Transdermal Estrogen (patches or gel).

Mandatory Blood Monitoring

Test Panel	Frequency	Target Range / Warning	Action Needed
Liver Enzymes (ALT/AST)	Month 1, 2, 3 → Then every 3-6 months	Keep within standard lab ranges	If > 3x the max limit: Stop drug.
Prolactin (PRL)	Baseline, then every 6 months	PRL < 50 ng/mL	If > 50 ng/mL: Scan pituitary.
Testosterone (T)	Month 1, then every 3-6 months	T < 50 ng/dL	If stable, stay at low dose.

Quitting Cold Turkey

Unlike estrogen (which you must cautiously taper down to prevent bone loss/psychological ruin), the progestin half-life of CPA clears out rapidly. If you suffer acute liver or tumor symptoms, you can absolutely drop CPA cold turkey. Your testosterone will slowly reboot, so you must secure a replacement blocker rapidly ^[2] .

Global Access & The FDA Ban

• In the United States: CPA is heavily banned by the FDA and absolutely unreachable through legitimate pharmacies, forcing American trans women to rely on Spironolactone.
• In Europe/UK/Australia/Asia: Widely prescribed and perfectly legal, serving as the infrastructural backbone for non-US trans healthcare.
• The Grey Market: DIY groups globally smuggle CPA across borders in staggering quantities. If you are ordering CPA from unregulated international pharmacies, you run the risk of tampered or deeply expired medications. Proceed with absolute caution.

品牌图鉴

🇩🇪德国

Androcur

厂商

拜耳 (Bayer)

规格

50mg × 20片

外观

白色圆形片，一面有十字刻痕（可四分）

原研 CPA，十字刻痕方便切为 12.5mg 使用

🇹🇼台湾

色谱龙 Androcur

厂商

拜耳 (Bayer Taiwan)

规格

50mg × 20片

外观

白色圆形片，十字刻痕

台湾版，中文圈最常见来源之一

🇮🇳印度

Androcur

厂商

Zydus (拜耳印度授权)

规格

50mg × 10片

外观

白色圆形片

印度产 CPA，价格显著低于欧洲/台湾版

🇮🇳印度

Cypotero

厂商

多种印度仿制药厂

规格

50mg

外观

白色圆形片

印度仿制 CPA，确认厂商资质后可用

🇳🇿新西兰

Siterone

厂商

AFT Pharmaceuticals

规格

50mg / 100mg

外观

白色圆形片

新西兰产，部分经印度渠道流通

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