Spironolactone
Spironolactone is a potassium-sparing aldosterone-receptor antagonist licensed as a diuretic and for heart failure and hypertension, and it is also an anti-androgen. PED users use it for fluid retention and blood-pressure support, but its anti-androgen activity makes it a poor choice for men on cycle. It has strong clinical evidence in its licensed roles.
01 Overview
Spironolactone competitively blocks the mineralocorticoid (aldosterone) receptor in the distal nephron, promoting sodium and water loss while retaining potassium. This gives it a gentler, potassium-sparing diuretic action than loop or thiazide agents and cardiovascular outcome benefit in heart failure (RALES). It also antagonises the androgen receptor and inhibits androgen synthesis.
For PED users the diuretic and blood-pressure effects can help with oestrogen-driven fluid retention, but the anti-androgenic activity directly opposes the goal of a male cycle — reducing libido, encouraging gynaecomastia and blunting androgen effect. It therefore sits awkwardly in a support role for men and is more logically used for water/BP control by those where anti-androgen action is acceptable or desired. Hyperkalaemia is the key safety concern.
02 Mechanism
Competitive aldosterone (mineralocorticoid) receptor antagonist causing potassium-sparing diuresis; additionally antagonises the androgen receptor and inhibits androgen biosynthesis.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Fluid / BP support | 25–50 mg/day | Oral | Anti-androgen activity makes it unsuitable for most men on cycle. |
| Oedema / hypertension (label) | 25–100 mg/day | Oral | Diuretic and antihypertensive dosing. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Potassium-sparing diuresisReduces fluid retention and blood pressure without wasting potassium. | mild-moderate | Clinical | |
| Anti-androgen activityBlocks androgen receptors — undesirable for men on cycle, occasionally exploited for female or feminising use. | significant | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| HyperkalaemiaDangerous rises in serum potassium, potentially causing arrhythmia. | Severe | Common (dose/renal-dependent) | Clinical | |
| Gynaecomastia / low libido (men)Breast tenderness/growth and reduced libido from anti-androgen and mild oestrogenic action. | Moderate | Common in men | Clinical |