Cycle & PCT Support

What is the difference between an aromatase inhibitor and a SERM?

An aromatase inhibitor (AI) blocks the aromatase enzyme to reduce estrogen production — used on-cycle to control water retention, blood pressure, and gynecomastia risk from aromatizing compounds. A SERM (Selective Estrogen Receptor Modulator) does not lower estrogen; it blocks estrogen receptors in specific tissues. Tamoxifen blocks breast tissue receptors to prevent gynecomastia. Clomiphene blocks pituitary receptors to stimulate LH and FSH for testosterone recovery — making it a PCT compound, not an on-cycle tool. Running a SERM instead of an AI on-cycle does not reduce systemic estrogen or its cardiovascular and water retention effects.

What is the standard PCT protocol after a testosterone cycle?

The standard PCT for a testosterone-only or moderate injectable cycle is Clomiphene (Clomid) 50 mg/day for 4 weeks combined with Tamoxifen (Nolvadex) 20 mg/day for 4–6 weeks. Some protocols run Clomiphene at 100 mg/day for the first two weeks before tapering. For cycles involving nandrolone or trenbolone — which suppress the testosterone axis more deeply — HCG at 500–1000 IU every other day for 2 weeks before SERM-based PCT begins is a standard addition. PCT duration extends to 6–8 weeks for heavier or longer cycles.

When should PCT start after the last injection?

PCT timing is determined by the ester half-life of the last compound used. For long-ester compounds (Enanthate, Cypionate, Decanoate) — start PCT 14 days after the last injection, allowing plasma levels to clear below the suppression threshold. For short-ester compounds (Propionate, Acetate) — start PCT 3–4 days after the last injection. Starting PCT too early while active hormone levels are still present will reduce SERM effectiveness; starting too late extends the period of hypogonadism and slows recovery.

What compounds control prolactin during a steroid cycle?

Cabergoline (Dostinex) is the primary prolactin management compound — it acts as a dopamine agonist at the D2 receptor, suppressing prolactin synthesis in the pituitary. Standard dose is 0.25–0.5 mg twice per week, started when nandrolone or trenbolone use begins rather than reactively after symptoms appear. Bromocriptine is an older alternative with a shorter half-life and more frequent dosing requirements. Prolactin management is specifically relevant for 19-nor compounds (nandrolone, trenbolone) — standard testosterone cycles with well-controlled estrogen do not typically elevate prolactin to symptomatic levels.

Do SARMs require post-cycle therapy?

Suppressive SARMs require PCT — the degree depends on the specific compound and dose. LGD-4033 (Ligandrol) and RAD-140 produce measurable testosterone suppression at standard doses and typically require a 4-week Tamoxifen-only PCT at 20 mg/day. Ostarine at lower doses (10–15 mg) is mildly suppressive and may recover naturally without PCT in shorter cycles. MK-2866 at higher doses or longer cycles benefits from a short Tamoxifen run. Non-suppressive SARMs such as MK-677 do not affect the HPTA and require no PCT.