Clomid (Clomiphene)
Clomiphene · Clomid · SERM
SERM that blocks hypothalamic estrogen receptors, boosting LH/FSH; primary PCT agent.
Key takeaways
- Blocks hypothalamic estrogen receptors, raising LH/FSH to restart endogenous testosterone.
- Very long ~5-day half-life; it accumulates, so response lags the first doses.
- Primary PCT agent; that off-label use rests on mechanism and practice, not trials.
- Visual disturbance is a stop signal; higher doses bring mood changes and estradiol elevation.
Overview
What it is
Clomid (clomiphene) is a selective estrogen receptor modulator approved for ovulation induction and used off-label as a primary post-cycle therapy agent in men. It blocks hypothalamic estrogen receptors, removing estradiol's negative feedback, so GnRH pulse amplitude rises and LH/FSH climb, restarting testicular testosterone production.
Pharmacokinetics
The half-life is very long, roughly 5 days, with near-complete oral bioavailability. It accumulates over weeks, so the gonadotropin response lags the first doses and lingers after the last one.
What the evidence says
Decades of fertility trial data support the labeled use, and smaller studies show it raises testosterone in hypogonadal men; PCT use itself rests on mechanism and community practice rather than trials. Side effects at higher or prolonged doses include visual disturbance (a stop signal), mood changes, and elevated estradiol as testosterone recovers. Bloodwork (LH, FSH, total T, estradiol) is what distinguishes recovery from lingering suppression.
Reported dosing protocols
Protocols reported in research literature and clinic/community use — informational context, not a dosing recommendation.
| Use case | Dose | Route | Frequency | Duration |
|---|---|---|---|---|
| Ovulation induction (label) | 50 mg | Oral | Once daily × 5 days | One 5-day course per cycle |
| PCT (community) | 25–50 mg | Oral | Once daily | ~4 weeks |
| Male hypogonadism (off-label clinical) | 25 mg | Oral | Daily or every other day | Ongoing, bloodwork-monitored |
Pharmacokinetic summary
- Model tier
- Advanced (t½ + Cmax + Tmax + F)
- Half-life
- 5 days
- Cmax
- 40 ng/mL
- Tmax
- 0.2 days
- Bioavailability
- 95%
- Typical dose
- 25–100 mg
Frequently asked questions
Clomid vs nolvadex for PCT — what's the difference?
Both are SERMs, but clomiphene acts mainly at the hypothalamus to raise LH and FSH, while tamoxifen also blocks breast estrogen receptors. Some protocols combine them; most pick one, since stacking SERMs adds side effects without proven benefit.
Why do visual side effects matter with clomiphene?
Visual disturbance (blurring, spots, after-images) is a known clomiphene effect, more likely at higher or prolonged doses. It's treated as a stop signal because persistence after discontinuation has been reported. Anyone experiencing it needs medical review.
Does clomiphene actually restore natural testosterone?
In hypogonadal men, studies show it raises LH, FSH, and testosterone while fertility is often preserved, unlike TRT. After a suppressive cycle, recovery speed varies and isn't trial-proven; LH, FSH, and total T bloodwork over weeks is the honest measure.
References
- PubMed clomiphene PK
- Clomiphene citrate isomer PK study, J Clin Pharmacol 2009 — Single-dose pharmacokinetics of the clomiphene isomers behind the plotter model.
Related compounds
Nolvadex (Tamoxifen)
SERM used in PCT and on-cycle gynecomastia management. Active metabolite endoxifen.
Estradiol Topical (EstroGel)
Transdermal estradiol for feminizing HRT. Steady low-level delivery.
Estradiol Cypionate
Injectable estradiol cypionate used in feminizing HRT.
Protocols featuring Clomid (Clomiphene)
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