Short answer: both work, in different ways that matter. Nolvadex (tamoxifen) and Clomid (clomiphene) are both SERMs: they block estrogen’s feedback in the brain, so LH, FSH and testosterone go up. Tamoxifen has strong trial evidence for preventing drug-induced gynecomastia and lasts for days; clomiphene has more data on raising testosterone in men with low levels but tends to raise estradiol and carries a visual-symptom warning. Neither has been tested in a trial for recovery after SARMs, so claims about which is “best for PCT” rest on mechanism and experience, not trials.
Nolvadex vs Clomid at a glance
| Tamoxifen | Clomiphene | |
|---|---|---|
| What it is | Selective estrogen receptor modulator (SERM) | Selective estrogen receptor modulator (SERM); a mixture of two isomers, enclomiphene (trans) and zuclomiphene (cis) |
| Approval | Approved (FDA 1977, Nolvadex) for breast cancer in women and men | Approved (FDA 1967) for ovulatory dysfunction in women; off-label in men |
| Human studies (counted in our records) | 2342 | 815 |
| Half-life | ~5–7 days (tamoxifen); ~14 days (N-desmethyltamoxifen, main active metabolite) | No single value: enclomiphene part ~5–10 h; zuclomiphene part ~24 h with a very long tail (detectable for over a month) |
| Testosterone suppression score | 0/3 | 0/3 |
| Liver risk score | 1/3 | 1/3 |
| Evidence score | 2/3 | 2/3 |
| WADA | Prohibited at all times (in and out of competition) (S4.2 Anti-estrogenic substances) | Prohibited at all times (in and out of competition) (S4.2 Anti-estrogenic substances) |
| Gynecomastia evidence | Strong: meta-analysis of 9 RCTs (RR 0.18) | Not a gyno treatment; estradiol rises |
| Effect on IGF-1 | Lowers it (−25% in healthy men) | Not a major effect reported |
| SwissChems product | Tamoxifen (20mg/capsule), 60 Capsules | Clomiphene, 1500mg (25mg/capsule) |
Scores run from 0 (none) to 3 (high); see our methodology. Data from the SARMs database.
Source: Sarmguide compound database; Tamoxifen value: Tamoxifen citrate tablets – prescribing information (DailyMed, Mylan) (2026).
How they work
Both block estrogen receptors in the hypothalamus and pituitary, which takes the brake off LH and FSH. In healthy men, 2 weeks of tamoxifen raised testosterone about 40% and LH about 70%; clomiphene at 50 mg/day for 30 days more than doubled testosterone and LH. They differ elsewhere in the body: tamoxifen blocks estrogen in breast tissue, which is why it prevents gynecomastia, and it lowers IGF-1 and raises SHBG. Clomiphene raises estradiol along with testosterone.
What the trials show in men
| Evidence | Tamoxifen (Nolvadex) | Clomiphene (Clomid) |
|---|---|---|
| Raises LH, FSH, testosterone | Yes: healthy men, subfertile men | Yes: meta-analysis of 19 studies, 1,642 hypogonadal men |
| Gynecomastia | Prevented it in men on bicalutamide: 10% vs 73% placebo (and 51% on anastrozole); a 2025 meta-analysis of 9 RCTs found an 82% risk reduction | No; estradiol and breast tenderness can rise |
| Compared with testosterone gel | Not studied | Similar testosterone, lower libido scores |
| Long-term data in men | Mainly cancer and infertility; fewer than 5% of men stopped for side effects in a review | Studies of 1–3+ years in hypogonadal men |
| PCT after steroids or SARMs | No trial; reviews call PCT evidence limited and mostly observational | No trial; observational data only |
Side effects
| Tamoxifen | Clomiphene |
|---|---|
| Blood clots and stroke: more thromboembolic events in trials; boxed warning in the risk-reduction setting | Visual symptoms (blurring, spots, flashes): label warning; usually reversible |
| Loss of libido and impotence led some men to stop (label) | Mood changes and breast tenderness in long-term male users |
| Hot flushes at doses of 5 mg/day or more (men on bicalutamide) | Estradiol rises; HDL fell in one trial |
| Liver enzyme changes; rare fatty liver or hepatitis | Raised liver enzymes in post-marketing reports |
| Eye changes (cataract, retinopathy) in label data | PSA and hematocrit unchanged in a year-long study |
Half-life
Tamoxifen’s half-life is about 5–7 days, and its main active metabolite, N-desmethyltamoxifen, about 14 days; steady state takes about 4 weeks. Clomiphene has no single half-life: its enclomiphene part clears in about 5–10 hours, while zuclomiphene stays detectable for over a month. Both linger, which matters for testing in sport.
Which is used for PCT after SARMs?
Both are used off-label for post-cycle therapy, often by people trying to restart LH and FSH after SARM suppression. No trial has tested either for this. In men recovering after anabolic steroids, most had testosterone back within 3 months without treatment, and post-cycle therapy has only been linked to faster recovery in observational data. If gynecomastia is the concern, tamoxifen is the one with trial evidence. We do not give PCT protocols; see SARMs PCT, the PCT and bloodwork planner, Nolvadex PCT and Clomid PCT. Enclomiphene, the single-isomer version of clomiphene, is compared in enclomiphene vs clomiphene.
Legal status and sport
Both are prescription medicines: tamoxifen was approved in 1977 (Nolvadex) for breast cancer, clomiphene in 1967 (Clomid) for ovulation problems in women; use in men for hormone recovery is off-label. Both are banned in sport at all times under WADA S4.2 (anti-estrogenic substances) and are specified substances.
Verdict
For raising testosterone, both work, and clomiphene has more data in hypogonadal men. For gynecomastia, tamoxifen is clearly better supported. Tamoxifen’s main risks are blood clots and, in men, libido loss; clomiphene’s are visual symptoms and higher estradiol. Neither has been tested for PCT after SARMs. For estrogen control without a SERM, see anastrozole vs tamoxifen.
Frequently asked questions
Is Nolvadex or Clomid better for PCT?
Unknown; neither tested for PCTEvidence: Limited
Neither has been tested in a trial for PCT after SARMs or steroids; both raise LH, FSH and testosterone. Tamoxifen has strong evidence against gynecomastia, while clomiphene has more data on raising testosterone in hypogonadal men.
What is the difference between Nolvadex and Clomid?
Two SERMs that act differentlyEvidence: Human data
Nolvadex is tamoxifen and Clomid is clomiphene; both are SERMs. Tamoxifen blocks estrogen in breast tissue and lasts for days, while clomiphene is a mix of two isomers and tends to raise estradiol.
Does Nolvadex prevent gyno?
Yes, in drug-induced gynoEvidence: Trial
In men on the anti-androgen bicalutamide, tamoxifen cut gynecomastia to 10% vs 73% on placebo, and a meta-analysis of 9 trials found an 82% risk reduction. It has not been tested for SARM-related gyno.
Can you take Nolvadex and Clomid together?
Not tested togetherEvidence: Limited
Some people combine them, but no trial has tested the combination in men after SARMs or steroids.
What are the side effects of Nolvadex in men?
Clots, libido lossEvidence: Law
The label notes more blood clots, and loss of libido and impotence led some men to stop. Hot flushes, liver enzyme changes and eye changes are also listed.
What are the side effects of Clomid in men?
Visual symptoms, higher estradiolEvidence: Law
Visual symptoms (blurring, spots, flashes) are the label warning and are usually reversible. Mood changes, breast tenderness and higher estradiol are also reported.
How long do Nolvadex and Clomid stay in your system?
Days to over a monthEvidence: Human data
Tamoxifen's half-life is about 5–7 days, and its main metabolite's about 14 days. Clomiphene's zuclomiphene part stays detectable for over a month.
Are Nolvadex and Clomid banned in sport?
Yes, banned by WADAEvidence: Law
Both are under WADA S4.2 (anti-estrogenic substances), prohibited at all times.
Sources
- Evaluation of tamoxifen and anastrozole in the prevention of gynecomastia and breast pain induced by bicalutamide monotherapy of prostate cancer
- Tamoxifen as prophylaxis for prevention of gynaecomastia and breast pain associated with bicalutamide 150 mg monotherapy in patients with prostate cancer: a randomised, placebo-controlled, dose-response study
- Prevention of bicalutamide-induced breast events in patients with prostate cancer: a meta-analysis of randomized controlled trials
- Neuroendocrine regulation of growth hormone and androgen axes by selective estrogen receptor modulators in healthy men
- The effect of selective estrogen receptor modulator administration on the hypothalamic-pituitary-testicular axis in men with idiopathic oligozoospermia
- Tamoxifen in men: a review of adverse events
- Tamoxifen citrate tablets – prescribing information (DailyMed, Mylan)
- Clomiphene citrate for men with hypogonadism: a systematic review and meta-analysis
- Clomiphene citrate versus testosterone replacement therapy in male hypogonadism: a systematic review of literature and meta-analysis
- Hypothalamic-Pituitary-Testicular Axis Effects and Urinary Detection Following Clomiphene Administration in Males
- Long-Term Safety and Efficacy of Clomiphene Citrate for the Treatment of Hypogonadism
- Effects of clomiphene citrate on male obesity-associated hypogonadism: a randomized, double-blind, placebo-controlled study
- Characterising the safety of clomiphene citrate in male patients through prostate-specific antigen, haematocrit, and testosterone levels
- CLOMID (clomiphene citrate) tablets – prescribing information (DailyMed)
- Disruption and recovery of testicular function during and after androgen abuse: the HAARLEM study
- Factors predicting normalization of reproductive hormones after cessation of anabolic-androgenic steroids in men: a single center retrospective study
- Post-cycle therapy after androgen abuse: a narrative review of mechanisms, evidence, and clinical perspectives
- World Anti-Doping Code International Standard: Prohibited List 2026
