Comparison
Clomiphene vs Modafinil
Side-by-side of Clomiphene and Modafinil. Every row below is pulled from the compound schema and will update as our data grows. For deeper reads, follow through to each compound page.
Clomiphene
Clomiphene citrate raises LH/FSH and endogenous testosterone in men. SERM TRT alternative, 25 to 50 mg, fertility preserved, visual side effects flagged.
Modafinil
Modafinil cognitive enhancement profile: wakefulness-promoting agent, 100-200 mg dosing, 12-15 hour half-life, off-label nootropic use, Schedule IV status.
Effects at a glance
Clomiphene
- •SERM that blocks estrogen-receptor negative feedback at the hypothalamus, raising LH and FSH
- •FDA approved 1967 for ovulation induction in anovulatory women at 50 to 100 mg cycle days 5 to 9
- •Off-label in men at 12.5 to 25 mg daily raises endogenous testosterone while preserving fertility
- •Enclomiphene (trans-isomer) is preferred for male use; cleaner PK and less estrogenic side effect burden
- •Visual disturbances occur in ~1 to 2% of users; persistent symptoms warrant immediate cessation
- •Letrozole has displaced clomiphene as first-line ovulation induction in PCOS (Legro 2014)
Modafinil
- •FDA approved in 1998 for narcolepsy, with later additions for shift-work sleep disorder and OSA residual sleepiness
- •Schedule IV controlled substance in the US; prescription-only in EU, UK, Australia
- •Increases wakefulness via weak dopamine reuptake inhibition plus histaminergic, noradrenergic, and orexinergic activation
- •Long half-life of 12 to 15 hours requires morning dosing to avoid sleep disruption
- •Modest cognitive enhancement signal in non-sleep-deprived adults at 100 to 200 mg (Battleday meta-review 2015)
- •Substantial CYP3A4 induction reduces hormonal contraceptive efficacy; barrier methods recommended
Side-by-side
| Attribute | Clomiphene | Modafinil |
|---|---|---|
| Category | pharmaceutical | pharmaceutical |
| Also known as | Clomid, clomiphene citrate, Serophene, enclomiphene | Provigil, Modalert, Modvigil, diphenylmethylsulfinyl-acetamide |
| Half-life (hr) ↗ | 168 | 13 |
| Typical dose (mg) ↗ | 25 | 200 |
| Dosing frequency | 5-day pulse cycle days 5 to 9 (women); daily or every other day (men, off-label) | daily, morning |
| Routes | oral | oral |
| Onset (hr) | 6 | 1 |
| Peak (hr) | 7 | 3 |
| Molecular weight | 405.96 | 273.35 |
| Molecular formula | C26H28ClNO | C15H15NO2S |
| Mechanism | Selective estrogen receptor modulator that antagonizes estrogen at the hypothalamus and pituitary, increasing GnRH and gonadotropin output, which drives gonadal steroidogenesis. | Weak dopamine reuptake inhibition plus downstream activation of histaminergic, noradrenergic, and orexinergic wake-promoting systems. |
| Legal status | Prescription only (FDA approved for ovulation induction; off-label in men) | Schedule IV (US); prescription-only globally; not a supplement |
| WADA status | banned | banned |
| DEA / Rx | Rx only (not a controlled substance) | Schedule IV |
| Pregnancy | Category X; contraindicated in pregnancy | Not recommended |
| CAS | 911-45-5 | 68693-11-8 |
| PubChem CID | 1548953 | 4236 |
| Wikidata | Q416785 | Q422968 |
Safety profile
Clomiphene
Common side effects
- hot flushes
- mood changes
- abdominal discomfort
- breast tenderness
- visual disturbances (rare)
- headache
Contraindications
- pregnancy
- active liver disease
- ovarian cysts (not PCOS-related)
- uncontrolled thyroid or adrenal disorder
- abnormal uterine bleeding of undetermined origin
- hormone-sensitive cancer
Interactions
- tamoxifen: competing SERM activity; not used together(moderate)
- ospemifene: competing SERM activity(moderate)
- anastrozole: additive estrogen reduction; sometimes combined in male protocols(minor)
- TRT (exogenous testosterone): TRT suppresses HPT axis that clomiphene targets; do not combine(moderate)
Modafinil
Common side effects
- headache
- nausea
- anxiety
- insomnia (with late-day dosing)
- dry mouth
- mild blood pressure elevation
Contraindications
- recent myocardial infarction
- unstable angina
- left ventricular hypertrophy
- significant arrhythmia
- history of Stevens-Johnson syndrome
- psychotic disorders
- pregnancy
- concurrent MAOI use
Interactions
- hormonal contraceptives: CYP3A4 induction reduces contraceptive efficacy; use barrier method(major)
- cyclosporine: reduced cyclosporine levels via CYP3A4 induction(major)
- warfarin: CYP2C9 inhibition raises INR(moderate)
- phenytoin: CYP2C19 inhibition raises phenytoin levels(moderate)
- MAOIs: potential hypertensive reaction(major)
- classical stimulants (amphetamine, methylphenidate): additive cardiovascular and sleep-disruption effects(moderate)
Which Should You Take?
Modafinil comes out ahead for most readers on the criteria we weight: 3 catalogued goals, controlled substance, oral dosing, with a Tier-A outcome catalogued. Clomiphene is the right call when one of the conditionals below applies.
- → If your priority is hormonal optimization, pick Clomiphene.
- → If your priority is fertility, pick Clomiphene.
- → If your priority is wakefulness, pick Modafinil.
- → If your priority is focus or working memory, pick Modafinil.
Edge case: Clomiphene is contraindicated in pregnancy; Modafinil is the safer pick if that applies.
Default choice: Modafinil. Wider use case, a Tier-A evidence outcome catalogued, and broader goal coverage. Reach for Clomiphene only if your priority sits squarely in the goals it owns above.
This verdict is generated from each compound's schema (goals, legal status, evidence outcomes, dosing route). It updates automatically as our compound data evolves; the deeper read sits on each individual compound page.
Common questions
What is the difference between Clomiphene and Modafinil?
Clomiphene and Modafinil differ in category (pharmaceutical vs pharmaceutical), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, Clomiphene or Modafinil?
Clomiphene half-life is 168 hours; Modafinil half-life is 13 hours.
Can you stack Clomiphene with Modafinil?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
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