Comparison
Clomiphene vs Vitamin D3 + K2
Side-by-side of Clomiphene and Vitamin D3 + K2. 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.
Vitamin D3 + K2
Vitamin D3 K2 supplement profile: cholecalciferol at 1000-4000 IU/day corrects deficiency, MK-7 directs calcium to bone, away from arteries.
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)
Vitamin D3 + K2
- •Reduces non-vertebral fractures 10-20% in older adults at 800 IU/day or above when combined with calcium
- •VITAL trial showed neutral results on primary CV and cancer endpoints at 2000 IU/day over 5 years
- •Vitamin D supplementation reduces respiratory infection incidence ~10-20% in deficient populations
- •K2 MK-7 has 72-hour plasma half-life vs 1-2 hours for MK-4; once-daily dosing is sufficient
- •Synergy hypothesis is largely preclinical; dedicated combination RCTs are limited
- •Daily dosing outperforms bolus dosing for immune and infection outcomes
Side-by-side
| Attribute | Clomiphene | Vitamin D3 + K2 |
|---|---|---|
| Category | pharmaceutical | supplement |
| Also known as | Clomid, clomiphene citrate, Serophene, enclomiphene | cholecalciferol + menaquinone, D3/K2, vitamin D3 with MK-7 |
| Half-life (hr) ↗ | 168 | 360 |
| Typical dose (mg) ↗ | 25 | 0.05 |
| Dosing frequency | 5-day pulse cycle days 5 to 9 (women); daily or every other day (men, off-label) | daily with a fat-containing meal |
| Routes | oral | oral |
| Onset (hr) | 6 | 24 |
| Peak (hr) | 7 | 168 |
| Molecular weight | 405.96 | 384.64 |
| Molecular formula | C26H28ClNO | C27H44O (D3); C46H64O2 (MK-7) |
| Mechanism | Selective estrogen receptor modulator that antagonizes estrogen at the hypothalamus and pituitary, increasing GnRH and gonadotropin output, which drives gonadal steroidogenesis. | D3 converts to calcidiol then calcitriol, activating the vitamin D receptor (VDR) to increase intestinal calcium absorption and modulate immune and bone gene transcription. K2 carboxylates osteocalcin and matrix Gla protein, directing calcium toward bone and inhibiting vascular calcification. |
| Legal status | Prescription only (FDA approved for ovulation induction; off-label in men) | Dietary supplement (global) |
| WADA status | banned | allowed |
| DEA / Rx | Rx only (not a controlled substance) | Not scheduled |
| Pregnancy | Category X; contraindicated in pregnancy | Recommended at standard doses for fetal bone development; consult clinician at higher doses |
| CAS | 911-45-5 | 67-97-0 |
| PubChem CID | 1548953 | 5280795 |
| Wikidata | Q416785 | Q139347 |
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)
Vitamin D3 + K2
Common side effects
- GI upset at high doses
- headache (rare)
- hypercalcemia (only at sustained very high D3 doses)
Contraindications
- hypercalcemia
- sarcoidosis
- active hyperparathyroidism
- warfarin therapy (K2 component requires stable intake)
Interactions
- warfarin: K2 component can affect anticoagulation; maintain stable intake and inform anticoagulation clinic(moderate)
- thiazide diuretics: additive calcium retention; hypercalcemia risk with high-dose D3(moderate)
- digoxin and calcium channel blockers: additive effects from D3-induced hypercalcemia(moderate)
- glucocorticoids: reduced vitamin D efficacy and bone effects(moderate)
- cholestyramine and orlistat: bind fat-soluble vitamins; separate dosing by 2 to 4 hours(moderate)
Which Should You Take?
Vitamin D3 + K2 comes out ahead for most readers on the criteria we weight: 3 catalogued goals, OTC dietary supplement, 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 bone density, pick Vitamin D3 + K2.
- → If your priority is healthspan extension, pick Vitamin D3 + K2.
Edge case: If you want to avoid prescription-only, Vitamin D3 + K2 is the more accessible choice.
Default choice: Vitamin D3 + K2. Lower friction to source, 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 Vitamin D3 + K2?
Clomiphene and Vitamin D3 + K2 differ in category (pharmaceutical vs supplement), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, Clomiphene or Vitamin D3 + K2?
Clomiphene half-life is 168 hours; Vitamin D3 + K2 half-life is 360 hours.
Can you stack Clomiphene with Vitamin D3 + K2?
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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