Magnesium and vitamin B6 show up in almost every “best supplements for TTC” list, and in many cycle-support and prenatal products. Do you need them as separate add-ons, and how much is too much? This guide sticks to published intake guidance and label checks, so you can decide with your doctor.
This is educational, not medical advice. For the full overview of options, see fertility supplements to get pregnant.
1. What each nutrient is
Magnesium is a mineral involved in hundreds of body processes, including muscle and nerve function. Vitamin B6 (pyridoxine) is a water-soluble vitamin involved in protein metabolism and is often included in prenatal and cycle-support formulas. Both are needed every day; neither is a “fertility switch.”
2. Intake limits to know (NIH Office of Dietary Supplements)
| Nutrient | Adult guidance | Upper limit |
|---|---|---|
| Magnesium | RDA for adult women is about 310–320 mg/day from food and supplements combined | 350 mg/day applies to supplemental magnesium only; higher amounts can cause diarrhea and cramping |
| Vitamin B6 | RDA for adults 19–50 is 1.3 mg/day | 100 mg/day for adults; long-term high intake has been linked to nerve problems |
Many standalone products far exceed the RDA, so the total across all your products matters — prenatal, cycle formula, sleep blend and multivitamin all count. Check current figures on the NIH ODS site and confirm your own targets with your doctor.
3. What the research does and does not show
- Fertility outcomes: there is no large, high-quality trial showing that extra magnesium or B6 raises the chance of pregnancy in the general TTC population.
- Cycle symptoms: some small studies look at B6 or magnesium for PMS-type symptoms; that is a different question from conception.
- Deficiency: if a blood test shows low levels, your doctor may suggest correcting it — that is care guided by a result, not a guess.
If irregular cycles are the real worry, start with a work-up — see ovulation cycle tracking and AGO Eva for luteal-phase support.
4. Who should ask a doctor first
- Kidney conditions: magnesium is cleared by the kidneys — ask before supplementing.
- Medications such as certain antibiotics, bisphosphonates, thyroid medicine or diuretics can interact with magnesium; timing may need to be separated — see levothyroxine timing.
- Numbness or tingling in hands or feet: report it to your doctor before continuing any B6 product.
- In an IVF or IUI cycle: follow your clinic’s protocol — read what to ask your clinic.
5. Buying magnesium or B6: 5 quick checks
- Add up the total. List every product you take and the mg of magnesium and B6 in each.
- Form and elemental amount: magnesium labels should state elemental mg, not only the compound weight.
- B6 amount in mg clearly listed — avoid doubling up across blends.
- Third-party testing (USP, NSF or a certificate of analysis). In Canada, look for an NPN.
- Ask for the full label of any AGO product you are considering — the care team shares it on request so you can compare per-serving amounts.
Results vary and no supplement guarantees pregnancy. Bring the labels to your next visit — our doctor checklist helps, and the couples guide shows how to plan for both partners. Get a free personalized plan.
FAQ
Should I take magnesium and vitamin B6 when trying to conceive?
Both are everyday nutrients, and many people get part of their needs from food and from a prenatal or TTC formula. Whether to add more is a question for your doctor, ideally based on your diet and any test results.
How much magnesium is too much from supplements?
The NIH sets 350 mg/day as the upper level for supplemental magnesium in adults. Amounts above that can cause digestive upset. Count every product you take.
How much vitamin B6 is safe?
The NIH upper level for adults is 100 mg/day. Long-term high intake has been associated with nerve symptoms, so check the total across your products.
Is B6 or magnesium already in AGO Mom?
Ask the AGO care team for the product label — they send it on request so you can see what is in each serving and avoid doubling up with other products.
Can he take them too?
Men have the same intake guidance. There is limited evidence for a fertility benefit from extra amounts, so ask his doctor before adding either.