Using Bioidentical Progesterone to Naturally Increase Progesterone Levels
January 14, 2016
No Comments
Last updated July 1, 2026
Half the US population is likely magnesium-deficient, and if you’re struggling with fertility, this hidden deficiency could be a major factor. Magnesium for fertility is one of the most underappreciated topics in reproductive health—this single mineral is involved in over 300 biochemical processes including hormone production, ovulation, blood sugar regulation, and even your sex drive.
In this guide, I’ll cover exactly how magnesium affects fertility, which type is best (there are 7+), the connection between magnesium glycinate and libido, and how to test and dose correctly.
Table of Contents
Magnesium is a mineral critical for over 300 biochemical functions: maintaining healthy blood pressure, balancing blood sugar, keeping your heart rate steady, and relaxing muscles. For fertility specifically, magnesium is responsible for:
Magnesium deficiency is dramatically under-diagnosed because only 1% is stored in blood—standard blood tests miss it. Look for these symptoms:
Standard serum magnesium blood tests are unreliable (only measures 1% of body stores). Request an RBC magnesium test (red blood cell magnesium)—this measures intracellular magnesium and is much more accurate. Optimal RBC magnesium: 6.0–6.5 mg/dL. Most labs consider 4.2–6.8 “normal,” but for fertility optimization, aim for the upper range.
Magnesium regulates the pituitary gland, which controls FSH and LH production—the hormones that trigger ovulation. When the pituitary functions properly, it signals healthy progesterone production after ovulation. Without adequate magnesium, your body produces less of the hormones needed for ovulation, implantation, and sustaining early pregnancy.
Magnesium also helps the body metabolize cortisol. When cortisol is elevated (from stress), it directly competes with progesterone for receptor sites. By reducing cortisol, magnesium indirectly supports progesterone levels. Read more: Bioidentical Progesterone.
This is one of the most searched magnesium topics and one I get questions about constantly.Here’s the science:
Magnesium directly supports sex hormone production. It’s required for the synthesis of estrogen, progesterone, and testosterone—all of which drive libido. It also supports neurotransmitters like dopamine and epinephrine that regulate the “urge” to have sex.
Magnesium keeps testosterone “free.” It makes it harder for testosterone to bind onto proteins (SHBG), keeping more testosterone available in your bloodstream. Higher free testosterone = higher sex drive.
Magnesium reduces cortisol and anxiety. Chronic stress kills libido. Magnesium calms the nervous system and reduces the cortisol that suppresses sexual desire.
Does magnesium glycinate cause loss of sex drive? No—the opposite. Magnesium glycinate supports libido by improving hormone production, reducing cortisol, and promoting relaxation. If you’ve noticed decreased sex drive, magnesium deficiency itself may be the cause. Supplementing typically improves libido within 2–4 weeks. See also: Where Did Your Sex Drive Go?.
Magnesium Glycinate – MY TOP RECOMMENDATION. Highest absorption, gentlest on the stomach, best for sleep and anxiety. The glycine component adds calming benefits. Ideal for fertility, hormone balance, and libido support.
Magnesium Citrate – Good absorption. Helpful for constipation (stool-softening effect). Use if digestion is a concern.
Magnesium Threonate – Crosses the blood-brain barrier. Best for cognitive function and anxiety. More expensive.
Magnesium Oxide – AVOID for fertility. Very poorly absorbed (4% bioavailability). Mostly useful as a laxative.
Magnesium Taurate – Good for cardiovascular health. Taurine supports blood sugar balance.
Magnesium Malate – Supports energy production and muscle recovery. Good daytime option.
Bottom line: for fertility, hormone balance, and libido, magnesium glycinate is the best choice. I recommend Designs for Health Magnesium Glycinate.
Women with PCOS are frequently magnesium-deficient, and supplementation addresses multiple PCOS pathways simultaneously:
Read more: Natural Remedies for PCOS.
Magnesium supports egg quality by stabilizing cellular energy production (ATP) and protecting eggs from oxidative stress. It also reduces the uterine cramping that can interfere with implantation after embryo transfer. Many IVF clinics now recommend magnesium supplementation as part of their prep protocols.
Read more: Better Egg Quality for Egg Freezing.
Magnesium isn’t just for women. In men, it supports testosterone production, sperm motility, and overall sperm quality. Research shows that men with higher magnesium intake have better reproductive markers. Magnesium also improves sleep quality and reduces stress—both critical for sperm health.
Here’s the cruel irony: stress depletes magnesium, and magnesium deficiency increases stress. As levels drop, you experience higher anxiety, irritability, and cortisol—which depletes magnesium further. This cycle directly sabotages fertility because cortisol suppresses GnRH (the hormone that triggers ovulation) and competes with progesterone.
Breaking this cycle requires both supplementation AND stress management. Neither alone is enough.
Organic produce is essential—conventional farmland is magnesium-depleted from intensive farming practices.
Dose: 300–400 mg magnesium glycinate at bedtime. Start with 200 mg and increase gradually to avoid loose stools. Take at bedtime because magnesium promotes relaxation and deep sleep—when your body does its most important hormone repair work.
I recommend Designs for Health Magnesium Glycinate Chelate (2–3 capsules at bedtime).
Epsom salts are magnesium sulfate—your body absorbs magnesium through the skin during a warm bath. Add 2 cups to a warm bath and soak for 20–30 minutes, 2–3 times per week. This combines magnesium absorption with stress-relieving relaxation—double benefit for fertility.
If you’re trying to get pregnant and looking for a solution-based, comprehensive approach, read my complete guide: What’s Actually Preventing Pregnancy — and How to Fix It.
If you’ve been told everything looks normal but you’re still not pregnant — or you have a diagnosis like PCOS, endometriosis, or poor egg quality and nothing is working — there’s almost always something deeper that hasn’t been found yet.
Standard fertility testing rarely evaluates the factors that actually determine whether pregnancy happens: egg quality, ovulation quality, metabolic health, inflammation, nutrient status, and how your body responds to stress.
After nearly 20 years and hundreds of clients, I’ve found that most fertility struggles come down to a small number of hidden biological drivers. When those drivers are identified and addressed in the right order, the body responds.
That’s exactly what we uncover inside The Fertility Code — my 12-week, high-touch fertility program for women who are done guessing. We find what’s been missed and build a clear, personalized strategy around your body, your labs, and your history.
With 1:1 coaching, direct access between calls, lab reviews, evidence-based content, and structured accountability, you get expert eyes on your case so you can stop second-guessing and start moving forward with clarity.
Over 90% of the women I work with go on to conceive.
If you’re ready to finally understand what your body needs for a successful pregnancy — and fix what’s been missed — you can explore the program here → The Fertility Code.
Or schedule a free Fertility Strategy Call to see if the program is right for you.
Sarah Jane Sandy is a certified nutrition therapist, and a fertility and women’s health expert. She has helped hundreds of women increase their fertility naturally and go on to have healthy full-term pregnancies. She has been working with women and couples trying to get pregnant for over 15 years and over 90% of the women who work with her get pregnant and have healthy babies. Learn more about her own fertility journey here. To send Sarah a message, complete her Contact Form.
© 2026 Sarah Jane Sandy. All rights reserved. Privacy Policy | Terms and Conditions | Medical Disclaimer | Editorial Policy
Curious about your fertility health? Take this simple quiz to find out what factors may be harming your fertility, and learn what you can do about it!
