The Functional Fueling® Podcast

Understanding MTHFR & Methylation for Fertility & Chronic Illness with Dr. Sam Shay
MTHFR is one of the most talked-about—and misunderstood—genes in the functional medicine world. But what does it actually mean to have an MTHFR mutation? How does methylation influence fertility, thyroid health, homocysteine levels, detox pathways, and chronic illness? And when is genetic testing truly helpful versus fear-driven?
In this episode, I’m joined by functional medicine expert Dr. Sam Shay to break down the science of methylation in a practical, clinically grounded way. We discuss how MTHFR variants impact folate metabolism, vitamin B12 utilization, homocysteine regulation, and oxidative stress—and why these pathways matter deeply for women navigating infertility, recurrent pregnancy loss, Hashimoto’s, PCOS, autoimmunity, and complex inflammatory conditions.
We also unpack common myths about MTHFR, including when high-dose methylated supplements may backfire.
If you’ve ever been told you have an MTHFR mutation and felt confused about what to do next—or if you’re struggling with unexplained fertility challenges, thyroid antibodies, chronic fatigue, or inflammatory symptoms despite “normal labs”—this episode will help you understand the bigger biochemical picture and how to approach methylation support in a personalized, root-cause way.
This conversation is especially important for active women who are trying to conceive, managing autoimmune thyroid disease, or navigating chronic illness through a functional medicine lens.
 
A few things we chat about in this episode 👇👇👇
What MTHFR actually does, and why it is often misunderstood
How methylation works, and why inflammation drives the process
Why slow methylation may have been protective evolutionarily, but problematic today
How methylation affects estrogen detoxification and hormone balance
What homocysteine reveals about methylation efficiency and cardiovascular risk
The three pathways the body uses to clear homocysteine
Which genetic variants matter most for fertility, autoimmunity, and chronic illness
How vitamin D receptor genes influence immune regulation and inflammation
 
Important show links 👇👇👇
Learn more about Dr. Sam Shay at www.DrSamShay.com
Apply to work with us 1:1 for fertility support
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AMA: Low Luteal BBT, Mold Exposure, Thyroid Antibodies & Thyroid Inflammation—What It All Really Means
In this AMA episode, I answer some of your frequently asked questions you submitted over on Instagram. We discuss the causes of low luteal phase basal body temperatures (BBT), progesterone dysfunction, mold-related inflammation, thyroid antibodies, and thyroid swelling.
A few things we chat about in this episode 👇👇👇
What low luteal phase BBT can signal about ovulation and progesterone
How progesterone drives body temperature and luteal phase health
What delayed or weak temperature rises suggest about follicle development
When low luteal temps indicate ovulation issues or luteal phase defects
How low progesterone contributes to PMS heavy periods and histamine symptoms
How low T3 and thyroid function impact the luteal phase
How immune stress inflammation and mold exposure affect cycles and fertility
What elevated thyroid antibodies or thyroid swelling may indicate
 
Important show links 👇👇👇
Take our FREE Low T3 Quiz to find out if low t3 is driving your symptoms
Receive a discount with GotMold? Home testing Kit use code Use code: laurenpapanos10
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Fertility Over 35: The Prenatal Supplement Roadmap for Women + Men with WeNatal Co-Founder
Trying to conceive after 35 requires more than just “taking a prenatal.” In this episode, we break down how to choose the right prenatal supplement for both women and men, and why fertility optimization starts months before conception.
We discuss why the number of capsules per serving actually matters, how iron and calcium should be dosed and timed, and how modern food systems contribute to widespread nutrient depletion. You’ll learn why sperm health plays a critical role in fertility and pregnancy outcomes, how lifestyle toxins and oxidative stress damage egg and sperm quality, and why mitochondrial health becomes increasingly important with age.
We also cover the key nutrients that support mitochondrial function, hormone balance, and reproductive health—and explain why the three months before conception are a critical window for both egg and sperm development.
 
A few things we chat about in this episode 👇👇👇
Why the number of capsules per serving of your prenatal matters
Why iron and calcium are separated and how iron needs change in pregnancy
How modern food systems contribute to nutrient depletion
What role sperm health plays in fertility and pregnancy outcomes
How lifestyle toxins and oxidative stress impact egg and sperm quality
Why mitochondrial health matters for fertility as women age
Key nutrients that support mitochondrial and reproductive health
Why the three months before conception are critical for egg and sperm development
Important show links 👇👇👇
Visit WeNatal for supplements and receive a free magnesium bottle 
Apply to work with us 1:1 for fertility support
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Overtraining Syndrome: When Your Body Stops Adapting and Starts Protecting Itself
Overtraining Syndrome isn’t just about doing too much—it’s what happens when your body stops adapting to exercise and shifts into a protective, survival state. In this episode, we break down what overtraining syndrome actually is, why it affects both recreational exercisers and competitive athletes, and how it’s often driven by inadequate recovery and fueling rather than training volume alone. We explore early warning signs that the body is no longer responding positively to exercise, the role of oxidative stress and mitochondrial dysfunction, and how chronic training stress disrupts thyroid function, cortisol, androgens, progesterone, metabolism, and ovulation. You’ll also learn how to strategically reduce training load, restore energy availability, and reintroduce exercise in a way that supports hormone balance, metabolic health, and long-term performance.
 
A few things we chat about in this episode 👇👇👇
What overtraining syndrome is and why it affects both recreational exercisers and competitive athletes
Why overtraining is often a recovery and fueling issue, not just a training issue
Common training patterns that push the body into overtraining
Early signs the body is no longer adapting positively to exercise
How overtraining affects thyroid function, androgens, cortisol, and progesterone
Why oxidative stress and mitochondrial dysfunction drive overtraining syndrome
How overtraining disrupts ovulation, cycles, and metabolic regulation
How to reduce training load, restore fueling, and reintroduce exercise to support hormone balance
 
Important show links 👇👇👇
Learn more about our Strength in Hormones Workout Program – join with a 7 day free trial
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How to Support Androgens: Navigating Both Low and High Testosterone and DHEA-S in Women
In this episode, we explore how to support androgens in women by understanding both low and high testosterone and DHEA-S, and what these patterns reveal about thyroid function, insulin signaling, adrenal health, inflammation, and stress. Androgens are essential for female energy, mood, muscle tone, libido, and fertility, and when they are either too low or too high, they signal deeper metabolic and immune imbalances rather than isolated hormone problems.
A few things we chat about in this episode 👇👇👇
Why women need androgens like testosterone, DHEA, and DHT for energy, mood, and fertility
The difference between ovarian and adrenal sources of androgens
Why both low and high testosterone can cause symptoms
How LH, insulin, thyroid function, and stress shape androgen levels
Why PCOS is not an ovary-first condition
Common signs of high & low androgens
How insulin resistance, inflammation, and immune stress drive androgen imbalance
Which labs actually matter for understanding androgen patterns
 
Important show links 👇👇👇
Apply to work with us 1:1 for androgen support
Listen to Adrenal Hormones episode with Dr. Kelly Ruef 
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Chinese Medicine for Kiddos w/ Dr. David Allen
In this episode of Strength in Hormones, we explore how Chinese Medicine approaches children’s health differently than Western medicine and why understanding these differences can transform the way you support your child’s digestion, sleep, emotions, and immune system. Chinese Medicine views children as physiologically and energetically developing, with immature digestive systems, sensitive nervous systems, and rapidly evolving emotional regulation, which means symptoms are often signals of deeper imbalances rather than isolated problems.
We discuss common pediatric concerns such as asthma, ADHD, sleep disturbances, digestive issues, and behavioral challenges, and how patterns like night waking, nightmares, bedwetting, irritability, and frequent illness can reflect underlying imbalances in the gut, nervous system, and immune function. You’ll learn why digestive health is often the foundation for emotional regulation, focus, sleep quality, and overall development in children.
 
A few things we chat about in this episode 👇👇👇
• How Chinese medicine views children differently than Western medicine
• Why kids’ digestion, nervous systems, and emotions are still developing
• Common patterns behind issues like asthma, ADHD, sleep problems, and digestive concerns
• What symptoms like night waking, nightmares, bedwetting, and irritability can signal
• Why digestive health is often the foundation for behavior and development
• How food temperature, simplicity, and meal timing matter for kids
• When and how herbs may be used safely in children
• How parents can support nervous system regulation and emotional resilience
• Why addressing root imbalances early can prevent long-term issues
 
Important show links 👇👇👇
We do work with kids clinically! Inquire here for more information
Learn more about Dr. David Allen's Healthy Kids Acupuncture & Herbs practice at www.davidallenlac.com
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How Inflammation & The Immune System Pushes You Into Low T3 and High Reverse T3
Low T3 is one of the most misunderstood thyroid patterns, and it’s rarely a problem that starts in the thyroid itself. In this episode, we explore how the immune system, inflammation, and metabolic stress drive changes in T3 and reverse T3, often long before the thyroid gland becomes the primary issue.
You’ll learn what T3 actually controls in the body, why normal TSH and T4 levels do not guarantee healthy thyroid function, and how mitochondrial health determines whether thyroid hormone can truly do its job. We break down the difference between low T3 and elevated reverse T3, explain why the body shifts into energy conservation mode under chronic stress, and cover the critical role of deiodinase enzymes (D1, D2, and D3) in thyroid hormone conversion.
A few things we chat about in this episode 👇👇👇
Why low T3 is not a thyroid-first problem
The link between inflammation, immune activation & thyroid suppression
What T3 actually controls
Why you can have normal TSH and T4 but still feel exhausted
The difference between low T3 vs. high RT3
How mitochondrial health dictates thyroid hormone effectiveness
Why the body enters energy conservation mode under chronic stress
The role of deiodinase enzymes (D1, D2, D3) in thyroid conversion
How chronic infections, gut dysfunction, and toxins impact T3
Why thyroid medication alone often fails to resolve symptoms
Important show links 👇👇👇
Take Free Quiz - Do You Have Low T3 Levels?
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Micronutrients, Probiotics & Prenatals for Fertility & Pregnancyw/ Ayla Barmer, Fullwell Fertility
In this episode, I sit down with Ayla Barmer, registered dietitian and founder of FullWell Fertility, to break down what the research actually says about micronutrients, probiotics, and prenatals for fertility, pregnancy, and postpartum health.
Despite the growing prenatal market, many supplements still miss the mark when it comes to evidence-based dosing, bioavailable nutrient forms, and individualized needs. We cover the most misunderstood and controversial topics in prenatal nutrition, including folate vs. folic acid, the role of methylated forms, and why blanket fear around vitamin A may be contributing to widespread deficiency and downstream thyroid, immune, and fertility issues. We also dive into why iron and omega-3s are often excluded from prenatals, how iron needs change across each trimester, and how to determine whether supplementation is necessary based on labs—not assumptions.
A few things we chat about in this episode 👇👇👇
Why many prenatals don’t align with the evidence on nutrient forms or dosing
Modern drivers of nutrient depletion—even with a “healthy” diet
Folate vs. methylfolate vs. folic acid: what matters most in pregnancy
The truth about vitamin A in pregnancy and why avoidance may backfire
Why iron and omega-3s are often intentionally excluded from prenatals
How iron needs shift across pregnancy and how to assess the right dose
What really matters for DHA and EPA for mom and baby
How to evaluate probiotics and support the microbiome intelligently
Important show links 👇👇👇
Apply to work with us 1:1 for pre-conception, pregnancy & postpartum support at functionalfueling.com/coaching-page
Visit Fullwell and shop pretnatals online - use code FullWell20 for up to 36% off your first order
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Low T3 With Normal TSH: How Energy Availability Impacts Thyroid Function
If your TSH looks “normal” but you still feel exhausted, with irregular cycles and slowed metabolism, this episode will help you understand what standard testing often misses.
In this episode, we break down energy availability—the balance between the energy you take in and the energy your body expends—and why it is one of the most overlooked drivers of thyroid dysfunction, particularly low T3, the active thyroid hormone that actually controls metabolism, energy, and the menstrual cycle.
A few things we chat about in this episode 👇👇👇
What T3 (active thyroid hormone) actually controls in the body
How you can have normal TSH and T4 but still feel exhausted
The connection between low energy availability and suppressed T3
Key variables that push the body into metabolic conservation mode
Why adequate nutrition is essential for T4 → T3 conversion
Hormones that inhibit thyroid function under stress or low fuel states
Common signs and symptoms of low T3
Why thyroid medication alone often falls short
How fueling, timing, and safety signals support thyroid and hormone restoration
If you are an active woman, athlete, or high-performing individual struggling with fatigue, stubborn symptoms, or “normal” TSH levels that don’t match how you feel, this episode will give you a new framework for understanding—and supporting—your thyroid from the inside out.
 
Important show links 👇👇👇
Find out if you may be experiencing low T3 levels - Take our t3 quiz
Uncover the labs that influence T3 levels - Get my Thyroid Inflammation Lab Decoder Guide
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[The LODown] Is Your Low Progesterone Actually a Thyroid Issue?
Low progesterone is one of the most common hormone concerns I see—but it’s also one of the most misunderstood. In this episode, we unpack why low progesterone is rarely a true progesterone deficiency and is far more often a downstream signal of poor ovulation quality driven by low T3, metabolic stress, or thyroid autoimmunity.
You’ll learn why progesterone is best understood as a marker of ovulation strength—not something the body simply “fails to make”—and how thyroid hormone, mitochondrial energy, inflammation, blood sugar, and nervous system safety all determine whether ovulation (and the corpus luteum) can function properly.
We also dive into why luteal phase defect is frequently misdiagnosed as PCOS, how Hashimoto’s can quietly disrupt ovulation even with normal cycles, and why progesterone supplementation alone often fails to fix the problem.
 
A few things we chat about in this episode 👇👇👇
Why progesterone reflects ovulation quality—not ovarian failure
The thyroid–progesterone axis and how low T3 weakens ovulation and the corpus luteum
How stress, cortisol, and reverse T3 put metabolic “brakes” on progesterone production
The overlooked role of thyroid autoimmunity in low progesterone, short luteal phases, and miscarriage risk
Luteal phase defect vs. PCOS: how to tell the difference 
What labs actually matter for identifying thyroid-driven low progesterone (and how to time them correctly)
Why progesterone supplementation is sometimes helpful—but rarely a root-cause solution
Treatment priorities that restore ovulation by fixing thyroid conversion, metabolism, and immune stress 
 
Important show links 👇👇👇
Take my free T3 QUIZ to find out if low t3 could be driving your low progesterone levels
Episode Period Problems: PCOS vs. Amenorrhea  
Book your 1:1 Functional Clarity Session www.functionalfueling.com/clarity-sessions
Get discount with inito using code functionalfueling15
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