Peter Attia talks about endocrine system

1) Dr. Peter Attia explains how the body regulates thyroid function at a cellular level. When nutrients are scarce or metabolism needs to slow down, the body produces more reverse T3 to block the effects of T3. During fasting, Dr. Attia noticed a significant deterioration in his thyroid function based on his levels of free T3 and reverse T3. This creates a challenge in evaluating a patient’s thyroid status through the traditional method of looking at their TSH level. Dr. Attia suggests that in cases where a patient has high amounts of reverse T3, it might make more sense to give them T3 instead of T4, bypassing the step where the body could turn T4 into reverse T3. While the standard treatment for hypothyroidism is to give T4, for some patients, giving T3 may be a more effective solution.

2) Peter discusses the use of T3 and T4 in treating hypothyroidism. In the past, T3 was often used alongside T4 to help patients whose thyroid had been removed, but nowadays a compounded control release T3 is favored for its higher tolerance and longer release. Desiccated thyroid is another common formulation that combines T3 and T4, but some doctors only prescribe T4 or T4 with a small dose of T3. Dr. Attia emphasizes that different patients have different needs and using whatever works for them is the ultimate goal.

3) Peter discusses the adrenal system, which is the most confusing and difficult system to diagnose because there is little information that can be obtained from blood tests. The majority of cortisol is bound to carrier proteins, so it's important to know the level of free cortisol. The free cortisol is then measured through either a saliva test or a urine test, with Dr. Attia preferring the urine test called The Dutch test which is useful in measuring cortisol metabolites. Additionally, it's important to understand that just because someone has low levels of cortisol, it doesn't necessarily mean that their adrenal glands are "fatigued", and it's possible that the cortisol is being turned into its inactive metabolite, cortisone, through enzymes called reductases.

4) Peter discusses the importance of properly assessing adrenal function, which is often misunderstood and overlooked. He explains that adrenal output is virtually always appropriate, but the rhythm must be looked at closely to ensure that it is normal. A far more common problem is in people who have very high or low levels of free cortisol, and symptoms associated with those levels must be addressed. The direction of travel of enzyme 11 beta hsd, which converts cortisol to cortisone and back, is determined by various factors, such as insulin resistance, obesity, inflammation, low thyroid function, and leptin resistance.

5) Peter discusses the balance of cortisol and cortisone in the adrenal system. He explains that the inactive cortisone is like a repository for excess cortisol, and that the balance between the two is crucial for proper adrenal function. Dr. Attia cautions against using glucocorticoid replacement as a treatment for low free cortisol, instead advocating for addressing the underlying issues that lead to low free cortisol through lifestyle management, as well as using licorice root or other adrenal supports. He next moves on to explain how female sex hormones work during the reproductive cycle, dividing it into two phases: the follicular phase and the luteal phase. He notes that a rising FSH during days 3-5 of the follicular phase can be an indicator of approaching menopause.

6) Peter discusses the female menstrual cycle in detail. He explains that during the luteal phase of the cycle, progesterone rises while estrogen has a second peak, and if the body is not pregnant, both hormones come crashing down, and the body begins to shed the endometrium at the end of the cycle. Dr. Attia also delves into the significance of having a blood draw of FSH, LH, estradiol, and progesterone on a woman in determining where she is in her menstrual cycle and the importance of knowing what is normal for each woman. He further addresses common issues such as PMS and how the use of progesterone is a simple and effective way to treat it.

7) Peter discusses the female endocrine system and how it differs from the male endocrine system due to the cyclic and abrupt changes in hormone levels. He explains how a woman's body experiences a profound level of withdrawal during the end of the luteal phase and how testosterone levels in women are significantly higher than estrogen levels. As a woman enters menopause, her body is less able to produce estradiol and progesterone, and the pituitary gland produces more FSH and LH. Hormone replacement therapy can help control the vasomotor symptoms and cardiovascular and bone risk factors.

8) Peter discusses the complexities of testosterone replacement therapy. While total testosterone levels may indicate a deficiency, the biologically active free testosterone may make up only one to three percent, making it difficult to diagnose. Symptoms of low testosterone in men include low libido, erectile dysfunction, low mood, difficulty putting on muscle, and insulin resistance. While testosterone replacement therapy can be beneficial, it might be overused without considering these factors or understanding the patient's hormone saturation.

9) Peter discusses the pros and cons of using Clomid or testosterone for men with low testosterone levels. While Clomid can stimulate the brain to produce more LH and FSH, it can also negatively affect the feedback of estrogen in the brain, leading to negative effects on mood. On the other hand, testosterone can cause LH and FSH to go to zero due to the body stopping production of it. This can cause an increase in DHT production and, as a result, accelerate hair loss in those susceptible to it and potentially lead to gynecomastia if estradiol levels become too high. However, testosterone replacement therapy may be beneficial in improving symptoms and bone health if free testosterone is low, but only if a biochemical and symptomatic case for it exists.

10) Peter briefly mentions the complexities of the male sex hormone system and its nuances with regards to diagnosis and treatment. He also introduces their membership program that offers exclusive content, comprehensive podcast show notes, monthly AMA episodes, access to their private podcast feed, steep discounts on endorsed products, and other benefits that will continue to trickle in over time. Dr. Attia reminds the listeners that the podcast is for general informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment.