Depression

Depression is fundamentally a state of low energy production in the brain, driven by a shift away from efficient oxidative metabolism toward stress metabolism. 5 Ray Peat argued that when thyroid and adrenal hormones are low, energy production falters, and the brain relies on emergency drivers like serotonin, estrogen, and adrenaline, which can create either mania or depression. 5 He identified serotonin as a universal indicator of stress, acting like "beating a tired horse" by temporarily increasing function at the risk of harming vital processes. 5 This perspective reframes the condition not as a simple chemical imbalance but as a bioenergetic crisis in which the brain's energy supply is insufficient to meet demands.

The primary therapeutic approach Peat recommended targets the restoration of mitochondrial energy production. He emphasized that quick-acting thyroid T3, combined with adequate vitamin D and calcium from low-fat milk, works to lower stress hormones and raise brain energy, sometimes resolving a major depression rapidly. 1 He noted that a large vitamin D supplement alone can occasionally bring a person out of a severe depressive episode. 1 Beyond these foundational supports, Peat identified methylene blue as a chemical substitute for active thyroid hormone that can repair the energy system, supported by DHEA, progesterone, and pregnenolone. 5 The goal of these interventions is to shift the organism away from the serotonergic stress cascade and back toward oxidative phosphorylation.

The role of serotonin in depression is one of pathological stress mediation, not happiness. Georgi Dinkov has highlighted that the vast majority of acute major depressive episodes are triggered by a single stressful event, which activates the adrenal system at the expense of the thyroid and gonadal axis. 7 Serotonin is a powerful activator of this stress cascade, and its elevation is incompatible with well-being. 7 Dinkov has also pointed to evidence that SSRI drugs robustly decrease empathy, creating a zombifying, psychopathic effect rather than addressing the underlying energetic deficit. 9 This aligns with Peat's view that serotonin and estrogen act as emergency drivers that risk harming vital functions when energy production is low. 5

The connection between hormonal balance and depression extends to the neurosteroid allopregnanolone, a metabolite of progesterone. Peat noted that the FDA-approved drug brexanolone is simply a synthetic version of this naturally occurring substance, administered as a $34,000 hospital infusion for postpartum depression, whereas inexpensive progesterone or pregnenolone would quickly convert to allopregnanolone in the body. 3 Dinkov has discussed allopregnanolone as a treatment mechanism relevant to both depression and Alzheimer's disease. 4 This underscores the broader principle that depression, particularly in its postpartum or hormonally-linked forms, is tied to a deficiency of protective steroids that support GABAergic tone and counteract the excitatory stress mediators.

Environmental and dietary factors further modulate the energetic state underlying depression. Peat experienced firsthand the depressive effects of light deprivation, noting that a lack of sunlight for two months triggered lethargy and depression, which sparked his interest in the hormonal effects of sunlight and its role in conditions like Seasonal Affective Disorder. 2 Dietarily, he warned that polyunsaturated fats are essential for the development of liver injury and, by extension, the systemic stress that can precipitate depression, advocating instead for protective saturated fats like those found in butter, beef fat, and coconut oil. 8 Danny Roddy has observed clinically that a vitamin D level of 50 ng/mL is optimal, and that low cholesterol or vitamin D can indicate an inability to synthesize protective steroids, perpetuating the depressive state. 6