Acne

Acne is fundamentally a sign of systemic hormonal imbalance, most often driven by low thyroid function and a corresponding deficiency of vitamin A, rather than a primary skin disorder. 3 Ray Peat argued that the surge of sex steroids at puberty increases the body's demand for vitamin A, which is crucial for skin cell differentiation, steroid production, and resistance to infection. 5 He noted that thyroid hormone is essential for preventing an imbalance of these steroids and for maintaining immune function and sebum production in the skin. 5 When thyroid function is low, the body relies on stress hormones, and the adrenals produce DHEA, which can be converted in the skin into potent androgens that drive the overproduction of sebum. 10 This sebum then feeds bacteria, creating the localized inflammatory reaction recognized as a pimple. 10

The connection between the gut and the skin is a critical pathway in the development of acne. Peat consistently emphasized that intestinal irritation from poorly digested foods or allergens can contribute to skin inflammation and problems with the excretion of fats and sweat. 2 Georgi Dinkov has elaborated on this, explaining that chronic gut irritation is not mutually exclusive from the hormonal pathway, as it will increase estrogen and cortisol while suppressing protective hormones. 4 Peat also observed that excess dietary fat, relative to sugar, can disturb the skin's energy production, suggesting that individuals who experience acne from drinking milk might benefit from consuming lower-fat varieties. 6 This aligns with the broader principle that polyunsaturated fatty acids (PUFAs) interfere with thyroid function and are a foundational dietary problem. 8

Peat described a specific phenomenon where a surge of youth-associated hormones, triggered by improved thyroid function, can cause what he called a "rejuvenation" of the skin's oil and moisture glands, leading to acne even in older individuals. 8 He personally experienced this when first supplementing DHEA, and noted that the process of converting cholesterol into progesterone and DHEA, which is stimulated by thyroid, dramatically increases the consumption of vitamin A. 8 A resulting vitamin A deficiency can cause the immune system to fail, allowing bacteria to proliferate on the skin. 8 Peat shared that he himself required 100,000 i.u. of vitamin A daily for several years to prevent acne and ingrown whiskers, and that the need for such high doses decreased only when his thyroid function improved, which he could track by the accumulation of carotene in his calluses. 3

For treatment, Peat recommended addressing the root causes by optimizing thyroid function and vitamin A status, while also employing topical agents to manage symptoms. 2 He found that a 10% sulfur soap leaves an antiseptic residue that can prevent infection, and that a solution of aspirin in water applied to the skin helps with inflammation and is mildly germicidal. 2 Dinkov has pointed to the efficacy of topical niacinamide as a desirable alternative to antibiotics for inflammatory acne, and noted that caffeine has progesterone-like and anti-estrogen effects that can be helpful against hormonally driven acne by opposing local tissue androgens. 9 Peat also noted that internal antibiotics like minocycline can be used for their anti-inflammatory effect, and that changing the diet while using an antibiotic can make the improvement permanent. 7 He cautioned that while estrogen-based contraceptives can clear acne by causing the oil glands to atrophy, this does not address the underlying metabolic problem. 5