Seasonal affective disorder hormones: How to tell SAD from low testosterone in men
Dr. Susan Carter, MD: Endocrinologist & Longevity Expert
Dec 29, 2025 · 13 min read
SAD usually follows a repeatable fall-to-winter pattern and improves in spring, while low testosterone is more likely when symptoms are persistent, come with libido or erection changes, and are confirmed on repeat morning blood tests. If your symptoms do not cleanly follow the calendar, or they come with sexual or sleep changes, it is time ...