When the Scalp Changes
In the Heian court a thousand years ago, a woman’s hair was treated as a record of her life. It was grown long, sometimes longer than she was tall, and it was never washed quickly. The washing was a slow event, scented with herbal infusions, and afterward the hair was combed through with camellia oil, tsubaki, worked patiently from root to end. Hair was read as a sign of inner health. When it changed, something in the woman was understood to be changing with it.
You wrote that your scalp began to feel dry and tight sometime after forty, and that a friend in Japan told you it was hormonal. She is right, and the Heian intuition was closer to the biology than it could have known.
The scalp is skin, and like all skin it depends on estrogen more than most of us are ever told. Estrogen supports the small sebaceous glands that keep skin supplied with its own oil, and it helps skin hold water. As estrogen begins its long decline through the forties, those glands quiet down. The scalp produces less of its own oil, its moisture barrier thins, and it starts to feel exactly as you described: tight, dry, and easily irritated, often most of all just after washing.
Japanese dermatology has paid unusually close attention to this stage of life. Where Western beauty writing tends to stop at the hair, Japanese research has looked underneath it, at how the scalp’s oil composition and even the balance of microbes living on it shift as a woman moves through her forties and fifties. The scalp at forty-four is a genuinely different environment than the scalp at thirty, and it is responding to a real biological change, not to anything you have done wrong.
This is also why your richer conditioner softened your hair but did nothing for the feeling you were trying to fix. Conditioner is made for the hair shaft. It was never meant to reach the skin underneath, and the skin underneath is what changed.
The Heian ritual was not vanity. It was slow, deliberate attention paid to skin that needed it, in the years when it needed it most. Your hair is doing what hair does at this age. It is not failing you. It is asking, the way the Heian women believed it always did, for a different kind of attention than it needed before. Now you know where to direct it.