Since I’m Sweating Less in the Cold Weather, Is That Why My Hair Looks Better?

I’ve been taking Propecia for around 6 months. Recently, I’ve noticed that there seems to be improvement in my diffuse crown thinning – however, this coincides with the recently colder weather. Would the less sweat from summer cause that big of a difference in perception of thinning? If I recall correctly, I don’t sweat that much from my scalp.

In some animals, the fur coats get thicker in the winter. We have never recognized that hair cycles change based upon seasons, so the official answer to your question is that no, it should not get thicker in cold weather. That being said, many patients have told me that their hair appears thicker in the winter, so that suggests that the scientists should get better data on human moulting.

Humans have an asynchronous hair cycle, which means that we grow and shed our hair in cycles. The shedding cycle for head hair (catogen) lasts 3-6 months and the growing cycle (anagen) lasts 2-4 years depending upon the age and sex of the person. In body hair, the catogen cycle is often the length of the anagen cycle, and I would expect that the anagen cycle should be longer in winter if the body hair cycle responded to cold weather.

So in conclusion, animal hairs respond to cold, but human hairs do not (officially) respond to cold weather. I don’t have any idea if you have more or less scalp sweat today than you did in the Summer months, or if it makes a difference in your crown’s appearance.