Summer Hair Loss: Fact or Fiction?

Whilst it is normal to lose around 50-100 strands of hair a day, ‘seasonal hair loss’ is real, according to Swedish researchers.

Published: Thursday 18 July 2019



Many people will notice their hair shedding more when it is warmer. Whilst it is normal to lose around 50-100 strands of hair a day, ‘seasonal hair loss’ is real, according to Swedish researchers. Learning how to distinguish what is the normal amount of hair loss with the type that needs medical attention is key to prevent further hair loss.

The study from the Swedish researchers monitored 800 women over a six-year period and found that during the summer, most of the hairs are in the resting stage. Every strand of hair goes through a hair growth cycle, and it will go through a series of three stages- anagen (growth), catagen (transition), telogen (resting). A typical strand of hair will have a life cycle of between 2 and 6 years, where hairs will grow normally. Around 10% of your hairs may be in the resting phase where they are in preparation for regrowth so it is prone to extra shedding and falling out.

During summer, the hairs will remain in the telogen phase for a longer period of time, at which point they might notice some fall out but it is not till Autumn where the largest amount of shedding will occur.

A study from John Hopkins and Washington University used Google trends data to research the term ‘hair loss’ from eight countries for 12 years. The data was compared month by month and season by season. The results showed that more people were searching for hair loss during the summer, followed by autumn. It was less researched during spring, which suggested that people’s hair was thicker during this season. The results also led the researchers to conclude the telogen hair loss phase was mainly during summer and winter.

So, why does this occur?

During the summer months, the increased exposure to sunlight means our body will naturally produce less melatonin, and this can affect the hormone levels in the scalp. This will mean that during the summer months, hairs will be in the resting phase for a longer period of time than usual, resulting in increased hair fall in Autumn. These hairs, however after they fall out will be replaced as a hair follicle and the cycle will eventually enter the growth phase again.

Not only this, but it is the level of testosterone that impacts hair loss in summer. Although it is primarily a male hormone, it does exist in women as well and the levels are usually higher during the summer and autumn seasons which can cause hair loss.

If it’s not seasonal hair loss, what is it?

Seasonal hair loss should not be a cause of concern, although it might be noticeable to you but each individual’s hair growth will alter throughout the year.

If you notice your hair thinning in specific areas such as the crown or temples, then it is best to seek help from your GP because it represents a different type of hair loss. In both men and female pattern baldness, hair loss generally occurs in these areas. In men, the first signs of male pattern baldness will usually be around these areas, and for females, it will begin in smaller patches which will then diffuse into the crown and temples. It’s important to note that if you notice a slow regrowth of hairs, increased shedding, or hair falling out in a specific pattern around the temples and crowns, then it might be an underlying hair loss condition in which you should seek help from your doctor.

Look after your hair