Does Human Hair Grow Faster in Summer

It is not your imagination. Many people notice their hair seems to grow faster during the summer months. You may find yourself booking trims more often or observing that your roots show through sooner than expected after colouring. This seasonal change in growth is a real phenomenon, but what causes it? And how much difference does it truly make?

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Hair Growth and the Natural Cycle

Hair does not grow continuously at the same pace. Each strand goes through its own natural cycle which includes a growing phase known as anagen, a transition phase called catagen, and a resting phase known as telogen. Most of the hair on your head is usually in the anagen phase at any given time, which can last for several years. During this phase, hair grows at a steady but gradual rate, typically around 1 centimetre a month.

However, the speed of this growth can vary depending on several internal and external factors including age, genetics, hormones, and general health. What many people are less aware of is that environmental changes such as temperature, sunlight, and even your activity levels can also play a role.

Why Summer Affects Hair Growth

Increased sunlight during summer months has a few effects on the body that may encourage faster hair growth. The most obvious is the higher exposure to UV light which stimulates the production of vitamin D. This vitamin plays a key role in the creation of new hair follicles, which can enhance the overall growth potential of your hair. Additionally, longer daylight hours tend to improve mood and encourage more outdoor activity, which can promote better blood circulation throughout the body and scalp.

Warmer weather also increases the rate at which your body carries out metabolic processes. This includes the delivery of nutrients and oxygen to your skin and hair follicles. As a result, your scalp may become more active, with a slight but noticeable increase in the speed of hair growth. Some dermatology researchers suggest that hair might grow up to 10 percent faster during summer, although this can vary greatly between individuals.

Other Seasonal Factors at Play

It is not just the weather itself that causes these seasonal shifts. Lifestyle habits tend to change during summer as well. People usually eat more fresh fruit and vegetables, spend more time outside, and exercise more regularly. All these behaviours can contribute to improved hair quality and growth. Better hydration, boosted circulation, and increased vitamin intake all support the development of strong, healthy hair.

There is also a hormonal component. Longer daylight hours can impact melatonin levels in the body, which in turn influence hormones involved in hair cycling. These subtle shifts may help prolong the growing phase of hair or trigger more follicles to enter it at once.

Is Hair Thicker in Summer Too?

Although summer may encourage faster growth, it does not necessarily mean your hair becomes thicker. The diameter of your hair strands and the total number of active follicles are largely determined by genetics. However, hair may appear fuller during summer due to increased volume and texture caused by heat and humidity. These environmental effects can create the illusion of thicker hair, especially if you use minimal styling products or allow your hair to air dry naturally.

You might also notice a bit more hair shedding as summer ends and autumn begins. This is normal and part of the natural cycle. Many people shed slightly more hair in late summer or early autumn, likely due to the end of a prolonged growing phase triggered earlier in the year.

Supporting Hair Growth Throughout the Year

While summer may give your hair a temporary boost, keeping it healthy and growing steadily all year round requires consistent care. This includes eating a balanced diet rich in protein, omega-3 fatty acids, vitamins A, C, and E, and zinc. Staying hydrated, managing stress, and avoiding harsh treatments like excessive heat styling or bleaching can also make a big difference in long-term hair health.

One area that often gets overlooked is the role of collagen in supporting the hair growth process. Collagen is a structural protein that provides strength and resilience to both the scalp and hair shaft. As collagen levels naturally decline with age, your hair can become more fragile, dry, or prone to breakage. Supporting your body’s collagen supply may help maintain a healthy scalp environment and the structure of growing hair.

Should You Change Your Hair Routine in Summer?

If you want to make the most of the natural growth boost that summer offers, consider adjusting your routine slightly. Give your scalp regular gentle massages to encourage circulation, and protect your hair from excess UV exposure with hats or leave-in conditioners containing UV filters. You may also want to use lightweight products that hydrate and protect without weighing down your hair or clogging follicles.

Washing your hair too often in the heat can also strip the scalp of its natural oils, which are important for hair health. Try to keep a good balance between cleansing and preserving your hair’s natural defences.

Conclusion

Yes, human hair can grow faster in summer, largely due to the effects of increased sunlight, vitamin D production, and better circulation. These changes may be small but are often enough to notice quicker root regrowth or longer strands after a few weeks. While you cannot control the seasons, you can support your hair from within by maintaining healthy habits and providing your body with the nutrients it needs to grow strong, beautiful hair year-round.