When we start to go grey depends a lot on genetics.

Your first grey hairs usually appear anywhere between your twenties and fifties. For men, grey hairs normally start at the temples and sideburns. Women tend to start greying on the hairline, especially at the front.

The most rapid greying usually happens between ages 50 and 60. But does anything we do speed up the process? And is there anything we can do to slow it down?

You’ve probably heard that plucking, dyeing and stress can make your hair go grey – and that redheads don’t. Here’s what the science says.

What gives hair its colour?

Each strand of hair is produced by a hair follicle, a tunnel-like opening in your skin. Follicles contain two different kinds of stem cells:

• keratinocytes, which produce keratin, the protein that makes and regenerates hair strands
• melanocytes, which produce melanin, the pigment that colours your hair and skin.

There are two main types of melanin that determine hair colour. Eumelanin is a black-brown pigment and pheomelanin is a red-yellow pigment.

The amount of the different pigments determines hair colour. Black and brown hair has mostly eumelanin, red hair has the most pheomelanin, and blonde hair has just a small amount of both.

So what makes our hair turn grey?

As we age, it’s normal for cells to become less active. In the hair follicle, this means stem cells produce less melanin – turning our hair grey – and less keratin, causing hair thinning and loss.

As less melanin is produced, there is less pigment to give the hair its colour. Grey hair has very little melanin, while white hair has none left.

Unpigmented hair looks grey, white or silver because light reflects off the keratin, which is pale yellow.

Grey hair is thicker, coarser and stiffer than hair with pigment. This is because the shape of the hair follicle becomes irregular as the stem cells change with age.

Interestingly, grey hair also grows faster than pigmented hair, but it uses more energy in the process.

Can stress turn our hair grey?

Yes, stress can cause your hair to turn grey. This happens when oxidative stress damages hair follicles and stem cells and stops them producing melanin.

Oxidative stress is an imbalance of too many damaging free radical chemicals and not enough protective antioxidant chemicals in the body. It can be caused by psychological or emotional stress as well as autoimmune diseases.

Environmental factors such as exposure to UV and pollution, as well as smoking and some drugs, can also play a role.

Melanocytes are more susceptible to damage than keratinocytes because of the complex steps in melanin production. This explains why ageing and stress usually cause hair greying before hair loss.

Scientists have been able to link less pigmented sections of a hair strand to stressful events in a person’s life. In younger people, whose stems cells still produced melanin, colour returned to the hair after the stressful event passed.

4 popular ideas about grey hair – and what science says

1. Does plucking a grey hair make more grow back in its place?

No. When you pluck a hair, you might notice a small bulb at the end that was attached to your scalp. This is the root. It grows from the hair follicle.

Plucking a hair pulls the root out of the follicle. But the follicle itself is the opening in your skin and can’t be plucked out. Each hair follicle can only grow a single hair.

It’s possible frequent plucking could make your hair grey earlier, if the cells that produce melanin are damaged or exhausted from too much regrowth.

2. Can my hair can turn grey overnight?

Legend says Marie Antoinette’s hair went completely white the night before the French queen faced the guillotine – but this is a myth.

Melanin in hair strands is chemically stable, meaning it can’t transform instantly.

Acute psychological stress does rapidly deplete melanocyte stem cells in mice. But the effect doesn’t show up immediately. Instead, grey hair becomes visible as the strand grows – at a rate of about 1 cm per month.

Not all hair is in the growing phase at any one time, meaning it can’t all go grey at the same time.

3. Will dyeing make my hair go grey faster?

This depends on the dye.

Temporary and semi-permanent dyes should not cause early greying because they just coat the hair strand without changing its structure. But permanent products cause a chemical reaction with the hair, using an oxidising agent such as hydrogen peroxide.

Accumulation of hydrogen peroxide and other hair dye chemicals in the hair follicle can damage melanocytes and keratinocytes, which can cause greying and hair loss.

4. Is it true redheads don’t go grey?

People with red hair also lose melanin as they age, but differently to those with black or brown hair.

This is because the red-yellow and black-brown pigments are chemically different.

Producing the brown-black pigment eumelanin is more complex and takes more energy, making it more susceptible to damage.

Producing the red-yellow pigment (pheomelanin) causes less oxidative stress, and is more simple. This means it is easier for stem cells to continue to produce pheomelanin, even as they reduce their activity with ageing.

With ageing, red hair tends to fade into strawberry blonde and silvery-white. Grey colour is due to less eumelanin activity, so is more common in those with black and brown hair.

Your genetics determine when you’ll start going grey. But you may be able to avoid premature greying by staying healthy, reducing stress and avoiding smoking, too much alcohol and UV exposure.

Eating a healthy diet may also help because vitamin B12, copper, iron, calcium and zinc all influence melanin production and hair pigmentation.

Theresa Larkin, Associate Professor of Medical Sciences, University of Wollongong

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Globally, the rates of common sexually transmissible infections (STIs) are increasing among people aged over 50. In some cases, rates are rising faster than among younger people.

Recent data from the United States Centers for Disease Control and Prevention shows that, among people aged 55 and older, rates of gonorrhoea and chlamydia, two of the most common STIs, more than doubled between 2012 and 2022.

Australian STI surveillance data has reflected similar trends. Between 2013 and 2022, there was a steady increase in diagnoses of chlamydia, gonorrhoea and syphilis among people aged 40 and older. For example, there were 5,883 notifications of chlamydia in Australians 40 plus in 2013, compared with 10,263 in 2022.

A 2020 study of Australian women also showed that, between 2000 and 2018, there was a sharper increase in STI diagnoses among women aged 55–74 than among younger women.

While the overall rate of common STIs is highest among young adults, the significant increase in STI diagnoses among midlife and older adults suggests we need to pay more attention to sexual health across the life course.

Why are STI rates rising among older adults?

STI rates are increasing globally for all age groups, and an increase among midlife and older people is in line with this trend.

However, increases of STIs among older people are likely due to a combination of changing sex and relationship practices and hidden sexual health needs among this group.

The “boomer” generation came of age in the 60s and 70s. They are the generation of free love and their attitude to sex, even as they age, is quite different to that of generations before them.

Given the median age of divorce in Australia is now over 43, and the internet has ushered in new opportunities for post-separation dating, it’s not surprising that midlife and older adults are exploring new sexual practices or finding multiple sexual partners.

It’s also possible midlife and older people have not had exposure to sexual health education in school or do not relate to current safe sex messages, which tend to be directed toward young people. Condoms may therefore seem unnecessary for people who aren’t trying to avoid pregnancy. Older people may also lack confidence negotiating safe sex or accessing STI screening.

Hidden sexual health needs

In contemporary life, the sex lives of older adults are largely invisible. Ageing and older bodies are often associated with loss of power and desirability, reflected in the stereotype of older people as asexual and in derogatory jokes about older people having sex.

With some exceptions, we see few positive representations of older sexual bodies in film or television.

Older people’s sexuality is also largely invisible in public policy. In a review of Australian policy relating to sexual and reproductive health, researchers found midlife and older adults were rarely mentioned.

Sexual health policy generally targets groups with the highest STI rates, which excludes most older people. As midlife and older adults are beyond childbearing years, they also do not feature in reproductive health policy. This means there is a general absence of any policy related to sex or sexual health among midlife or older adults.

Added to this, sexual health policy tends to be focused on risk rather than sexual wellbeing. Sexual wellbeing, including freedom and capacity to pursue pleasurable sexual experiences, is strongly associated with overall health and quality of life for adults of all ages. Including sexual wellbeing as a policy priority would enable a focus on safe and respectful sex and relationships across the adult life course.

Without this priority, we have limited knowledge about what supports sexual wellbeing as people age and limited funding for initiatives to engage with midlife or older adults on these issues.

How can we support sexual health and wellbeing for older adults?

Most STIs are easily treatable. Serious complications can occur, however, when STIs are undiagnosed and untreated over a long period. Untreated STIs can also be passed on to others.

Late diagnosis is not uncommon as some STIs can have no symptoms and many people don’t routinely screen for STIs. Older, heterosexual adults are, in general, less likely than other groups to seek regular STI screening.

For midlife or older adults, STIs may also be diagnosed late because some doctors do not initiate testing due to concerns they will cause offence or because they assume STI risk among older people is negligible.

Many doctors are reluctant to discuss sexual health with their older patients unless the patient explicitly raises the topic. However, older people can be embarrassed or feel awkward raising matters of sex.

Resources for health-care providers and patients to facilitate conversations about sexual health and STI screening with older patients would be a good first step.

To address rising rates of STIs among midlife and older adults, we also need to ensure sexual health promotion is targeted toward these age groups and improve accessibility of clinical services.

More broadly, it’s important to consider ways to ensure sexual wellbeing is prioritised in policy and practice related to midlife and older adulthood.

A comprehensive approach to older people’s sexual health, that explicitly places value on the significance of sex and intimacy in people’s lives, will enhance our ability to more effectively respond to sexual health and STI prevention across the life course.

Jennifer Power, Associate Professor and Principal Research Fellow, Australian Research Centre in Sex, Health and Society, La Trobe University

This article is republished from The Conversation under a Creative Commons license. Read the original article.