PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Intermittent fasting increases sex drive in male mice: an approach for low libido in humans?

Current findings could point the way for new therapy option / Serotonin plays key role

2025-03-28
(Press-News.org)

Long-term fasting in 24-hour cycles increases the sex drive of male mice by lowering the concentration of the neurotransmitter serotonin in the brain. This effect is linked to a diet-induced deficiency of the precursor substance tryptophan – an amino acid that must be obtained through food. Researchers from DZNE report on this in the journal Cell Metabolism, together with a Chinese team from Qingdao University and the University of Health and Rehabilitation Sciences. They suggest that similar mechanisms may exist in humans and view fasting as a potential approach for treating unwanted loss of sexual desire.

Fasting is a recurring subject of research because reduced food intake and thus calorie restriction has a variety of effects on the organism beyond the commonly observed weight loss. Dr. Dan Ehninger, research group leader at DZNE and lead author of the current study, and his team have also been working on this topic for quite some time. “We are interested in the effects of fasting on aging. Using mice as a model, we investigate the underlying biological mechanisms. Our aim is to gain insights that may also be relevant to humans,” says the Bonn-based scientist.

More offspring than expected

The research results now published are based on a fortuitous discovery, as Ehninger and his colleagues had originally set out to investigate something else. Their aim was to examine how fasting affects the offspring of male mice. However, one particular finding steered their research in a new direction: aged male mice – senior individuals by human standards – that had fasted for extended periods produced an unusually large number of offspring. Contrary to initial hypotheses, this phenomenon was not due to fasting effects on reproductive organs or the endocrine state of the animals. Age-related changes in the testes, reduced sperm quality and lower testosterone levels, for example, argued against high fertility. “It was a bit of detective work to uncover the real cause,” says Ehninger, whose research group collaborated on the current study with experts from Qingdao University and the University of Health and Rehabilitation Sciences led by Prof. Yu Zhou. “Eventually, we realized: it is a matter of behavior. The fasting males had significantly more sexual contacts than mice that could eat freely. In other words, these animals had an unusually high frequency of mating and, as a result, an unusually high number of offspring for their age. Their mating behavior more than compensated for the age-related physiological limitations.”

Fasting in a 24-hour rhythm

Starting at two months of age, these male mice were subjected to a specific form of intermittent fasting. Their access to food followed a recurring 24-hour pattern: the animals were allowed to feed ad libitum for 24 hours, followed by 24 hours with access to water only. During the 22-month fasting regimen, the males were housed together without any contact with females. They were later introduced to three-month-old females that had been raised without dietary restrictions.

Effect takes time

Increased mating behavior was also observed in younger mice. These males had also started intermittent fasting at the age of two months, but had followed this diet for only six months before being introduced to females. They, too, were more sexually active than age-matched peers that had been fed ad libitum. However, the effect was absent in other experimental groups – both young and old – that fasted for only a few weeks. “For intermittent fasting to increase sex drive, it takes some time,” says Zhou. “Based on our experiments, the minimum duration appears to be somewhere between six weeks and six months.”

A question of serotonin

In the course of investigating the causes, the attention eventually turned to neurotransmitters that influence sexual behavior. Some have a stimulating effect, while others act as inhibitors. Among the sexually active male mice, one factor stood out: serotonin – a chemical messenger generally associated with inhibitory effects – was present at unusually low levels. “These mice were, so to speak, sexually uninhibited, the usual regulatory restraint was diminished,” says Ehninger. Serotonin is primarily produced in the gastrointestinal tract, but also in the brain, where it acts as a neurotransmitter mediating communication between neurons. However, its synthesis depends on the amino acid tryptophan, which must be obtained through the diet or released through the breakdown of the body’s own protein stores, such as those found in muscle tissue. Tryptophan is considered an essential amino acid, meaning that neither mice nor humans can synthesize it on their own. As a result, dietary intake plays a key role in regulating tryptophan levels in the body. It is, in fact, found in many common foods. “The lack of serotonin was clearly a result of fasting,” explains the DZNE researcher.

Is the fasting regimen relevant?

“All in all, the fasting mice consumed almost fifteen percent fewer calories than the animals in the control group. This also roughly applies to their intake of tryptophan,” says Zhou. “However, it is currently unclear whether the reduction in serotonin levels is linked to our specific feeding regimen or would also occur with other types of fasting. Future studies will need to clarify this.” As the scientist notes, it is also possible that the effect could occur under a general caloric restriction, where food is continuously available but in reduced amounts.

A potential approach for therapy

“Chemical messengers also play an important role in regulating sexual behavior in humans. This applies in particular to serotonin,” says Ehninger. As he points out, this is evident, for example, in the use of SSRIs, a class of antidepressant drugs that increase serotonin levels. A potential side effect of this therapy is reduced libido. Conversely, lower serotonin levels are known to promote sexual desire. “In view of this, I consider it very plausible that sexual desire in humans can be influenced by fasting – possibly not only in men, but also in women, since serotonin affects their libido as well.” According to Ehninger, there are actually only a few scientific studies on the effects of fasting on human libido. “In my opinion, it would make sense to investigate this in more detail. I see potential for therapeutic application. A lack of sexual desire is not necessarily perceived as problematic – but some people suffer from it. This condition is known as ‘hypoactive sexual desire disorder’ and particularly affects older adults. Fasting could potentially serve as a useful addition to existing treatment options.”

--

About Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE (German Center for Neurodegenerative Diseases): DZNE is one of the world’s leading research centers for neurodegenerative diseases such as Alzheimer’s, Parkinson’s and ALS, which are associated with dementia, movement disorders and other serious health impairments. These diseases place an enormous burden on patients and their families, but also on society and the economy of healthcare. DZNE contributes significantly to the development and translation into practice of novel strategies for prevention, diagnosis, care and treatment. DZNE comprises ten sites across Germany and collaborates with universities, university hospitals, research centers and other institutions in Germany and throughout the world. DZNE is state-funded and a member of the Helmholtz Association and of the German Centers for Health Research. www.dzne.de/en

END



ELSE PRESS RELEASES FROM THIS DATE:

Scientists create protein ‘seeds’ that trigger key pathological features of ALS and frontotemporal dementia

2025-03-28
28 March 2024, Leuven, Belgium — Accumulation of a protein called TDP-43 is a key feature of ALS and frontotemporal dementia. In a newly published study, researchers report ‘seeding’ this accumulation through fragments of the culprit protein created in the lab. The findings provide further evidence for a prion-like paradigm wherein protein aggregation occurs in a templated fashion. This breakthrough provides the research field with a powerful way to model and study the mechanisms driving neurodegeneration. TAR DNA-binding ...

Discrimination-related depression, anxiety pronounced among multiracial, White, Asian populations

2025-03-28
EMBARGOED UNTIL 11 a.m. EST on Friday, March 28, 2025 Contact: Jillian McKoy, jpmckoy@bu.edu  Michael Saunders, msaunder@bu.edu ## Discrimination-related Depression, Anxiety Pronounced Among Multiracial, White, Asian Populations A new study found that more than half of US adults encounter some form of discrimination, and that this mistreatment may fuel higher chances of depression and/or anxiety among specific racial and ethnic groups due to cultural, social, and systemic factors.  A ...

New approach makes one type of clean fuel production 66% more efficient

2025-03-28
COLUMBUS, Ohio – Researchers have uncovered a more efficient way to turn carbon dioxide into methanol, a type of alcohol that can serve as a cleaner alternative fuel.  In the lab, synthesizing methanol can be extremely difficult, due to the extremely complex reaction pathway needed to select for it. Previous attempts by the same team to manufacture this valuable liquid fuel from carbon dioxide have used a combination of cobalt phthalocyanine (CoPc) molecules and electricity, but this method is inefficient as only about 30% of the carbon dioxide is converted to methanol.  To ...

AI meets oncology: New model personalizes bladder cancer treatment

2025-03-28
Leveraging the power of AI and machine learning technologies, researchers at Weill Cornell Medicine developed a more effective model for predicting how patients with muscle-invasive bladder cancer will respond to chemotherapy. The model harnesses whole-slide tumor imaging data and gene expression analyses in a way that outperforms previous models using a single data type. The study, published March 22 in npj Digital Medicine, identifies key genes and tumor characteristics that may determine treatment success. The ability to accurately anticipate ...

New approach could treat anthrax beyond the “point of no return”

New approach could treat anthrax beyond the “point of no return”
2025-03-28
Anthrax, an infectious disease caused by the bacterium Bacillus anthracis, is often treatable in its early stages. But once the disease has progressed beyond the “point of no return” after just a few days, patients are almost certainly doomed. In a new Nature Microbiology study, University of Pittsburgh researchers show that a cocktail of growth factors reversed would-be lethal cell damage in mice with anthrax, suggesting that this approach could be adapted for use in patients beyond the brink. “While only a few people die from anthrax in the United States each year, there is always the concern ...

Those constantly distracted by their phone will just find other ways to procrastinate if it isn’t nearby

2025-03-28
If you just put away your phone to read this, chances are you’re not alone. Our phones are an endless source of distraction, and we interact with them every four to six minutes. This is often driven by habit as well as notifications, leading to a disrupted flow of activity while we’re trying to be productive. A new study published in Frontiers in Computer Science investigated if placing smartphones just out of our reach while we’re at work influenced device use for activities not related ...

Ottoman Empire’s religious ‘tolerance’ another form of control

Ottoman Empire’s religious ‘tolerance’ another form of control
2025-03-28
Population surveillance. The carrying of identification while traveling. Add to that the public presence of diverse religions and it sounds like 2025, but this was life in the Ottoman Empire 200 years ago. Yet this seeming tolerance of non-Muslim faiths was in fact tied to the first two aspects, according to research by Osaka Metropolitan University Associate Professor Masayuki Ueno. The Ottoman Empire lasted from around 1300 until 1922, and at various points in its history ruled present-day Turkey, Egypt, Greece, Hungary, and beyond. In the wake of the 1821 Greek revolt, the Ottoman Empire instituted ...

Smartphone bans alone fail to equip children for healthy use of technology

2025-03-27
Banning smartphone and social media access alone fails to equip children for healthy use of technology, argues a group of international experts in The BMJ today. They say the focus should shift to a rights based approach, underpinned by age appropriate design and education, that protects children from harm while developing skills to help them participate in a digital society. Bans on smartphone and social media access have been advocated in many countries to protect children from harm despite ...

Discovery of novel small compounds that delay flowering in plants

Discovery of novel small compounds that delay flowering in plants
2025-03-27
Ikoma, Japan—In an era where climate change threatens food security, scientists worldwide are searching for reliable ways to improve crop production. Extreme weather and shifting seasonal patterns can disrupt traditional agricultural cycles, making technologies that regulate the timing of plant growth invaluable for farmers worldwide. Plant growth and development are dependent on many factors such as the environment, photoperiod, and genetics. Flowering is an important event in a plant’s life ...

Expanding access to anti-obesity medications delivers 13% return on investment for society

Expanding access to anti-obesity medications delivers 13% return on investment for society
2025-03-27
A new USC Schaeffer Center white paper finds expanded access to anti-obesity medications would lead to significant increases in life expectancy and disease-free years while generating a substantial societal return on investment, even after accounting for treatment costs.   More than 4 in 10 U.S. adults have obesity, which is linked to increased risk of over 200 diseases — including heart disease, diabetes, cancer and dementia — and costs society $260 billion annually to treat. Highly effective new anti-obesity medications can be a powerful tool against chronic disease, but fewer than one-third of health insurers cover them amid concerns about upfront ...

LAST 30 PRESS RELEASES:

Do authoritarian narratives shape Japanese public opinion?

New plesiosaur discovery sheds light on early Jurassic evolution and plausible endemism

Chance discovery improves stability of bioelectronic material used in medical implants, computing and biosensors

Using artificial intelligence to calculate the heart’s biological age through ECG data predicts increased risk of mortality and cardiovascular events

“She loves me, she loves me not”: physical forces encouraged evolution of multicellular life, scientists propose

The hidden superconducting state in NbSe₂: shedding layers, gaining insights

New AI models possible game-changers within protein science and healthcare

Highly accurate blood test diagnoses Alzheimer’s disease, measures extent of dementia

Mind the seismic gap: Understanding earthquake types in Guerrero, Mexico

One hour’s screen use after going to bed increases your risk of insomnia by 59%, scientists find

Canada needs to support health research at home and abroad

Cannabis use disorder among insured pregnant women in the US between 2015-2020

Education system needs overhaul to support school anxiety, psychologists say

Play “humanizes” pediatric care and should be key feature of a child-friendly NHS – report

Stricter oversight needed as financial misconduct drives risk-taking in banking

Cardiac arrest during long-distance running races

Preventable cardiac deaths during marathons are down, Emory study finds

New study finds peripheral artery disease often underdiagnosed and undertreated; opportunity to improve treatments, lower death rates

Use of antidepressant medication linked to substantial increase in risk of sudden cardiac death 

Atrial fibrillation diagnosed in midlife is linked to a 21% increased risk of dementia at any age and a 36% higher risk of early-onset dementia 

Mode of death in patients with heart failure with mildly reduced or preserved ejection fraction

Intravenous ferric carboxymaltose in heart failure with iron deficiency

Artificial intelligence in the prevention of sudden death

Oral semaglutide vastly reduces heart attacks, strokes in people with type 2 diabetes

Prothrombin complex concentrate vs frozen plasma for coagulopathic bleeding in cardiac surgery

Who needs a statin? New study compares prescribing recommendations based on traditional risk factors vs. coronary artery calcium scoring

Finerenone and atrial fibrillation in heart failure

Low coronary artery calcium score is associated with an excellent prognosis regardless of a person’s age, new study finds

Groundbreaking consensus statement on conduction system pacing released: a major milestone in the evolution of pacing therapy

Nuclear monitoring system suggests landslide cut off internet in west Africa

[Press-News.org] Intermittent fasting increases sex drive in male mice: an approach for low libido in humans?
Current findings could point the way for new therapy option / Serotonin plays key role