Originally used as an anti-cancer drug and as an immunosuppressant for organ transplant patients, rapamycin is now touted as a miracle antiaging drug.
The quest for being young forever is not new. Stories, records from ancient civilisations and movies have long portrayed eternal youth as one of the ultimate goals in this life. However, this fountain of youth remains elusive until some scientists discover that rapamycin might increase longevity and reduce the effects of aging.
While this is good news for many seeking to stop father time, the effects of rapamycin on longevity are only seen in animal model studies. There still need to be clinical trials examining the claim that rapamycin can increase longevity and delay the signs of aging.
What is rapamycin?
Rapamycin is a family of antibiotics that include macrolides such as clarithromycin, erythromycin and azithromycin. This drug was initially discovered on Easter Island from a bacterium that thrives in its soil. The bacterium is known as Streptomyces hygroscopicus and was found in 1972 to produce the drug. Rapamycin was taken from the original name of Easter Island, Rapa Nui.
How does rapamycin work?
Rapamycin can block cell growth and the spread of cancer cells by interrupting the mTOR pathway [3]. Once this signalling pathway is blocked, the cell undergoes autophagy or eating of its old organelles and dysfunctional proteins or cell parts. This autophagy is critical in promoting the health of the cells. This also results in recycling the old parts of the cell, thereby renewing and rejuvenating old cells.
The drug’s action on the mTOR might explain the antiaging effects of rapamycin. The continuous rejuvenation of the cells could lead to increased lifespan and health span of the animals. When applied to humans, blocking of the mTOR signalling pathway might be the answer to improving longevity and health.
Can rapamycin improve longevity?
Increasing longevity or the lifespan of individuals has long been an aim of modern medicine. Today, there are several drugs and supplements used to prolong life. These include antioxidants and substances taken from tea and even coffee.
Rapamycin is an exciting drug since it can suppress immunity and act as an immunosuppressant and an anti-cancer drug when given in high doses. However, it can boost immunity and promote animal longevity when given in low doses.
The effects of rapamycin on longevity are primarily seen in animal studies but have yet to be seen in human studies. It should be noted that large clinical trials are not only costly, but it is also time-consuming. A board should approve these clinical trials of ethics to ensure that there is convincing evidence from animal studies that the intervention might work in humans.
Current evidence from animal studies strongly supports the hypothesis that rapamycin can promote longevity. Hence, it may not be surprising if small clinical trials are designed and implemented to examine rapamycin’s effectiveness in delaying aging and promoting longevity and wellness.
Can rapamycin promote longevity in animals?
The answer is yes! There are animal model studies using mice and fruit flies that revealed the effects of rapamycin on longevity.
A study that used drosophila flies or fruit flies [1] showed that when these flies were given rapamycin from days 1-30, they tended to live longer than the control group. Notably, the effects of the drug are sustained even when this is discontinued on the 30th day of the life of the flies. The results appeared similar in flies treated with the medication at days 30 and 45. This showed that early drug administration and withdrawal from treatment could still increase longevity.
One of the flies in the study survived until 60 days old. A 60-day-old fruit fly is considered very old compared with the human lifespan. If you wonder if rapamycin is still effective when administered during old age, the answer is no. As the fruit fly study demonstrated, those treated late had a shorter lifespan. Early administration of rapamycin might result in a longer lifespan compared with those who received the drug later in life.
A second study [2] studied rapamycin’s effects on mice’s longevity. Results mirrored the findings in the fruit fly study. The mice in the study increased their lifespan by an average of two months after treatment with rapamycin. This is an average of six years of added life in human life. A month of a mouse’s lifespan is equivalent to roughly three years in human life.
In the mice study, mice in the experimental group were given rapamycin for three months, with the drug stopped at the end of the three months. All the mice in the study were 20 months old or, in human life, about 60 years old. One of the mice survived until three years and eight months. Converting to human-life years, this is about 140 years old! The average lifespan of mice is only 30 months.
Can rapamycin promote longevity in humans?
The results of the animal model studies are promising. On average, it might extend its lifespan by about six years! However, these results are only seen in animals and not in humans. As previously explained, there still needs to be human studies examining the effects of rapamycin on human longevity.
Despite the lack of clinical trials, rapamycin not only promote longevity or lifespan, but it also improves healthspan. One of the concerns among older people today is whether their improved lifespan also equates to improvement in healthspan. Healthspan refers to whether an older adult still enjoys relatively good health with no long-term conditions. Being free from disabilities associated with aging and long-term conditions remains one of the main goals of individuals and healthcare practitioners.
Findings from animal studies provide initial evidence that rapamycin does promote not only a longer lifespan but also healthspan. Here are some benefits of rapamycin recorded in animal model studies:
- Improved cardiovascular health
- Delay in onset and progression of dementia
- Improved immunity
- Improved gut health
- Lowering of blood pressure or hypertension
- Increasing blood flow to the brain, thereby promoting brain health
All these benefits point out that apart from increasing lifespan, rapamycin has the potential also to improve healthspan.
What are the common side effects of rapamycin?
The side effects noted in patients taking rapamycin include the following:
- Mouth sore
- Fatigue
- Diarrhoea
- Constipation
- Anaemia
- High blood pressure or hypertension
- Swelling of the hand and feet
Notably, these side effects were only recorded in immunocompromised and organ transplant patients. It is impossible to determine if these side effects are also present in those taking low doses of the drug for longevity and as antiaging.
With no medical records or studies documenting the side effects of rapamycin as an antiaging drug, it is best to consult your doctor when taking these medications. Your healthcare professional can explain the drug’s benefits and potential side effects.
What are the appropriate doses of the drug?
Since there are still no studies investigating the antiaging effects of rapamycin or its impact on longevity, there are also no recommended doses for the drug for these purposes.
Although there are no recommended doses to promote longevity, studies on anti-cancer patients showed that doses as high as 2-5 mg/day are well tolerated. The amount for promoting longevity might be lower as mice studies showed that lower doses resulted in increased longevity.
In a nutshell, rapamycin is a promising antiaging drug that can promote longevity. It might be the next wonder drug and restore youthfulness and better health in adults dreaming of staying healthy and living longer.
References:
- https://www.nature.com/articles/s43587-022-00278-w
- https://pubmed.ncbi.nlm.nih.gov/27549339/
- https://pubmed.ncbi.nlm.nih.gov/15460177/
