Biohacker Bryan Johnson 100mg doxycycline has revealed he takes erectile dysfunction medications every day to extend his lifespan. 

Johnson, who is 47 but has the body of a man in his 30s and the penile health of a 22 year old, told millions of his followers he takes a single dose of 2.5mg of the ED medication Cialis 'for longevity and not for his three hour long titanic nighttime erections.'

Cialis is typically prescribed to treat erectile dysfunction and can work for up to 36 hours in the body. While similar to Viagra in helping men get and maintain erections, the active drug in Cialis is tadalafil and the active drug in Viagra is sildenafil. 

Doctors advise only consuming 2.5 to 5 mg (depending on the body's response to the medication) of Cialis once a day or when needed for sexual activity.

Taking Cialis without needing it for erectile dysfunction or other conditions can lead to potentially dangerous side effects including low blood pressure, vision changes, dizziness and fainting. 

Some common side effects include headaches, heartburn, back pain and muscle pain in the arms and legs. 

However, Johnson believes the tiny tablet may have more dynamic uses. 

In a lengthy X thread where he quoted nearly 10 individual studies that supported tadalafil's effects on longevity, the biohacker noted that the erection medication has the potential to improve 'heart health, metabolism, and brain function.'




Biohacker Bryan Johnson has revealed that he takes 2.5mg of Cialis, an erectile dysfunction medication, every day to extend his lifespan

First, Johnson highlighted how Cialis can help improve blood circulation by increasing the levels of nitric oxide in the body. 

The anti-aging expert wrote: 'Cialis's effects on blood vessels might benefit many organs. It boosts nitric oxide (NO), relaxing arteries.  



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'Enabling better circulation, organ blood flow, and a bit lower blood pressure. Basically helping to keep your blood vessels and heart healthier, improve your fitness, and prevent age related disease and preventing premature death.'

Nitric oxide relaxes blood vessels by signaling the vascular smooth muscle cells (specialized cells that line the walls of blood vessels) to relax, causing the vessels to widen, which in turn improves blood flow and lowers blood pressure. 

Wider blood vessels and improved blood flow can ensure that adequate amounts of oxygen and nutrient supply is provided to the heart muscle - preventing heart attacks and strokes.  

To back his claim, he referenced a 2025 American Journal of Medicine study that suggested tadalafil (Cialis) and sildenafil (Viagra) use in erectile dysfunction patients can reduce the risk of mortality, cardiovascular disease and dementia. 

The longitudinal study analyzed over 500,000 US men above the age of 40 that were suffering from erectile dysfunction and over a million men with lower urinary tract symptoms that had been prescribed tadalafil or sildenafil between 2004 to 2021. 

Results found the medications helped reduce the risk of mortality by 34 percent, heart attack by 27 percent, strokes by 34 percent, blood clot formation by 21 percent and dementia by 32 percent. 




Doctors advise only consuming 2.5 to 5 mg of a Cialis tablet once a day or when needed for sexual activity 







It also found tadalafil showed more significant benefits than sildenafil.

Johnson also noted improved blood flow in the body increased levels of nitric oxide may also 'aid cognitive functions especially as we get older.'

An 2019 Clinical Psychopharmacology and Neuroscience study involving 25 men between the ages of 50-75 who had been suffering from erectile dysfunction for at least three months and had mild cognitive impairment were given 5mg of tadalafil once a day for eight weeks.

Results showed those on the medication had increased levels of blood flow in specific brain regions including the brainstem and precuneus, which is responsible for episodic memory as well as visuospatial processing. 

An increased blood flow can improves overall cognitive function, particularly in conditions such as Alzheimer's disease.

Another small clinical trial published in Alzheimer's & Dementia suggested Cialis can help prevent vascular dementia - a type of cognitive decline caused by damage to the blood vessels in the brain - by increasing blood flow in the brain. 

Lastly, Johnson went on to claim Cialis can also help 'improve metabolism, blood sugar control and can help increase fat burning' - indicating it may be beneficial for diabetic patients. 




Johnson highlighted how Cialis can help improve blood circulation by increasing the levels of nitric oxide in the body

He highlighted a 2022 Diabetology & Metabolic Syndrome study that found high levels of nitric oxide in the body can 'counteract insulin resistance in animals and humans.'

Insulin resistance is a condition in which the body's cells become less responsive to insulin - the hormone responsible for regulating blood sugar levels by allowing glucose (sugar) from the bloodstream into cells for energy.

Nitric oxide is a crucial information transmitting molecule that plays a vital role in maintaining blood vessel health and insulin sensitivity in the body. 

Low levels of nitric oxide can make the body become more resistant to insulin and pave the way for type 2 diabetes. 

According to the study, 45 people who were taking 5mg of tadalafil once a day for six months were found to have significantly improved long-term blood sugar control levels than their counterparts who were not on any erectile dysfunction medication.