Biohacker Bryan Johnson revealed he was ‘microdosing’ weight-loss drugs but stopped when his sleep ‘degraded’ and he began experiencing heart issues.
The 48-year-old, who claims to be more than a decade younger biologically than his actual age, wrote on X this week that he started taking 0.5 milligrams per day of tirzepatide, the active ingredient in the weight-loss injections Mounjaro and Zepbound.
It’s unclear exactly how long he was taking the drug. A typical dose of the drug starts at 2.5mg per week and slowly increases to a maximum of 15mg weekly.
Despite claiming to have less than 10 percent body fat, Johnson also said he tried liraglutide, sold under the brand names Victoza and Saxenda, and semaglutide, better known as Ozempic and Wegovy.
The drugs are all GLP-1 agonists, meaning they mimic the effects of the hormone glucagon-like peptide-1 (GLP-1) and increase satiety or fullness.
While he didn’t comment on any weight loss, Johnson claimed tirzepatide increased his resting heart rate by three beats per minute and lowered his heart rate variability (HRV) by seven.
HRV is when the amount of time between heartbeats fluctuates slightly. While these variations are normal, health experts note a higher HRV shows the body is better able to handle stressful situations without resting heart rate jumping up and putting strain on the heart.
A higher resting heart rate, meanwhile, makes it more difficult for the heart to pump blood throughout the body, increasing the risk of heart attack and stroke.
Biohacker Bryan Johnson, pictured here, revealed he has been ‘microdosing’ GLP-1 medications like tirzapatide
Johnson wrote: ‘GLP-1s raise your resting rate, which can degrade sleep quality and lower HRV.
‘Good to know in case you’re wondering why your heart rate is higher or your sleep a bit worse.’
Johnson claimed microdosing liraglutide raised his resting heart rate by six to 10 bpm. Semaglutide increased it by two to four bpm.
Johnson has previously claimed on his Blueprint blog that his resting heart rate is between 40 and 49 beats per minute (bpm). A resting heart rate below 60 is considered bradycardia, or a low heart rate typically caused by aging, certain medications like beta blockers and intense physical activity.
If the heart beats too slowly, it may not be able to pump enough blood to vital organs and tissues, increasing the risk of heart attack and stroke.
The biohacker said an increased resting heart rate ‘can degrade sleep quality.
While a healthy range during the day is 60 to 100 bpm, the average adult’s resting heart rate should be between 40 and 60 bpm while sleeping.
During sleep, the body’s parasympathetic nervous system signals a need for rest and repair, which lowers heart rate. Palpitations, however, may disrupt sleep, but the increases Johnson noted still put him within a healthy range for sleeping.
It’s unclear what Johnson’s exact heart rate variability was before or after microdosing GLP-1s, but a healthy range for adults is 20 to 100 milliseconds.
Resting heart rates change based on what a person is doing. Rest or relaxation generally lowers it, while exercise or stress increases it. HRV measures the amount resting heart rate shifts based on the situation.
According to the Cleveland Clinic, a higher HRV shows that the nervous system is better able to adapt to stress and new situations than a lower HRV, so a higher HRV is seen as ideal.
Johnson said microdosing weight-loss drugs increased his resting heart rate and heart rate variability
Though GLP-1 medications are primarily meant to help users lose weight, Wegovy, Victoza and Trulicity (which uses dulaglutide) are all also approved to reduce the risk of cardiovascular risks like heart attacks in people with heart disease.
The drugs have been shown to lower glucose (blood sugar) and reduce inflammation around the heart, lowering the risk of heart attack and stroke.
A study presented earlier this year by researchers at Mass General Brigham in Boston found using tirzepatide reduced the risk of people with heart conditions being hospitalized by up to 58 percent.
And those specifically taking semaglutide, used in Ozempic and Wegovy, were 42 percent less likely to wind up in the hospital compared to patients taking a placebo.
A 2023 study also found semaglutide was three times more effective than existing heart failure treatments in reversing signs of the disease.
Johnson claimed he was taking a 0.5-milligram dose of tirzepatide, far less than the initial 2.5 milligram dose once per week that can eventually increase to five, 10 and 15 milligrams weekly.
However, taking GLP-1 agonists can lead to gastrointestinal symptoms ranging from vomiting and diarrhea to stomach paralysis, as well as low blood sugar, especially in people who do not have diabetes or obesity.