Mark Rosenberg, M.D.

Mark Rosenberg, M.D., completed his undergraduate studies at the University of Pennsylvania before earning his medical degree from the Georgetown University School of Medicine. He completed his residency in emergency medicine at Brooke Army Medical Center and subsequently served as Assistant Chief of Emergency Medicine at Walter Reed Army Medical Center. During his tenure there, Dr. Rosenberg also acted as a consultant on the management of drug toxicities and overdoses. He left military service in 1996 with the rank of Major. While in residency, he was honored as both Resident of the Year and Teacher of the Year, and he continued teaching during his time at Walter Reed.

In 2004, Dr. Rosenberg diagnosed his mother with metastatic lung cancer, an experience that redirected his professional focus. He began researching therapies targeting cancer stem cells and later founded a pharmaceutical company that ultimately merged with a Harvard spinout. More recently, he was awarded a patent for developing an extracorporeal filtration device designed to capture and eliminate circulating tumor clusters.

Dr. Rosenberg has also served for more than 20 years as a board member and consultant to the American Academy of Anti-Aging Medicine. He currently practices internal medicine, longevity medicine, and integrative oncology.

Tirzepatide vs. Semaglutide

Dr. Rosenberg’s take:

I have had the opportunity to follow many patients who were taking semaglutide and tirzepatide. There is no question that these drugs are extremely effective tools for treating diabetes and overweight/obesity. But keep in mind that these drugs are tools and they are not the sole answer to treating type II diabetes or obesity. A systematic review and meta-analysis included data from 37 studies. The investigators evaluated rate of weight regain from end of treatment in patients who had used either semaglutide or tirzepatide vs. only a behavioral weight management program.

This review found that cessation of semaglutide or tirzepatide was followed by rapid weight regain and reversal of beneficial effects on cardiometabolic markers. Interestingly, the weight gain was faster in individuals who were just treated with GLP-1s, vs. those treated with behavioral management.

Bottom line:

No free lunch! No matter what drugs you take, you have to improve your lifestyle.

The Benefits of NAD+

Dr. Rosenberg’s Take:

I intermittently take subcutaneous NAD, as do many of my patients. I find that some individuals notice improvement in their sense of well-being, while others do not. Personally, I have not noticed significant changes in how I feels with NAD. Having said that, because of my lifestyle, I feel excellent on most days. The literature supports the fact that individuals who are aging poorly, secondary to poor diet, high alcohol intake, inadequate exercise, overweight, etc, tend to have their NAD levels decrease at a faster rate, than healthy aging individuals.

So it is plausible that the greatest effects of NAD may be seen in individuals who are not aging well. While NAD is important for energy production, there is no evidence that “extra” NAD is beneficial. This is an example of how one size does not fit all. Having said that, I see now downside to using NAD in individuals without cancer.

Sexual Health Medications - A Patient's Guide

Dr. Rosenberg’s Take:

All of these PDE5 inhibitors are effective for ED, and they can also be helpful for symptoms associated with BPH (benign prostatic hyperplasia), such as urinary frequency.

Choosing the best one depends on how quickly you want the effect and how long you want the effect. As mentioned previously, there may be benefits beyond erectile function. Real-world patient data (insurance claims) have suggested that individuals taking PDE5 inhibitors may have a lower incidence of Alzheimer’s disease, particularly in men. PDE5 inhibitors have shown promise in improving cerebral blood flow and reducing neuroinflammation.

For most individuals, there is little if any downside to taking these drugs, and possibly significant upside. I personally take tadalafil 5 mg daily, for the potential positive effects on the brain.

Tadalafil and Workout Performance - The Off-Label Conversation

Dr. Rosenberg’s Take:

I have many patients who are on tadalfil chronically, but none of them report a noticeable change in vascularity or strength since starting. It may be that the effect is dose dependent, but that has not been studied. Again, I must say that “there is no free lunch,” you have to put in the work. But for most individuals, tadalafil is unlikely to cause harm.

In my opinion, you will get a much greater bang for your buck with hard work and creatine supplementation, as opposed to adding tadalafil.