The page we read lists no specific side effects, but it does flag the main cautions. These are the ones that matter for arginine-based products.
L-Arginine can lower blood pressure. Combined with nitrate medicines (used for chest pain), ED drugs or blood-pressure medicine, it may cause a dangerous drop. Do not combine them unless a doctor has approved it. Blood thinners also deserve a doctor’s check.
Chest pain, fainting, a racing or irregular heartbeat, severe dizziness, a sudden drop in energy with lightheadedness, rash, or swelling of the face or throat. Mild stomach upset can occur with amino acids.
Maxentra is a general wellness supplement. It is not intended to diagnose, treat, cure or prevent any disease, and it is not a treatment for erectile dysfunction or heart conditions. Ongoing circulation or erection changes can be early signs of heart disease or diabetes, so see a doctor rather than relying on a supplement.
See also what research shows for each ingredient.