We cannot list Strong Peak’s exact side effects, because amounts and a full label were not published. We can describe the cautions that apply to the ingredients it names.
L-Arginine can lower blood pressure. Combined with nitrate medicines (used for chest pain) or ED drugs, it may cause a dangerous drop. Do not combine them unless a doctor has approved it.
Chest pain, fainting, a racing or irregular heartbeat, severe dizziness, rash, swelling of the face or throat, or an erection lasting more than four hours (an emergency).
Strong Peak 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 low testosterone. Ongoing changes in desire or erections 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.