Nitric oxide products, also known as pre-workout, NO, or NO2 products, contain L-arginine, an amino acid that increase the amount of nitric oxide produced in the body. Nitric oxide is a free-form gas that acts to control blood flow in the body. Creatine is an amino-acid-like substance synthesized in the liver from the amino acids glycine, methionine, and arginine. Nitric oxide and creatine may have synergistic health and fitness benefits, but they may also cause side effects in some individuals.
Nitric oxide supplements may aggravate the herpes virus. L-arginine, the main ingredient in NO products, can drastically impact the replication of the herpes virus, causing outbreaks or worsening existing conditions. The amino acid L-lysine helps inhibit the replication of the herpes virus. A diet consisting of low lysine-to-arginine ratios may be responsible for more frequent herpes outbreaks. Anecdotal reports suggest that it is not uncommon to experience a herpes outbreak within days of beginning nitric oxide supplementation. Those with genital herpes or frequent cold sores should avoid NO2 products, decrease arginine consumption and consider supplementing with lysine. Foods naturally high in arginine include chocolate, meat, seafood, and nuts and seeds.
Vasodilation and Bleeding
Nitric oxide products create an effect in the body known as vasodilation, which allows blood vessels to relax and opens up pathways for blood flow. This side effect has many benefits for athletic performance, anti-aging and heart health. However, adverse side effects from vasodilation can include the risk of excessive bleeding and low blood pressure. If you're on heart medications, like blood pressure medication, check with your physician before using any of these products. Nitric oxide supplements mimic this effect and may cause other adverse effects on the heart when combined with certain drugs.
Miscellaneous Arginine Side Effects
Overdosing with nitric oxide products can be toxic. Adverse effects on waste-handling organs, such as the liver and kidneys, are possible. Too much L-arginine can cause diarrhea, weakness nausea, headaches, increased heart rate and palpitations, water retention, fatigue, skin irritations and dry mouth. Fainting is a common anecdotal side effect reported by users. Serious side effects may include breathing problems, severe allergy or rash, hives, itching, wheezing or life-threatening asthma complications. The Mayo Clinic reports a rare side effect known as anaphylaxis, or shock involving sudden chills, sweating, tremors, vomiting and fainting. Recent heart attack patients, those on blood thinners, pregnant or nursing mothers, and/or those with liver disease or sickle cell anemia should avoid NO2 products completely.
Creatine Side Effects
The most common side effect of creatine use is gastrointestinal upset, including loss of appetite, stomach discomfort, diarrhea, and/or nausea, according to the Mayo clinic. Reports of muscle cramps, strains and sprains, heat intolerance, dehydration, fever and electrolyte imbalances are also common. Creatine causes muscle cells to retain water, which usually manifests as water-weight gain. It is not uncommon to gain 5 to 10 lb. in as little as two weeks of creatine use. The Mayo Clinic also reports that individuals with kidney and/or liver disease should avoid creatine because it may put excess stress on these organs. Creatine may also affect the activity of the insulin hormone, which means hypoglycemic and diabetic users should be monitored by a doctor and closely monitor their blood glucose levels. Inflammation and ischemia of the lower leg, also known as compartment syndrome, may be exacerbated by creatine supplementation. Other side effects can include thirst, mild headache, anxiety, irritability, aggression, nervousness, sleepiness, depression, abnormal heart rhythm, fainting or dizziness, blood clots in the legs, seizure or swollen limbs.