Maca Man is a supplement marketed by GNC, a manufacturer and distributor of thousands of vitamins and nutritional supplements. The label says Maca Man contains 900 milligrams of Peruvian maca, 5 milligrams of Yohimbe, as well as L-arginine, niacin, and gingko biloba. Side effects may occur with the use of most of these ingredients.
According to Drugs.com, maca has very few, if any, adverse side effects. The root, grown mainly in the Andes of South America, contains up to 80 percent water. Other constituents include glucosinolates and isothiocyanates, which "have anticancer activity and may be responsible for some of the activity in the plant species. The aromatic isothiocyanates may be associated with aphrodisiac activity." It is used to increase sexual desire in men.
It also contains several amino acids, trace minerals, vitamins, sterols, protein, fiber and fatty acids, as well as compounds that have antioxidant properties.
According to Drugs.com, yohimbine, which is the generic form of yohimbe, increases the amount of blood that is allowed to flow into the penis and prevents blood from flowing out of the penis. It can cause an erection.
Side effects can include an allergic reaction, which may include difficulty breathing, closing of the throat, swelling of the lips, tongue or face; hives; irregular or fast heartbeat; confusion or unusual behavior; dizziness; anxiety, irritability, or nervousness; tremor; headache; or skin flushing. Other undocumented side effects may also occur.
According to the National Institutes of Health's website, Medline Plus, side effects of the amino acid L-arginine include stomach discomfort and a worsening of symptoms in people with asthma, which may be related to allergy, if arginine is inhaled.
Other potential side effects include hypotension, or low blood pressure, and changes in numerous chemicals and electrolytes in the blood. These may include high potassium, high chloride, low sodium, low phosphate, high blood urea nitrogen and high creatinine levels. People with liver or kidney diseases should avoid taking products containing arginine except under medical supervision.
Arginine may also increase bleeding in patients using blood thinners or antiplatelet drugs, or with underlying bleeding disorders. Arginine in Maca Man may increase blood sugar and potassium levels, and may worsen symptoms of sickle-cell disease.
Drugs.com lists niacin's side effects as possible allergic reaction; feeling light-headed, fainting; fast, pounding, or uneven heart beats; shortness of breath; swelling; yellowing of the skin or eyes; muscle pain, tenderness, or weakness with fever or flu symptoms and dark-colored urine.
Less serious side effects of niacin include mild dizziness; warmth, redness, or tingly feeling under the skin; itching, dry skin; sweating or chills; nausea, diarrhea, belching, gas; muscle pain, leg cramps; or insomnia.
Although side effects from the use of gingko are rare, Drugs.com says some serious side effects have been reported. They include allergic reaction; irregular heartbeat; muscle spasms, seizures and loss of consciousness. Less serious side effects may include headache, stomach upset or dizziness.