The term “natural” on a product label doesn’t always mean it’s healthy—or even safe. Often when people want to try alternative or complementary treatments, they turn to herbs and supplements. And yes, they come from nature, but many of these products haven’t been well studied and can be sold without being tested and regulated. But that’s starting to change: By next year, all supplement makers will be required to test their products for contaminants and ensure they’re correctly manufactured and labeled.
In the meantime, be aware that natural products may do more harm than good and can even interfere with prescription drugs. Before you take any natural products, talk with your healthcare provider and check out the chart at right for the latest research on the 10 most commonly used supplements.
What it’s used for: Colds, flu and other infections
Effectiveness: It won’t prevent infection, and studies on whether it can treat colds and flu have had mixed results.
Risks/possible side effects: It’s generally safe, but some people experience gastrointestinal problems. Others, especially those with asthma or certain allergies, may have a reaction.
What it’s used for: Erectile dysfunction, hepatitis C, menopausal symptoms, high blood glucose and blood pressure
Effectiveness: Studies show it may lower blood sugar, but more research is needed to confirm its use for this and other conditions.
Risks/possible side effects: Headaches, sleep problems, gastrointestinal problems, allergic reactions
What it’s used for: Memory loss/dementia, asthma, bronchitis, fatigue, ringing in the ears, leg pain caused by narrowed arteries, sexual dysfunction and multiple sclerosis
Effectiveness: New research finds it does not prevent dementia or memory loss; studies on other uses are ongoing.
Risks/possible side effects: Headache, nausea, stomach upset, diarrhea, dizziness and allergic skin reactions. Ginkgo may increase bleeding risk, and ginkgo seeds can cause seizures.
What it’s used for: High cholesterol and blood pressure; some people use it to try to prevent some types of cancer
Effectiveness: It may improve high cholesterol levels and atherosclerosis, and some studies say eating garlic may lower the risk of certain cancers.
Risks/possible side effects: It’s generally safe but may have a blood-thinning effect, so it’s not recommended before or after surgery or dental work.
What it’s used for: Osteoarthritis (OA)
Effectiveness: It works best on knee OA and may help with other forms of OA.
Risks/possible side effects: Upset stomach, drowsiness, insomnia, headache, skin reactions and sun sensitivity
St. John’s Wort
What it’s used for: Depression, anxiety, sleep disorders and nerve pain
Effectiveness: Some research suggests it helps mild or moderate depression—but not more serious depression.
Risks/possible side effects: Anxiety, dry mouth, dizziness, gastrointestinal symptoms, fatigue, headache, sexual dysfunction and increased sensitivity to sunlight. It may interfere with some drugs.
What it’s used for: Nausea, indigestion, colds, headaches, muscle and nerve pain and irritable bowel syndrome (IBS)
Effectiveness: It seems to work for IBS and indigestion, but other uses haven’t been studied enough.
Risks/possible side effects: In small doses, it seems to be safe for most adults but can cause allergic reactions and heartburn.
Fish oil/omega-3 fatty acids
What it’s used for: High blood pressure, high triglycerides, inflammation, asthma, rheumatoid arthritis (RA) and many other conditions. It may also help with infant brain development.
Effectiveness: It’s best for lowering high blood pressure and triglycerides, and it seems to help with RA, inflammation and brain development.
Risks/possible side effects: Some fish contain mercury, but supplements are safe. The most common side effects are stomach pain, burping, heartburn and diarrhea.
What it’s used for: Stomachache, nausea, diarrhea, rheumatoid arthritis, osteoarthritis and joint and muscle pain
Effectiveness: It seems to relieve pregnancy-related nausea, but how it helps with other conditions is unclear.
Risks/possible side effects: Ginger’s side effects are rare when it’s taken in small doses, but powdered ginger can cause gas, bloating, heartburn and nausea.
What it’s used for: High cholesterol, menopausal hot flashes, osteoporosis, memory problems, high blood pressure and breast and prostate cancers
Effectiveness: Daily soy may lower LDL cholesterol and reduce hot flashes, but more research is needed for other uses.
Risks/possible side effects: It’s considered safe in foods, but supplements may cause nausea, bloating and constipation. Soy has been said to both increase and decrease breast cancer risk, but more research is needed.
Source: National Center for Complementary and Alternative Medicine; Mayo Clinic