Herb Pharm Feverfew

Our assessment

The evidence shows that while feverfew is a traditional herb, the specific data provided does not support strong conclusions for this product. The data available is for calcium, not feverfew. For the ingredient calcium, our assessment is that it plays a critical role in bone health, but you should be aware of potential risks with high intake [NIH ODS].

How it works

For calcium, think of it as a structural building block — it supports bone mineralization and density, and also helps your muscles relax and your nerves send signals properly [NIH ODS].

Safety profile

FDA received 592,059 total adverse event reports across all supplements. For calcium specifically, high intakes may increase the risk of heart disease and prostate cancer. Symptoms of very high calcium levels include constipation, nausea, weight loss, extreme tiredness, frequent urination, and abnormal heart rhythms [NIH ODS] [FDA data].

Our recommendation

Data not available for feverfew specifically. For calcium, do not exceed 2,000 mg daily from all sources without medical supervision. Be aware that calcium can reduce absorption of medications like tetracycline antibiotics and levothyroxine [NIH ODS].

Supplement labels contain several key sections regulated by the FDA:

• Serving Size — The recommended amount per dose. Always check this — some products require multiple capsules per serving.
• Amount Per Serving — Shows the quantity of each nutrient in the product, typically in IU (International Units), mg (milligrams), or mcg (micrograms).
• % Daily Value (%DV) — Indicates how much a nutrient in a serving contributes to a daily diet. 5% DV or less is low; 20% DV or more is high.
• Other Ingredients — Lists inactive ingredients like fillers, binders, and capsule materials (e.g., gelatin, cellulose, magnesium stearate).
• Suggested Use — The manufacturer's recommended directions for taking the supplement, including timing and dosage.

Source: FDA Dietary Supplement Labeling Guide