Phenylalanine comes in several forms as a supplement:
L-phenylalanine is an essential amino acid. It's also found in protein in the foods we eat.
DL-phenylalanine, which contains both the D- and L-forms
Some research shows that stinging nettle root may be helpful in treating this problem. Experts are not sure which components in the plant may have an effect on BPH. More research is needed to show that the treatment is indeed effective.
Allergies. Stinging nettle leaf may be useful in reducing the symptoms of hay fever by acting as an anti-inflammatory. Some research has linked treatment with stinging nettle leaf to relief of symptoms such as sneezing, runny nose, and itchy eyes. But more well-designed studies are needed to confirm this effect.
Joint pain. Research has found some evidence that rubbing stinging nettle leaves on painful joints can provide pain relief. One study also found that eating stewed nettle leaves was a helpful addition to the anti-inflammatory drug diclofenac.
People have also used stinging nettle as a diuretic -- a treatment that causes the body to shed more water in the urine. Research has found this effect from stinging nettle in rats.
Optimal doses of stinging nettle have not been set for any condition. Quality and active ingredients in supplements may vary widely from maker to maker. This makes it hard to set a standard dose.
Can you get stinging nettle naturally from foods?
Stinging nettle can be eaten on its own or as an ingredient in foods. Nettle leaves must first be cooked or steamed to destroy the hairs on them, which contain a number of irritating chemicals.
Most medicinal uses of stinging nettle use more of the plant than you would typically eat.