Magnolia Bark Extract

Magnolia officinalis is a traditional chinese medicine known for its neuroprotective and relaxing properties, being used to treat depression and anxiety as well as acting as a slight sedative. It may also possess anti-cancer effects in higher doses.
The dosage of magnolia officinalis to take varies on goal. For those related to GABA (including anxiety, sedation, stress, and epilepsy) an oral dose of 0.2mg/kg in mice appears effective and suggests very lose doses (5-10 mg) are effective in humans.

For those goals related to learning or depression, higher doses may be required. This usually means 15-30mg/kg in rats, and suggests a human dose of:

160-330 mg for a 150lb person

220-440 mg for a 200lb person

270-550 mg for a 250lb person

The above doses refer to the total neolignans (usually magnolol plus honokiol), which are usually at 1-10% of a basic bark extract unless otherwise concentrated.

Infromation from Google