Vitex - correct dosage

[Fay]

hello

Im hoping i can get clarity about the amount of Vitex to take for PMS symptoms such as breast pain, brown spotting etc?
In know in the book Lara says there are different strengths from 200mg to 1000mg but its difficult to decipher what is the theraputic dose for PMS and also what to look out for on supplement bottles.

For example the brand Thompsons sells it labelled as: "Vitex agnus-castus (Chaste Tree) ext. 187.5 mg, derived from dry fruit 1.5 g (1500 mg)".

So in this case am i getting 187.5mg of vitex or 1500mg?

Any clarification would be amazing!