I had an extremely low milk supply partially due to a medical condition that constricts my blood vessels/circulation. I tried everything under the sun so I'll give you my list of what I tried and what did and did not work.
Hospital Grade Medela Pump (rented): Worked much better/faster than the Pump In Style Medela did. I discontinued use after 3 weeks because it was too costly to rent.
Fenugreek: 12 caps per day (3 caps four times per day) in combination with 3 caps of Blessed Thistle (1 cap three times per day) worked best as far as Fenugreek was concerned. FG can be used alone however yields the best results in combo w/ BT. This dosage was recommended by my daughter's M.D. who's also a lactation educator. Loved my maple fragrance, I smelled like pancakes!
Domperidom: By far yielded the best results. Went from 2oz. of milk to 4oz. in 2-3 days. The caveat is that this is a medical drug that is not approved in the U.S. although it is readily thoughout the UK and Canada. This drug produces milk as a side effect and is often used by apdoptive mothers. I did a LOT of research on this drug, consulted doctors, pharmacists, and lactation specialists and then felt comfortable enough to use it. I got it with a presciption (from daughter's M.D.) through a compounding pharmacy. It cost me $89 for 100 pills and I took 3 pills per day. One typically can go off this med in 8-12 weeks (I think) w/ success. It was too costly for me so I discontinued use.
Mother's Milk Tea: Cheap fix but FG and BT caps work better and cost less considering how often you have to drink the tea.
Beer (w/ hops, w/o hops, alcoholic, non-alch): Didn't do a thing for me.
7 up: Someone suggested...I tried...no results.
It was really painful fo me to BF most of the time. Even still at 4 months due to my medical condition; although the meds I took for this condition, while BFing, dilated my veins to increase blood flow thus easing the pain to some degree.
I became a slave to my pump and so obsessed w/ producing milk that I kinda lost myself during the process. I eventually gave up at 5.5 months but I did try everything I could that seemed reasonably safe.
BTW, I also supplemented w/ formula the entire time I breastfed because I simply could not produce enough milk. I think if I could have continued w/ both the Domperidome and the hosp. grade pump I would have seen better results. HTH