Help me with the passage

[guest]

I have a medical document to translate but there are some sentences i can't understand what they exactly mean. Help me. Like this passage:
"I thought the time was right to ask cometic companies if they were ready to wok with alpha hydroxy acids. Much to my surprise, not a single company was interested. One company even conducted a short study to test the efficacy of glycolic acid in the treatment of dry skin and told me, in no uncertain terms, that glycolic acid was not the least bit effective"
I can understand most of the passage but the last part "glycolic acid was not the least bit effective" makes me a little confused. It means acid glycolic was but not as effective as they expected?

[Alan]