How do pills work?

[Schizophriend]

So right now I'm trying to get the achievement where you have to "grow" 5 times, most likely with the red mushroom item or the "One makes you bigger" pills.
I've tried dozens of runs now trying to get the size pills but it feels like they just never show up. I just get the same pill effects over and over, but never the one I need. How exactly does it work, does the game decide at the beginning of each run, which pill effects are gonna appear? And then some just never appear in that run?

Just asking since I know there's just a certain number of pill colors, less colors than effects.

[Abby]

Pills, Cards and Ruins are all decided by the seed of the run. You can allso use the Strength card to grow in size, though it wears off after you leave the room. What I suggest is using Greed Mode and breaking it with the D20, to reroll pennies into chest over and over.

I highly suggest while hunting for this achievement to check chest and shops for Baggie of Pills, since it'll put more pills in your pool and replace are cards/runes with pills. Also try and save up 15 pennies to get Placeblo from the shops, that way you only need to find 1 "One that makes you larger" pill, and use placeblo to grow 4 out of 5 of those times. PHD might help, as I don't think it removes "One that makes you larger" from the pill pool.

Otherwise, you can try to get a Strength card in Greed mode, with the Blank card, and rerolling the shop until you find a battery, and then use the strength card 5 times in the same room.

[Jeff]

I recommend starting with Lazarus. He starts with a random pill. You can immediately take the pill and hold R until the pill is "one makes you larger".

Then, scour the shop for placebo, mom's bottle of pills, or little baggy. These should make it possible one way or another to find 4 more during your run.

As stated above it also works in greed mode. Not sure which has a higher % of working...might be greed mode tbh, because it has more guaranteed shops and more guaranteed $$ and also you get auto-restock.