So, after finishing the related quest, I had seven doses of the serum in my inventory. Jack never offered a point in dialogue for me to give it to him, so that's where it remained. unused, until I decided to restart my character.

In inventory, its in the AID tab, and shows 36,000 points of rad removal per dose. I don't know if it works like Radaway over time (very long-term radiation immunity?) or instantly. Curiosity has gotten the better of me though. so, I'm wondering if anybody knows what it does, or how it works?

Yes, works over time, lasts for about an hour or so. Basically makes you immune to radiation unless you go soak in a vat of toxic waste or wander naked through the glowing sea. Depending on how you finish the quest you can get access to an unlimited supply although you can only have 1 at a time.

Over time. If they just wanted to remove all rads instantly, they only need -1,000 rads; the extra 35,000 is wasted, because you die at 1,000 rads.

Ah, thanks guys! So is this serum ever pointed toward a particular quest or exploration area? I mean, I haven't thus far run into anyplace where my hazmat suit hasn't been sufficient for the most part.

Nope, you never -need- the serum. But it is amazing for tough fights I find. Fighting deathclaws in the glowing sea is made much easier when you are in your combat armor as opposed to your hazmat suit. It is also free, so cheaper than radaways/rad-x for dealing with radiation, and the +5 strength is handy for looting, or if you are melee. I keep one around because it is useful in many different circumstances.

Get the ghoulish perk and try it out together. Stand in a pool of water and get instant healing.

I am level 50, have been all over the map, and have yet to even hear rumors about where I could find a hazmat suit........ I have never seen one in random loot.

Try near dunwich borers, there is a little hideaway with a hazmat suit. A few places in the glowing sea have them. The reactor in the institute might have one, the mass fusion building if I recall. I have about 5 of them so far, none of them were loot.

I had two with a previous character. I don't remember where I got the second one, but I'm fairly certain I got the first one in the Polymer labs...

There's also one for sale at Fallon's Basemant, and two more at The Switchboard.

I've got at least 15 in my inventory. Level 52 and have pretty much completed all quest and 250 locations or so. I know the quest to go find Virgil kind of led me to one or two suits.

If memory serves, Dr. Amari either gives you one when she points you to the Glowing Sea or there is one laying around in the Memory Den. That's usually where I snag my first one. There are two on a shelf in the Switchboard (Railroad quest, but you might be able to get in without it being active - haven't tried, so don't know). I don't think they are on any of the leveled loot lists, so they won't show up as dropped loot, but clothing merchants would likely have one on occasion at your level. I'm pretty sure that I saw one last night somewhere in or near the fish packing plant.

Fallon's basemant? That place was full of Supermutants when I went there......

I know of three off the top of my head. Two can be found in the Switchboard during the Railroad quest 'Tradecraft'. If you don't want to do any Railroad quests, head to Cambridge Polymer Labs and complete the quest there. In the research area, you'll find a Hazmat suit. I want to say it's in the room where you open the door to the room with the radioactive isotope, which lets you don it while facing the Glowing One there, but I haven't done the quest in a while, so I'm not sure. I do know for a fact that there is one there, though.

You can buy one from Fallon's store in DC. You can pick some up in the Mass Fusion building, and at switch board with Railroad.

As far as radiation protection I haven't come across a situation yet where RadX, Radaway, and a stimpack couldn't handle. I have a mob gangster PC who wears a clean blue suit and I swam to Spectacle Island without the Aquaboy perk. I just popped a RadX and Radaway half way there and a stimpack.

Not Fallons Department Store. Her basemant in Diamond City.

ninja'd

You're probably thinking of the Department store.

The basemant is in Diamond City market.