what's your favorite hydration drink? bonus points if it's a drink mix

Water.

Okay, so this isn’t actually about hydration, it’s about the fact that SSRIs commonly cause dry mouth as a side effect due to anticholinergic effects which reduce saliva release Some SSRIs are worse than others, and older TCAs are worse still. But OP is not dehydrated.
Water is great for hydration, but it is unfortunately not very effective at managing dry mouth due to these side effects. Flavoured beverages typically work better because they promote saliva release.
I would suggest OP add something with a sour note to their water, like lemon or lime juice which are unsweetened and have effectively no caloric component. Alternatively even just a splash of carbonated water will also work as the bubbles are irritants and will similarly stimulate saliva release.
- I was just thinking some shrub syrup fits the bill and is tasty, convenient, and a touch unconventional these days so you can look like a trendsetter.
  Your comment seems to fit shrub perfectly.
  
  Shrubs are delectable! But they could be seen as an intimidating suggestion in this context. IKEA has some affordable fruit concentrates of lingonberry, blueberry, and elderflower you could substitute with a splash of vinegar for a refreshing lower effort treat.
- lol this isn't about dry mouth. I already had dry mouth, which I manage with xylitol (lmk if they make any of those fruit things that can adhere to the side of your mouth like xylitol melts)
  SSRIs cause dehydration. when I drink straight water on them, it sends me to the bathroom pretty frequently. I don't find Gatorade particularly more refreshing than water, but it tends to stay inside me after I drink it, when I'm on SSRIs. yes I've had my blood sugar checked
  
  The water moving right through is probably a good sign someone is well hydrated! There can be total body water versus intravascular volume depletion scenarios, but not super likely unless someone is sick in other ways.
  The xylitol itself may be contributing to GI water losses (it’s only about 50% absorbed through the gut, and osmotically draws water into/keeps water from being absorbed from the intestinal lumen). Depending on the SSRI, this could be exacerbated by bowel irritability that can present as diarrhea (sertraline is notorious for this).
  Some folks also report more urination with intake of sugar alcohols like xylitol. I don’t have a mechanism of action for that, so take those reports with a grain of salt. (And also some glucose because sodium-glucose symport allows for water absorption without the need for an ATP pump.)

Water.

Honestly not sure what's wrong with water.
Unless you live in Flint?

Huge fan of water, personally. I drink literally a gallon of it every day. Usually more.
- A gallon or more is generally unhealthy unless your sweating a lot. Or have an underlying health issue.

Cold water

Water. Cold brew black or green tea if I'm feeling frisky.

Soda water. That I get from my tap and fizz in my Sodastream machine.
Right now, two entirely different beverage gatekeeping factions are gasping and clutching their pearls. Suck it, pearl-clutchers. Or don't, because this one's mine.
- Why would anyone be clutching pearls here?
  
  Some loud people on the internet hate it when someone drinks soda water. Others, tap water.

It’s a bit psychopathic but if you know you need electrolytes, can’t really beat a little salt in some water. Like just a pinch.
Best part is it’s nearly free!
- Takes a balance of multiple electrolytes potassium, magnesium, calcium, salt, and others. Salt only makes the arteries less able to expand and contract and makes the body hold in water sometimes in unwanted areas. Feet, legs, arms, heart, etc. This is why alot seniors are on water pills.

I like water. It sounds boring, but for me, it's enough to hydrate.

Straight chilled water.
If I need extra hydration aka eletrolytes, I either put pure electrolytes in it or a flavored powder like Liquid IV.

BRAWNDO
- of course.
  
  It's got what plants crave

generally ice water, but i also like Pocari sweat if its on hand.

Gatorade mixed with seltzer and vodka.

For long term hydration:
• Alcohol free beer (non-American, preferably German-style, cold)
• water (little lower than room temp)
• unsweetened tea (cold)
For quick hydration:
• sparkling water (littler lower than room temp)
• sparkling water with lemon (not fridge cold but cold)
Oh, and no ice cubes.

Wa'uh

Ice cold water with a slice of lemon.

Unsweet tea. Wife has made green tea for the last few batches, liking that even more.
If I'm outdoors, kayaking or hiking or whatever, I carry frozen water.
- Watch out for caffeine in teas people. After 2 weeks of loving green tea 3 or 4 times a day. I got massive migraines when I stopped or even slowed down on consumption. 25mg to 50mg per cup.
- If you're exploring the green tea world, I highly recommend mint green tea. Exactly what it sounds like. I find it quite refreshing, especially after a hot day. The mint adds a nice coolness.

Ordinarily I just drink water, but if I feel myself being actually dehydrated then coconut water followed up by actual water.

I honestly don't think there's anything as refreshing as a glass of water at 10°C. Sure, sodas or electrolyte drinks like Gatorade are nice, but it really doesn't hit the same.

Coconut water.

Hammer fizz is the best but it is low sugar.

Propel/Gatorade Zero powder drink mixes. No specific flavor.
Pack of 10 costs as much as 1 regular Gatorade bottle. More cost effective.

mostly just water but if I need electrolytes I've found most pre-made powders, tablets, or drinks are too sweet, more so if they use alternative sweeteners like Stevia. so, I found a place that sells electrolyte powder, unsweetened and unflavoured, and mix it up myself with some water, lemon juice, and a bit of Stevia. much better than the premade mixes.
although I do like pocari sweat as a rare thing. you can buy that as a powder online, but the local asian market sells cans of it so I keep a few around.

I prefer water, but my wife really likes Body Armor. Specifically a Tropical/Pineapple flavor.
- Cost adds up but their far cheaper than coconut water. Good balance of vitamins and electrolytes. The sugars are high though. Otherwise their solid choices. The lytes are the real choice then if you must add sugar as desired.
  
  Totally agree. I think she craves them because breastfeeding puts her at such a calorie deficit.

Cream of Earl Grey black tea if before 3pm.
If after 3pm, A Bourbon-flavoured rooibos.
If after 8pm, its not just bourbon flavoured anymore.
- … it’s pure bourbon then, isn’t it?
  
  Its adding whiskey, gin, rum or bourbon, depending on the tea(white/herbal or Rooibos for no caffeine) for variations on the Hot Toddy.

This is a very hot take but milk. I get straight bullied for it by my friends and family but atleast I have the excuse of a medical reason.
For me, milk is incredibly hydrating and satisfying to drink. Genuine pick me up in the mornings, the coldness is refreshing but I've had water at that temp and it isn't the same. Its like my head clears and suddenly I am awake. I think the reason for this is a mixture. I drank a lot of milk as a kid, especially in the mornings because water tasted gross (only in the morning), so it could partly just be nostalgic or comforting but also it satisfies my cravings. However, I chug that shit, the glass is gone in less than a second, so perhaps its the coldness mixed with how fast I am drinking it just waking me up idk.
My medical reason is that I piss all my calcium away so I am constantly craving it
- I remember that advertising campaign back in the day
- Dude yeah chugging cold milk after waking up is elite.

Boulder salt.

Cherry Lime Gatorlyte (the white one)
So refreshing. A couple sips on a hot day and I feel rehydrated.

An americano. when particularly thirsty, an americano with water on the side.

I like to drink Body Armor when I'm cycling or riding my motorcycle on a hot day.

Ice cold water, or Gatorade if I need the electrolytes (usually due to hangover, rather than exercise). Orange or yellow-green, red and white are tolerable, fuck blue

Liquid IV. I'll bring a few packets if I know I'm going to be sweating. It's also great for a hangover.

lol thanks for all the suggestions of water, but when I'm on SSRIs it runs right through me.
- Water with electrolytes? I got unflavored electrolyte drops for times I fast, and for my kid who has to do band camp in the summer here. You can get flavored ones too, I don't like them. Dilute them more than the bottle says to, sometimes a splash of lemon.
  Topo Chico and orange juice is great, if you are just looking for something that tastes good.
  Ask your doctor if it's safe for you to take creatine, that certainly helps muscles retain water.
- Idk im on SSRIs as well but I still prefer water. Is it maybe some side effect of the ones you're taking? Maybe you should talk to your doc about it.

Look into drink mixes for endurance athletes. We use this stuff constantly.
I personally love Skratch. They make a more traditional 70cal/scoop mix and also make an electrolyte-only mix that's easier on the digestive track if you don't need the sugar for exercise.
- A bit expensive. Does look too bad though. Wish it was cheaper alternative to body armours. Its super basic and could be made much cheaper they just from sourcing the ingredients yourself.

Ginger tea is my bag baby yeah.