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Hiya Kids Probiotic vs First Day Kids Belly-Biotic: The Clear Winner


The new buzz is all about probiotics, and both Hiya and First Day have come out with one, so it’s time for a showdown.

To preface this, we tried Hiya probiotics as soon as they came out, and we’ve been including them in my kids’ daily routine ever since.

We tried the First Day vitamins a while back, and I don’t recommend them. But I’m giving their Belly-Biotic a shot at redemption and crowning a winner at the end.

Disclaimer: The thoughts and opinions expressed in this blog post are my opinions only and do not reflect the opinions of Hiya or First Day. This blog post should also not be taken as medical advice.

Do Kids Need a Probiotic?

I explain everything you need to know about probiotics in this article, but here’s the total layman’s version:

If your child has diarrhea, doesn’t poop that often, has bad gas or bloating, deals with eczema or other skin concerns, or is sick all the time, you should try a probiotic.

Sorry to be so blunt about it, but if you read my stuff, you know I’m going to give it to you straight! 😂

packaging of first day and hiya probiotics

Benefits of probiotics for kids

Restoring and maintaining that balance in the gut can:

  • Boost immunity
  • Prevent diarrhea and constipation
  • Aid in digestion
  • Boost cognitive function
  • Support respiratory, heart, and oral health
  • Prevent allergies, asthma, eczema, and obesity
  • Help the body absorb vitamins and nutrients – which is why both Hiya and First Day emphasize their probiotics pair perfectly with their multivitamins

You can find probiotics in foods like plain yogurts that list “live and active cultures” on the label, Kefir, Sauerkraut, and Kimchi, but what toddler eats enough of those, right?

That’s where a daily probiotic can step in.

Hiya Probiotic vs First Day Belly-Biotic Texture and Taste

The Takeaway: Hiya's chewable tablets offer a worry-free experience for parents, and the kids love the fruity taste. First Day’s probiotics, on the other hand, are slimy gummies with an overpowering artificial orange flavor.

Winner: Hiya

Hiya’s probiotic comes in a chewable tablet, just like their vitamins. They start dissolving on your tongue the second you bite into them – resembling a Tums or a SweeTART.

I love their texture because I don’t have to be worried about choking, and my kids love the taste of them.

They taste like fruit – an overall pleasant experience.

inside of both probiotics
First Day on the left; Hiya on the right

First Day’s probiotics are gummies, and they have a slimy feel when you take them out of the package. The taste is very in-your-face artificial orange. The packaging only says “natural flavors,” but I found the taste very offputting.

For the record, my kids liked both, so the taste wasn’t as big of a deal to them.

Packaging and Sustainability From Hiya and First Day

The Takeaway: First Day skips the refillable bottle and sends a pouch each month, whereas Hiya makes it fun for kids while keeping it eco-friendly with their sticker-filled refillable bottles.

Winner: Hiya

With your first order of Hiya Kids Probiotics, you get a blue refillable glass bottle and a sticker pack to decorate it, which every one of my kids has loved.

hiya and first day probiotics laid out

Each month after, they send you an eco-friendly pouch to refill the bottle. My kids have loved decorating all of our Hiya bottles with the stickers!

First Day only sends a refill pouch. My order didn’t come with any kind of container to pour the pouch contents into. 

packaging of first day probiotics

I do like that it’s a pouch instead of a plastic pill bottle, but the kids’ multivitamins have a refillable container, so why don’t the probiotics? 

Hiya Probiotic vs First Day Belly-Biotic Serving Size

The Takeaway: Hiya's serving size is 1 probiotic per day, and First Day's is 2 gummies per day.

Winner: Hiya

Hiya Kids Probiotics are taken just once a day. They get straight to the point and don’t fill their tablet up with extra junk, so they can keep the serving size down to one.

First Day’s Kids Belly-Biotic is a 2-gummy serving size.

And since both companies’ probiotics are formulated to go with their daily multivitamins, with Hiya, you would only be giving your kids 2 tablets a day, whereas, with First Day, you would have to give them 4 gummies.

first day chewable vs first day gummy
Hiya yellow tablet up top; First Day orange gummy on bottom

Hiya Probiotic vs First Day Belly-Biotic Price

The Takeaway: Even with First Day's bundle option with their multivitamin, Hiya comes in cheaper, especially if you have multiple kids.

Winner: Hiya

Both companies offer a monthly subscription deal. Hiya’s 30-day supply is $30 for the first kid and gets a bit cheaper for each extra one – I pay just $25 per kid with my three munchkins.

Hiya offers a 50% discount on your first buy, and you can cancel the subscription at any time.

upright first day and hiya probiotics for kids

First Day has a few options. You can grab a one-time 30-day supply for $49 plus shipping or go for the subscription at $41.65 with free shipping.

They also have a TLC starter pack available, which bundles their multivitamin and probiotics for $79 ($67.15 if you subscribe), which would save you about 4 or 5 bucks compared to buying them separately.

Either way, First Day is more expensive than Hiya.

Hiya vs First Day Sugar and Sweeteners

The Takeaway: Hiya's probiotic has natural sweeteners like monk fruit extract and xylitol, which means 0g of added sugar. First Day's Belly-Biotic is sweetened with 2g of organic cane sugar per serving.

Winner: Hiya

One of the biggest reasons I love Hiya over any other vitamin/probiotic company is they put 0g of added sugar in their products.

hiya probiotic up close

The probiotics are sweetened with monk fruit extract, a superfruit that is way better for you and tastes even sweeter than sugar, and a dash of xylitol, a sweetener so good that it’s recommended by dentists as a sugar substitute.

First Day’s Kids Belly-Biotics have 2g of added sugar per serving, which is organic cane sugar.

It’s not a significant amount in the big picture, but their vitamins also have 2g, so if you’re including those in your daily routine, you should account for 4g of sugar total.

first day gummy probiotic up close

According to the AAP, a toddler should aim for less than 25 grams of added sugar per day. That means First Day’s vitamin and probiotic combo would already be accounting for nearly a fifth of your child’s ideal sugar intake for the entire day.

Hiya vs First Day Age Range

The Takeaway: Hiya wins here because you can start at age 2 compared to First Day, which is suitable for ages 4 and up.

Winner: Hiya

As with anything, you should talk to your pediatrician before giving your kids probiotics – better safe than sorry!

Hiya’s probiotics are good to go for kids 2 and up, while First Day’s Belly-Biotics are only for kids 4 and up.

Probiotics – and Other Biotics – of Hiya and First Day

The Takeaway: With Hiya, you get 3 strands of probiotics that have been specifically studied for use in children, plus a prebiotic fiber. With First Day, you get 1 prebiotic, 1 probiotic, and 1 postbiotic.

Winner: Hiya – because of it’s kids-centric formula.

Alright, let’s dive into the good stuff – the probiotics! Hiya and First Day take different routes here.

Hiya’s Probiotic Lineup

Hiya’s chewable probiotic has 10 billion live cultures, specially crafted for childhood immunity, gut health, and nutrient absorption.

back of hiya probiotics packaging

They use 3 strands and make seasonal adjustments so that your kids get the very best there is based on the science at the time:

Added bonus: Hiya also includes Larch Tree Fiber, a prebiotic known to reduce cold symptoms.

First Day’s Probiotic Lineup

First Day packs a trio of “biotics” for gut health, oral support, immunity, and overall wellness:

  • Livaux (Prebiotic) – Comes from whole fruit golden kiwi powder, helps feed the probiotic, and reduces cold and flu symptoms.
  • SNZ 1969 (Probiotic): Bacillus coagulans SNZ 1969, designed to support immune, oral, and gut health. Known to reduce infant diarrhea caused by rotavirus.
  • LAC-shield (Postbiotic): Heat-treated Lactobacillus paracasei MCC1849, enhances immunity and resistance to the common cold.
supplement facts of first day probiotics

One thing I feel I should point out here is Hiya’s 3 probiotics are backed by studies specifically on children, emphasizing their effectiveness for little ones.

On the other hand, other than the one study showing reduced rotavirus diarrhea in infants, the studies I found supporting the pre, pro, and post-biotics in First Day – including some of the studies that they themselves linked to in their FAQs – were looking at healthy adults and the elderly.

That’s not to say they aren’t also effective for children, but the science has spoken, and I’m personally more confident with Hiya’s formula.

Other ingredients

The Takeaway: Hiya's Kids Probiotic delivers potent probiotics with natural ingredients, avoiding compromising additives. The First Day Belly-Biotic includes some added sugars and gummy ingredients.

Winner: Hiya

The other ingredients listed in the Hiya Kids Probiotic are:

  • Xylitol
  • Natural plant-based flavor
  • Vegetable fatty acid
  • Beetroot
  • Lemon juice powder
  • Organic rice hull concentrate
  • Organic rice bran extract
  • Organic gum arabic
  • Organic sunflower oil
  • Monk fruit extract

One thing Hiya points out is live probiotic strands are really quite delicate, and they can be easily destroyed by added sugar, gummy additives, and incompatible ingredients, essentially turning them into glorified Tums.

first day and hiya probiotics

Hiya doesn’t have any of those compromising ingredients, so you know the probiotics get to your kids’ bellies with strong, active probiotics.

The other ingredients listed in the First Day Belly-Biotic are:

  • Organic Tapioca Syrup
  • Organic Cane Sugar
  • Water
  • Pectin
  • Natural Flavors
  • Citric Acid
  • Natural Colors
  • Organic Carnauba Wax

There are no dyes, high-fructose corn syrup, gluten, eggs, tree nuts, wheat, peanuts, artificial flavors, and preservatives, but there are added sugars, carnauba wax, and pectin to hold the gummies together.

first day probiotic gummy

So, Which Children’s Probiotic Brand Wins?

Let’s sum all of this up.

Price for 30 days
Age Range
# of CFUs
Grams of added sugar
$30 (less if you have more kids)
3 Probiotics + 1 Prebiotic fiber
10 billion
Monk fruit extract & xylitol
First Day
1 Prebiotic, 1 Probiotic, 1 Postbiotic
1 billion
Cane sugar

Hiya Kids Daily Probiotics takes the crown in literally every aspect of comparison and testing.

I can’t say I’m surprised because of how much I love their vitamins, and I won’t be making the switch anytime soon.

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