4.8 stars from 12,322+ reviewers

GLP-1 Shrinks Your Appetite, Not Your Nutrient Needs. Fill The Gap In One Ready-To-Pour Packet.

When you're eating less, protein and fiber are the first to fall short. One packet adds 15g of complete protein, 8g of gentle fiber and 2.5g of VERISOL® collagen to a glass of water. No big shake to finish.

Fill My Nutrient Gap
45 Day Money Back Guarantee**
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When you're eating less, protein and fiber are the first to fall short. One packet adds 15g of complete protein, 8g of gentle fiber and 2.5g of VERISOL® collagen to a glass of water. No big shake to finish.

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Fill My Nutrient Gap
45 Day Money Back Guarantee**

Eating Less On A GLP-1? Here's What Quietly Goes Missing

GLP-1 medications quiet your appetite. They don't lower what your body needs. A 2025 joint advisory from four nutrition and obesity medicine organizations names nutrient deficiencies and muscle loss as priorities to manage during treatment.¹

Eating Less On A GLP-1? Here's What Quietly Goes Missing

GLP-1 medications quiet your appetite. They don't lower what your body needs. A 2025 joint advisory from four nutrition and obesity medicine organizations names nutrient deficiencies and muscle loss as priorities to manage during treatment.¹

Smaller meals icon

Your Meals Got Smaller. Your Needs Didn't.

Half a plate carries half the protein, fiber and nutrients it used to. Your body's requirements don't shrink with your appetite, so what you do eat has to work harder.
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Protein Is The First Thing To Fall Short

In a 2025 study of adults on GLP-1 medications, protein intake was significantly under daily needs once body weight was taken into account.² Each packet adds 15g of complete protein to support lean muscle.
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Fiber Drops With Every Smaller Meal

The same study found participants averaged just 14.5g of fiber a day,² well below what adults are advised to get. 8g from five sources supports healthy digestion and regularity.
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Your Stomach Is Already Adjusting

Digestive changes are common on GLP-1 medications.¹ Single-source fiber supplements are known for bloating, so ours spreads 8g across five gentle, low-FODMAP sources. Want extra gut support? Add our 3-in-1 Pre+ Post+ Probiotic.
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A Big Shake Feels Like A Chore

A thick protein shake is hard to finish when you're not hungry. Our packet is already dissolved: tear, pour into cold water and sip. 90 calories, no scoop, no clumps.
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Vitamins And Minerals Need Attention Too

Experts list preventing micronutrient deficiencies as a priority during GLP-1 therapy.¹ Protein + Fiber covers protein, fiber and collagen. For daily vitamins and minerals, pair it with the Women's or Men's "No Junk"™ Multi.

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How One Packet Fills The GLP-1 Gap

How This Helps*

Experts recommend adequate protein alongside strength training to help preserve lean mass during GLP-1 therapy.¹ One protein source can't cover every job, so we use three.

🏋️ 15g complete protein with the full amino acid profile to support lean muscle.

🥛 Whey isolate, cultured protein and collagen peptides in one blend.

🚶 Pair it with strength training, as the advisory recommends.

Adults’ Protein + Fiber + Collagen
Adults’ Protein + Fiber + Collagen
Adults’ Protein + Fiber + Collagen
Adults’ Protein + Fiber + Collagen
Adults’ Protein + Fiber + Collagen
Adults’ Protein + Fiber + Collagen
Adults’ Protein + Fiber + Collagen
Adults’ Protein + Fiber + Collagen
Adults’ Protein + Fiber + Collagen
Adults’ Protein + Fiber + Collagen
Adults’ Protein + Fiber + Collagen
Adults’ Protein + Fiber + Collagen
Customers rate us 4.7/5 based on 11684 reviews.

Adults’ Protein + Fiber + Collagen Protein + Fiber + Collagen Ready-To-Pour Mix. Beauty From Within, At A Clinical Dose.

Complete protein. Every kind of fiber. Clinical-dose collagen. Three protein sources, five fibers and 2.5g of VERISOL® collagen in one ready-to-pour liquid packet. Tear, pour into water, done. No scoop, no shaker, no clumps.

Build & Maintain Muscle Build & Maintain Muscle
66%

of adults we surveyed don't get enough protein for energy, muscle and metabolism.†

15g of complete protein per packet: Clear Protein (whey isolate) for a fast leucine trigger, cell-based cultured protein for all 9 essential amino acids, and collagen for structure.*

Support for skin elasticity, hydration and fine lines Support for skin elasticity, hydration and fine lines
2.5g

of clinically studied VERISOL® for to help support elasticity, hydration and fine lines.

Improve Skin, Hair & Nails Improve Skin, Hair & Nails
+65%

procollagen synthesis vs placebo at 8 weeks with VERISOL® (Proksch 2014).

2.5g of VERISOL®, exactly the clinically studied dose, clinically shown to increase skin elasticity, reduce wrinkles, strengthen nails and increase hair thickness.*

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30 Servings Per Bottle

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Ingredients

Bio-Protein Matrix: bioactive collagen peptides (incl. VERISOL®), cell-based cultured protein (S. cerevisiae), whey protein isolate.

Bio-Adaptive Fiber Blend: organic Jerusalem artichoke (Helianthus tuberosus) (tuber) extract, digestion-resistant dextrin, tapioca fiber, partially hydrolyzed guar gum, acacia fiber.

Sweetened with: stevia (Reb M). No added sugar.

Contains: milk (whey). Free from the other 8 major allergens. Gluten-free. Non-GMO.

Other Ingredients: Water, Citric Acid, Natural Flavors. Less than 2% of: Reb M, Beta-Carotene (For Color), Rowanberry Fruit Extract, Mushroom Extract.
Supplement Facts
Supplement Facts
Subscription Details

Receive a fresh pouch of 15 ready-to-pour packets every 30 days.

Plus, you'll receive these benefits:

  • Savings every single month.
  • Free shipping on your first order.
  • Easy management: skip or pause whenever you need.
  • VIP access to sales, gifts, early access & more.
  • Cancel anytime.

Three Gaps, One Small Packet

Protein shakes skip the fiber. Fiber supplements skip the protein. And both are a lot to finish on a small appetite. We put all three in one ready-to-pour packet.

15g
Protein

The Muscle Keeper

A complete protein blend with the full amino acid profile to support lean muscle while you lose weight. When you're eating less, every gram has to count.

8g
Fiber

The Gentle Gap Filler

Five low-FODMAP sources instead of one big dose, to support digestion and regularity without the bloating single-source fiber is known for.

2.5g
VERISOL® Collagen

The Rebuild

The exact daily dose used in VERISOL®'s published research, clinically shown to improve skin elasticity and hydration, and support hair and nails while your body changes.

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Trusted By Experts and Families Like Yours

Dr. Lei Chen

"These vitamins are exactly what I recommend to parents looking for quality nutrition."

Dr. Lei Chen

MD, MHS at Yale University

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Diana V.

"These are the best tasting vitamins I ever purchased. It feels like I am having a treat. These are the only ones so far that my kids like too."

Diana V.

Verified Purchaser

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"A revolutionary approach to children's health."

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Dr. Ed Giovannucci

"We choose partners carefully, and First Day’s dedication to research, formulation integrity, and transparent quality practices makes them a brand we’re proud to align with."

Dr. Ed Giovannucci

MD, MPH, ScD at Harvard University

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Why Should You Choose First Day?

Active adults usually end up with an adult protein tub in one cabinet and a fiber supplement nobody takes in the other.

First Day
Adult Protein Powders
15g protein + 8g fiber in one packet
2.5g clinically studied VERISOL®
Dissolves instantly, no blender
No added sugar
Gluten-free and non-GMO
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Before It Becomes A Problem

Lose The Weight. Keep What You've Built.

Muscle loss and nutrient gaps are named risks during GLP-1 therapy,¹ and they build quietly on a smaller appetite. Covering protein and fiber from week one means you're not playing catch-up later.

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FAQs

Can I take this with my GLP-1 medication?

This is a food-based supplement with protein, fiber and collagen, not a medication. Check with your prescriber before adding any supplement, especially if you're managing digestive side effects.
Is this a meal replacement?

No. It's designed to fill protein and fiber gaps alongside the meals you are eating, not to replace them.
Will the fiber upset my stomach?

The fiber is spread across five gentle, low-FODMAP sources instead of one large dose, which is designed to avoid the bloating common with single-source fiber supplements.
Do I still need a multivitamin?

Protein + Fiber covers protein, fiber and collagen. It isn't a multivitamin. Experts also recommend paying attention to vitamins and minerals during GLP-1 therapy, so ask your provider whether a multi is right for you. First Day makes a Women's Multi and a Men's Multi.
Should I add a probiotic?

Some people like extra digestive support. Our 3-in-1 Pre+ Post+ Probiotic combines prebiotics, probiotics and postbiotics in one daily gummy to support digestive and immune health. It comes in Women's and Men's versions. Check with your provider first.
How do I take it?

Tear open one packet, pour into 15 to 24 fl oz of cold water, shake for 5 seconds and drink. It also works in smoothies and blended drinks.
Does it contain any allergens?

Yes. It contains whey protein, which is milk. It's gluten-free and non-GMO.
Should I subscribe if I've never tried First Day before?

Subscribing gets the lowest price, and you can cancel anytime. Every first order is covered by our 45-day money back guarantee.