Why protein retention works differently
Protein is bought on a schedule, used on a schedule and judged on a schedule. The customer scoops the same amount most days, trains to a goal and expects to see something change in the mirror or the gym log within a few months.
That makes it easy to time and easy to get wrong. A 5lb tub on a 30-day subscription stacks up in the cupboard for someone who has 1 shake a day. A flavour that tasted great in week 1 is a chore by week 6. And a customer who expected results in 3 weeks gives up before the product has had a fair run.
Supplements already sit inside the largest subscription category. Eightx puts typical monthly churn for supplement subscriptions at 5-8%, and estimates 60-70% of replenishment subscribers are lost between order 1 and order 3. For protein, orders 1 to 3 cover the first 2 to 3 months, which is exactly when flavour fatigue and "not seeing results" set in.
Reorder timing by tub size and servings
Time reorder emails from servings per tub and how many shakes the customer has a day, then send the reminder about 7 days before the tub runs out. Read the serving count from your own label: scoop sizes vary a lot between whey, plant and mass gainer products.
| Tub | Servings (example label) | Shakes per day | Days of supply | Reorder email on day |
|---|---|---|---|---|
| 1kg / 2lb | 30 | 1 | 30 | 21 to 23 |
| 1kg / 2lb | 30 | 2 | 15 | 8 to 9 |
| 2.27kg / 5lb | 75 | 1 | 75 | 66 to 68 |
| 2.27kg / 5lb | 75 | 2 | 37 | 28 to 30 |
| Creatine, 300g | 60 (5g) | 1 | 60 | 51 to 53 |
We ask shakes per day and training days per week in a short goal quiz and save them in Klaviyo. Training days matter: someone who only has a shake after training goes through a tub at roughly half the speed of a daily user.
For subscribers, the same numbers set the default frequency in Loop. Across the subscription brands we run on Loop, "I have enough or too much product" is already the number 1 cancel reason, at about 23% of cancel attempts in the last 90 days (20,000+ cancel-flow events).
Flavour fatigue and flavour swaps
Flavour is the cancel reason protein brands under-plan for. The product works, the price is fine, the customer is just sick of chocolate.
- Ask before they leave. Around the 3rd order, send a short "still loving the flavour?" email with a one-click swap in the portal.
- Swap in the cancel flow. "I'm bored of the flavour" goes to a flavour swap or a sample of a new one in the next order, before any discount.
- New flavour drops go to subscribers first, as a one-click add-on to the next box.
- Flavour data lives in Klaviyo, so campaigns never push a flavour the customer already dropped.
Stack bundles and the second product
The second product is where sports nutrition earns its margin: creatine, pre-workout, electrolytes or a shaker, as long as each has its own job.
- Pairings in the post-purchase flow. One suggestion per product, chosen from what customers already buy together in Shopify.
- Stack bundles in Loop. Subscribers add a second product at renewal through upsell profiles, without placing a new order.
- Add-on in the upcoming order email. One click, added to the next shipment.
Creatine is worth planning for on its own. SPINS data shows creatine sales up 71.9% in the 52 weeks to 30 Nov 2025, and women made up 30% of GNC creatine purchases, up from 18% in 2020.
Training goals as segmentation
Goal is the most useful thing a sports nutrition brand can know about a customer. Ask it once in the welcome quiz and use it everywhere.
- Build muscle gets training-day timing, protein targets and the creatine pairing.
- Lose weight or lean out gets meal-replacement use, lower-calorie recipes and the products that fit a calorie target.
- Endurance gets hydration, electrolytes and recovery timing around long sessions.
- General health gets simple daily-use content and recipes.
The results timeline
Customers who expect a change in 3 weeks cancel in week 4. The first 90 days of email set honest expectations from your own guidance.
- Days 0 to 7. How to use it, when to take it and recipes that make it easy every day.
- Days 14 to 30. What real customers say about their first month, quoted as written.
- Days 45 to 90. A progress check-in, a review ask and the bigger tub or the stack.
In the cancel flow, "not seeing results" gets usage help and a realistic timeline before any discount.
Claims in protein and sports nutrition emails
Sports nutrition copy follows the same rules as the label. We write every claim from your product page and claim list:
- US. Protein sold as a dietary supplement can make structure/function claims with the FDA disclaimer. Disease claims are not allowed, and the FTC expects health claims to be backed by competent and reliable scientific evidence.
- UK and EU. Only authorised health claims, such as "protein contributes to a growth in muscle mass", worded as approved and only when the product meets the conditions.
- Never. Treats, cures, prevents or reverses, and no medical claims of any kind.
- Before and after. Real customer photos and reviews only, quoted as written and typical of the product.
None of this is legal advice. Your regulatory advisor signs off the claim list once and we write from it.
Klaviyo flows that work for protein and sports nutrition brands
| Flow | Trigger | What it does |
|---|---|---|
| Welcome series | Pop-up or goal quiz | Asks goal, training days and shakes per day, then suggests tub size and frequency |
| First 30 days | Order delivered | How to use it, recipes, what to expect when |
| Replenishment | Order date plus days of supply | Fires about 7 days before the tub runs out |
| Flavour check | Around order 3 | One-click flavour swap before fatigue becomes a cancel |
| Stack cross-sell | Day 14 to 30 or second order | Creatine, pre-workout or electrolytes matched to goal |
| Upcoming order | Subscription app event | Skip, swap flavour or add a stack item |
| Failed payment | Loop, Appstle or Checkout Champ events | Card update links before the tub runs out |
| Cancel and winback | Cancellation | Flavour swap, slower frequency or bigger tub before any discount |
We run about 120 flow A/B tests across our clients at any time, and the first flow is live within 72 hours of starting.
Results from subscription brands like yours
We don't run a protein brand today. The subscription work below is the same work a protein brand needs.
Kaori, Japanese persimmon soap, subscriptions on Loop. Case study
- Cancel-flow saves went from 4.3% to 60%, after we rebuilt the cancel page inside Loop and tested a video against the text.
- Email grew from 3.3% to 19% of store revenue.
KittySpout, cat water fountains and filters, subscriptions on Loop. Case study
- Cancel-flow saves went from 6% to 43%, after we put video on the cancel page and swapped a 3-month discount for one simple 40% last-chance offer.
- 46% of revenue attributed to Klaviyo.
Klaviyo publishes its own sports nutrition case study with Good Protein. For the supplement side of this work, read our supplement brand guide and the Ritual Labs case study.
What to ask a sports nutrition email agency
- How do you time reorders? The answer should use servings per tub and shakes per day, not one 30-day default.
- What happens when a subscriber is bored of the flavour? A swap should come before a discount.
- How do you segment by training goal? Ask to see the quiz and where the answers are stored.
- How do you handle health claims in the US and UK? They should know the difference between structure/function claims and authorised claims.
- Which subscription apps have you run, with numbers? Ask for cancel save rates you can read on a case study.
- How fast is the first flow live? Ours is live in 72 hours.
Related guides
- Retention and Klaviyo agency for supplement brands
- How to design a subscription cancel flow that saves
- Failed payment recovery for Shopify subscriptions
- Loop Subscriptions agency and partner
Book your free Klaviyo check
We will look at your reorder timing, your first 90 days after purchase and your cancel flow, and show you where customers are dropping out. Your first flow can be live in 72 hours.
Prefer a written review of your whole Klaviyo account? Get a free Klaviyo audit.
