tiergain
Cross-sell + bundle stacking for supplements in 2026
Goal stacks set the anchor. Complementary cross-sells add on top. Post-purchase stack additions add more. Three layers that compound the health protocol.
48%
Compound AOV lift from 3-layer supplement stack
7.8%
Add-to-cart rate on goal-based supplement cross-sells
7.8%
Post-purchase conversion on stack addition offers
Supplement stacking is the most natural compound in e-commerce. Customers already think in stacks. Three offer layers just structure that behavior.
The hacks
Layer 1: goal stack as the default offer
The energy stack on the collection page sets the anchor at 3 products. When customers see "Energy Stack $69" instead of "$34 per bottle," the session starts at the stack price.
Layer 2: complementary supplement cross-sell on product pages
On the protein page: "Complete your recovery stack - add BCAA for $26 (save 15%)." The stack completion framing makes the cross-sell feel prescribed. Tiergain triggers stack-aware complementary suggestions.
Layer 3: stack addition on the thank-you page
After checkout: "Add fish oil to your stack - $22, one click." Supplement buyers at the thank-you page are in health-optimization mode. The stack addition feels like completing the protocol.
Suppress cross-sells for supplements already in the stack
If the energy stack includes B12, suppress the B12 cross-sell. Show a complementary product the stack does not include. Tiergain tracks stack contents to avoid overlap.
Free trial-size threshold spanning the layered order
"Spend $79: free trial-size of our new collagen blend." The threshold applies to the total - stack + cross-sells + add-ons. The trial introduces the next expansion product.
Test each supplement layer independently
Goal stacks alone for 14 days. Add complement cross-sells. Measure. Then add post-purchase. Supplement stacking compounds well, but measure each layer to confirm the lift is additive, not cannibalistic.
Supplements are the easiest category to stack three layers
Supplement buyers already think in stacks and protocols. Layer 1 (goal stack) captures that naturally. Layer 2 (complement) extends the protocol. Layer 3 (post-purchase) adds one more. The stacking behavior is built into the category.