Heat the berries with lemon juice and date syrup in a small saucepan over medium heat, stirring occasionally until they break down and get jammy (about 5–10 minutes).
Mash lightly with a fork or potato masher to reach your desired texture.
Remove from heat, then stir in chia seeds and collagen peptides.
Let it sit for 10–15 minutes, so the chia seeds absorb liquid and thicken the jam. Give it a taste and add more sweetener if you need to.
Transfer to a glass jar.Store in the fridge for up to 1 week.