For practitioners designing health behaviour interventions, our research suggests a few guiding principles:

1. Do not just deliver information to individuals but consider the social context (who they talk to, whom they trust, which peer networks they’re part of).
2. Use social network mapping or peer‐leader selection to identify leverage points (influencers, connectors, brokers).
3. Facilitate the creation or strengthening of active ties (not just static ones). For example, peer groups, buddy systems, community meet‐ups, online forums.
4. Consider diffusion effects: interventions may spread beyond the direct recipients via their networks.
5. Monitor network‐level metrics (e.g., tie formation, density changes, centrality of key actors) alongside behavioural outcomes.
6. Social network interventions are complementary to individual‐level behaviour change techniques, but they hold under-used potential.