The highest return-on-investment interventions for under $100/month — every item RCT-backed.
Once lifestyle foundations are in place, a small number of generic, evidence-backed supplements produce outsized returns. Vitamin D (VITAL trial, n≈25,000), omega-3 EPA+DHA (REDUCE-IT, ASCEND), magnesium (multiple meta-analyses on BP/sleep/insulin sensitivity), and creatine (300+ RCTs over 30+ years) are available inexpensively in generic form, all have large randomized human evidence, and collectively address the most common nutritional deficiencies that drive accelerated aging. This is also the right starting point for evidence-first skeptics: every item here is supported by well-powered human RCTs, not just mechanism.
Time commitment: 5–8 hours. Complexity: Beginner. Cost level: Budget.
People with solid lifestyle habits who want to layer in targeted, RCT-backed supplementation without breaking the bank — and evidence-first skeptics who only want interventions proven in large human trials.