The longevity supplement market has exploded. Hundreds of compounds are marketed as anti-aging solutions. Most of them are riding hype, not evidence.
Our science team evaluated hundreds of ingredients over the course of building Coastline's formulation. We reviewed published clinical trials, consulted with leading researchers, analyzed data from the Intervention Testing Program, and hosted in-depth conversations with experts on our Reason & Wellbeing channel. Here's what survived that process — and what didn't.
How we evaluated each compound
We focused on three questions for every ingredient. Does it have peer-reviewed evidence in humans or rigorous animal models? Is the mechanism of action well understood? And can you actually get an effective dose from available supplements?
We also leaned heavily on data from the Intervention Testing Program (ITP) — a National Institute on Aging program that tests compounds for lifespan extension across three independent labs simultaneously. If something passes the ITP, it's been tested more rigorously than 99% of what's on the market.
What works: strong evidence
These compounds have consistent, high-quality evidence behind them. That doesn't mean they're guaranteed to extend your life — but the science is genuinely compelling.
Ergothioneine
Your body built a dedicated transport protein (OCTN1) just to absorb this compound. Biology doesn't do that for unimportant molecules. OCTN1 is concentrated in tissues under the most oxidative stress — your brain, liver, kidneys, lungs, and eyes.
Unlike most antioxidants that react indiscriminately with free radicals, ergothioneine is an adaptive antioxidant. It targets harmful oxidative damage while leaving beneficial reactive oxygen species intact. Population studies consistently link higher blood ergothioneine levels with lower rates of cognitive decline, dementia, and Parkinson's disease.
Ergothioneine is currently under investigation by the ITP — one of only a handful of compounds selected for their most rigorous testing protocol. Typical effective dose: 5-25mg per day.
Taurine
A 2023 paper in Science — one of the most prestigious journals in the world — showed that restoring taurine levels in aging mice extended healthy lifespan by 10 to 12 percent. The supplemented animals showed improvements in bone density, metabolic health, immune function, and body composition.
The finding that matters most: blood taurine levels drop by up to 80% between youth and old age. This decline is consistent across mice, monkeys, and humans. The research suggests taurine deficiency may be a driver of aging itself, not just a consequence.
Human equivalent dose from the study: 3-6 grams per day, well within established safety margins. The European Food Safety Authority considers up to 6g daily safe for long-term use.
Creatine
Most people associate creatine with gym performance. The newer research tells a more interesting story. Creatine is fundamentally a spatial and temporal energy buffer — it stores and delivers energy to tissues with high, fluctuating demand.
Your brain is one of those tissues. During metabolic stress — sleep deprivation, hypoxia, concussion — supplemental creatine maintains cellular bioenergetics that would otherwise collapse. It also shows promise for preserving bone geometry in aging adults when combined with resistance training.
Creatine has one of the strongest safety profiles of any supplement ever studied. It doesn't increase fat mass. Older adults and vegans tend to benefit most, since they have lower baseline stores. Effective dose: 3-5g per day.
Glycine
Glycine punches well above its weight. It's a simple amino acid, but it serves multiple functions that are directly relevant to aging. It supports collagen production, improves sleep quality, and acts as a methionine restriction mimetic — meaning it may trigger some of the same protective pathways as caloric restriction.
The ITP has confirmed glycine's ability to extend lifespan in genetically diverse mice. That's a high bar to clear. The typical dose used in sleep research is about 3 grams taken before bed, which also supports overnight tissue repair and recovery.
Astaxanthin
Astaxanthin is a carotenoid pigment with unusually potent anti-inflammatory and antioxidant properties. It spans the cell membrane bilayer, giving it the ability to protect against oxidative damage from both the inside and outside of the cell.
The ITP has shown astaxanthin can deliver a 12% lifespan extension in genetically diverse mice — a significant finding from the gold-standard testing program. It also provides UV protection for the skin and has a strong safety profile at typical supplement doses.
Lutein and zeaxanthin
These are the two carotenoids that accumulate in the macula of your eye, forming a protective pigment layer that filters blue light and neutralizes free radicals. The AREDS and AREDS2 trials — large, multi-year, randomized controlled trials — demonstrated meaningful protection against age-related macular degeneration.
What's less well known: lutein and zeaxanthin also accumulate in brain tissue, where they appear to support cognitive function. These are among the best-studied protective nutrients with a clear, well-understood mechanism.
Omega-3 fatty acids (EPA/DHA)
The evidence for omega-3s spans cardiovascular health, brain function, and inflammation management. A particularly interesting recent finding: higher omega-3 levels are associated with slower epigenetic aging as measured by DNA methylation clocks — one of the most promising biomarkers of biological age.
The effective dose for cardiovascular and cognitive benefits is approximately 1 gram per day of combined EPA and DHA. Quality matters — look for third-party tested products with verified EPA/DHA content.
Disappointing: evidence weaker than the hype
These are the compounds you'll see most often in marketing. The science behind them is real — but the gap between what's promised and what's been demonstrated is significant.
NAD+ precursors (NR and NMN)
This is the biggest gap between hype and evidence in the longevity space right now. Nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) do reliably elevate NAD+ levels in humans. That part is true.
The problem: elevating NAD+ hasn't translated into the functional improvements people expected. NR was tested by the ITP and failed to extend lifespan. NMN sits in an FDA regulatory gray area, with its status as a supplement under ongoing dispute.
There's also a quality problem. Independent testing has found that roughly 85% of NMN products on Amazon are significantly underdosed compared to their labels. You may not even be getting what you're paying for. Until functional outcome data improves, NAD+ precursors remain expensive and underdelivering.
Resveratrol
Resveratrol was the darling of longevity research for years, driven by early studies linking it to the "French Paradox." The hope was enormous. The follow-up data has been disappointing.
Later studies failed to replicate the initial lifespan extension findings. More concerning, some research suggests resveratrol may blunt exercise adaptations — meaning it could interfere with one of the most reliable health interventions we have. At this point, the evidence doesn't justify the price or the hype.
Urolithin A
Urolithin A has a plausible mechanism — it promotes mitophagy, the process of clearing damaged mitochondria. The company behind it has invested heavily in clinical trials, which is commendable.
However, the functional improvements in published trials have been underwhelming relative to the price point. One study showed a minor increase in hamstring torque. That's a real measurement, but it's a long way from the broad anti-aging benefits suggested in marketing materials. The science may mature, but right now the value proposition is hard to justify.
Promising but needs more data
These compounds show genuinely exciting signals, but we need more evidence before drawing strong conclusions.
Alpha-ketoglutarate (AKG)
One published study found that calcium alpha-ketoglutarate reduced biological age by an average of 7 years as measured by DNA methylation clocks. That's a striking finding — but it's one study. The ABLE trial, a larger follow-up, is currently underway.
AKG has a plausible mechanism through its role in the TCA cycle and epigenetic regulation. If the ABLE trial confirms the initial findings, this could move firmly into the "strong evidence" category. For now, it's a credible watch-this-space compound.
GlyNAC (glycine + N-acetylcysteine)
Dr. Rajagopal Sekhar's research at Baylor has shown that the combination of glycine and NAC can produce massive functional improvements in older adults — including gains in walking speed, grip strength, cognitive function, and markers of oxidative stress.
The doses used are high. The study populations have been relatively small. But the magnitude of improvement is unusual enough to warrant serious attention. GlyNAC is being evaluated for the ITP, which will provide much stronger evidence. The early signal is hard to ignore.
Pharmaceutical interventions (not supplements)
For completeness, these are the leading pharmacological candidates in aging research. They require a prescription and medical supervision. We include them because they show up in longevity conversations, and you should know the tradeoffs.
Rapamycin
Rapamycin is considered the top gerotherapeutic candidate by many aging researchers. It extends lifespan in nearly every organism tested and targets the mTOR pathway, a central regulator of growth and aging.
The tradeoff: rapamycin blunts muscle protein synthesis. For a compound meant to extend healthspan, impairing the body's ability to build and maintain muscle is a significant limitation — especially for aging adults who are already losing muscle.
Metformin
Metformin shows clear metabolic benefits, particularly for blood sugar regulation. It's being tested in the large-scale TAME trial for potential anti-aging effects.
However, multiple studies have found that metformin is antagonistic to exercise adaptations. It can blunt improvements in aerobic fitness and muscle function from training. Since exercise is arguably the single most effective healthspan intervention, any compound that interferes with it deserves careful consideration.
Acarbose
Acarbose slows carbohydrate digestion, reducing post-meal blood sugar spikes. The ITP has shown it postpones metabolic disease and extends lifespan in male mice. It's less discussed than rapamycin or metformin but has a solid evidence base. The main drawback is gastrointestinal side effects that many users find difficult to tolerate.
What this means for choosing a supplement
The honest takeaway from reviewing 20+ compounds is this: most longevity supplements are overpriced relative to their evidence. A handful of compounds have genuine, rigorous science behind them. Many more are selling a story that the data doesn't yet support.
Here's what to look for:
- ITP-tested compounds — if it passed the most rigorous longevity testing program in existence, that means something
- Clinical dosing — the dose on the label should match what was used in research, not a fraction of it
- Transparent formulations — proprietary blends hide underdosing. You deserve to know exactly what you're getting
- Multiple mechanisms of action — aging isn't one problem. A system that addresses multiple hallmarks of aging is more logical than a single-molecule bet
- Honest communication — if a brand tells you their product will transform your life overnight, they're selling hope, not science
"The compounds that perform best in rigorous testing are rarely the ones getting the most attention on social media. Evidence and hype are often moving in opposite directions."
Why we chose what we chose
When we built the Coastline system, we started with this same review. We selected ingredients from the "strong evidence" tier — compounds with ITP data, robust human studies, well-understood mechanisms, and established safety profiles. We dosed them at levels that match the research, not levels that fit a marketing budget.
We didn't include NAD+ precursors, resveratrol, or urolithin A. Not because they're bad science — but because the evidence isn't there yet. If it gets there, we'll consider them. That's how an evidence-led approach works.
See which of these we chose and why — and the doses we use
Frequently asked questions
Are longevity supplements worth taking?
Some are. The key is choosing compounds with rigorous evidence behind them — not just promising preclinical data or compelling marketing. Ingredients tested through programs like the ITP, backed by peer-reviewed human studies, and dosed at clinically meaningful levels are worth serious consideration. Most products on the market don't meet that standard.
Why do NAD+ supplements get so much attention if the evidence is disappointing?
NAD+ precursors have a compelling biological story — NAD+ levels do decline with age, and restoring them sounds logical. The problem is that elevating NAD+ in blood tests hasn't led to the functional improvements people expected. The marketing outpaced the science. That may change with future research, but right now the data doesn't match the hype.
What's the ITP and why does it matter?
The Intervention Testing Program is funded by the National Institute on Aging. It tests compounds for lifespan extension in genetically diverse mice across three independent labs simultaneously. This design eliminates many of the problems that plague single-lab studies — like genetic uniformity or lab-specific conditions. If a compound extends lifespan in the ITP, it's among the most credible evidence available outside of human clinical trials.
Should I take rapamycin or metformin for longevity?
These are prescription medications with real tradeoffs. Rapamycin blunts muscle protein synthesis. Metformin can interfere with exercise adaptations. Both require medical supervision and ongoing monitoring. They're not supplements you can self-prescribe safely. If you're interested, discuss them with a physician who understands the longevity research.
Written by the Coastline science team. This article draws on data from the NIA Intervention Testing Program, the 2023 taurine study in Science, AREDS/AREDS2 trial data, and the Longevity Supplement Roundtable on Reason & Wellbeing. We have no financial relationship with any competitor mentioned in this review.
* These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
