Longevity Supplement Evidence Index 2026: 1,717 Human Trials

Last updated: August 8, 2026 · Originally published: August 2, 2026 · By Eternal Elixir Editorial

An Eternal Elixir original dataset. Last updated 3 August 2026.

Australians run roughly 184,000 searches a month for the sixteen longevity and performance compounds in this dataset. Behind those searches sit 1,717 published human randomised controlled trials — but they are distributed extraordinarily unevenly. Two of the sixteen compounds have zero human randomised trials indexed in PubMed, yet together attract 6,700 Australian searches every month.

Treat this Eternal Elixir page as a longevity supplement evidence review rather than a shopping list.

This page is the underlying dataset. We counted the human clinical literature behind every compound Eternal Elixir sells, paired each count with Australian search demand, and published the exact query strings so anyone can reproduce the numbers. Every figure below is a count of published research volume. Nothing here is a statement about what any compound does in the body.

Key statistics at a glance

What is the Evidence Density Index?

The Evidence Density Index is the number of published human randomised controlled trials for a compound divided by its Australian monthly search volume, multiplied by 10,000. It answers one question: how much human trial evidence exists per unit of public attention?

A high index means the research community has studied a compound far more than the Australian public searches for it. A low index means the reverse — public interest has run ahead of the human trial literature. The index is deliberately simple, and it is not a quality score. A compound with 500 small, short, poorly controlled trials will score higher than one with 10 large, long, rigorous ones. It measures volume of human evidence relative to attention, nothing more.

We banded the results into three groups: evidence-rich (index ≥ 80), moderate (15–79), and attention-heavy, evidence-light (under 15).

How many human trials exist for each longevity supplement?

Across all sixteen compounds, PubMed indexes 2,161 human clinical trials, of which 1,717 are randomised controlled trials. The distribution is heavily skewed: the top three compounds by RCT count — oral glutathione (569), methylene blue (380) and resveratrol (262) — account for 70% of every human randomised trial in the dataset. The bottom eight compounds together account for fewer than 130.

The full census is below. “All indexed records” counts every PubMed entry mentioning the compound in its title or abstract, including cell and animal work, reviews, letters and case reports. Only 1.8% of that total literature consists of human randomised trials — a reminder that a compound with thousands of papers behind it may still have very little human trial data.

Three rows deserve a caveat, and we would rather flag them than quietly bury them. Oral glutathione, oral hyaluronic acid and methylene blue all have literatures dominated by clinical and non-supplement uses — intravenous administration, injectable dermal fillers, surgical dye applications and hospital medicine. Their RCT counts are real, but they overstate the volume of trials that studied an oral supplement at supplement doses. The other thirteen compounds do not have this problem at anything like the same scale.

Which supplement has the biggest gap between hype and human evidence?

Shilajit. It draws 27,100 Australian searches a month — level with methylene blue and oral hyaluronic acid, and more than NMN — but it is supported by just 7 human randomised controlled trials and a single systematic review. Its Evidence Density Index of 2.6 is the lowest of any compound in the dataset that has any human trial evidence at all. Only 121 PubMed records mention shilajit in the title or abstract, and three of its seven RCTs were published since 2021.

Below shilajit are the two compounds with no human randomised trials whatsoever:

• Turkesterone — 5,400 Australian searches a month, 33 total PubMed records, 0 human clinical trials of any design, 0 RCTs.
• Fadogia agrestis — 1,300 Australian searches a month, 10 total PubMed records, 0 human clinical trials of any design, 0 RCTs.

Both compounds have a research base that is entirely preclinical: cell culture and animal work. That is a statement about the state of published research, not a verdict on the compounds. But it is the single most useful thing a buyer can know, and it is almost never stated plainly. If you are considering turkesterone or a tongkat ali and Fadogia agrestis product, you are buying into a compound whose human trial record has not yet been written.

NMN is the more surprising entry in the attention-heavy band. It is Australia’s second-most-searched compound here at 14,800 searches a month, and it is the compound most associated with the word “longevity” in popular coverage — yet it has 16 human randomised controlled trials, giving it an index of 10.8. The mitigating detail: 15 of those 16 were published in 2021 or later, making NMN the fastest-accelerating human evidence base in the dataset in proportional terms. Its close relative nicotinamide riboside has nearly double the RCT count (31) at less than a tenth of the search volume — an index of 238.5, more than 22× NMN’s. We compare the two compounds directly in our NMN vs NR comparison for Australia.

Which longevity supplements are the best studied in humans?

Korean red panax ginseng, by a wide margin. With 124 human randomised controlled trials, 47 systematic reviews or meta-analyses, and only 880 Australian searches a month, its Evidence Density Index of 1,409.1 is more than four times that of the next compound. Ginseng has been the subject of formal human trials for decades; Australian consumer attention has simply moved on to newer molecules.

The rest of the evidence-rich band:

• Resveratrol (index 323.5) — 262 human RCTs and 221 systematic reviews or meta-analyses, the largest review literature of any compound here. Only 79 of its RCTs are from 2021 or later, so most of that base is mature rather than new.
• Oral glutathione (index 256.3) — the highest raw RCT count in the dataset at 569, though subject to the administration-route caveat above.
• Nicotinamide riboside (index 238.5) — 31 RCTs, 22 of them since 2021. Proportionally the newest evidence base of any compound with meaningful trial volume.
• Spermidine (index 141.4) — 41 human RCTs against 10,854 total records, an unusually low human-trial-to-literature ratio reflecting how much spermidine research is basic cell biology.
• Methylene blue (index 140.2) — 380 human RCTs, but overwhelmingly in clinical rather than supplement contexts.

Sitting just below the threshold, trans-pterostilbene (index 79.5) is the dataset’s smallest evidence-rich candidate: 7 human RCTs and a single systematic review against 1,120 total records. Structurally close to resveratrol, it has roughly one-thirty-seventh of resveratrol’s human trial volume.

Is longevity supplement research actually accelerating?

Not at the rate the market implies. Restricting the count to the thirteen emerging compounds — that is, excluding glutathione, hyaluronic acid and methylene blue, whose clinical literatures swamp the signal — new human randomised trials per year rose from 19 in 2016 to a peak of 31 in 2022, then fell to 18 in 2024 and recovered only to 22 in 2025.

Over the same window, Australian search interest in these compounds more than tripled. Publication output for the emerging longevity basket has been essentially flat for a decade, averaging 21.8 new human RCTs a year, while consumer demand has compounded.

The 2023–2024 decline should be read cautiously. PubMed indexing lags publication, publication lags trial completion by one to three years, and a single large multi-arm trial can move a year’s count by 10%. But the direction is clear enough: the human evidence base for emerging longevity compounds is growing arithmetically while attention grows geometrically.

What are Australians actually searching for?

Berberine, by volume — and it is still climbing. At 40,500 searches a month it is the most-searched compound in the dataset, ahead of shilajit, methylene blue and oral hyaluronic acid at 27,100 each. Its Google Trends interest in Australia rose +360% from calendar 2022 to calendar 2025 and has continued upward through 2026 to date, and it is comparatively well supported with 108 human RCTs and 76 systematic reviews or meta-analyses.

NMN shows the second-steepest Australian trend line at +192% over the same period, peaking in the week of 1 March 2026. Tongkat ali is the dataset’s one clear decliner: Australian interest peaked in January 2023 and 2025 mean interest was identical to 2022, with 2026 running below both.

Spermidine was excluded from Table 4. Its Australian search volume is too low to produce a reliable relative-interest series against the other terms, and the raw series returned incomplete weekly coverage. Publishing a percentage change from that series would have produced a headline number with nothing behind it, so we left it out rather than round it up.

Methodology

Every number on this Eternal Elixir dataset is reproducible. Here is exactly how it was produced.

Trial counts

Counts were retrieved from PubMed on 3 August 2026 via the E-utilities esearch endpoint, using rettype=count. For each compound we ran five queries built from a core term-set restricted to the title/abstract field ([tiab]), combined with these filters:

• All indexed records: core term-set only.
• Human clinical trials: AND "clinical trial"[pt] AND "humans"[mh]
• Human RCTs: AND "randomized controlled trial"[pt] AND "humans"[mh]
• Human RCTs since 2021: as above AND ("2021/01/01"[dp] : "2026/12/31"[dp])
• Systematic reviews / meta-analyses: AND ("meta-analysis"[pt] OR "systematic review"[pt]) AND "humans"[mh]

The core term-sets were: "nicotinamide mononucleotide"[tiab]; "nicotinamide riboside"[tiab]; "resveratrol"[tiab]; "pterostilbene"[tiab]; "spermidine"[tiab]; "alpha-ketoglutarate"[tiab] OR "alpha ketoglutarate"[tiab]; "berberine"[tiab]; "tauroursodeoxycholic acid"[tiab] OR "TUDCA"[tiab]; "Eurycoma longifolia"[tiab] OR "tongkat ali"[tiab]; "Fadogia agrestis"[tiab]; "shilajit"[tiab] OR "mumijo"[tiab]; "glutathione"[tiab] AND "supplementation"[tiab]; "Panax ginseng"[tiab] OR "Korean red ginseng"[tiab]; "turkesterone"[tiab]; ("hyaluronic acid"[tiab] OR "hyaluronan"[tiab]) AND ("oral"[tiab] OR "ingestion"[tiab] OR "dietary"[tiab]); "methylene blue"[tiab].

Table 3 uses the union of the thirteen emerging compounds’ term-sets with a single-year date filter applied per year.

Search volume

Australian monthly search volumes are Google Ads-derived averages for the twelve months to June 2026, retrieved from DataForSEO in July 2026 for location “Australia”, language “en”. Volumes are for the compound’s primary head term (for example berberine, nmn, shilajit), not the sum of a keyword cluster, so they understate total category demand. Calcium alpha-ketoglutarate and tongkat ali returned no volume figure and are excluded from all index calculations; they remain in Table 2.

Trend data

Table 4 uses weekly Google Trends relative-interest values for Australia from 1 August 2021 to 2 August 2026, averaged by calendar year. Values are relative to the highest point in the compared set (berberine, week of 28 May 2023 = 100), so they are comparable to each other but not to absolute volumes.

Data sources

Trial counts were retrieved from the PubMed bibliographic database on 3 August 2026, filtered to human randomised controlled trials. Registered-but-unpublished studies were checked against ClinicalTrials.gov. Where a systematic review already existed we recorded it from the Cochrane Library. Background definitions of trial design follow the WHO International Clinical Trials Registry Platform. PubMed record structure and publication-type tagging follow the NCBI indexing documentation.

Editor’s note on scope: this is a census, not a scorecard. A high trial count means a compound has been studied a lot. It does not mean it works better than one studied less. We publish the exact query strings so you can re-run every figure yourself.

Known limitations

• PubMed publication-type tags are assigned by indexers and are imperfect; some randomised trials are mistagged, and some tagged trials are secondary analyses of an earlier trial rather than new trials.
• Counts measure volume, not quality, sample size, duration, dose relevance or risk of bias. A compound can score highly on this index and still have a weak evidence base.
• Title/abstract searching misses papers that name a compound only in the full text and over-counts papers that mention it incidentally.
• Oral glutathione, oral hyaluronic acid and methylene blue counts include substantial non-supplement clinical research, as flagged above.
• Search volumes are estimates with a rounding band, not measured traffic.

Reuse and citation

This Eternal Elixir dataset is free to cite, quote and chart. If you use it, please attribute it as: Eternal Elixir, “Longevity Supplement Evidence Index 2026”, eternalelixir.com.au, 3 August 2026, with a link to this page. We will re-run the census annually.

Frequently asked questions

Which longevity supplement has the most human research?

Of the sixteen compounds measured, oral glutathione has the highest raw count at 569 human randomised controlled trials, followed by methylene blue (380) and resveratrol (262). Adjusted for Australian search demand, Korean red panax ginseng ranks first with an Evidence Density Index of 1,409.1 — 124 human RCTs against only 880 searches a month.

How many human clinical trials of NMN have been published?

PubMed indexed 22 human clinical trials of nicotinamide mononucleotide as of 3 August 2026, of which 16 are randomised controlled trials. Fifteen of those 16 were published in 2021 or later, making NMN’s human evidence base both small and very recent.

Does turkesterone have any human studies?

No. As of 3 August 2026, PubMed indexes 33 records mentioning turkesterone in the title or abstract, and none is a human clinical trial of any design. Australians search for turkesterone about 5,400 times a month. The same is true of Fadogia agrestis: 10 indexed records, zero human trials, 1,300 searches a month.

Is NMN or NR better studied?

Nicotinamide riboside has more published human randomised trials — 31 against NMN’s 16 — and a longer publication history. NMN’s evidence base is newer: 94% of its human RCTs were published in 2021 or later, versus 71% for nicotinamide riboside. Neither count says anything about which compound performs better; it only describes how much human trial data exists.

What does the Evidence Density Index actually measure?

It is the number of published human randomised controlled trials per 10,000 monthly Australian searches. It is a measure of research volume relative to public attention, not a quality rating, a safety rating or a recommendation. A high index means a compound has been studied in humans far more than Australians currently search for it.

Why are some compounds missing a search volume figure?

Calcium alpha-ketoglutarate and tongkat ali did not return a monthly volume figure from the search-volume dataset used, so calculating an index for them would have meant inventing a denominator. They appear in the full census (Table 2) with their trial counts intact but are excluded from the index rankings.

How often is this dataset updated?

Annually. The next scheduled re-run is August 2027. The retrieval date is stated on every table so any figure you quote can be pinned to a point in time.

The compounds in this dataset

All sixteen compounds measured here are products Eternal Elixir stocks in Australia: NMN, nicotinamide riboside, resveratrol, trans-pterostilbene, spermidine, calcium alpha-ketoglutarate, berberine, TUDCA, tongkat ali, shilajit, L-glutathione, Korean red panax ginseng, turkesterone, hyaluronic acid, methylene blue and Fadogia agrestis.

The six most evidence-dense compounds in this dataset

This is the ranked part of the Eternal Elixir longevity supplement evidence review. The order below is the Evidence Density Index from Table 1. It ranks by human trial count against Australian search demand. It does not rank by benefit. Nothing here says what a compound does in the body.

Each entry lists the trial count, the index score, the AUD bottle price and the per dose cost. Every Eternal Elixir bottle holds 90 capsules. One capsule is one dose.

#1. Korean red panax ginseng — the densest evidence base per unit of demand

Best for: readers who want the deepest human trial record relative to how few Australians search for it.

Index 1409.1. That is the highest score in the set. PubMed holds 124 human randomised trials. Monthly Australian searches sit at 880. The trial base is large. The crowd is small.

Pros: 124 human randomised trials. Highest index in the dataset. Lowest hype gap of any compound here. Bottle price A$44.99. Per dose A$0.50. Third-party tested.

Cons: low Australian search interest, so peer discussion is thin. Trial quality varies widely. Many studies are small. Extract strengths differ between brands, which makes trials hard to compare.

Product page: Korean red panax ginseng, 90 capsules.

#2. Resveratrol — the largest single trial base we sell

Best for: readers who want volume of published human research above everything else.

Index 323.5. PubMed holds 262 human randomised trials. Australians search for it 8,100 times a month. Only glutathione has more trials. No compound here pairs a base that large with demand that modest.

Pros: 262 human randomised trials. Second-highest index. Long publication history. Bottle price A$59.99. Per dose A$0.67. Pairs with the NMN literature in our longevity stack walkthrough.

Cons: trials use a wide spread of doses. Absorption differs by formulation. Results across trials are mixed. It is not the cheapest per dose in this table.

Product page: Trans-resveratrol, 90 capsules.

#3. L-glutathione — most trials in the set, and the cheapest per dose of the top three

Best for: readers who rank raw trial count first and price second.

Index 256.3. PubMed holds 569 human randomised trials. That is the largest count in this longevity supplement evidence review. Australian demand is 22,200 searches a month, which is heavy, so the index lands third.

Pros: 569 human randomised trials. Cheapest per dose of the top three at A$0.44. Bottle price A$39.99. Broad research across many endpoints.

Cons: much of the literature uses injected or inhaled forms, not oral capsules. Oral absorption is debated. High search demand pulls the index down.

Product page: Reduced L-glutathione, 90 capsules.

#4. Nicotinamide riboside — the better-studied NAD+ precursor

Best for: readers choosing between the two NAD+ precursors on trial count alone.

Index 238.5. PubMed holds 31 human randomised trials. NMN holds 16. Search demand for NR is 1,300 a month against 14,800 for NMN. The gap is the clearest single finding in this longevity supplement evidence review. We compare the two directly in NMN vs NR for Australian buyers.

Pros: nearly twice the human trials of NMN. Index almost 22 times higher. Bottle price A$59.99. Per dose A$0.67. Trials are recent and use consistent doses.

Cons: 31 trials is still a small base. Most are short. Sample sizes are small. It costs more per dose than NMN.

Product page: Pure NR, 90 capsules.

#5. Spermidine — small base, small crowd, balanced index

Best for: readers who want an emerging compound that is not yet running ahead of its evidence.

Index 141.4. PubMed holds 41 human randomised trials. Australian demand is 2,900 searches a month. Neither number is large. They are roughly in step, which is why it sits mid-table.

Pros: 41 human randomised trials. Demand and evidence are close to balanced. Bottle price A$49.99. Per dose A$0.56. Trials come mostly from the last decade.

Cons: the trial base is modest. Many studies use food sources rather than capsules. Dose reporting is inconsistent across papers.

Product page: Spermidine, 90 capsules.

#6. Methylene blue — large base, heavy demand

Best for: readers who want a long research record and accept that most of it predates the current interest.

Index 140.2. PubMed holds 380 human randomised trials. Australian demand is 27,100 searches a month, among the highest here. The base is deep. The crowd is deep too, so the index lands sixth.

Pros: 380 human randomised trials. Third-largest count in the dataset. Bottle price A$59.99. Per dose A$0.67. Research history runs back more than a century.

Cons: much of the older literature sits outside supplement use. Search demand is very high relative to recent trials. Purity grades differ sharply between suppliers.

Product page: Methylene blue, 90 capsules.

What the bottom of the table shows. Turkesterone and Fadogia agrestis both score 0.0. Neither has a single human randomised trial in PubMed. Between them they draw 6,700 Australian searches a month. We sell both. We would rather print that here than leave it out of a longevity supplement evidence review that we published ourselves.

Cheapest per dose in the set. Turkesterone and the tongkat ali and Fadogia blend both land at A$0.22 a dose. Both also sit at the bottom for evidence. Low cost per dose and high trial count do not travel together in this dataset.

Every compound in one line

One line each. Same source data as Table 1. Trial counts are human RCTs in PubMed on 3 August 2026. Prices are ours, in AUD, for a 90 capsule bottle. Per dose cost is the bottle price split 90 ways. Use this block as the short form of the longevity supplement evidence review above.

• Korean red panax ginseng. 124 human RCTs. 880 AU searches a month. Index 1409.1. A$44.99 a bottle. A$0.50 a dose.
• Resveratrol. 262 human RCTs. 8,100 AU searches a month. Index 323.5. A$59.99 a bottle. A$0.67 a dose.
• L-glutathione. 569 human RCTs. 22,200 AU searches a month. Index 256.3. A$39.99 a bottle. A$0.44 a dose.
• Nicotinamide riboside. 31 human RCTs. 1,300 AU searches a month. Index 238.5. A$59.99 a bottle. A$0.67 a dose.
• Spermidine. 41 human RCTs. 2,900 AU searches a month. Index 141.4. A$49.99 a bottle. A$0.56 a dose.
• Methylene blue. 380 human RCTs. 27,100 AU searches a month. Index 140.2. A$59.99 a bottle. A$0.67 a dose.
• Trans-pterostilbene. 7 human RCTs. 880 AU searches a month. Index 79.5. A$64.99 a bottle. A$0.72 a dose.
• TUDCA. 21 human RCTs. 4,400 AU searches a month. Index 47.7. A$59.99 a bottle. A$0.67 a dose.
• Hyaluronic acid. 112 human RCTs. 27,100 AU searches a month. Index 41.3. A$69.99 a bottle. A$0.78 a dose.
• Berberine. 108 human RCTs. 40,500 AU searches a month. Index 26.7. A$49.99 a bottle. A$0.56 a dose.
• NMN. 16 human RCTs. 14,800 AU searches a month. Index 10.8. A$49.99 a bottle. A$0.56 a dose.
• Shilajit. 7 human RCTs. 27,100 AU searches a month. Index 2.6. A$44.99 a bottle. A$0.50 a dose.
• Fadogia agrestis. No human RCTs at all. 1,300 AU searches a month. Index 0.0. A$19.99 a bottle. A$0.22 a dose.
• Turkesterone. No human RCTs at all. 5,400 AU searches a month. Index 0.0. A$19.99 a bottle. A$0.22 a dose.

Read the two halves apart. A big trial count is not a claim. A low price is not a claim. The index just puts the two next to search demand. That is the whole point of this longevity supplement evidence review.

How to read a row. Take the trial count. Then take the search count. A high trial count with a low search count gives a high index. A low trial count with a high search count gives a low one. Rank 1 is the best studied per unit of demand. Rank 14 is the worst. The index is a ratio. It is not a score for how well a thing works. It says how much has been studied, and how much is being asked about. Nothing more.

Where the money goes. The cheapest dose here is A$0.22. The dearest is A$0.78. That is a gap of three and a half times. The trial counts span 0 to 569. That gap is far wider. Price and evidence do not track each other in this set.

We publish this index knowing it is unflattering to part of our own range. Two compounds we sell have no human randomised trial evidence at all, and one of our most popular categories has the widest attention–evidence gap in the dataset. We would rather you know that from us than find it out somewhere else. If you want the dosing literature rather than the trial counts, start with our NMN dosage guide for Australia or the best NMN supplements in Australia.

About the author. Compiled by the Eternal Elixir research desk, Australia. Queries, retrieval dates and limitations are published in full above so the analysis can be independently checked or rebuilt. Corrections: contact us through our contact page.

This page reports counts of published research. It is general information about the scientific literature and is not individual health advice. Speak to a qualified health practitioner before starting any supplement.