Last updated: · Originally published September 23, 2026 · Published by Eternal Elixir
Edited by Elaine Fletcher, Researcher
Quick answer: Source Naturals is a family-owned US supplement maker that has sold its Wellness Formula since 1982. It makes much of its range at its own facility in Scotts Valley, California, tests ingredients and finished products in its own lab, and is easy to find in health food stores. For longevity buyers, its main product is NR Nicotinamide Riboside: 300 mg per capsule, 60 capsules for $39.98, or $2.22 per gram of NR. It sells no NMN, TUDCA, spermidine, Ca-AKG or pterostilbene, and many of its listings showed as sold out on its own store when we checked. Our pick is Eternal Elixir Nicotinamide Riboside 500mg: 500 mg per capsule, 60 capsules for $59.99, or $2.00 per gram.
Eternal Elixir makes Nicotinamide Riboside 500mg and competes with Source Naturals, so read this as a competitor’s review. Every Source Naturals figure below comes from its own product pages, FAQ and shipping policy, or the Supplement Facts image on its NR page, all read on September 25, 2026. We did not buy or test Source Naturals products. Here is how we write and review content.
Source Naturals review 2026: who makes it
Source Naturals says it has been in business since 1982 and describes itself as family-owned for more than 40 years. A 2020 company press release credits Ira Goldberg, founder of Threshold Enterprises, with creating its Wellness Formula in 1982. That immune blend is still the brand’s best-known product.
The range is large. Its online store listed 471 products when we checked, covering vitamins, minerals, herbs, sleep, digestion and a Healthy Aging collection. Its site has store pages for Sprouts, Erewhon, Fresh Thyme, Mother’s Market and Natural Grocers, which tells you where most people buy it.
That matters because the brand’s own store is patchy. Only 87 of those 471 listings showed an in-stock option when we checked. If you want a specific product, a health food store or an online retailer may be the easier route.
How Source Naturals makes and tests its supplements
Source Naturals’ FAQ answers the manufacturing question directly:
- It does “much of our own manufacturing” at its facility in Scotts Valley, California, and also uses outside manufacturers that it monitors through a supplier quality program.
- An outside certifying body checks that its own production follows cGMP.
- Every ingredient is tested before manufacturing, and the finished product is tested again afterward.
- Its lab uses methods including HPTLC, HPLC, LC-MS, and ICP-MS for heavy metals.
That is a clear description, and it covers raw materials and finished products. It is also mostly in-house testing. The NR product page we read does not post a certificate of analysis for the current lot, so you have to take the process on trust or ask the company.
One more point from the FAQ is worth knowing. Source Naturals says the label on your bottle may differ from the one on its website, because it updates potencies and ingredients over time. Read the Supplement Facts panel on the bottle you actually buy.
What is on the Source Naturals Healthy Aging shelf
The Healthy Aging collection held eight products when we checked: NR Nicotinamide Riboside, MitoNight with Melatonin, HGH Surge, EnerVital, Acetyl L-Carnitine, Acetyl L-Carnitine and Alpha-Lipoic Acid, Telomeron and Fisetin. Only one of them, the 60-capsule bottle of 300 mg NR, showed as in stock.
Outside that collection, Source Naturals lists an NAD+ lozenge at 25 mg per lozenge (60 for $26.98, in stock) and four single-ingredient resveratrol products at 80 mg, 100 mg, 200 mg and 500 mg. All four showed as sold out on its store. It lists no NMN, no TUDCA, no spermidine, no Ca-AKG and no pterostilbene.
Source Naturals vs Eternal Elixir: doses and prices
These are the prices on each brand’s US store as of Sep 2026, before any multi-bottle discount.
| Active | Eternal Elixir | Source Naturals |
|---|---|---|
| Nicotinamide riboside | Nicotinamide Riboside 500mg: 500 mg per capsule, one capsule per serving, 60 capsules, $59.99. That is $1.00 per serving and $2.00 per gram of NR. | NR Nicotinamide Riboside: 300 mg per capsule, one capsule per serving, 60 capsules, $39.98. That is $0.67 per serving and $2.22 per gram of NR. A 500 mg version was listed but sold out. |
| NMN | NMN 500mg: 500 mg per capsule, 90 capsules, $49.99. That is $1.11 per gram of NMN. | Not sold |
| Resveratrol | Trans-Resveratrol 600mg: one capsule per serving, 90 capsules, $59.99. That is $0.67 per serving. | Resveratrol 500: 500 mg per tablet, one tablet daily, $20.98 for 30. Sold out, as were its 80 mg, 100 mg and 200 mg versions. |
| Pterostilbene | Trans-Pterostilbene 500mg: one capsule per serving, 90 capsules, $64.99. That is $0.72 per serving. | Not sold |
| Ca-AKG | Ca-AKG 500mg: one capsule per serving, 60 capsules, $49.99. That is $0.83 per serving. | Not sold |
| Spermidine | Spermidine 10mg: one capsule per serving, 60 capsules, $49.99. That is $0.83 per serving. | Not sold |
| TUDCA | TUDCA 500mg: one capsule per serving, 60 capsules, $59.99. That is $1.00 per serving. | Not sold |
Add Nicotinamide Riboside 500mg to cart · $59.99
On NR, the two products are close. Source Naturals costs less per capsule, $0.67 against our $1.00, and ours costs less per gram because each capsule holds 500 mg instead of 300 mg. If you take 300 mg a day, Source Naturals is cheaper. If you take 500 mg or more, ours works out cheaper and needs fewer capsules. Our nicotinamide riboside comparison runs the same maths across other brands, and our Tru Niagen review looks at the best-known NR brand.
Buying two or more bottles of any of ours takes 10% off two, 15% off three and 20% off five, and US orders over $100 ship free. Source Naturals ships free on orders of $75 or more within the contiguous US.
What the research says about these doses
Nicotinamide riboside: dose-dependent rise in blood NAD+
In an eight-week randomized, placebo-controlled trial in Scientific Reports (Conze and colleagues, 2019), healthy overweight adults took 100 mg, 300 mg or 1,000 mg of NR a day. Whole blood NAD+ rose by 22%, 51% and 142% at those doses within two weeks, and the rise held for the rest of the study. Adverse events did not differ from placebo. The study was funded by ChromaDex, which sells NR, and two authors were its employees.
Source Naturals’ 300 mg capsule matches the middle dose in that trial. Our 500 mg capsule sits between the 300 mg and 1,000 mg arms, so its exact effect was not measured there. A crossover trial in Nature Communications (Martens and colleagues, 2018) also found NR well tolerated in healthy middle-aged and older adults and found that it raised NAD+ metabolism.
Evidence level: small randomized human trials measuring blood NAD+. NR has not been shown to extend human lifespan. Our NMN versus NR comparison covers how the two precursors differ, and our NAD+ supplement guide ranks the options.
Resveratrol: one long trial at a modest dose
The RESHAW trial, published in the Journal of Bone and Mineral Research in 2020 (Wong and colleagues), gave postmenopausal women 75 mg of resveratrol twice a day in a 24-month crossover design. After 12 months, bone density in the lower spine was 0.016 grams per square centimeter higher than on placebo. That is 150 mg a day, well below both our 600 mg capsule and Source Naturals’ 500 mg tablet. A higher dose has not been shown to work better.
Evidence level: one long human trial with a specific group of women. Our resveratrol supplement comparison and our NMN versus resveratrol breakdown cover the rest of the research.
Add Trans-Resveratrol 600mg to cart · $59.99
Where the Source Naturals longevity range stops
For a brand with a Healthy Aging collection, the gaps are large. There is no NMN, the precursor most buyers compare NR against. There is also no TUDCA, spermidine, Ca-AKG or pterostilbene. A Source Naturals buyer building a longevity routine will end up ordering from two brands. Our guides to the best NMN supplements and the best Ca-AKG supplements cover those gaps, and our pterostilbene dosage guide covers the resveratrol relative.
How Source Naturals compares with other brands we’ve reviewed
Source Naturals sits with the big retail brands. Our Solaray review covers another long-running health food store brand, and our NOW Foods review covers a large range sold on value. For a practitioner brand, see our Pure Encapsulations review. Our Double Wood Supplements review covers a budget brand that posts a lab report for each lot. For the full category view, start with our longevity supplement comparison.
Who should buy Source Naturals, and who shouldn’t
Source Naturals suits you if you want an established immune blend, everyday vitamins or herbs, or a 300 mg NR capsule at a low price per capsule. It also suits you if you shop in health food stores and like to pick up a bottle the same day.
Look elsewhere if you want NMN, TUDCA, spermidine, Ca-AKG or pterostilbene, which it does not sell, or resveratrol today, since all four of its versions were sold out on its store. Look elsewhere too if you take 500 mg or more of NR a day, where our capsule costs less per gram. Note the return terms as well. Source Naturals accepts new, unopened items within 30 days, and our 30-day guarantee is a money-back guarantee.
Source Naturals review: frequently asked questions
Is Source Naturals a reputable supplement company?
Yes. It has sold supplements since 1982, describes itself as family-owned, makes much of its range in its own California facility and explains how it tests ingredients and finished products. Its testing is mostly in-house, and its NR page does not post a lot certificate. Its longevity range is narrow and was mostly out of stock on its own store when we checked.
Is Source Naturals third-party tested?
Partly. Source Naturals says an outside certifying body checks that its manufacturing follows cGMP. Its ingredient and finished-product testing is done in its own lab, using methods such as HPLC, LC-MS and ICP-MS. That is different from an outside lab testing each finished lot, and we did not find lot certificates on the product page we read.
Which supplement company is the most trustworthy?
No company earns that title for every product. Check four things instead: the exact form and amount of each active per serving, whether that amount matches what human trials used, whether an outside lab tested the finished lot, and whether the brand says what hasn’t been shown. Our product pages state the evidence level for each active, so you can hold us to the same checks.
Who owns Source Naturals supplements?
Source Naturals describes itself as a family-owned company. A 2020 company press release names Threshold Enterprises founder Ira Goldberg as the creator of its Wellness Formula in 1982. Its website does not name any outside parent company.
Where are Source Naturals supplements made?
Its FAQ says it does much of its own manufacturing in Scotts Valley, California, and also uses outside manufacturers under cGMP. It sources botanicals and other raw materials from around the world and tests them before use.
Does Source Naturals sell NMN?
No. Its NAD+ products are NR Nicotinamide Riboside, an NAD+ lozenge and NADH lozenges. For NMN, Eternal Elixir NMN 500mg declares 500 mg per capsule on the front label, with 90 capsules for $49.99.
Add NMN 500mg to cart · $49.99
What is Source Naturals’ return policy?
Items bought on sourcenaturals.com can be returned new and unopened within 30 days for a refund, and the customer pays return shipping. Products bought from a store or another website follow that seller’s policy.
What is the best alternative to Source Naturals NR?
Our pick is Eternal Elixir Nicotinamide Riboside 500mg, which we make. It gives 500 mg of NR per capsule, 60 capsules for $59.99, or $2.00 per gram against $2.22 for Source Naturals’ 300 mg capsules. If you only want 300 mg a day, Source Naturals costs less per day.
Add Nicotinamide Riboside 500mg to cart · $59.99
Our verdict on Source Naturals
Source Naturals is an established, family-owned brand with a famous immune blend, a clear account of how it makes and tests its products and wide health food store distribution. For longevity, its range is thin: one NR capsule in stock, no NMN, and resveratrol sold out on its store when we checked. If NR is what you came for, our Nicotinamide Riboside 500mg puts 500 mg in each capsule and costs less per gram.
See the rest of our range in the Eternal Elixir shop.
Sources
- Conze D, Brenner C, Kruger CL. Safety and metabolism of long-term administration of NIAGEN (nicotinamide riboside chloride) in a randomized, double-blind, placebo-controlled clinical trial of healthy overweight adults. Scientific Reports, 2019. PubMed 31278280
- Martens CR, Denman BA, Mazzo MR, et al. Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults. Nature Communications, 2018. PubMed 29599478
- Wong RH, Thaung Zaw JJ, Xian CJ, Howe PR. Regular supplementation with resveratrol improves bone mineral density in postmenopausal women: a randomized, placebo-controlled trial. Journal of Bone and Mineral Research, 2020. PubMed 32564438
- Source Naturals NR Nicotinamide Riboside page and Supplement Facts image, Resveratrol 500 page, FAQ and shipping and returns policy, read September 25, 2026.
- Threshold Enterprises press release on the Wellness Formula, October 28, 2020. PR Newswire
- Eternal Elixir product pages for Nicotinamide Riboside 500mg, NMN 500mg, Trans-Resveratrol 600mg, Trans-Pterostilbene 500mg, Ca-AKG 500mg, Spermidine 10mg and TUDCA 500mg (US, September 2026).
