Best L-Lysine 2026: Tablets vs Powder, by Cost per Trial-Dose Gram
Informational summary — not medical advice. This page ranks product value at a given dose; on whether lysine actually works for cold-sore prevention, see the full evidence reckoning. Lysine is not a treatment for an active cold sore. This statement has not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.
If you're trying lysine for cold-sore prevention despite the mixed evidence, you need a sustained ~1–3 g/day — so cost per gram (where powder wins) matters more than the bottle price, and there's no reason to bother with a sub-gram dose no positive trial supports. Of the 5 plain L-lysine products tracked, the cheapest at the 3 g/day trial-relevant dose is Nutricost L-Lysine Powder (500 g) ($0.10/day). The cheapest sticker price is a different product, Nature's Bounty, whose small count and per-gram cost make it the most expensive way to sustain the dose — see below.
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The one-line takeaway Every product here is the identical plain L-lysine molecule — so pay for the dose, not the brand. Powder costs the least per gram; a 1,000 mg tablet product means 3 pills/day to hit the trial range; and the lowest sticker price (Nature's Bounty, $7.42) is actually the priciest per gram once you account for its small 60-count bottle.
The awards
Plain powder, the cheapest cost per gram of the five — a full 3 g/day dose costs about a dime. Measure the amount directly; no pill-counting.
A label-confirmed 1 g serving from a widely recognized bulk-supplement brand, second-cheapest per gram, and easy to titrate precisely to your target dose.
If you want tablets over powder, this 240-count bottle has the lowest cost per gram of the three tablet products — 3 tablets/day reaches the trial-relevant dose for about a quarter a day.
A longer-standing, widely trusted supplement brand in 1,000 mg tablets — priced between the Nutricost tablet value pick and the small Nature's Bounty bottle.
Every product compared: cost per gram & cost at the trial dose
Sorted cheapest cost at the 3 g/day trial-relevant dose first. "Units/day" is how many scoops or tablets it takes to reach 3 g — read it before the sticker price, since a small high-count-per-serving bottle can look cheap and still cost more per day than a bigger, better-priced one. Full data is a public CC BY JSON file.
| Product | Form | mg/serving | Price | $ / gram | Units/day @ 3g | $ / day @ 3g | Days/container @ 3g |
|---|---|---|---|---|---|---|---|
| Nutricost L-Lysine Powder (500 g) | Powder | 1000 mg | $15.95 | $0.032 | 3 | $0.10 | 166 |
| BulkSupplements BulkSupplements.com L-Lysine Powder (500 g) | Powder | 1000 mg | $19.97 | $0.040 | 3 | $0.12 | 166 |
| Nutricost L-Lysine 1,000 mg (240 Tablets) | Tablet | 1000 mg | $19.95 | $0.083 | 3 | $0.25 | 80 |
| Solgar L-Lysine 1,000 mg (250 Tablets) | Tablet | 1000 mg | $23.01 | $0.092 | 3 | $0.28 | 83 |
| Nature's Bounty L-Lysine 1,000 mg (60 Tablets) | Tablet | 1000 mg | $7.42 | $0.124 | 3 | $0.37 | 20 |
Prices are live Amazon buy-box figures, July 2026; they move. Cost per gram = price ÷ total grams of L-lysine (servings × mg per serving ÷ 1000). Cost at the 3 g/day trial dose = cost per gram × 3. 3 g/day is Griffith 1987's dose — the strongest positive cold-sore-prevention RCT in this evidence set; the actual positive-trial range spans 1-3 g/day (see the dosage guide).
What none of these products claim — and why that matters
Every product in this comparison is a plain L-lysine (HCl) mono-ingredient, sold under a general structure/function supplement label. None of them are marketed or labeled as a "cold sore treatment," "antiviral," or "cure" — and that's appropriate, given how mixed the underlying trial evidence actually is (three positive RCTs, three null RCTs, and a Cochrane review that couldn't confirm efficacy). None of them replace antiviral medication (acyclovir, valacyclovir, docosanol) for an active outbreak. Buying the cheapest-per-gram option here is a rational way to test the trial-relevant dose at low cost and low risk — it is not a guarantee the trial's positive results will apply to you.
Frequently asked questions
What is the best L-lysine supplement?
Nutricost L-Lysine Powder (500 g) is cheapest at the 3 g/day trial-relevant dose ($0.10/day). Powder beats tablets on cost per gram across the board.
Why isn't the cheapest sticker price the best value?
Nature's Bounty's $7.42 bottle is the lowest sticker price but has the highest cost per gram and lasts only 20 days at the trial dose — the opposite of a bargain for sustained use.
Powder or tablets?
Powder is cheaper per gram and lets you measure any amount precisely. Tablets are more convenient but cost more per gram, and 3 g/day means swallowing 3 tablets.
Are any of these a cold-sore treatment?
No — all are plain structure/function L-lysine supplements, not drugs, and none replace antivirals for an active outbreak.
Related
- L-lysine: what it is & the honest evidence
- L-lysine dosage guide — why 500 mg once a day probably isn't the trial dose
- L-lysine for cold sores — how people actually use it
- Does lysine actually prevent cold sores? — the full trial reckoning
Sources
- Manufacturer labels and live Amazon pricing for all listed products, July 2026. Full dataset: /lysine/cost-by-brand.json (CC BY 4.0).
- Griffith RS, Walsh DE, Myrmel KH, et al.. "Success of L-lysine therapy in frequently recurrent herpes simplex infection. Treatment and prophylaxis." Dermatologica. 1987. PMID: 3115841 (3,000 mg/day trial-dose basis).
- McCune MA, Perry HO, Muller SA, O'Fallon WM. "Treatment of recurrent herpes simplex infections with L-lysine monohydrochloride." Cutis. 1984. PMID: 6435961