Alpha-Lipoic Acid Dosage: 600 mg/day (and Why That's 300 mg Active R)
Educational summary — not medical advice. ALA can lower blood sugar; if you take insulin or a sulfonylurea, clear the combination with your clinician — see the safety cautions.
The honest answer
The standard studied oral dose is 600 mg/day (trial range ~300–1,800 mg/day), and those trials used racemic ALA. The catch: only the R-(+) enantiomer is active, so a 600 mg racemic dose = ~300 mg active R. An R-ALA or Na-R-ALA product labeled 100 mg is 100 mg of active R. Take it on an empty stomach (~30 min before a meal). The strongest evidence is for the intravenous form, not the oral cap — see does it work.
The key thing most people get wrong: half of a racemic dose is inactive
Alpha-lipoic acid exists as two mirror-image forms, and only the R-(+) enantiomer is the one your body makes and the active one (Salehi 2019). Standard "alpha-lipoic acid" is racemic — a 50/50 mix of R and S — so a labeled 600 mg cap delivers ~300 mg of active R and ~300 mg of the inactive S form. The trials that established the 600 mg/day dose used racemic ALA, so 600 mg racemic is the studied dose — you don't need to "double up" to 1,200 mg to hit it. The active-R math matters mainly when you compare products: a 100 mg R-ALA cap and a 200 mg racemic cap both supply ~100 mg of active R.
| Question | Answer |
|---|---|
| How much? | 600 mg/day (standard studied oral dose) |
| Studied range? | ~300–1,800 mg/day; little added benefit above ~600 mg for most |
| How much active R is that? | 600 mg racemic = ~300 mg active R (racemic is 50% R) |
| R-ALA / Na-R-ALA? | 100% active R — a 100 mg cap = 100 mg active R (better absorbed, not cheaper per mg R) |
| When? | Empty stomach, ~30 min before a meal (food lowers absorption) |
| Which form has the strongest evidence? | Intravenous (hospital), not the oral capsule |
Active-R calculator: what your label really delivers
Enter the labeled alpha-lipoic acid per serving, pick the form, and your servings per day. Racemic products are counted at 50% active R; R-ALA and stabilized sodium-R-lipoate at 100%. You'll see your labeled ALA/day, your active R/day, and how that compares with the ~300 mg of active R implied by the 600 mg/day studied dose.
How to take it
- Target ~600 mg/day of racemic ALA (or the R-form equivalent, ~300 mg active R) — the standard studied oral dose. Higher doses were used up to ~1,800 mg/day, but benefit doesn't clearly keep rising.
- Take it on an empty stomach, ~30 minutes before a meal — food reduces absorption. Split doses above ~600 mg into two.
- Don't chase a bigger labeled number. If you want active R cheaply, a 600 mg racemic product is the least expensive source; R-ALA/Na-R-ALA is an absorption upgrade, not a cheaper active dose — see R vs racemic.
- Mind the blood-sugar interaction. ALA can lower glucose; with insulin or a sulfonylurea this can add up to hypoglycemia. Monitor and discuss with your clinician — see the safety section.
The cheapest way to hit the dose
To match the 600 mg/day studied dose (~300 mg active R) at the lowest cost, the cheapest source of active R across the 13 products we track is a bulk racemic. Full ranking on best value.
Racemic 600 mg = ~300 mg active R per serving — the studied 600 mg/day dose — at $0.03/100 mg of actual active R, the lowest of the field.
As an Amazon Associate we earn from qualifying purchases. Ranked by cost per 100 mg of active R-ALA, never commissions.
Frequently asked questions
How much alpha-lipoic acid should I take per day?
600 mg/day is the standard studied oral dose (range ~300–1,800; trials used racemic). Take on an empty stomach ~30 min before a meal. The strongest overall evidence is for the IV form, not the oral cap.
Does 600 mg mean 600 mg of the active form?
No, not for racemic. Only R-(+) is active, and racemic is 50/50, so 600 mg racemic = ~300 mg active R. A 100 mg R-ALA/Na-R-ALA cap is 100 mg active R.
Should I take R-ALA for a higher active dose?
You can, but it's not the cheapest active R. Bulk racemic is the least expensive source per mg of active R; R-form costs several times more per mg of R. R-ALA's real edge is absorption, not a cheaper active dose.
When should I take it?
On an empty stomach, ~30 min before a meal (food lowers absorption); split doses above ~600 mg. The bigger caution is the blood-sugar interaction with insulin/sulfonylureas — clear it with your clinician.
Related
- R vs racemic — why only R is active, and why bulk racemic is still the cheapest source of it
- Best value — every product ranked by cost per 100 mg of active R
- Does it work? — neuropathy, glycemic, weight, and the safety landmines
Sources
- Salehi B, et al. "Insights on the Use of α-Lipoic Acid for Therapeutic Purposes." Biomolecules. 2019. PMID: 31405030 (R-(+) is the natural, active enantiomer; commercial ALA is widely racemic).
- Ziegler D, et al. "Treatment of symptomatic diabetic polyneuropathy with α-lipoic acid (SYDNEY 2)." Diabet Med. 2004. PMID: 14984445 (IV 600 mg/day; strongest evidence).
- Hsieh RY, et al. "Oral alpha-lipoic acid for diabetic peripheral neuropathy: a systematic review and meta-analysis." Nutrients. 2023. PMID: 37630823 (10 RCTs; favorable, dose-related).
- Full product dataset: /alpha-lipoic-acid/cost-by-brand.json (CC BY 4.0).