What is it used for?
Source of (an) antioxidant(s)/Provides (an) antioxidant(s) (Borcea et al. 1999, Marangon et al.1999).
Source of (an) antioxidant(s)/Provides (an) antioxidant(s) that help(s) fight/protect (cell) against/reduce (the oxidative effect of/the oxidative damage caused by/cell damage caused by) free radicals (Borcea et al. 1999, Marangon et al.1999).
Helps to promote healthy glucose metabolism (Morcos et al. 2001, Jacob et al. 1999, Konrad et al. 1999).
Note: If DL-alpha-Lipoic or R-alpha-Lipoic acid is combined with other active ingredients with antioxidant properties at Class II and III, there is an option to use the claim in plural. The singular should be used when the product only contains one chemical substance as the active ingredient associated with this claim.
What this guide covers
The solidus (/) indicates that the terms and/or statements are synonymous. Either term or statement may be selected by the applicant on the label.
Who does this guide cover?
Adults 18 years and older
How is it taken?
Oral
Which forms are covered?
this reference excludes foods or food-like dosage forms as indicated in the Compendium of references Guidance Document.
Quantities
DL-alpha-Lipoic acid
Antioxidant
Not to exceed 600 milligrams of DL-alpha-Lipoic acid, per day (Morcos et al. 2001, Borcea et al. 1999, Marangon et al.1999).
Glucose metabolism
600 milligrams of DL-alpha-Lipoic acid, per day (Jacob et al. 1999, Konrad et al. 1999).
R-alpha-Lipoic acid
Antioxidant
Not to exceed 300 milligrams of R-alpha-Lipoic acid*, per day.
Glucose metabolism
300 milligrams of R-alpha-Lipoic-acid*, per day.
*Note: The quantity of R-alpha-lipoic acid is calculated from the quantity of DL-alpha-lipoic acid (i.e. 50%).
How is it used?
The reference does not require an additional label statement in this section. This does not establish an absence of risk.
How long is it used?
The reference does not require an additional label statement in this section. This does not establish an absence of risk.
Warnings and precautions
All products
Ask a healthcare professional before use if you are pregnant or breastfeeding.
Ask a healthcare professional before use if you have diabetes (Jacob et al. 1999, Konrad et al. 1999, Packer et al. 1995).
Products providing 42 milligrams or more DL-alpha-lipoic acid or 21 milligrams or more R-alpha-lipoic acid, per day
Stop use and ask a healthcare professional if you experience sweating, paleness, chills, headache, dizziness and/or confusion (as these may be symptoms of serious low blood sugar) [Source note 2].
When should it be avoided?
The reference does not require an additional label statement in this section. This does not establish an absence of risk.
Possible side effects
The reference does not require an additional label statement in this section. This does not establish an absence of risk.
Storage
Must be established in accordance with the requirements described in the applicable product regulations.
Conditions for combined preparations
No permitted combinations between the two active ingredients listed in this reference.
Preparation details
Ingredient identity, preparation requirements, and other details that define the scope of this guide.
Ingredients and preparations
| Proper name(s) | Common name(s) | Source information / Source ingredient(s) | Source information / Preparation(s) |
|---|---|---|---|
|
| DL-alpha-Lipoic acid | Synthetic |
| 1,2-Dithiolane-3-pentanoic acid, (R) |
|
| Synthetic |
References: Proper names: NIH 2023; Common names: NIH 2023; Source information: NIH 2023.
Other ingredients
Must be chosen from the current source ingredient database and must meet the limitations outlined in the database.
Preparation and quality requirements
The finished product specifications must be established in accordance with the requirements described in the source authority source’s product quality guidance.
The active ingredient must comply with the requirements outlined in the source ingredient database.
Guide change history
Updates to this SupplementSafety.org guide.
Minor updates
Updated guide wording, organization, and source presentation. Added our editorial change history.
Initial release
Initial SupplementSafety.org guide prepared from source reference material.
Validation: Not yet completed. Editorial updates do not constitute clinical validation.
Sources
Source information
This guide organizes source material about uses, preparations, amounts, and precautions. Read the conditions alongside each statement; the information may apply only to particular preparations or populations.
The source document includes supporting references. We have not independently summarized or assessed every cited study for this guide.
- Source document version
- June 27, 2025
- Source captured
- Aug 15, 2026
- Editorial work
- Editorial preparation. Independent clinical review has not been recorded for this guide.
Full citations are available through the link above. Verification is required to open them; reading this guide does not require verification.
Taking a medication too?
Explore our supplement–medication interaction checker. Its coverage and review status are shown with the results; a missing finding does not establish that a combination is safe.