Is Alpha Lipoic Acid Natural? Separating Fact from Synthetic Supplements

December 23, 2025 •

3 min read

Did you know your body produces its own alpha lipoic acid, a powerful antioxidant present in every cell to help turn food into energy? The question of whether alpha lipoic acid is natural, however, has a more nuanced answer when considering supplements versus dietary and bodily sources.

Quick Summary

Alpha lipoic acid is made naturally by the body, but commercial supplements typically contain a mix of natural and synthetic forms. The body's natural R-form is more potent.

Key Points

Natural Production: Your body naturally synthesizes alpha lipoic acid, specifically the R-enantiomer, to aid in energy production.
Dietary Sources: Small amounts of the natural R-ALA form are found in foods like organ meats, spinach, and broccoli.
Synthetic Supplements: Most ALA supplements contain a 50/50 racemic mixture of the natural R-form and the synthetic S-form.
Superior Bioavailability: The naturally occurring R-lipoic acid is more potent and more easily absorbed and utilized by the body than its synthetic counterpart.
Read Labels Carefully: To ensure you are getting the most potent, natural form, look for supplements that specifically state "R-lipoic acid" or "R-ALA".
Antioxidant Power: As a fat- and water-soluble antioxidant, ALA can protect cells from damage throughout the body and regenerate other antioxidants.
Health Benefits: Supplemental ALA may offer benefits for managing conditions like diabetic neuropathy and supporting healthy blood sugar levels.

What is Alpha Lipoic Acid?

Alpha-lipoic acid (ALA), also known as thioctic acid, is an organic compound found in every cell of the human body that is crucial for converting nutrients into usable energy. ALA acts as a necessary cofactor for mitochondrial enzyme complexes and functions as a versatile antioxidant in both water- and fat-soluble environments, neutralizing free radicals. This unique property helps protect cells from damage.

The Dual Nature of ALA: Natural vs. Synthetic

ALA is naturally produced by the body and found in certain foods. However, supplements often contain a synthetic version. ALA has an asymmetric carbon atom, creating two forms: R-lipoic acid and S-lipoic acid.

Natural Sources of R-ALA

The body only uses R-alpha-lipoic acid (R-ALA). This form is bound to proteins and is essential for energy production. Small amounts of R-ALA come from foods like organ meats, spinach, broccoli, tomatoes, and yeast.

The Synthesis of S-ALA

S-alpha-lipoic acid (S-ALA) is a synthetic form not found naturally. Most standard ALA supplements are a 50/50 mix of R-ALA and S-ALA, called a racemic mixture. S-ALA is less active and can interfere with R-ALA absorption.

Natural R-ALA vs. Synthetic S-ALA: What's the Difference?

The potency and bioavailability of ALA differ between the natural and synthetic forms, which is important for supplement choices.


Feature	Natural R-Alpha Lipoic Acid (R-ALA)	Synthetic S-Alpha Lipoic Acid (S-ALA)
Source	Produced naturally by the body; found in food	Synthesized in a lab; not found naturally
Bioavailability	Higher; more efficiently absorbed and utilized by the body	Lower; less effectively absorbed and used by the body
Potency	Biologically active and more potent	Less biologically active and less potent
Availability in Supplements	Available as isolated R-ALA, or as part of a racemic mixture	Almost always included in a standard racemic (50/50) ALA supplement

The Role of ALA in the Body

ALA's antioxidant properties contribute to various health benefits:

Nerve function: Helps reduce symptoms of diabetic neuropathy.
Blood sugar: May improve insulin sensitivity and regulate blood sugar.
Heart health: Protects against oxidative stress linked to cardiovascular diseases.
Brain health: Crosses the blood-brain barrier, offering neuroprotection.
Skin: Topical use may protect against UV damage and reduce signs of aging.
Antioxidant regeneration: Helps regenerate other antioxidants like vitamin C, E, and glutathione.

Is Your Supplement Natural? How to Tell

Check supplement labels carefully. If it says "alpha lipoic acid" or "ALA", it's likely a racemic mix of R-ALA and S-ALA. These are effective but less potent than supplements with only the R-form. For the most active form, look for "R-lipoic acid" or "R-ALA" on the label. Choosing R-ALA ensures better absorption and utilization.

Conclusion: The Bottom Line on Natural ALA

Alpha lipoic acid is natural, produced by the body and found in food. However, most supplements are a mix of natural (R-ALA) and synthetic (S-ALA) forms. The natural R-form is more potent and bioavailable. To maximize benefits, choose supplements labeled specifically as R-lipoic acid. For more information, visit the Linus Pauling Institute at Oregon State University.

Linus Pauling Institute at Oregon State University

Frequently Asked Questions

While the ALA from food is the natural R-form, the amount is significantly smaller than what is available in supplements. Supplements offer a concentrated dose, but most contain a mix of natural and synthetic ALA, which is less potent than pure R-ALA.

The most common form of ALA in supplements is a 50/50 mix of R-ALA and S-ALA, often labeled simply as 'Alpha Lipoic Acid'. To get the natural, more potent R-form, you must look for products specifically labeled as 'R-lipoic acid' or 'R-ALA'.

R-ALA is the biologically active, natural form of alpha lipoic acid that the body can use efficiently. S-ALA is a synthetic mirror image of R-ALA and is less effective and bioavailable.

Your body produces enough ALA for essential metabolic functions, but supplements provide much higher concentrations that may offer additional benefits, particularly for specific health conditions like diabetic neuropathy.

Alpha lipoic acid is generally considered safe for most adults when taken in appropriate doses. Mild side effects like nausea or skin rash may occur, but higher doses should be monitored, especially for those with diabetes or thyroid conditions.

Foods containing naturally occurring alpha lipoic acid include red meat, organ meats like liver and heart, and certain vegetables such as spinach, broccoli, and tomatoes.

While a balanced diet provides small amounts of natural R-ALA, it is generally not sufficient to achieve the therapeutic levels required for specific health goals like managing diabetic neuropathy. This is why supplementation is common.