Benefits
Universal antioxidant
Unlike most antioxidants, ALA and its reduced form DHLA are active in both aqueous and lipid environments, and can regenerate other antioxidants including vitamins C and E, CoQ10, and glutathione from their oxidized forms.
Nerve comfort support
In people with diabetic nerve discomfort, oral ALA at 600 mg/day improved symptom scores versus placebo in the 5-week SYDNEY 2 trial. The strongest neuropathy results come from short-term intravenous ALA, which is a different route than an oral supplement, and the 4-year oral NATHAN 1 trial did not meet its primary nerve endpoint. Effects on oral symptom scores are real but modest, and ALA is not a treatment for diabetic neuropathy.
Insulin sensitivity
ALA activates GLUT4 glucose transporter translocation via PI3K and AMPK pathways, improving skeletal muscle glucose uptake. Pooled trials show ALA lowers insulin and HOMA-IR (better insulin sensitivity), but does not significantly change fasting glucose or HbA1c.
Glutathione recycling
DHLA (reduced ALA) reduces oxidized glutathione (GSSG) back to active GSH, effectively amplifying the body's endogenous antioxidant capacity.
Mechanism of action
Mitochondrial cofactor activity
ALA is an essential cofactor for pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase — key enzyme complexes in the TCA cycle at the center of mitochondrial energy metabolism.
Nrf2 pathway activation
ALA activates the Nrf2-Keap1 pathway, inducing transcription of antioxidant response element (are) genes including glutathione peroxidase, superoxide dismutase, and heme oxygenase-1.
Metal chelation
ALA chelates redox-active metals (iron, copper, cadmium, mercury), preventing them from participating in Fenton reactions that generate hydroxyl radicals — particularly relevant in heavy metal toxicity.
Clinical trials
Multicenter, randomized, double-blind, placebo-controlled trial in 181 diabetic patients (Russia and Israel) with distal symmetric polyneuropathy. Once-daily oral ALA at 600 mg, 1,200 mg, 1,800 mg, or placebo for 5 weeks after 1-week placebo run-in. Primary outcome: change in Total Symptom Score (TSS). (Diabetes Care)
181 diabetic patients with distal symmetric polyneuropathy. 5-week intervention.
All ALA doses significantly improved TSS, NIS, and global assessment vs placebo. The 600 mg/day dose appeared optimal — providing therapeutic benefit with the best tolerability. Higher doses (1,200 and 1,800 mg) showed dose-dependent increases in nausea without proportional symptom improvement. Basis for therapeutic approval of ALA for diabetic neuropathy in Germany.
Randomized, controlled trial in 57 patients with type 2 diabetes randomized to ALA (300 mg/day) or placebo for 8 weeks. Outcomes: fasting blood glucose, 2-hour postprandial glucose, fasting insulin, insulin resistance (HOMA-IR), and glutathione peroxidase activity. (Saudi Medical Journal)
57 type 2 diabetes patients (14 men, 43 women, mean age 53). 8-week intervention.
ALA significantly reduced fasting blood glucose, postprandial glucose, fasting insulin, and HOMA-IR vs placebo. Glutathione peroxidase activity increased in the ALA group. No serious adverse events. Authors concluded ALA at 300 mg/day improves glycemic control and oxidative status in T2DM patients.
Multicenter, randomized, double-blind, placebo-controlled, 4-year trial in 460 diabetic patients with mild-to-moderate distal symmetric sensorimotor polyneuropathy. Oral ALA 600 mg/day vs placebo. Primary outcome: composite of Neuropathy Impairment Score-Lower Limb (NIS-LL) and 7 nerve conduction tests. (Diabetes Care)
460 diabetic patients with mild-moderate DSPN. 4-year intervention — longest ALA clinical trial.
The primary composite endpoint did not reach significance (P=0.105). Some secondary measures (NIS and NIS-LL) improved with ALA versus placebo. Serious adverse events were more frequent on ALA (38.1%) than on placebo (28.0%). The authors concluded that 4 years of ALA did not affect the primary endpoint but slowed progression of some neuropathic impairments.