Explore Neuroprotective Effect of Lipoic Acid in Amyotrophic Lateral Sclerosis

Inclusion Criteria: 1. Age range from 20 to 75 (including 20 and 75 years old), regardless of ethnic group or gender; 2. The subjects should meet the diagnostic criteria for ALS by El Escorial revised criteria: "Definite ALS", "Probable ALS" and "Probable, laboratory-supported ALS". 3. ALS Functional Rating Scale-Revised (ALSFRS-R 12 items) each item score ≥2 points; 4. The onset (the symptoms of limbs weakness, muscle atrophy or bulbar involvement ) of the disease is less than 2 years 5. Baseline breath function: Forced Vital Capacity≥70% . 6. Disease Progression Rate FS=(48- ALSFRS-R at "time of diagnosis")/duration from onset to diagnosis (month), progression rate FS≤1; Exclusion Criteria: 1. Combined with one of cerebrovascular disease, spinal cord disease, spinal muscular atrophy, juvenile myoatrophy of distal upper extremity, multifocal motor neuropathy, Kennedy disease, epilepsy, etc; 2. Severe renal insufficiency: creatinine clearance rate \<30 mL/min (Cockcroft-Gault formula, urea nitrogen and (or) blood creatinine\> 1.5 times the upper limit of normal, or other known severe renal insufficiency diseases; 3. Severe liver damage: ALT, AST\> 3 times the upper limit of normal, or other known liver diseases such as acute and chronic hepatitis, cirrhosis, etc.; 4. Obvious tachycardia or bradycardia; patients with acute myocardial infarction or interventional therapy in the past 6 months (patients with grade III-IV according to NYHA classification); 5. Combined with malignant tumor, blood, digestion or other serious diseases; 6. Female patients during pregnancy and lactation; 7. Participated in other clinical trials within 30 days before randomization, or are participating in other clinical trials;