This is a three-week crossover study that will compare how the body absorbs and tolerates two different forms of lipoic acid: R form and racemic form.

This three-week double-blind crossover trial will compare two different forms of lipoic acid (LA). Every participant will take one week of daily oral 600mg R LA, have a one week washout period without LA, and take one week of daily oral 1200mg racemic LA. The order of LA type will be determined by randomization. Blood analyses will be performed to determine which form is better absorbed and a side effects questionnaire will be completed at each visit in order to determine which form is better tolerated.

Inclusion Criteria:

• Diagnosis of Progressive Multiple Sclerosis
• 18 years of age or older
• Able to give informed consent and adhere to the study activities
• Able to swallow large oral capsules

Exclusion Criteria:

• Clinical Multiple Sclerosis relapse in the prior 1 year
• Oral or IV steroids in the prior 3 months
• Have taken LA in last 30 days
• Clinically significant kidney disease as determined by the PI including, but not limited to, major kidney disease diagnoses, abnormal laboratory values related to renal function, or other related conditions
• Insulin-dependent diabetes
• Other significant ongoing medical illness that may interfere with study procedures
• Taking oral anticoagulants (e.g. Coumadin). Aspirin, clopidogrel, and dipyridamole are acceptable to take
• Pregnant or breast-feeding
• Any condition which would make the patient, in the opinion of the investigator, unsuitable for the study